2024-03-28T13:41:47Z
https://eprints.whiterose.ac.uk/cgi/oai2
oai:eprints.whiterose.ac.uk:1314
2014-06-05T16:28:03Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/1314/
Sediment transport over a flat bed in a unidirectional flow: simulations and validation
Heald, J.
McEwan, I.
Tait, S.
A discrete particle model is described which simulates bedload transport over a flat bed of a unimodal mixed-sized distribution of particles. Simple physical rules are applied to large numbers of discrete sediment grains moving within a unidirectional flow. The modelling assumptions and main algorithms of the bedload transport model are presented and discussed. Sediment particles are represented by smooth spheres, which move under the drag forces of a simulated fluid flow. Bedload mass-transport rates calculated by the model exhibit a low sensitivity to chosen model parameters. Comparisons of the calculated mass-transport rates with well-established empirical relationships are good, strongly suggesting that the discrete particle model has captured the essential elements of the system physics. This performance provides strong justification for future interrogation of the model to investigate details of the small-scale constituent processes which have hitherto been outside the reach of previous experimental and modelling investigations.
The Royal Society
2004-09-15
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/1314/1/taits1.pdf
Heald, J., McEwan, I. and Tait, S. (2004) Sediment transport over a flat bed in a unidirectional flow: simulations and validation. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 362 (1822). pp. 1973-1986. ISSN 1471-2962
http://www.journals.royalsoc.ac.uk/openurl.asp?genre=article&id=doi:10.1098/rsta.2004.1426
doi:10.1098/rsta.2004.1426
oai:eprints.whiterose.ac.uk:3397
2013-02-08T16:55:09Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/3397/
Application of discontinuity layout optimization to plane
plasticity problems
Smith, C.
Gilbert, Matthew
A new and potentially widely applicable numerical analysis procedure for continuum mechanics problems is described. The procedure is used here to determine the critical layout of discontinuities and associated upper-bound limit load for plane plasticity problems. Potential discontinuities, which interlink nodes laid out over the body under consideration, are permitted to crossover one another giving a much wider search space than when such discontinuities are located only at the edges of finite elements of fixed topology. Highly efficient linear programming solvers can be employed when certain popular failure criteria are specified (e. g. Tresca or Mohr Coulomb in plane strain). Stress/velocity singularities are automatically identified and visual interpretation of the output is straightforward. The procedure, coined 'discontinuity layout optimization' (DLO), is related to that used to identify the optimum layout of bars in trusses, with discontinuities (e. g. slip-lines) in a translational failure mechanism corresponding to bars in an optimum truss. Hence, a recently developed adaptive nodal connection strategy developed for truss layout optimization problems can advantageously be applied here. The procedure is used to identify critical translational failure mechanisms for selected metal forming and soil mechanics problems. Close agreement with the exact analytical solutions is obtained.
Royal Society
2007-10
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/3397/1/gilbertm1.pdf
Smith, C. and Gilbert, Matthew (2007) Application of discontinuity layout optimization to plane plasticity problems. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 463 (2086). pp. 2461-2484. ISSN 1364-5021
http://dx.doi.org/10.1098/rspa.2006.1788
doi:10.1098/rspa.2006.1788
oai:eprints.whiterose.ac.uk:3666
2013-02-08T16:55:47Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
756E69743D536865666669656C64:536865666669656C642E464353:536865666669656C642E415243
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/3666/
Nonlinear analysis of orthotropic composite slabs in fire
Yu, X.M.
Huang, Z.H.
Burgess, I.
Plank, R.
In this study an orthotropic slab finite element is developed to model orthotropic slabs in fire, using a layered 9-noded isoparametric slab element and a 3-noded beam element. The element is assembled from a solid slab element which represents the continuous upper portion of the profile, and a special beam element which represents the ribbed lower portion. An equivalent width for the cross-section of this beam element is determined according to the dimensions of the solid slab element and the cross-section of the ribbed profile, and the beam shares the nodes of the solid slab element. The temperature within each layer of the slab element can vary between adjacent Gauss integration points so as to reflect temperature variations in the horizontal plane. Several fire tests on composite slabs have been modelled to validate the approach. Cases of orthotropic slabs with wide range of parameters defining the ribbed profile have been studied, which show that the orthotropic slab model is robust and effective in reflecting the influence of the shape of ribs on the thermal and structural performance of the slabs in fire. The study shows the influence of decking shape on the thermal and structural behaviours of orthotropic slabs. A simple evaluation method for profile selection is proposed.
Elsevier B.V.
2008-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/3666/1/yux1.pdf
Yu, X.M., Huang, Z.H., Burgess, I. et al. (1 more author) (2008) Nonlinear analysis of orthotropic composite slabs in fire. Engineering Structures, 30 (1). pp. 67-80. ISSN 0141-0296
http://dx.doi.org/10.1016/j.engstruct.2007.02.013
doi:10.1016/j.engstruct.2007.02.013
oai:eprints.whiterose.ac.uk:4080
2014-06-05T06:44:12Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/4080/
Procedures for vibration serviceability assessment of high-frequency floors
Brownjohn, J.M.W.
Middleton, C.T.
Manufacturing plants that produce micro-electronic components, and facilities for extremeprecision
experimental measurements have strict vertical vibration serviceability requirements due to sub-micron feature size or optical/target dimensions. Failure to meet these criteria may result in extremely costly loss of production or failure of experiments. For such facilities floors are massive but stiff, generally have first mode natural frequencies above 10Hz and are typically classed as
‘high frequency floors’. The process of design to limit in-service vibrations to within specific or generic vibration criteria is termed ‘vibration control’.
Several guidance documents for vibration control of high frequency floors have been published, for different applications. These design guides typically propose simplifications of complex floor systems and use of empirical predictive design formulae. A recently published guide uses a more rigorous approach based on first-principle modal analysis and modeling footfalls as effective
impulses, but there remain unresolved issues about its application, and this paper addresses these in order to develop an improved methodology.
First, the significant but conventionally discounted contribution of resonance well above the conventionally accepted boundary between low and high frequency floors is examined. The level of necessary modeling detail is then considered along with the effect of accounting for adjacent bays in simulation of a regular multi-bay floors. Finally, while it is assumed that contributions of higher modes to impulsive response decrease so that a cut-off frequency can be prescribed, simulations demonstrate that with both effective impulse and real footfall forces, there is not necessarily asymptotic response with rising floor mode frequency.
The conclusion is that there are no shortcuts to predicting response of high frequency floors to footfall excitation. Simulations must consider resonant response due to high order harmonics, provide adequate detail in finite element models and adopt a cutoff frequency that depends more on
usage than on features of the floor or of the walking.
Elsevier Ltd
2008-06
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/4080/1/brownjohnj1.pdf
Brownjohn, J.M.W. and Middleton, C.T. (2008) Procedures for vibration serviceability assessment of high-frequency floors. Engineering Structures, 30 (6). pp. 1548-1559. ISSN 0141-0296
http://dx.doi.org/10.1016/j.engstruct.2007.10.006
doi:10.1016/j.engstruct.2007.10.006
oai:eprints.whiterose.ac.uk:8728
2017-11-05T19:23:23Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/8728/
Biodegradability of organic matter associated with sewer sediments during first flush
Sakrabani, R.
Vollertsen, J.
Ashley, R.M.
Hvitved-Jacobsen, T.
The high pollution load in wastewater at the beginning of a rain event is commonly known to originate from the erosion of sewer sediments due to the increased flow rate under storm weather conditions. It is essential to characterize the biodegradability of organic matter during a storm event in order to quantify the effect it can have further downstream to the receiving water via discharges from Combined Sewer Overflow (CSO). The approach is to characterize the pollutograph during first flush. The pollutograph shows the variation in COD and TSS during a first flush event. These parameters measure the quantity of organic matter present. However these parameters do not indicate detailed information on the biodegradability of the organic matter. Such detailed knowledge can be obtained by dividing the total COD into fractions with different microbial properties. To do so oxygen uptake rate (OUR) measurements on batches of wastewater have shown itself to be a versatile technique. Together with a conceptual understanding of the microbial transformation taking place, OUR measurements lead to the desired fractionation of the COD. OUR results indicated that the highest biodegradability is associated with the initial part of a storm event. The information on physical and biological processes in the sewer can be used to better manage sediment in sewers which can otherwise result in depletion of dissolved oxygen in receiving waters via discharges from CSOS.
Elsevier
2009-04-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/8728/5/Sakrabani_Biodegradability1.pdf
text
en
https://eprints.whiterose.ac.uk/8728/6/Sakrabani_figures2.pdf
Sakrabani, R., Vollertsen, J., Ashley, R.M. et al. (1 more author) (2009) Biodegradability of organic matter associated with sewer sediments during first flush. Science of the Total Environment, 407 (8). pp. 2989-2995. ISSN 0048-9697
http://dx.doi.org/10.1016/j.scitotenv.2009.01.008
10.1016/j.scitotenv.2009.01.008
oai:eprints.whiterose.ac.uk:9269
2013-02-08T16:59:01Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4543
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/9269/
Dispersion relations and wave operators in self-similar quasicontinuous linear chains
Michelitsch, T.M.
Maugin, G.A.
Nicolleau, F.C.G.A.
Nowakowski, A.F.
Derogar, S.
We construct self-similar functions and linear operators to deduce a self-similar variant of the Laplacian operator and of the D'Alembertian wave operator. The exigence of self-similarity as a symmetry property requires the introduction of nonlocal particle-particle interactions. We derive a self-similar linear wave operator describing the dynamics of a quasicontinuous linear chain of infinite length with a spatially self-similar distribution of nonlocal interparticle springs. The self-similarity of the nonlocal harmonic particle-particle interactions results in a dispersion relation of the form of a Weierstrass-Mandelbrot function that exhibits self-similar and fractal features. We also derive a continuum approximation, which relates the self-similar Laplacian to fractional integrals, and yields in the low-frequency regime a power-law frequency-dependence of the oscillator density.
American Physical Society
2009-07
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/9269/1/Nicolleau.pdf
Michelitsch, T.M., Maugin, G.A., Nicolleau, F.C.G.A. et al. (2 more authors) (2009) Dispersion relations and wave operators in self-similar quasicontinuous linear chains. Physical Review -Series E, 80 (1). Art no.011135. ISSN 1539-3755
http://dx.doi.org/10.1103/PhysRevE.80.011135
10.1103/PhysRevE.80.011135
oai:eprints.whiterose.ac.uk:10239
2013-02-08T16:59:39Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10239/
Robust saturated control of human-induced floor vibrations via a proof-mass actuator
Diaz, I.M.
Reynolds, P.
This paper is concerned with the design of a robust active vibration control system that makes use of a proof-mass actuator for the mitigation of human-induced vibrations in floor structures. Ideally, velocity feedback control (VFC) is unconditionally stable and robust to spillover effects, interlacing of poles and zeros of collocated control is then accomplished. However, the use of a proof-mass actuator influences the system dynamics and the alternating pole-zero pattern of the system formed by the actuator and structure is no longer fulfilled. However, a controlled migration of the two zeros of the root locus plot at the origin, resulting from the acceleration output, can be achieved by adding a feed-through term (FTT) to the structure acceleration output. That is, the FTT enables us to control the position of a pair of complex conjugate zeros (an anti-resonance in the frequency domain). This paper proposes the introduction of an FTT designed in such a way that the anti-resonance at the origin is located between the actuator resonance and the structure fundamental resonance. Hence, an integral controller leads to infinite gain margin and significant phase margin. Simulation and experimental results on a concrete slab strip have validated the proposed control strategy. Significant improvements in the stability properties compared with VFC are reported.
Institute of Physics
2009-12
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/10239/1/Reynolds1.pdf
Diaz, I.M. and Reynolds, P. (2009) Robust saturated control of human-induced floor vibrations via a proof-mass actuator. Smart Materials and Structures , 18 (12). Art no.125024 . ISSN 0964-1726
http://dx.doi.org/10.1088/0964-1726/18/12/125024
10.1088/0964-1726/18/12/125024
oai:eprints.whiterose.ac.uk:10275
2013-02-08T16:59:44Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10275/
Acceleration feedback control of human-induced floor vibrations
Diaz, I.M
Reynolds, P.
Active vibration control (AVC) via a proof-mass actuator is considered to be a suitable technique for the mitigation of vibrations caused by human motions in floor structures. It has been observed that actuator dynamics strongly influence structure dynamics despite considering collocated actuator/sensor control. The well-known property of the interlacing of poles and zeros of a collocated control system is no longer accomplished. Therefore, velocity-based feedback control, which has been previously used by other researchers, might not be a good solution. This work presents a design process for a control scheme based on acceleration feedback control with a phase-lag compensator, which will generally be different from an integrator circuit. This first-order compensator is applied to the output (acceleration) in such a way that the relative stability and potential damping to be introduced are significantly increased accounting for the interaction between floor and actuator dynamics. Additionally, a high-pass filter designed to avoid stroke saturation is applied to the control signal. The AVC system designed according to this procedure has been assessed in simulation and successfully implemented in an in-service open-plan office floor. The actual vibration reductions achieved have been approximately 60% for walking tests and over 90% for a whole-day vibration monitoring. (C) 2009 Elsevier Ltd. All rights reserved.
Elsevier
2010-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/10275/1/Reynolds_10275.pdf
Diaz, I.M and Reynolds, P. (2010) Acceleration feedback control of human-induced floor vibrations. Engineering Structures , 32 (1). pp. 163-173. ISSN 0141-0296
http://dx.doi.org/10.1016/j.engstruct.2009.09.003
10.1016/j.engstruct.2009.09.003
oai:eprints.whiterose.ac.uk:10744
2013-02-08T17:00:29Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10744/
Upper and lower bound limit analysis of plates using FEM and second-order cone programming
Le, C.V.
Nguyen-Xuan, H.
Nguyen-Dang, H.
This paper presents two novel numerical procedures to determine upper and lower bounds on the actual collapse load multiplier for plates in bending. The conforming Hsieh–Clough–Tocher (HCT) and enhanced Morley (EM) elements are used to discrete the problem fields. A Morley element with enhanced moment fields is used. The constant moment fields is added a quadratic mode in which the pressure is equilibrated by corner loads only, ensuring that exact equilibrium relations associated with a uniform pressure can be obtained. Once the displacement or moment fields are approximated and the bound theorems applied, limit analysis becomes a problem of optimization. In this paper, the optimization problems are formulated in the form of a standard second-order cone programming which can be solved using highly efficient interior point solvers. The procedures are tested by applying it to several benchmark plate problems and are found good agreement between the present upper and lower bound solutions and results in the literature.
Elsevier Ltd
2010-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/10744/1/CAS_canhle.pdf
Le, C.V., Nguyen-Xuan, H. and Nguyen-Dang, H. (2010) Upper and lower bound limit analysis of plates using FEM and second-order cone programming. Computers & Structures, 88 (1-2). pp. 65-73. ISSN 0045-7949
http://dx.doi.org/10.1016/j.compstruc.2009.08.011
doi:10.1016/j.compstruc.2009.08.011
oai:eprints.whiterose.ac.uk:10764
2013-02-08T17:00:24Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10764/
Real-time performance monitoring of tuned mass damper system for a 183 m reinforced concrete chimney
Brownjohn, J.M.W.
Carden, E.P.
Goddard, C.R.
Oudin, G.
A 183 m reinforced concrete chimney for a coal-fired power station was instrumented in the latter part of its life during the construction of a replacement chimney. Because of concerns about large-amplitude response induced by interference effects from the new chimney in the prevailing upwind direction, a response monitoring system was installed, quickly followed by a tuned mass damper (TMD) system. As well as providing live display of the chimney response, the monitoring system was also used to check the functioning of the TMD. The monitoring system featured a direct implementation of the stochastic subspace identification procedure in the 'virtual instrument' controlling the system, so that modal damping values for the system were displayed automatically, in real-time. The system thus provided an immediate visual indication of increased damping levels during strong winds, showing the correct functioning of the TMD. The paper describes the chimney, the monitoring system and its installation, the data processing and system identification procedure, together with performance data before, during and after installation of the TMD. (C) 2009 Elsevier Ltd. All rights reserved.
Elsevier
2010-03
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/10764/1/Brownjohn_10764.pdf
Brownjohn, J.M.W., Carden, E.P., Goddard, C.R. et al. (1 more author) (2010) Real-time performance monitoring of tuned mass damper system for a 183 m reinforced concrete chimney. Journal of Wind Engineering and Industrial Aerodynamics , 98 (3). pp. 169-179. ISSN 0167-6105
http://dx.doi.org/10.1016/j.jweia.2009.10.013
10.1016/j.jweia.2009.10.013
oai:eprints.whiterose.ac.uk:10817
2014-09-15T01:20:39Z
7374617475733D7375626D6974746564
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10817/
Limit analysis of plates and slabs using a meshless equilibrium formulation
Le, Canh V.
Gilbert, Matthew
Askes, Harm
A meshless Element-Free Galerkin (EFG) equilibrium formulation is proposed to compute the limit loads which can be sustained by plates and slabs. In the formulation pure moment fields are approximated using a moving least-squares technique, which means that the resulting fields are smooth over the entire problem domain. There is therefore no need to enforce continuity conditions at interfaces within the problem domain, which would be a key part of a comparable finite element formulation. The collocation method is used to enforce the strong form of the equilibrium equations and a stabilized conforming nodal integration scheme is introduced to eliminate numerical instability problems. The combination of the collocation method and the smoothing technique means that equilibrium only needs to be enforced at the nodes, and stable and accurate solutions can be obtained with minimal computational effort. The von Mises and Nielsen yield criteria which are used in the analysis of plates and slabs, respectively, are enforced by introducing second-order cone constraints, ensuring that the resulting optimization problem can be solved using efficient interior-point solvers. Finally, the efficacy of the procedure is demonstrated by applying it to various benchmark plate and slab problems.
Wiley
2010
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/10817/2/NME_LB_CanhLe.pdf
Le, Canh V., Gilbert, Matthew and Askes, Harm (2010) Limit analysis of plates and slabs using a meshless equilibrium formulation. International Journal for Numerical Methods in Engineering. ISSN 0029-5981 (Submitted)
http://dx.doi.org/10.1002/nme.2887
doi:10.1002/nme.2887
oai:eprints.whiterose.ac.uk:10831
2014-05-13T09:36:35Z
7374617475733D707562
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10831/
Adaptive Element-Free Galerkin method applied to the limit analysis of plates
Le, Canh V.
Askes, Harm
Gilbert, Matthew
The implementation of an h-adaptive Element-Free Galerkin (EFG) method in the framework of limit analysis is described. The naturally conforming property of mesh- free approximations (with no nodal connectivity required) facilitates the implementation of h-adaptivity. Nodes may be moved, discarded or introduced without the need for complex manipulation of the data structures involved. With the use of the Taylor expansion technique, the error in the computed displacement field and its derivatives can be estimated throughout the problem domain with high accuracy. A stabilized conforming nodal integration scheme is extended to error estimators and results in an efficient and truly meshfree adaptive method. To demonstrate its effectiveness the procedure is then applied to plates with various boundary conditions.
Elsevier Ltd
2010-04-18
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/10831/1/CMAME_CanhLe.pdf
Le, Canh V., Askes, Harm and Gilbert, Matthew (Completed: 2010) Adaptive Element-Free Galerkin method applied to the limit analysis of plates. Computer Methods in Applied Mechanics and Engineering, 199 (37-40). pp. 2487-2496. ISSN 0045-7825
http://dx.doi.org/10.1016/j.cma.2010.04.004
doi:1016/j.cma.2010.04.004
oai:eprints.whiterose.ac.uk:10832
2013-02-08T17:00:29Z
oai:eprints.whiterose.ac.uk:10834
2014-05-13T09:37:58Z
7374617475733D707562
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10834/
A cell-based smoothed finite element method for kinematic limit analysis
Le, Canh V.
Nguyen-Xuan, H.
Askes, Harm
Bordas , Stéphane P. A.
Rabczuk, T.
Nguyen-Vinh, H.
This paper presents a new numerical procedure for kinematic limit analysis problems, which incorporates the cell-based smoothed finite element method with second-order cone programming. The application of a strain smoothing technique to the standard displacement finite element both rules out volumetric locking and also results in an efficient method that can provide accurate solutions with minimal computational effort. The non-smooth optimization problem is formulated as a problem of minimizing a sum of Euclidean norms, ensuring that the resulting optimization problem can be solved by an efficient second-order cone programming algorithm. Plane stress and plane strain problems governed by the von Mises criterion are considered, but extensions to problems with other yield criteria having a similar conic quadratic form or 3D problems can be envisaged.
John Wiley
2010-05-20
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/10834/1/SFEM_LimitAnalysis_CanLe.pdf
Le, Canh V., Nguyen-Xuan, H., Askes, Harm et al. (3 more authors) (2010) A cell-based smoothed finite element method for kinematic limit analysis. International Journal for Numerical Methods in Engineering, 83 (12). pp. 1651-1674. ISSN 0029-5981
http://dx.doi.org/10.1002/nme.2897
http://dx.doi.org/10.1002/nme.2897
oai:eprints.whiterose.ac.uk:10835
2013-02-08T17:00:32Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10835/
Limit analysis of plates using the EFG method and second-order cone programming
Le, Canh V.
Gilbert, Matthew
Askes, Harm
The meshless element-free Galerkin (EFG) method is extended to allow computation of the limit load of plates. A kinematic formulation that involves approximating the displacement field using the moving least-squares technique is developed. Only one displacement variable is required for each EFG node, ensuring that the total number of variables in the resulting optimization problem is kept to a minimum, with far fewer variables being required compared with finite element formulations using compatible elements. A stabilized conforming nodal integration scheme is extended to plastic plate bending problems. The evaluation of integrals at nodal points using curvature smoothing stabilization both keeps the size of the optimization problem small and also results in stable and accurate solutions. Difficulties imposing essential boundary conditions are overcome by enforcing displacements at the nodes directly. The formulation can be expressed as the problem of minimizing a sum of Euclidean norms subject to a set of equality constraints. This non-smooth minimization problem can be transformed into a form suitable for solution using second-order cone programming. The procedure is applied to several benchmark beam and plate problems and is found in practice to generate good upper-bound solutions for benchmark problems.
John Wiley
2009-06-25
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/10835/1/EFG_UB_CanhLe.pdf
Le, Canh V., Gilbert, Matthew and Askes, Harm (2009) Limit analysis of plates using the EFG method and second-order cone programming. International Journal for Numerical Methods in Engineering, 78 (13). pp. 1532-1552. ISSN 0029-5981
http://dx.doi.org/10.1002/nme.2535
http://dx.doi.org/10.1002/nme.2535
oai:eprints.whiterose.ac.uk:11116
2013-02-08T17:01:04Z
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https://eprints.whiterose.ac.uk/11116/
Ambient vibration re-testing and operational modal analysis of the Humber Bridge
Brownjohn, J.M.W.
Magalhaes, F.
Caetano, E.
Cunha, A.
An ambient vibration survey of the Humber Bridge was carried out in July 2008 by a combined team from the UK, Portugal and Hong Kong. The exercise had several purposes that included the evaluation of the current technology for instrumentation and system identification and the generation of an experimental dataset of modal properties to be used for validation and updating of finite element models for scenario simulation and structural health monitoring. The exercise was conducted as part of a project aimed at developing online diagnosis capabilities for three landmark European suspension bridges.
Ten stand-alone tri-axial acceleration recorders were deployed at locations along all three spans and in all four pylons during five days of consecutive one-hour recordings. Time series segments from the recorders were merged, and several operational modal analysis techniques were used to analyse these data and assemble modal models representing the global behaviour of the bridge in all three dimensions for all components of the structure.
The paper describes the equipment and procedures used for the exercise, compares the operational modal analysis (OMA) technology used for system identification and presents modal parameters for key vibration modes of the complete structure.
The results obtained using three techniques, natural excitation technique/eigensystem realisation algorithm, stochastic subspace identification and poly-Least Squares Frequency Domain method, are compared among themselves and with those obtained from a 1985 test of the bridge, showing few significant modal parameter changes over 23 years in cases where direct comparison is possible.
The measurement system and the much more sophisticated OMA technology used in the present test show clear advantages necessary due to the compressed timescales compared to the earlier exercise. Even so, the parameter estimates exhibit significant variability between different methods and variations of the same method, while also varying in time and having inherent variability. (C) 2010 Elsevier Ltd. All rights reserved.
Elsevier
2010-08
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/11116/1/Brownjohn_11116.pdf
Brownjohn, J.M.W., Magalhaes, F., Caetano, E. et al. (1 more author) (2010) Ambient vibration re-testing and operational modal analysis of the Humber Bridge. Engineering Structures, 32 (8). pp. 2003-2018. ISSN 0141-0296
http://dx.doi.org/10.1016/j.engstruct.2010.02.034
10.1016/j.engstruct.2010.02.034
oai:eprints.whiterose.ac.uk:11204
2016-11-18T17:09:50Z
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74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E435045
756E69743D536865666669656C64:536865666669656C642E464350:536865666669656C642E504859
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
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https://eprints.whiterose.ac.uk/11204/
Adhesive and conformational behaviour of mycolic acid monolayers
Zhang, Z.
Pen, Y.
Edyvean, R.G.
Banwart, S.A.
Dalgliesh, R.M.
Geoghegan, M.
We have studied the pH-dependent interaction between mycolic acid (MA) monolayers and hydrophobic and hydrophilic surfaces using molecular (colloidal probe) force spectroscopy. In both cases, hydrophobic and hydrophilic monolayers (prepared by Langmuir-Blodgett and Langmuir-Schaefer deposition on silicon or hydrophobized silicon substrates, respectively) were studied. The force spectroscopy data, fitted with classical DLVO (Derjaguin, Landau, Verwey, and Overbeek) theory to examine the contribution of electrostatic and van der Waals forces, revealed that electrostatic forces are the dominant contribution to the repulsive force between the approaching colloidal probe and MA monolayers. The good agreement between data and the DLVO model suggest that beyond a few nm away from the surface, hydrophobic, hydration, and specific chemical bonding are unlikely to contribute to any significant extent to the interaction energy between the probe and the surface. The pH-dependent conformation of MA molecules in the monolayer at the solid-liquid interface was studied by ellipsometry, neutron reflectometry, and with a quartz crystal microbalance. Monolayers prepared by the Langmuir-Blodgett method demonstrated a distinct pH-responsive behaviour, while monolayers prepared by the Langmuir-Schaefer method were less sensitive to pH variation. It was found that the attachment of water molecules plays a vital role in determining the conformation of the MA monolayers. (C) 2010 Elsevier B.V. All rights reserved.
Elsevier
2010-09
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/11204/1/Geoghegan_11204.pdf
Zhang, Z., Pen, Y., Edyvean, R.G. et al. (3 more authors) (2010) Adhesive and conformational behaviour of mycolic acid monolayers. Biochimica et Biophysica Acta - Biomembranes, 1798 (9). pp. 1829-1839. ISSN 0005-2736
http://dx.doi.org/10.1016/j.bbamem.2010.05.024
10.1016/j.bbamem.2010.05.024
oai:eprints.whiterose.ac.uk:11210
2013-02-08T17:01:18Z
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/11210/
The behaviour of reinforced concrete slabs in fire
Huang, Z.H.
In this paper a robust model is presented based on the previous layer procedure developed by the author to also take into account the effects of concrete spalling on the behaviour of concrete slabs under fire conditions. In this study, a detailed analysis of a uniformly loaded reinforced concrete slab subject to different degrees of concrete spalling under a standard fire regime is first carried out. Further, a series of analysis of floor slabs with different degrees of concrete spalling is also performed on a generic reinforced concrete building. A total of 16 cases have been analysed using different degrees of spalling on the slabs, with different extents and positions of localised fire compartments. It is clear that adjacent cool structures provide considerable thermal restraint to the floor slabs within the fire compartment. And it is evident that the compressive membrane force within the slabs is a major player in reducing the impact of concrete spalling on the structural behaviour of floor slabs in fire. (C) 2010 Elsevier Ltd. All rights reserved.
Elsevier
2010-08
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/11210/1/Huang_11210.pdf
Huang, Z.H. (2010) The behaviour of reinforced concrete slabs in fire. Fire Safety Journal, 45 (5). pp. 271-282. ISSN 0379-7112
http://dx.doi.org/10.1016/j.firesaf.2010.05.001
10.1016/j.firesaf.2010.05.001
oai:eprints.whiterose.ac.uk:42646
2013-02-08T17:29:39Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42646/
Geo-environmental mapping using physiographic analysis: constraints on the evaluation of land instability and groundwater pollution hazards in the Metropolitan District of Campinas, Brazil
Fernandes-da-Silva, P.C.
Vedovello, R.
Ferreira, C.J.
Cripps, J.C.
Brollo, M.J.
Fernandes, A.J.
Geo-environmental terrain assessments and territorial zoning are useful tools for the formulation and implementation of environmental management instruments (including policy-making, planning, and enforcement of statutory regulations). They usually involve a set of procedures and techniques for delimitation, characterisation and classification of terrain units. However, terrain assessments and zoning exercises are often costly and time-consuming, particularly when encompassing large areas, which in many cases prevent local agencies in developing countries from properly benefiting from such assessments. In the present paper, a low-cost technique based on the analysis of texture of satellite imagery was used for delimitation of terrain units. The delimited units were further analysed in two test areas situated in Southeast Brazil to provide estimates of land instability and the vulnerability of groundwater to pollution hazards. The implementation incorporated procedures for inferring the influences and potential implications of tectonic fractures and other discontinuities on ground behaviour and local groundwater flow. Terrain attributes such as degree of fracturing, bedrock lithology and weathered materials were explored as indicators of ground properties. The paper also discusses constraints on- and limitations of- the approaches taken.
Springer
2010-11
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42646/2/Cripps_42646.pdf
text
en
https://eprints.whiterose.ac.uk/42646/3/Cripps_%28Figures%29.pdf
text
en
https://eprints.whiterose.ac.uk/42646/4/Cripps_%28Tables%29.pdf
Fernandes-da-Silva, P.C., Vedovello, R., Ferreira, C.J. et al. (3 more authors) (2010) Geo-environmental mapping using physiographic analysis: constraints on the evaluation of land instability and groundwater pollution hazards in the Metropolitan District of Campinas, Brazil. Environmental Earth Sciences, 61 (8). pp. 1657-1675. ISSN 1866-6280
http://dx.doi.org/10.1007/s12665-010-0480-z
10.1007/s12665-010-0480-z
oai:eprints.whiterose.ac.uk:42718
2013-02-08T17:29:55Z
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https://eprints.whiterose.ac.uk/42718/
Modelling the bond between concrete and reinforcing steel in a fire
Huang, Z.
A non-linear procedure is presented for modelling the bond characteristic between concrete and reinforcing steel for reinforced concrete structures in a fire. The accuracy and reliability of the model are demonstrated by the analysis of one pull-out test and one beam test at ambient temperature and four full-scale beams tested under two fire conditions. The model is clearly capable of predicting the response of reinforced concrete members and structures in a fire with acceptable accuracy. The bond-link element has been found to have good computational stability and efficiency for 3D analysis of reinforced concrete structures in fires. It is shown that the bond condition between the concrete and reinforcing steel bar has an important influence on the fire resistance of reinforced concrete structures, especially when the temperature of the reinforcing steel bar is high (more than 500 degrees C). Hence, the current assumption of a perfect bond condition for analysis of reinforced concrete structures under fire conditions is unconservative. (C) 2010 Elsevier Ltd. All rights reserved.
Elsevier
2010-11
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42718/2/Huang_42718.pdf
Huang, Z. (2010) Modelling the bond between concrete and reinforcing steel in a fire. Engineering Structures, 32 (11). pp. 3660-3669. ISSN 0141-0296
http://dx.doi.org/10.1016/j.engstruct.2010.08.010
10.1016/j.engstruct.2010.08.010
oai:eprints.whiterose.ac.uk:42805
2013-02-08T17:30:38Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42805/
Seismic behaviour of deficient RC frames strengthened with CFRP composites
Garcia, R.
Hajirasouliha, I.
Pilakoutas, K.
A full-scale two-storey RC building with poor detailing in the beam–column joints was tested on a shake table as part of the European research project ECOLEADER. After the initial tests which damaged the structure, the frame was strengthened using carbon fibre reinforced materials (CFRPs) and re-tested. This paper investigates analytically the efficiency of the strengthening technique at improving the seismic behaviour of this frame structure. The experimental data from the initial shake table tests are used to calibrate analytical models. To simulate deficient beam–column joints, models of steel–concrete bond-slip and bond-strength degradation under cyclic loading are considered. The analytical models are used to assess the efficiency of the CFRP rehabilitation using a set of medium to strong seismic records. The CFRP strengthening intervention enhanced the behaviour of the substandard beam–column joints, and resulted in substantial improvement of the seismic performance of the damaged RC frame. It is shown that, after the CFRP intervention, the damaged building would experience on average 65% less global damage compared to the original structure if it was subjected to real earthquake excitations.
Elsevier
2010-10
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42805/2/WRRO_42805.pdf
Garcia, R., Hajirasouliha, I. and Pilakoutas, K. (2010) Seismic behaviour of deficient RC frames strengthened with CFRP composites. Engineering Structures, 32 (10). pp. 3075-3085. ISSN 0141-0296
http://dx.doi.org/10.1016/j.engstruct.2010.05.026
oai:eprints.whiterose.ac.uk:42806
2013-02-08T17:30:38Z
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74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42806/
Design issues for concrete reinforced with steel fibers, including fibers recovered from used tires
Neocleous, K.
Tlemat, H.
Pilakoutas, K.
The writers are investigating the use of steel fibers, recovered from used tires (RSF), as concrete reinforcement, aiming at the development of design recommendations. This paper presents part of this research and examines initially an existing design guideline, developed by RILEM for steel fiber-reinforced concrete (SFRC), in order to assess the suitability of the guideline for the flexural design of concrete reinforced with RSF (RSFRC). This examination indicates that, although the RILEM guideline is in general suitable for the flexural design of RSFRC, there are some fundamental issues related to the evaluation of the tensile stress-strain behavior of SFRC that affect the accuracy of the guideline. Thus, based on this conclusion, a new approach is outlined for the evaluation of the tensile stress - strain behavior of SFRC and models are derived for different types of RSF and industrially produced fibers. These models are applied to the flexural design of concrete reinforced with RSF (RSFRC) and results are compared with those obtained by using the RILEM tensile stress-strain models. It is concluded that the model proposed in this study is more conservative and accurate than the RILEM models. Recommendations are also made on values of tensile strain to be used as the ultimate limit state, when predicting the resistance capacity of SFRC and RSFRC. © 2006 ASCE.
American Society of Civil Engineers
2006-10
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42806/2/WRRO_42806.pdf
Neocleous, K., Tlemat, H. and Pilakoutas, K. (2006) Design issues for concrete reinforced with steel fibers, including fibers recovered from used tires. Journal of Materials in Civil Engineering, 18 (5). pp. 677-685. ISSN 0899-1561
http://dx.doi.org/10.1061/(ASCE)0899-1561(2006)18:5(677)
oai:eprints.whiterose.ac.uk:42807
2013-02-08T17:30:44Z
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756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42807/
Behaviour of concrete columns with drilled holes
Son, K.S.
Pilakoutas, K.
Neocleous, K.
Holes drilled out to install additional services or equipment, such as for ducts through columns, beams or walls, can lead to loss of strength and possible structural failure. Until now little work has been done on holes in columns and, hence, the present study aims to examine the amount of strength lost owing to the presence of holes in columns. The reported experimental work deals with different parameters such as the number and dimensions of the holes and their relative position. It is shown that, for large diameter holes, a section capacity loss of up to 50% is possible. © 2006 Thomas Telford Ltd.
Thomas Telford
2006
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42807/2/WRRO_42807.pdf
Son, K.S., Pilakoutas, K. and Neocleous, K. (2006) Behaviour of concrete columns with drilled holes. Magazine of Concrete Research, 58 (7). pp. 411-419. ISSN 0024-9831
http://dx.doi.org/10.1680/macr.2006.58.7.411
oai:eprints.whiterose.ac.uk:42808
2013-02-08T17:30:38Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
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https://eprints.whiterose.ac.uk/42808/
Stress-strain characteristic of SFRC using recycled fibres
Tlemat, H.
Pilakoutas, K.
Neocleous, K.
This paper presents work from a comprehensive study on the development of a flexural design framework for concrete reinforced with steel fibres that are recovered from used tyres. The experimental flexural behaviour of notched concrete prisms reinforced with these fibres is initially presented. For comparison purposes, prisms reinforced with industrially produced fibres are also considered. An attempt to adopt an existing RILEM design framework to derive appropriate tensile stress-strain blocks is made, but problems are identified with key parameters of the framework. The influence of crack propagation and location of neutral axis depth on the tensile stress distribution is examined. Following an analytical study, it is concluded that the uniaxial stress-strain model, proposed by RILEM overestimates the load-carrying capacity and should be modified by utilising more advanced analytical techniques. © RILEM 2006.
Springer Verlag
2006-04
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42808/2/WRRO_42808.pdf
Tlemat, H., Pilakoutas, K. and Neocleous, K. (2006) Stress-strain characteristic of SFRC using recycled fibres. Materials and Structures/Materiaux et Constructions, 39 (3). pp. 365-377. ISSN 1359-5997
http://dx.doi.org/10.1007/s11527-005-9009-4
oai:eprints.whiterose.ac.uk:42809
2013-02-08T17:30:37Z
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756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42809/
Modelling of SFRC using inverse finite element analysis
Tlemat, H.
Pilakoutas, K.
Neocleous, K.
A method of inverse finite element analysis is used to determine the constitutive relationship of SFRC in tension, using primary experimental data. Based on beam bending test results and results from pull-out tests, an attempt is made to explain the physical processes taking place during the cracking stage. Basic models predicting the behaviour of SFRC in tension are proposed. © RILEM 2006.
Springer Verlag
2006-03
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42809/2/WRRO_42809.pdf
Tlemat, H., Pilakoutas, K. and Neocleous, K. (2006) Modelling of SFRC using inverse finite element analysis. Materials and Structures/Materiaux et Constructions, 39 (286). pp. 221-233. ISSN 1359-5997
http://dx.doi.org/10.1617/s11527-005-9010-y
oai:eprints.whiterose.ac.uk:42810
2013-02-08T17:30:44Z
7374617475733D707562
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756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42810/
Failure-mode-hierarchy-based design for reinforced concrete structures
Neocleous, K.
Pilakoutas, K.
Guadagnini, M.
Innovations in concrete construction can be held back by the inability of codes of practice to accommodate new materials. The current design and safety philosophy (DSP) of reinforced concrete relies heavily on the properties of steel reinforcement. The need to embrace new materials, such as fibre-reinforced polymer (FRP) reinforcement, led to an in-depth examination of the DSP of European concrete codes of practice and resulted in a new philosophy, presented in this paper. The basis of the new philosophy remains the limit-state design and achievement of target notional structural reliability levels, but aims at the attainment of a desired failure mode hierarchy. The implementation of the philosophy, through a proposed framework, utilises the concept of average measure of closeness for the determination of appropriate material partial safety factors. An example of the application of the proposed framework is presented for FRP reinforcement. © 2005 Thomas Telford and fib.
Thomas Telford
2005-03
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42810/2/WRRO_42810.pdf
Neocleous, K., Pilakoutas, K. and Guadagnini, M. (2005) Failure-mode-hierarchy-based design for reinforced concrete structures. Structural Concrete, 6 (1). pp. 23-32. ISSN 1464-4177
http://dx.doi.org/10.1680/stco.6.1.23.62460
oai:eprints.whiterose.ac.uk:42811
2013-02-08T17:30:44Z
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756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42811/
Reuse of tyre steel fibres as concrete reinforcement
Pilakoutas, K.
Neocleous, K.
Tlemat, H.
To attain economically viable and environmentally friendly tyre recycling, it is necessary to develop new applications and products, which will use tyre by-products (especially the steel cord) as raw materials. The authors demonstrate that the steel fibres recovered from used tyres can be used to reinforce concrete elements. This application has a great potential, as it is estimated that more than 500000 t of high-quality steel fibres could be recovered annually from used tyres in the EU alone. This paper presents the work carried out as part of various ongoing projects on the use of steel fibres in concrete construction. The first part of the paper deals with waste management issues, the methods used to recover steel fibres from tyres, and existing applications of used tyres. The second part presents the mechanical behaviour of concrete elements reinforced with these steel fibres and discusses the relevant design and economic issues. It is concluded that the use of these steel fibres in concrete construction will benefit not only the construction industry, but also the producers and recyclers of used tyres.
Institution of Civil Engineers
2004
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42811/3/WRRO_42811.pdf
Pilakoutas, K., Neocleous, K. and Tlemat, H. (2004) Reuse of tyre steel fibres as concrete reinforcement. Proceedings of the ICE - Engineering Sustainability, 157 (3). pp. 131-138. ISSN 1478-4629
http://dx.doi.org/10.1680/ensu.157.3.131.48644
oai:eprints.whiterose.ac.uk:42812
2013-02-08T17:30:39Z
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756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42812/
Structural safety uncertainties in codes of practice for reinforced concrete
Neocleous, K.
Pilakoutas, K.
Waldron , P.
The limit-state design approach, currently used in codified design of concrete structures reinforced with steel reinforcement, is based on semi-probabilistic procedures. Although modern concrete codes of practice are more sophisticated than older codes based on the permissible stress approach, they still have fundamental uncertainties with regards to structural safety. The work reported in this paper investigates these uncertainties for the BS 8110 and Eurocode-2 codes of practice by performing a structural reliability assessment using the Monte-Carlo Simulation method in conjunction with the Latin Hypercube and Conditional Expectation variance reduction techniques. The assessment considers both the flexural and shear failure modes. In the case of BS 8110, it is shown that it may be more appropriate to increase the characteristic value of the tensile strength of steel reinforcement rather than to use the reduced partial safety factor of 1.05. © Kyriacos Neocleous, Kyprous Pilakoutas, Peter Waldron.
Institution of Structural Engineers
2004-04-20
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42812/2/WRRO_42812.pdf
Neocleous, K., Pilakoutas, K. and Waldron , P. (2004) Structural safety uncertainties in codes of practice for reinforced concrete. Structural Engineer, 82 (8). pp. 28-33. ISSN 1466-5123
http://www.istructe.org/thestructuralengineer/
oai:eprints.whiterose.ac.uk:42813
2013-02-08T17:30:37Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42813/
Design philosophy issues of fiber reinforced polymer reinforced concrete structures
Pilakoutas, K.
Neocleous, K.
Guadagnini, M.
The conventional design philosophy for reinforced concrete (RC) relies heavily on the ductile properties of steel. These ductile properties are used as a "fuse" and conceal the large uncertainty in the determination of modes of failure caused directly by concrete. Current design guidelines for fiber reinforced polymer (FRP) RC structures have inappropriately adopted the same design philosophy used for steel RC, leading either to the adoption of conservative safety factors or reduced structural reliability. A reliability-based analysis of FRP RC beams shows that the current, very conservative partial safety factors for FRP reinforcement on their own do not influence the structural safety of overreinforced concrete elements. Proposals are made for the modification of the material partial safety factors to achieve target safety levels.
American Society of Civil Engineers
2002-08
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42813/2/WRRO_42813.pdf
Pilakoutas, K., Neocleous, K. and Guadagnini, M. (2002) Design philosophy issues of fiber reinforced polymer reinforced concrete structures. Journal of Composites for Construction, 6 (3). pp. 154-161. ISSN 1090-0268
http://dx.doi.org/10.1061/(ASCE)1090-0268(2002)6:3(154)
oai:eprints.whiterose.ac.uk:42814
2017-01-23T16:03:27Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42814/
Fibre-reinforced roller-compacted concrete transport pavements
Neocleous, K.
Angelakopoulos, H.
Pilakoutas, K.
Guadagnini, M.
Concrete pavements are generally more expensive to construct than asphalt pavements, and are thus mostly used in heavily trafficked sections and to reduce maintenance. The research work presented in this paper, however, indicated that the use of rapid construction techniques (such as roller compaction) and materials with lower embodied energy (such as low-energy cements, recycled aggregates and recycled steel fibres) can lead to concrete pavements that are more economical and environmentally friendly than asphalt pavements (40% less energy consumption during the life cycle of the pavement). The first part of this paper presents an overview of this research, which was undertaken as part of the EU FP6 STREP project ‘EcoLanes’ and investigated the development of long-lasting rigid pavements made with steel-fibre-reinforced roller-compacted concrete. The second part of the paper outlines the work undertaken for the development and optimisation of several trial concrete mixes. It is shown that the flexural behaviour of roller-compacted concrete, under static loads, can be enhanced by the addition of fibres. Furthermore, the results of this study demonstrated the potential of recycling concrete pavements, at the end of their life, for the construction of new pavements.
Institution of Civil Engineers
2011-05
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42814/4/WRRO_42814.pdf
Neocleous, K., Angelakopoulos, H., Pilakoutas, K. et al. (1 more author) (2011) Fibre-reinforced roller-compacted concrete transport pavements. Proceedings of the ICE - Transport, 164 (2). pp. 97-109. ISSN 0965-092X
https://doi.org/10.1680/tran.9.00043
10.1680/tran.9.00043
oai:eprints.whiterose.ac.uk:42818
2014-06-06T00:48:41Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42818/
Thin FRP/GFRC structural elements
Kim, G.B.
Pilakoutas, K.
Waldron , P.
This paper presents background work leading to the development of thin structural elements made of GFRC (Glass Fibre Reinforced Concrete) reinforced with FRP (Fiber Reinforced Polymer) bars. Such thin structural elements are suitable for a variety of applications such as cladding, security screens, etc, but this paper focuses on their use as permanent formwork. The first part of the paper deals with optimising a uniform thickness GFRC section to achieve maximum flexural capacity at minimum weight. The second part deals with the interaction between FRP and GFRC, in particular with the issues of bond. The third part presents the performance of a 3 m span thin GFRC permanent formwork panel system reinforced with FRP. Both experimental and analytical studies are presented and it is concluded that FRP/GFRC thin structural elements can be designed using conventional techniques requiring only the use of appropriate material characteristics.
Elsevier
2008-02
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42818/1/f-__thin_FRP_GFRC_structural_elements.pdf
Kim, G.B., Pilakoutas, K. and Waldron , P. (2008) Thin FRP/GFRC structural elements. Cement and Concrete Composites, 30 (2). pp. 122-137. ISSN 0958-9465
http://dx.doi.org/10.1016/j.cemconcomp.2007.04.011
oai:eprints.whiterose.ac.uk:42819
2013-02-08T17:30:43Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42819/
FE modelling of bond interaction of FRP bars to concrete
Achillides, Z.
Pilakoutas, K.
In this paper a computational modelling approach is used to investigate the bond behaviour of fibre-reinforced plastic (FRP) bars in concrete. Two finite element packages (ANSYS and ABAQUS) are used to model the bond interaction of FRP reinforcing bars in cubes and beams. The main purpose of this work is to develop additional understanding of how FRP bars ‘cooperate’ with concrete to sustain the pullout load. Two modelling approaches are presented. In the first approach, a spring describing the behaviour of short embedment lengths in pullout tests was used for predicting the behaviour of longer embedment lengths. In the second approach, spring characteristics obtained from an experimentally determined bond stress against anchorage length envelope are used in FE modelling of beams. Both approaches showed good agreement between analytical and experimental results. However, further development on the analytical modelling of the bond interaction is required, in order to consider the effect of all parameters that influence bond.
Thomas Telford
2006
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42819/1/WRRO_42819.pdf
Achillides, Z. and Pilakoutas, K. (2006) FE modelling of bond interaction of FRP bars to concrete. Structural Concrete, 7 (1). pp. 7-16. ISSN 1464-4177
http://dx.doi.org/10.1680/stco.2006.7.1.7
doi:10.1680/stco.2006.7.1.7
oai:eprints.whiterose.ac.uk:42820
2014-09-15T04:01:15Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42820/
Bond behavior of fiber reinforced polymer bars under direct pullout conditions
Achillides, Z.
Pilakoutas, K.
This paper examines the behavior of Eurocrete fiber-reinforced polymer (FRP) bars (glass, carbon, aramid, and hybrid) in concrete under direct pullout conditions. More than 130 cube specimens were tested in direct pullout where no splitting was allowed to develop. In normal concrete, the mode of bond failure of FRP bars was found to differ substantially from that of deformed steel bars because of damage to the resin rich surface of the bar when pullout takes place. Bond strengths developed by carbon fiber-reinforced polymer and glass fiber-reinforced polymer bars appear to be very similar and just below what is expected from deformed steel bars under similar experimental conditions. The load slip curves highlight some of the fundamental differences between steel and FRP materials. This paper reports in detail on the influence of various parameters that affect bond strength and development such as the embedment length, type, shape, surface characteristics, and diameter of the bar as well as concrete strength. The testing arrangement is also shown to influence bond strength because of the “wedging effect” of the bars.
American Society of Civil Engineers
2004-03
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42820/2/WRRO_42820.pdf
Achillides, Z. and Pilakoutas, K. (2004) Bond behavior of fiber reinforced polymer bars under direct pullout conditions. Journal of Composites for Construction, 8 (2). pp. 173-181. ISSN 1090-0268
http://dx.doi.org/10.1061/(ASCE)1090-0268(2004)8:2(173)
doi:10.1061/(ASCE)1090-0268(2004)8:2(173)
oai:eprints.whiterose.ac.uk:42821
2013-02-08T17:30:37Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42821/
RC column strengthening by lateral pre-tensioning of FRP
Mortazavi, A.
Pilakoutas, K.
Son, K.S.
This paper presents a unique strengthening technique for existing concrete columns that use expansive materials to apply lateral pre-tensioning. The technique increases the capacity and ductility of a column as well as achieving better utilisation of the confining FRP (Fibre Reinforced Polymer) material. The confinement material properties and the confined cylinder performance are investigated experimentally. From the results, it is shown that it is possible to control the degree of applied pre-tension by controlling the amount of expansive material used. In addition, it is confirmed that jacketing columns by pre-tensioned FRP materials can increase the load bearing capacity up to 35% compared with no pre-tensioning and up to more than four times compared with unconfined concrete. The paper presents details of experimental work undertaken for the development of the confinement pressure with different confining materials (Carbon-CFRP, Glass-GFRP and Steel) and makes comparisons with predictive models.
Elsevier
2003-09
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42821/2/WRRO_42821.pdf
Mortazavi, A., Pilakoutas, K. and Son, K.S. (2003) RC column strengthening by lateral pre-tensioning of FRP. Construction and Building Materials, 17 (6-7). pp. 491-497. ISSN 0950-0618
http://dx.doi.org/10.1016/S0950-0618(03)00046-1
doi:10.1016/S0950-0618(03)00046-1
oai:eprints.whiterose.ac.uk:42822
2013-02-08T17:30:37Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42822/
Punching shear behavior of fiber reinforced polymers reinforced concrete flat slabs: experimental study
El-Ghandour, A. W.
Pilakoutas, K.
Waldron, P.
This paper presents the results of a two-phase experimental program investigating the punching shear behavior of fiber reinforced polymer reinforced concrete (FRP RC) flat slabs with and without carbon fiber reinforced polymer (CFRP) shear reinforcement. In the first phase, problems of bond slip and crack localization were identified. Decreasing the flexural bar spacing in the second phase successfully eliminated those problems and resulted in punching shear failure of the slabs. However, CFRP shear reinforcement was found to be inefficient in enhancing significantly the slab capacity due to its brittleness. A model, which accurately predicts the punching shear capacity of FRP RC slabs without shear reinforcement, is proposed and verified. For slabs with FRP shear reinforcement, it is proposed that the concrete shear resistance is reduced, but a strain limit of 0.0045 is recommended as maximum strain for the reinforcement. Comparisons of the slab capacities with ACI 318-95, ACI 440-98, and BS 8110 punching shear code equations, modified to incorporate FRP reinforcement, show either overestimated or conservative results.
American Society of Civil Engineers
2003-08
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42822/2/WRRO_42822.pdf
El-Ghandour, A. W., Pilakoutas, K. and Waldron, P. (2003) Punching shear behavior of fiber reinforced polymers reinforced concrete flat slabs: experimental study. Journal of Composites for Construction, 7 (3). pp. 258-265. ISSN 1090-0268
http://dx.doi.org/10.1061/(ASCE)1090-0268(2003)7:3(258)
doi:10.1061/(ASCE)1090-0268(2003)7:3(258)
oai:eprints.whiterose.ac.uk:42823
2013-02-08T17:30:37Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42823/
Concrete beams with externally bonded flexural FRP-reinforcement: analytical investigation of debonding failure
Pesic, N.
Pilakoutas, K.
This paper studies the problem of early concrete cover delamination and plate-end failure of reinforced concrete beams strengthened with externally bonded FRP-reinforcement. The accuracy of analytical models and finite element (FE) methods for predicting this type of failure is assessed against published experimental data. Two design approaches based on the maximum concrete tensile strength and the shear capacity of concrete beams were examined first and it was found that linear elastic analysis cannot accurately predict the brittle plate-end concrete failure. It was also found that the extent of strengthening that can be achieved is limited by the shear capacity of concrete beams. The FE analysis is used to examine the effects of internal tensile reinforcement on the magnitude of principal tensile stresses in the critical region. The non-linear behaviour of FRP-strengthened beams is also examined in the FE analysis using the smeared crack model for concrete which is shown to adequately display the inelastic deformation of the beam. Finally, the mixed mode of failure due to the combined shear and concrete cover delamination is addressed through modelling plate-end and shear crack discontinuities using the discrete crack approach.
Elsevier
2003-06
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42823/2/WRRO_42823.pdf
Pesic, N. and Pilakoutas, K. (2003) Concrete beams with externally bonded flexural FRP-reinforcement: analytical investigation of debonding failure. Composites Part B: Engineering, 34 (4). pp. 327-338. ISSN 1359-8368
http://dx.doi.org/10.1016/S1359-8368(02)00139-7
doi:10.1016/S1359-8368(02)00139-7
oai:eprints.whiterose.ac.uk:42824
2013-02-08T17:30:37Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42824/
Alternative shear reinforcement for reinforced concrete flat slabs
Pilakoutas, K.
Li, X.
This paper presents the first series of validation tests for a patented shear reinforcement system for reinforced concrete flat slabs. The system, called “Shearband,” consists of elongated thin steel strips punched with holes, which undulate into the slab from the top surface. The main advantages of the new reinforcement system are structural effectiveness, flexibility, simplicity, and speed of construction. Four reinforced concrete slabs were tested in a specially designed test rig. The slabs reinforced in shear exhibited ductile behavior after achieving their full flexural potential, thus proving the effectiveness of the new reinforcement. This paper reviews briefly existing types of shear reinforcement and identifies the need for more efficient and economic solutions. Details of the experimental setup and results are given, including strain and deflection measurements as well as photographs of sections through the slabs. Finally, comparisons are made with the ACI 318 and BS8110 code predictions, which confirm that the system enabled the slabs to avoid punching shear failure and achieve their flexural potential. In addition, both codes are shown to lead to conservative estimates of flexural and punching shear capacities of reinforced concrete slabs.
American Society of Civil Engineers
2003-09
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42824/1/WRRO_42824.pdf
Pilakoutas, K. and Li, X. (2003) Alternative shear reinforcement for reinforced concrete flat slabs. Journal of Structural Engineering, 129 (9). pp. 1164-1172. ISSN 0733-9445
http://dx.doi.org/10.1061/(ASCE)0733-9445(2003)129:9(1164)
doi:10.1061/(ASCE)0733-9445(2003)129:9(1164)
oai:eprints.whiterose.ac.uk:42924
2013-02-08T17:31:49Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434343
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42924/
Fibre-reinforced roller-compacted concrete transport pavements
Neocleous, K
Angelakopoulos, H
Pilakoutas, K
Guadagnini, M
Concrete pavements are generally more expensive to construct than asphalt pavements, and are thus mostly used in heavily trafficked sections and to reduce maintenance. The research work presented in this paper, however, indicated that the use of rapid construction techniques (such as roller compaction) and materials with lower embodied energy (such as low-energy cements, recycled aggregates and recycled steel fibres) can lead to concrete pavements that are more economical and environmentally friendly than asphalt pavements (40% less energy consumption during the life cycle of the pavement). The first part of this paper presents an overview of this research, which was undertaken as part of the EU FP6 STREP project ‘EcoLanes’ and investigated the development of long-lasting rigid pavements made with steel-fibre-reinforced roller-compacted concrete. The second part of the paper outlines the work undertaken for the development and optimisation of several trial concrete mixes. It is shown that the flexural behaviour of roller-compacted concrete, under static loads, can be enhanced by the addition of fibres. Furthermore, the results of this study demonstrated the potential of recycling concrete pavements, at the end of their life, for the construction of new pavements.
Institution of Civil Engineers
2011-05
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42924/1/WRRO_42814.pdf
text
en
https://eprints.whiterose.ac.uk/42924/3/images.pdf
Neocleous, K, Angelakopoulos, H, Pilakoutas, K et al. (1 more author) (2011) Fibre-reinforced roller-compacted concrete transport pavements. Proceedings of the ICE - Transport, 164 (TR2). pp. 97-109. ISSN 0965-092X
http://dx.doi.org/10.1680/tran.9.00043
oai:eprints.whiterose.ac.uk:42966
2013-02-08T17:31:49Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42966/
A connection element for modelling end-plate connections in fire
Huang, Z.
In this paper a robust 2-noded connection element has been developed for modelling the bolted end-plate connection between a steel beam and column at elevated temperatures. The connection element allows the element nodes to be placed at the reference plane with offset and the non-uniform temperature distributions within the connection. In this model the connection failure due to bending, axial tension, compression and vertical shear are considered. The influence of the axial tensile force of the connected beam on the connection is also taken into account. This model has the advantages of both the previous simple and component-based models. A total of 23 fire tests were used to extensively validate the model. It can be seen that the current model is robust and has a capability to predict the behaviour of a bolted end-plate connection under fire attack with reasonable accuracy. Compared to the tested results the predictions of the current model were mainly on the conservative side. Hence, the model can be used for structural fire engineering design on steel-framed composite buildings. The idea described in this paper can also easily be applied to develop other kinds of connections, such as simple connections, column based connections or hollow section connections, and so on. (c) 2010 Elsevier Ltd. All rights reserved.
Elsevier
2011-05
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42966/1/WRRO_42966.pdf
Huang, Z. (2011) A connection element for modelling end-plate connections in fire. Journal of Constructional Steel Research, 67 (5). pp. 841-853. ISSN 0143-974X
http://dx.doi.org/10.1016/j.jcsr.2010.12.009
10.1016/j.jcsr.2010.12.009
oai:eprints.whiterose.ac.uk:43458
2018-03-24T01:51:22Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/43458/
The mechanics of inelastic buckling using a Shanley-like model
Huang, S-S.
Burgess, I.
Huang, Z.
Plank, R.
This paper presents a study of the mechanics of inelastic buckling using a Shanley-like simplified column model. The model is an extension of the original Shanley model with multiple springs and two dampers. The inclusion of damping enables the dynamic response of the model under constant loading to be captured. The model has been evaluated against the tangent-modulus and reduced-modulus critical buckling loads, and has been found effective in representing the progressive change in the regions of loading and unloading during inelastic buckling. It is also able to simulate the extreme situations of inelastic buckling by varying the ratio of the two damping coefficients. It is seen that high rotational damping, relative to vertical damping, causes the buckling to move towards the reducedmodulus buckling load at much lower deflections than when the relationship is reversed.
2011-06
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/43458/1/SSH0_The%20mechanics%20of%20inelastic%20buckling%20using%20a%20Shanley-like%20model.pdf
Huang, S-S., Burgess, I., Huang, Z. et al. (1 more author) (2011) The mechanics of inelastic buckling using a Shanley-like model. Proceedings of the Institution of Civil Engineers: Engineering and Computational Mechanics, 164 (2). 103 - 119. ISSN 1755-0777
http://dx.doi.org/10.1680/eacm.2011.164.2.103
10.1680/eacm.2011.164.2.103
oai:eprints.whiterose.ac.uk:43495
2013-02-08T17:35:30Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464341:536865666669656C642E414150
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4543
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/43495/
Abrasive and impact wear of stone used to manufacture axes in Neolithic Greece
Lewis, R.
Tsoraki, C.
Broughton, J.
Cripps, J.C.
Afodun, S.A.
Slatter, T.
Roubos, V.
Excavations at the Neolithic settlement at Makriyalos in Northern Greece brought to light a large number of stone axe heads, the majority of which were manufactured from serpentinite and igneous rocks. Detailed study of the manufacturing traces on the archaeological implements identified that both percussive (pecking) and abrasive techniques (sawing and grinding/polishing) were employed for the production of the axes. There is limited evidence, however, of how these processes may have been undertaken.
The aim of this work was to build on previous research investigating sawing and polishing methods and the materials that may have been used in these tasks.
Modern samples of two types of serpentinite and a dolerite were collected from the environs of the archaeological site. These were tested for strength and porosity. Through archaeological research the materials available to Neolithic people were established and some testing was carried out to establish sliding speeds and loads and percussive impact velocities achievable by a human to feed into the tribological test design.
Pin-on-disc wear tests were carried out using quartz, chalcedony and sandstone as the pin material in wet and dry conditions to study sawing and polishing behaviour. Reciprocating tests were carried out using leather and combinations of lubricant (animal fat and water) and abrasive medium (sand) to study effects on polishing. Percussive impact tests were also carried out.
The tests indicated that with certain combinations of materials and test conditions, both sawing and polishing could be achieved. A series of stages for the polishing were identified which are in line with observations made by archaeologists. (C) 2011 Elsevier B.V. All rights reserved.
Elsevier
2011-07-29
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/43495/1/WRRO_43495.pdf
Lewis, R., Tsoraki, C., Broughton, J. et al. (4 more authors) (2011) Abrasive and impact wear of stone used to manufacture axes in Neolithic Greece. Wear, 271 (9-10). pp. 2549-2560. ISSN 0043-1648
http://dx.doi.org/10.1016/j.wear.2010.12.074
10.1016/j.wear.2010.12.074
oai:eprints.whiterose.ac.uk:43500
2013-02-08T17:35:32Z
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/43500/
On the buckling of axially restrained steel columns in fire
Shepherd, P.G.
Burgess, I.W.
This paper describes the behaviour of restrained steel columns in fire. It follows the introduction of extra load into the column through the axial restraint of the surrounding cooler structure and the consequential buckling. Key to this understanding is the post-failure behaviour and re-stabilisation of the column, which is discussed with reference to a finite element model and an analytical model. Through bi-directional control of the temperature, the finite element model allows the snap-back behaviour to be modelled in detail and the effects of varying slenderness and load ratio are investigated. The analytical model employs structural mechanics to describe the behaviour of a heated strut, and is capable of explaining both elastic and fully plastic post-buckling behaviour.
Through this detailed explanation of what happens when a heated column buckles, the consequences for steel-framed building design are discussed. In particular, the need to provide robustness is highlighted, in order to ensure that alternative load paths are available once a column has buckled and re-stabilised. Without this robustness, the dynamic shedding of load onto surrounding structures may well spread failure from a fire's origin and lead to progressive collapse. (C) 2011 Elsevier Ltd. All rights reserved.
Elsevier
2011-10
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/43500/2/WRRO_43500.pdf
Shepherd, P.G. and Burgess, I.W. (2011) On the buckling of axially restrained steel columns in fire. Engineering Structures, 33 (10). pp. 2832-2838. ISSN 0141-0296
http://dx.doi.org/10.1016/j.engstruct.2011.06.007
10.1016/j.engstruct.2011.06.007
oai:eprints.whiterose.ac.uk:75383
2014-07-04T12:00:03Z
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74797065733D61727469636C65
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696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/75383/
Topography discretization techniques for Godunov-type shallow water numerical models: a comparative study
Kesserwani, G.
This paper compares various topography discretization approaches for Godunov-type shallow water numerical models. Many different approaches have emerged popular with Godunov-type water wave models. To date, literature lacks an investigative study distinguishing their pros and the cons, and assessing their reliability relating to issues of practical interest. To address this gap, this work reviews and assesses five standard topography discretization methods that consist of the Upwind, the surface gradient method (SGM), the mathematically balanced set of the SWE (Etta-SWE), the hydrostatic reconstruction technique (Hydr-Rec) and the RKDG2 model. The study further considers mix-mode approaches that incorporate wetting and drying together with the topography discretization. Steady and transient hydraulic tests are employed to measure the performance of the approaches relating to the issues of mesh size, topography’s differentiability, accuracy-order of the numerical scheme, and impact of wetting and drying.
Taylor & Francis
2013
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/75383/1/WRRO.pdf
Kesserwani, G. (2013) Topography discretization techniques for Godunov-type shallow water numerical models: a comparative study. Journal of Hydraulic Research , 51 (4). pp. 351-367. ISSN 0022-1686
http://dx.doi.org/10.1080/00221686.2013.796574
10.1080/00221686.2013.796574
oai:eprints.whiterose.ac.uk:75856
2014-07-01T08:40:34Z
7374617475733D707562
74797065733D61727469636C65
756E69743D4C65656473:4C656564732E46412D4541454E:4C656564732E52432D47454F47
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D4C65656473
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https://eprints.whiterose.ac.uk/75856/
Water-sensitive urban design: opportunities for the UK
Ashley, R
Lundy, L
Ward, S
Shaffer, P
Walker, AL
Morgan, C
Saul, A
Wong, T
Moore, S
Water-sensitive urban design (WSUD) is a concept that is gaining support as a means to manage urban water systems in an integrated way through the better positioning of the topic of water in urban planning and design processes. Water-sensitive urban design is emerging in the UK and this paper sets the scene and identifies the opportunities and constraints from a UK perspective. Recent developments in integrated water management, ecosystem services and multifunctional land use provide new opportunities for ‘getting more for less’. These can range from seeing all forms of water as a resource, exploiting opportunities to contribute to the green and blue infrastructure agendas, resilience to climate and other changes. This paper draws on international experience as to how water-sensitive urban design can deliver opportunities; mitigate the urban development challenges; implement and support institutional, regulatory and practical opportunities and demonstrate the benefits of taking a water-sensitive urban design approach in the UK. The key requirements for delivery are highlighted and a proposed vision for water-sensitive urban design in the UK outlined.
ICE Publishing
2013-06
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/75856/1/Ashley%20et%20al.pdf
Ashley, R, Lundy, L, Ward, S et al. (6 more authors) (2013) Water-sensitive urban design: opportunities for the UK. Proceedings of the Institution of Civil Engineers: Municipal Engineer, 166 (ME2). 65 - 76. ISSN 0965-0903
http://dx.doi.org/10.1680/muen.12.00046
10.1680/muen.12.00046
oai:eprints.whiterose.ac.uk:75870
2018-03-25T01:19:38Z
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https://eprints.whiterose.ac.uk/75870/
www.daylighting.org.uk: case study website supporting research into daylighting urban rivers
Broadhead, A.T.
Lerner, D.N.
Deculverting, or 'daylighting', involves opening up buried watercourses and restoring them to more natural conditions. It is often claimed to provide multiple benefits to society, the environment and the economy. However, the outcomes and objectives of deculverting projects are rarely published, which makes it difficult to evaluate their true effectiveness, determine the best methods to use, or provide quantitative evidence to encourage future projects.
At the Catchment Science Centre, we have developed www.daylighting.org.uk in response to this research need. This map-based website of international daylighting case studies records the project drivers, costs and the environmental, social and economic objectives and outcomes. Practitioners are encouraged to enter their own case study details and add to our findings.
Wiley
2013-06-06
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/75870/1/Broadhead%20and%20Lerner%20-%20Daylighting%20-%20Invited%20commentary%20HPToday%20-%202013-02-12.pdf
Broadhead, A.T. and Lerner, D.N. (2013) www.daylighting.org.uk: case study website supporting research into daylighting urban rivers. Hydrological Processes, 27 (12). pp. 1840-1842. ISSN 0885-6087
http://dx.doi.org/10.1002/hyp.9781
10.1002/hyp.9781
oai:eprints.whiterose.ac.uk:75871
2014-09-15T03:20:30Z
7374617475733D707562
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/75871/
Captured streams and springs in combined sewers: A review of the evidence, consequences and opportunities
Broadhead, A.T.
Horn, R.
Lerner, D.N.
Captured streams and springs may be flowing in combined sewers, increasing clean baseflow in pipes and wastewater treatment works (WwTWs), reducing pipe capacity and increasing treatment costs. The UK water industry is aware of this in principle, but there has been no explicit discussion of this in the published literature, nor have there been any known attempts to manage it. Instead, the current focus is on the similar intrusion of groundwater infiltration through pipe cracks and joints. We have conducted a thorough review of literature and international case studies to investigate stream and spring capture, finding several examples with convincing evidence that this occurs. We identify three modes of entry: capture by conversion, capture by interception, and direct spring capture. Methods to identify and quantify capture are limited, but the experience in Zurich suggests that it contributed 7–16% of the baseflow reaching WwTWs. There are negative impacts for the water industry in capital and operational expenditure, as well as environmental and social impacts of loss of urban streams. For a typical WwTW (Esholt, Bradford) with 16% of baseflow from captured streams and springs, we conservatively estimate annual costs of £2 million to £7 million. A detailed case study from Zurich is considered that has successfully separated captured baseflow into daylighted streams through the urban area, with multiple economic, environmental and social benefits. We conclude that there is a strong case for the UK water industry to consider captured streams and springs, quantify them, and assess the merits of managing them.
Elsevier
2013-09-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/75871/7/Captured_Streams_and_Springs_in_Combined_Sewers_Broadhead_wr.pdf
Broadhead, A.T., Horn, R. and Lerner, D.N. (2013) Captured streams and springs in combined sewers: A review of the evidence, consequences and opportunities. Water Research, 47 (13). pp. 4752-4766. ISSN 0043-1354
http://www.sciencedirect.com/science/article/pii/S0043135413004284
http://dx.doi.org/10.1016/j.watres.2013.05.020
oai:eprints.whiterose.ac.uk:75909
2014-09-15T03:19:34Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
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7072696D6F3D6E6F5F646F63756D656E74735F617661696C61626C65
https://eprints.whiterose.ac.uk/75909/
Modelling Viscous Effects during and after Construction in London Clay
Clarke, SD
Hird, CC
A new approach to allow the modelling of the viscous behaviour of clay soils has recently been developed (Clarke & Hird, 2012) based on the BRICK constitutive model (Simpson, 1992). In this approach viscous effects, such as creep and stress relaxation, and the effects of strain history on soil stiffness are modelled within a single conceptual framework. The developed model, SRD (strain-rate dependent) BRICK, has been incorporated in a finite element program, allowing boundary value problems to be analysed. In this paper two case histories involving London Clay, where viscous effects possibly had an influence on the observed displacements, are back-analysed. These cases are the Jubilee Line extension at St James’s Park (Standing et al., 1996, Nyren et al., 2001) and a deep basement at Horseferry Road (May, 1975, Chapman, 1999). The results of the numerical modelling show that, in each case, the SRD BRICK model is able to achieve closer agreement with the recorded displacements when compared with the un-modified BRICK model.
Southeast Asian Geotechnical Society
2013-05-08
Article
NonPeerReviewed
Clarke, SD and Hird, CC (2013) Modelling Viscous Effects during and after Construction in London Clay. Geotechnical Engineering Journal of the SEAGS & AGSSEA, 44 (2). 48 - 54 (7). ISSN 0046-5828
http://www.seags.ait.ac.th/48-54%20Clarke%20et%20al%20-SEAGS%20EJournal%202013-06.pdf
oai:eprints.whiterose.ac.uk:75928
2014-09-15T03:19:00Z
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https://eprints.whiterose.ac.uk/75928/
Modelling discrete soil reinforcement in numerical limit analysis
Clarke, SD
Gilbert, M
Smith, CC
Soil reinforcement is widely used in geotechnical engineering. While there are various means of accounting for the presence of soil reinforcement in limit analysis and limit equilibrium type calculations, these are often highly problem specific. In this paper a general means of incorporating soil reinforcement within numerical limit analysis calculations is presented. A key feature of this implementation is that the reinforcement is modelled 'in parallel' with the soil model such that allows the soil to flow past the reinforcement as might occur for soil nailing. To illustrate this the Discontinuity Layout Optimization (DLO) numerical analysis procedure is used, and the efficacy of the approach is evaluated via application to reinforced slope problems involving rigid soil nails under plane-strain conditions. The analyses are calibrated against a two-part wedge analysis method such as presented in British Standard BS8006:1995 or AASHTO LRFD Bridge design specifications. It is shown that the DLO-based procedure produces identical results only when the two-part wedge collapse mechanism is prescribed in advance (achieved by artificially strengthening the soil except along predefined failure planes). A more critical mechanism is otherwise predicted, with the soil strength at collapse required to be approximately 10% higher than predicted by the two-part wedge method (or alternatively soil nail lengths required to be approximately 20% greater).
NRC Research Press
2013-05-03
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/75928/8/WRRO_75928.pdf
Clarke, SD, Gilbert, M and Smith, CC (2013) Modelling discrete soil reinforcement in numerical limit analysis. Canadian Geotechnical Journal, 50 (7). 705 - 715 (11). ISSN 0008-3674
http://dx.doi.org/10.1139/cgj-2012-0387
10.1139/cgj-2012-0387
oai:eprints.whiterose.ac.uk:75929
2014-09-15T03:19:02Z
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7072696D6F3D6E6F5F646F63756D656E74735F617661696C61626C65
https://eprints.whiterose.ac.uk/75929/
Book review, Rudolph Glossop and the rise of geotechnology
Clarke, SD
Thomas Telford
2012-04-01
Article
NonPeerReviewed
Clarke, SD (2012) Book review, Rudolph Glossop and the rise of geotechnology. Geotechnique, 62 (4). 369 - 369 (1). ISSN 0016-8505
http://dx.doi.org/10.1680/geot.11.B.004
10.1680/geot.11.B.004
oai:eprints.whiterose.ac.uk:75930
2014-09-15T03:19:05Z
7374617475733D707562
74797065733D7075626C69736865645F636F6E666572656E63655F70726F63656564696E6773
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696E737469747574696F6E3D536865666669656C64
7072696D6F3D6E6F5F646F63756D656E74735F617661696C61626C65
https://eprints.whiterose.ac.uk/75930/
The Role of Geotechnical Parameters on the Impulse Generated by Buried Charges
Clarke, S
Warren, JA
Fay, SD
Rigby, SE
Tyas, A
It has recently been shown that an increase in moisture content independently of bulk density can lead to an increase in measured total impulse from a buried charge. This implies that water has a greater effect on the enhancement of buried charges than its mass alone would suggest. This has brought into question a number of aspects regarding common assumptions made when designing numerical and physical experiments that incorporate buried charges, most notably the role of moisture content in conjunction with the particle size distribution. The latest work done by the authors is attempting to differentiate between the direct effects of mass confinement and the unique relationships that exist in soils between the interrelated phases, which can be defined in terms of their geotechnical properties.
Military Aspects of Blast and Shock (MABS)
Sochet, I
2012
Proceedings Paper
NonPeerReviewed
Clarke, S, Warren, JA, Fay, SD et al. (2 more authors) (2012) The Role of Geotechnical Parameters on the Impulse Generated by Buried Charges. In: Sochet, I, (ed.) MABS 22 Bourges (2012). The 22nd International Symposium on Military Aspects of Blast and Shock (MABS22) , November 4-9, 2012, Bourges, France. Military Aspects of Blast and Shock (MABS) .
http://www.mabs.ch/spiezbase/mabs22/P131-clarke.pdf
oai:eprints.whiterose.ac.uk:75931
2022-12-19T13:25:22Z
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696E737469747574696F6E3D536865666669656C64
7072696D6F3D6E6F5F646F63756D656E74735F617661696C61626C65
https://eprints.whiterose.ac.uk/75931/
The influence of soil density and moisture content on the impulse from shallow buried explosive charges
Clarke, SD
Warren, JA
Tyas, A
A series of experimental trials has been conducted at University of Sheffield, UK to assess the effect of density and moisture content of Leighton Buzzard sand on the impulse applied to a target when exposed to loading from the detonation of a shallow-buried charge. Sand samples have been prepared in stiff cylindrical steel bins 1000mm internal diameter and 750mm deep, and loading has been generated using explosive charges of up to 1kg PE4 buried at a depth of <100mm. Preparation of the sand has been carefully controlled, with densities consistent to within +/- 3kg/m3 and moisture content within +/-0.05% of target values in sand masses >1000kg. The impulse has been determined from vertical displacement vs time records of a c. 1500kg reaction mass, recorded using high-speed digital video and laser displacement gauges. Results will be presented which demonstrate that it is possible to achieve a very high level of consistency in the loading even at this relatively large scale, with measured impulses typically within a spread of +/-2% for nominally identical tests. This spread is considerably lower than in previously reported studies at this scale, and facilitates a careful and accurate parametric analysis of the effect of variations in the geotechnical conditions on the impulse imparted to the target.
Shapiro, J
2011-09-19
Proceedings Paper
NonPeerReviewed
Clarke, SD, Warren, JA and Tyas, A (2011) The influence of soil density and moisture content on the impulse from shallow buried explosive charges. In: Shapiro, J, (ed.) Proceedings of the 14th International Symposium on Interaction of the Effects of Munitions with Structures (ISIEMS). 14th International Symposium on Interaction of the Effects of Munitions with Structures (ISIEMS), 19-23 Sep 2011, Seattle, USA. .
oai:eprints.whiterose.ac.uk:75932
2014-09-15T03:18:18Z
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74797065733D7075626C69736865645F636F6E666572656E63655F70726F63656564696E6773
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696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/75932/
Analysis of the stability of sheet pile walls using discontinuity layout optimization
Clarke, SD
Smith, CC
Gilbert, M
CRC Press
2010
Proceedings Paper
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/75932/7/WRRO_75932.pdf
Clarke, SD, Smith, CC and Gilbert, M (2010) Analysis of the stability of sheet pile walls using discontinuity layout optimization. In: Proceedings of the 7th European Conference in Numerical Methods in Geotechnical Engineering. 7th European Conference in Numerical Methods in Geotechnical Engineering, June, 2010, Trondheim, Norway. CRC Press , 163 - 168. ISBN 9780415592390
http://dx.doi.org/10.1201/b10551-30
10.1201/b10551-30
oai:eprints.whiterose.ac.uk:75934
2022-12-19T13:25:22Z
74797065733D7075626C69736865645F636F6E666572656E63655F70726F63656564696E6773
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696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/75934/
Shear wave velocity measurement of Kaolin during undrained unconsolidated triaxial compression
Black, JA
Stanier, SA
Clarke, SD
2009
Proceedings Paper
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/75934/1/Final%20Paper_13-05-09_.pdf
Black, JA, Stanier, SA and Clarke, SD (2009) Shear wave velocity measurement of Kaolin during undrained unconsolidated triaxial compression. In: Proceedings of the 62nd Canadian Geotechnical Conference. 62nd Canadian Geotechnical Conference, 20-23 Sep 2009, Halifax, Canada. .
oai:eprints.whiterose.ac.uk:75935
2018-03-27T04:57:04Z
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https://eprints.whiterose.ac.uk/75935/
The development of a small-scale geotechnical teaching centrifuge
Black, JA
Clarke, SD
Royal Academy of Engineering
2012
Book Section
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/75935/6/geotechnical_teaching_centrifuge.pdf
Black, JA and Clarke, SD (2012) The development of a small-scale geotechnical teaching centrifuge. In: Enhancing Engineering Higher Education. Royal Academy of Engineering , 37 - 41. ISBN 1903496896
http://www.raeng.org.uk/eehe
oai:eprints.whiterose.ac.uk:76556
2022-12-19T13:25:41Z
7374617475733D707562
74797065733D7075626C69736865645F636F6E666572656E63655F70726F63656564696E6773
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696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/76556/
An in-situ monitoring system for natural temperature and relative humidity
Taylor, A.J.
Cripps, J.C.
Clarke, S.D.
Oxidation of pyrite-rich, carbonaceous mudrocks used as fill beneath ground bearing floor slabs is currently causing significant problems to domestic and other properties in Ireland. Due to the precipitation of gypsum and other minerals the fill expands and this causes heave of slabs, together with distortion and cracking of the structure. Temperature is known to have an effect on both the rate and amount of this expansion; however, the full impact of human habitation on this process is not fully understood. The paper gives details of the development and testing of a system for monitoring temperature, humidity and pressure conditions within the material. This system is designed to minimise cost and disruption to the homeowner, whilst facilitating reliable measurements over period of 3 to 12 months
Taylor & Francis
Kwasniewski, M.
Lydzba, D.
2013-09-06
Proceedings Paper
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/76556/7/WRRO_76556.pdf
Taylor, A.J., Cripps, J.C. and Clarke, S.D. (2013) An in-situ monitoring system for natural temperature and relative humidity. In: Kwasniewski, M. and Lydzba, D., (eds.) Eurock 2013 - Rock Mechanics for Resources, Energy and Environment. Eurock 2013 - Rock Mechanics for Resources, Energy and Environment, 21-26 Sep 2013, Wroclaw, Poland. Taylor & Francis , 351 - 356 . ISBN 978-1-138-00080-3
oai:eprints.whiterose.ac.uk:76557
2018-03-26T10:01:38Z
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https://eprints.whiterose.ac.uk/76557/
Briefing: UK Ministry of Defence Force Protection Engineering Programme
Warren, J.
Kerr, S.
Tyas, A.
Clarke, S.
Petkovski, M.
Jardine, A.
Church, P.
Gould, P.
Williams, A.
The Defence Science and Technology Laboratory sponsored, QinetiQ-led Force Protection Engineering Research Programme has two main strands, applied and underpinning research. The underpinning strand is led by Blastech Ltd. One focus of this research is into the response of geomaterials to threat loading. The programme on locally won fill is split into four main characterisation strands: high-stress (GPa) static pressure–volume; medium-rate pressure–volume (split Hopkinson bar); high-rate (flyer plate) pressure–volume; and unifying modelling research at the University of Sheffield, which has focused on developing a high-quality dataset for locally won fill in low and medium strain rates. With the test apparatus at Sheffield well-controlled tests can be conducted at both high strain rate and pseudo-static rates up to stress levels of 1 GPa. The University of Cambridge has focused on using one-dimensional shock experiments to examine high-rate pressure–volume relationships. Both establishments are examining the effect of moisture content and starting density on emergent rate effects. Blastech Ltd has been undertaking carefully controlled fragment impact experiments, within the dataspace developed by the Universities of Sheffield and Cambridge. The data from experiments are unified by the QinetiQ-led modelling team, to predict material behaviour and to derive a scalable locally won fill model for use in any situation.
Institution of Civil Engineers
2013-09-01
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/76557/1/eacm166-0119.pdf
Warren, J., Kerr, S., Tyas, A. et al. (6 more authors) (2013) Briefing: UK Ministry of Defence Force Protection Engineering Programme. Proceedings of the ICE - Engineering and Computational Mechanics, 166 (EM3). 119 - 123 . ISSN 1755-0777
http://dx.doi.org/10.1680/eacm.13.00014
10.1680/eacm.13.00014
oai:eprints.whiterose.ac.uk:77140
2016-11-16T08:44:09Z
7374617475733D707562
74797065733D7075626C69736865645F636F6E666572656E63655F70726F63656564696E6773
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/77140/
Michell structure for a uniform load over multiple spans
Pichugin, A.V.
Tyas, A.
Gilbert, M.
2011
Proceedings Paper
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/77140/7/WRRO_77140.pdf
Pichugin, A.V., Tyas, A. and Gilbert, M. (2011) Michell structure for a uniform load over multiple spans. In: 9th World Congress on Structural & Multidisciplinary Optimization. 9th World Congress on Structural and Multidisciplinary Optimization, June 13 - 17, 2011, Shizuoka, Japan. .
oai:eprints.whiterose.ac.uk:77307
2018-03-21T02:37:36Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/77307/
Single-Degree-of-Freedom response of finite targets subjected to blast loading – The influence of clearing
Rigby, S.E.
Tyas, A.
Bennett, T.
When evaluating the dynamic response of a structure subjected to a high explosive detonation, it is common to simplify both the target properties and the form of the blast pressure load - a standard approach is to model the target as an equivalent Single-Degree-of-Freedom (SDOF) system with the blast load idealised as a pulse which decays linearly with time. Whilst this method is suitable for cases where the reflecting surface is large, it is well known that for smaller targets, the propagation of a rarefaction 'clearing' wave from the edges of the target may cause a premature reduction in the magnitude of the blast pressure and hence reduce the total impulse acting on the structure. In this article, a simple method for calculating clearing relief, based on an acoustic approximation of the rarefaction wave, is coupled with an SDOF model to investigate the influence of clearing on the dynamic response of elastic targets. Response spectra are developed for a range of target sizes and blast events that may be of interest to the engineer, enabling the effects of blast wave clearing to be evaluated and situations where blast wave clearing may increase the peak displacement of the target to be determined. When the natural period of the target is large compared to the duration of loading, the reduction in positive phase impulse leads to significantly lower values of peak displacement when compared to an identical system subjected to a triangular blast load. For systems where the natural period is comparable to the duration of the loading, the early onset of negative pressure (attributed to blast wave clearing) can coincide with the rebound of the target and result in greater peak displacements. It is concluded that blast wave clearing should be evaluated and its influence quantified in order to ensure that blast resistant designs are efficient and safe. © 2012 Elsevier Ltd.
Elsevier
2012-12
Article
PeerReviewed
text
en
cc_by_nc_nd_4
https://eprints.whiterose.ac.uk/77307/1/SR-AT-TB-clearing.pdf
Rigby, S.E., Tyas, A. orcid.org/0000-0001-6078-5215 <https://orcid.org/0000-0001-6078-5215> and Bennett, T. (2012) Single-Degree-of-Freedom response of finite targets subjected to blast loading – The influence of clearing. Engineering Structures, 45. pp. 396-404. ISSN 0141-0296
http://dx.doi.org/10.1016/j.engstruct.2012.06.034
10.1016/j.engstruct.2012.06.034
oai:eprints.whiterose.ac.uk:77308
2014-09-15T02:29:31Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/77308/
Clearing of blast waves on finite-sized targets - an overlooked approach
Tyas, A
Bennett, T
Warren, J.A
Rigby, S.E
Fay, S.D
The total impulse imparted to a target by an impinging blast wave is a key loading parameter for the design of blast-resistant structures and façades. Simple, semi-empirical approaches for the prediction of blast impulse on a structure are well established and are accurate in cases where the lateral dimensions of the structure are sufficiently large. However, if the lateral dimensions of the target are relatively small in comparison to the length of the incoming blast wave, air flow around the edges of the structure will lead to the propagation of rarefaction or clearing waves across the face of the target, resulting in a premature reduction of load and hence, a reduction in the total impulse imparted to the structure. This effect is well-known; semi-empirical models for the prediction of clearing exist, but several recent numerical and experimental studies have cast doubt on their accuracy and physical basis. In fact, this issue was addressed over half a century ago in a little known technical report at the Sandia Laboratory, USA. This paper presents the basis of this overlooked method along with predictions of the clearing effect. These predictions, which are very simple to incorporate in predictions of blast loading, have been carefully validated by the current authors, by experimental testing and numerical modelling. The paper presents a discussion of the limits of the method, concluding that it is accurate for relatively long stand-off blast loading events, and giving some indication of improvements that are necessary if the method is to be applicable to shorter stand-off cases. © (2011) Trans Tech Publications.
Trans Tech Publications
2011
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/77308/7/WRRO_77308.pdf
Tyas, A, Bennett, T, Warren, J.A et al. (2 more authors) (2011) Clearing of blast waves on finite-sized targets - an overlooked approach. Applied Mechanics and Materials, 82. 669 - 674. ISSN 1660-9336
http://dx.doi.org/10.4028/www.scientific.net/AMM.82.669
10.4028/www.scientific.net/AMM.82.669
oai:eprints.whiterose.ac.uk:77744
2014-09-15T02:01:04Z
7374617475733D707562
74797065733D61727469636C65
756E69743D4C65656473:4C656564732E46412D46455053:4C656564732E52432D43495645:4C656564732E53522D49504345
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D4C65656473
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/77744/
CFD simulation of airborne pathogen transport due to human activities
Hathway, EA
Noakes, CJ
Sleigh, PA
Fletcher, LA
Computational Fluid Dynamics (CFD) is an increasingly popular tool for studying the impact of design interventions on the transport of infectious microorganisms. While much of the focus is on respiratory infections, there is substantial evidence that certain pathogens, such as those which colonise the skin, can be released into, and transported through the air through routine activities. In these situations the bacteria is released over a volume of space, with different intensities and locations varying in time rather than being released at a single point. This paper considers the application of CFD modelling to the evaluation of risk from this type of bioaerosol generation. An experimental validation study provides a direct comparison between CFD simulations and bioaerosol distribution, showing that passive scalar and particle tracking approaches are both appropriate for small particle bioaerosols. The study introduces a zonal source, which aims to represent the time averaged release of bacteria from an activity within a zone around the entire location the release takes place. This approach is shown to perform well when validated numerically though comparison with the time averaged dispersion patterns from a transient source. However, the ability of a point source to represent such dispersion is dependent on airflow regime. The applicability of the model is demonstrated using a simulation of an isolation room representing the release of bacteria from bedmaking.
Elsevier
2011-12
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/77744/7/Hathway_BAE_2011_WRRO.pdf
Hathway, EA, Noakes, CJ, Sleigh, PA et al. (1 more author) (2011) CFD simulation of airborne pathogen transport due to human activities. Building and Environment, 46 (12). 2500 - 2511. ISSN 0360-1323
http://dx.doi.org/10.1016/j.buildenv.2011.06.001
10.1016/j.buildenv.2011.06.001
oai:eprints.whiterose.ac.uk:77745
2014-09-15T02:01:20Z
7374617475733D707562
74797065733D61727469636C65
756E69743D4C65656473:4C656564732E46412D46455053:4C656564732E52432D43495645:4C656564732E53522D49504345
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D4C65656473
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/77745/
The role of nursing activities on the bioaerosol production in hospital wards
Hathway, EA
Noakes, CJ
Fletcher, LA
Sleigh, PA
Clifton, I
Elliot, MW
Transport of infectious particles through the air has the potential to contaminate the indoor environment creating reservoirs of infectious material on surfaces. There is evidence that typical nursing activities can release large quantities of bacteria including MRSA into the hospital air, which may lead to surface contamination thereby increasing opportunities for further spread. Air sampling studies were conducted over a period of 5 days on a four-bed bay in a respiratory ward. Results showed that sampled bioaerosols are more likely to be carried on large particles >5 µm in diameter, and that the relationship between bioaerosols and particle size varies when respiratory interventions are in use. Increased activity in the hospital bay was shown to correlate to increased concentrations of bioaerosols whereas sedentary visitors did not. In particular, the occurrence of patient washing that occurred behind closed curtains correlated to large values of bioaerosol release. Floor cleaning generated large number of particles, but with no significant increase in sampled bioaerosols. This provides valuable information for understanding when and where bioaerosols are released on a hospital ward which may inform future research into physical segregation of patients and the definition of bioaerosol sources in computer simulations.
Sage publications
Yu, C
2013-04
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/77745/7/Hathway_IndoorBuiltEnv_2013_FINAL.pdf
Hathway, EA, Noakes, CJ, Fletcher, LA et al. (3 more authors) (2013) The role of nursing activities on the bioaerosol production in hospital wards. Indoor and Built Environment, 22 (2). 410 - 421. ISSN 1420-326X
http://dx.doi.org/10.1177/1420326X11428088
10.1177/1420326X11428088
oai:eprints.whiterose.ac.uk:77758
2018-03-29T00:38:17Z
7374617475733D756E707562
74797065733D6F74686572
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/77758/
Hudson_Clearing.m
Rigby, S.E
This MATLAB code allows the user to generate a series of keyword files for use with LS-DYNA to predict the blast load and evaluate the effects of blast wave clearing on a finite-sized, deformable target. User doccumentation is provided.
CMD Group, University of Sheffield
2014-02-11
Other
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/77758/1/Using%20Hudson_Clearing%20to%20model%20blast%20loads%20acting%20on%20finite-sized%20targets.pdf
Rigby, S.E (2014) Hudson_Clearing.m. CMD Group, University of Sheffield. (Unpublished)
oai:eprints.whiterose.ac.uk:77857
2014-03-05T12:56:57Z
7374617475733D707562
74797065733D6F74686572
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/77857/
MeshGen.m
Rigby, S.E
When modelling explosive detonations and blast wave propagation it is important that material movement is aligned with the elements. If a spherical charge is modelled in a rectangular mesh, an advection error is introduced. By modelling the blast wave in a radially symmetric mesh, this problem can be avoided. This MatLab script will generate a mesh file based on four inputs: The radius of the explosive; the radius of the air domain; the number of circumferential elements and the number of radial elements.
CMD Group, University of Sheffield
2014-02-21
Other
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/77857/2/MeshGen.m
Rigby, S.E (2014) MeshGen.m. CMD Group, University of Sheffield.
http://cmd.shef.ac.uk/software/matlab-script-generating-ls-dyna-mesh-file-spherical-expansion-blast-wave
oai:eprints.whiterose.ac.uk:77858
2014-02-24T11:12:13Z
7374617475733D707562
74797065733D6F74686572
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/77858/
Blast.m
Rigby, S.E.
Tyas, A.
This simple MatLab script will provide pressure, impulse, arrival time and duration predictions for a user defined explosive charge mass and stand-off. The parameter predictions for positive and negative phase are given by digitised data from UFC-3-340-02, Structures to Resist the Effects of Accidental Explosions. The negative phase is approximated with a cubic expression from Granstrom, Loading Characteristics of Air Blasts From Detonating Charges, Technical Report 100, Transactions of the Royal Institute of Technology, Stockholm.
CMD Group, University of Sheffield
2014-02-21
Other
NonPeerReviewed
archive
en
https://eprints.whiterose.ac.uk/77858/1/Blast.m.zip
Rigby, S.E. and Tyas, A. (2014) Blast.m. CMD Group, University of Sheffield.
http://cmd.shef.ac.uk/software/blastm-simple-tool-predicting-blast-pressure-parameters
oai:eprints.whiterose.ac.uk:77933
2022-12-19T13:26:17Z
7374617475733D707562
74797065733D7075626C69736865645F636F6E666572656E63655F70726F63656564696E6773
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/77933/
An alternative simplified model of tensile membrane action of slabs in fire
Burgess, I.W.
Dai, X.
Huang, S.S
CTU Publishing House
2013-04
Proceedings Paper
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/77933/1/Burgess%20ASFE%202013.pdf
Burgess, I.W., Dai, X. and Huang, S.S (2013) An alternative simplified model of tensile membrane action of slabs in fire. In: Proceedings of International Conference Application of Structural Fire Engineering. Applications of Structural Fire Engineering conference, 19-20 Apr 2013, Prague, Czech Republic. CTU Publishing House , Czech Technical University in Prague . ISBN 9788001052044
oai:eprints.whiterose.ac.uk:77942
2019-08-31T03:18:35Z
oai:eprints.whiterose.ac.uk:77944
2014-09-15T01:53:43Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/77944/
Linking distribution system water quality issues to possible causes via hydraulic pathways
Furnass, W.R.
Mounce, S.R.
Boxall, J.B.
Our limited understanding and quantification of the variety and complexity of chemical, physical and biological reactions and interactions occurring within drinking water distribution systems currently prohibit the development of a deterministic model of water quality. The causes of known water quality anomalies can however be investigated through mining the large volumes of water quality, hydraulic and asset data currently being collected by utility companies. The data-driven methodology described here permits historical cause-effect linkages to be identified in a scalable, largely automatable fashion. Under Distribution System Integrated Modelling (DSIM), spatio-temporal searches within the set of pipes that typically lie upstream of a known water quality anomaly are used to identify possible causes. Understanding of the flow paths that connect causes and effects are derived from the results of hydraulic network simulations. DSIM was used to investigate contacts regarding discolouration and smell/taste issues from customers within a Water Supply Zone in England, UK, over a six-year period. 17.6% of discolouration issues and 17.4% of smell/taste issues were linked to maintenance jobs using the methodology, much smaller proportions than were identified using radial cause searches. The DSIM search results contained a greater proportion of one-to-one linkages and so are less ambiguous than the results of the radial spatio-temporal searches. DSIM was found to be a useful and informative tool for data mining multiple water quality related datasets. © 2012 Elsevier Ltd.
Elsevier
2013-02
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/77944/7/WRRO_77944.pdf
Furnass, W.R., Mounce, S.R. and Boxall, J.B. (2013) Linking distribution system water quality issues to possible causes via hydraulic pathways. Environmental Modelling and Software, 40. 78 - 87. ISSN 1364-8152
http://dx.doi.org/10.1016/j.envsoft.2012.07.012
10.1016/j.envsoft.2012.07.012
oai:eprints.whiterose.ac.uk:77965
2014-09-15T01:51:30Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/77965/
A mass matrix formulation for cohesive surface elements
Hetherington, J.
Askes, H.
A well-known method for modelling crack propagation in structural finite element analysis is the use of interface elements employing the theory of cohesive surfaces. However, the use of cohesive surfaces in explicit dynamics is problematic since they have zero mass and must initially be very stiff in order to avoid the introduction of artificial compliance. These properties lead to an often drastic reduction in the critical time step of the analysis. In this paper we use the bipenalty method to derive a mass matrix for a 2D cohesive surface interface element that does not add net physical mass to the overall system. This allows for cohesive surfaces with very high initial stiffness that have no effect on the critical time step of the analysis. Not only does this lead to a more robust and stable system, it also greatly simplifies the choice of parameters since there is no need to adjust the time step, and no need to limit the initial penalty stiffness according to time step stability considerations.
Elsevier
2014-02
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/77965/7/WRRO_77965.pdf
Hetherington, J. and Askes, H. (2014) A mass matrix formulation for cohesive surface elements. Theoretical and Applied Fracture Mechanics, 69. pp. 110-117.
http://dx.doi.org/10.1016/j.tafmec.2013.11.011
10.1016/j.tafmec.2013.11.011
oai:eprints.whiterose.ac.uk:78006
2016-10-24T23:32:58Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78006/
Full-scale shaking table tests on a substandard RC building repaired and strengthened with post-tensioned metal straps
Garcia, R.
Hajirasouliha, I.
Guadagnini, M.
Helal, Y.
Jemaa, Y.
Pilakoutas, K.
Mongabure, P.
Chrysostomou, C.
Kyriakides, N.
Ilki, A.
Budescu, M.
Taranu, N.
Ciupala, M.A.
Torres, L.
Saiidi, M.
The effectiveness of a novel Post-Tensioned Metal Strapping (PTMS) technique at enhancing the seismic behavior of a substandard RC building was investigated through full-scale, shake-table tests during the EU-funded project BANDIT. The building had inadequate reinforcement detailing in columns and joints to replicate old construction practices. After the bare building was initially damaged significantly, it was repaired and strengthened with PTMS to perform additional seismic tests. The PTMS technique improved considerably the seismic performance of the tested building. While the bare building experienced critical damage at an earthquake of PGA = 0.15 g, the PTMS-strengthened building sustained a PGA = 0.35 g earthquake without compromising stability.
Taylor & Francis
2014-02-17
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78006/13/WRRO_78006.pdf
Garcia, R., Hajirasouliha, I., Guadagnini, M. et al. (12 more authors) (2014) Full-scale shaking table tests on a substandard RC building repaired and strengthened with post-tensioned metal straps. Journal of Earthquake Engineering, 18 (2). 187 - 213. ISSN 1363-2469
http://dx.doi.org/10.1080/13632469.2013.847874
10.1080/13632469.2013.847874
oai:eprints.whiterose.ac.uk:78007
2017-11-05T23:09:03Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78007/
Bond behaviour of substandard splices in RC beams externally confined with CFRP
Garcia, R.
Helal, Y.
Pilakoutas, K.
Guadagnini, M.
Bond splitting failures of substandard lap-spliced columns have led to collapse of many RC buildings during recent earthquakes in developing countries. The strengthening of lap-spliced regions with CFRP confinement can reduce the seismic vulnerability of such buildings. This paper investigates bond splitting using flexural tests on twelve RC beams with substandard lap splices (25 bar diameters) at midspan. Different confinement configurations (no confinement, internal stirrups or CFRP sheets), concrete covers and bar sizes are examined at the splice region. The results show that light CFRP confinement enhances the splice bond strength by up to 65% compared to unconfined specimens. Predictive equations from the literature are shown to yield a large scatter in results and to overestimate the strain developed in the CFRP confinement. An alternative approach to calculate the confinement strain and the additional bond strength provided by CFRP confinement is proposed and validated.
Elsevier
2014-01-15
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78007/13/WRRO_78007.pdf
Garcia, R., Helal, Y., Pilakoutas, K. et al. (1 more author) (2014) Bond behaviour of substandard splices in RC beams externally confined with CFRP. Construction and Building Materials, 50. 340 - 351. ISSN 0950-0618
http://dx.doi.org/10.1016/j.conbuildmat.2013.09.021
10.1016/j.conbuildmat.2013.09.021
oai:eprints.whiterose.ac.uk:78008
2015-11-03T00:39:25Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78008/
Bond strength of short lap splices in RC beams confined with steel stirrups or external CFRP
Garcia, R.
Helal, Y.
Pilakoutas, K.
Guadagnini, M.
This paper investigates the bond behaviour of lapped steel bars using fifteen RC beams tested in flexure. Twelve of the beams were designed to fail by bond splitting at midspan, where the main flexural reinforcement was lapped 10 bar diameters. The parameters studied include the amount and type of confinement at midspan (no confinement, internal steel stirrups or externally bonded carbon FRP), concrete cover and bar size. The results show that the CFRP confinement enhanced the bond strength of the lapped bars by up to 49 % with reference to unconfined beams, and improved significantly the overall behaviour of the specimens. The experimental results are compared with existing models to predict the bond strength enhancement provided by CFRP confinement. It is shown that existing models overestimate considerably the CFRP strains and show a large scatter when predicting experimental results. Based on the test results, a new approach to predict the bond strength enhancement due to CFRP confinement is proposed. This can be used during the assessment and strengthening of substandard RC constructions. © 2013 RILEM.
Springer
2013
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/78008/7/Bond%20strength%20of%20short%20lap%20splices%20in%20RC%20beams%20confined%20with%20steel%20stirrups%20or%20external%20CFRP.pdf
text
en
https://eprints.whiterose.ac.uk/78008/13/WRR0_78008.pdf
Garcia, R., Helal, Y., Pilakoutas, K. et al. (1 more author) (2013) Bond strength of short lap splices in RC beams confined with steel stirrups or external CFRP. Materials and Structures. Published Online 9th October 2013. 1 - 17. ISSN 1359-5997
http://dx.doi.org/10.1617/s11527-013-0183-5
10.1617/s11527-013-0183-5
oai:eprints.whiterose.ac.uk:78009
2017-03-08T10:49:57Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78009/
Seismic strengthening of severely damaged beam-column RC joints using CFRP
Garcia, R.
Jemaa, Y.
Helal, Y.
Guadagnini, M.
Pilakoutas, K.
This article investigates the seismic behavior of three full-scale exterior reinforced concrete (RC) beam-column joints rehabilitated and strengthened with externally bonded carbon fiber–reinforced polymers (CFRP). The specimens had inadequate detailing in the core zone and replicated joints of a real substandard building tested as part of the EU-funded project BANDIT. Seven tests were performed in two successive phases. The bare joints were first subjected to reversed cyclic loading tests to assess their basic seismic performance. As these initial tests produced severe damage in the core, the damaged concrete was replaced with new high-strength concrete. The specimens were subsequently strengthened with CFRP sheets and the cyclic tests were repeated. The results indicate that the core replacement with new concrete enhanced the shear strength of the substandard joints by up to 44% over the bare counterparts. ASCE guidelines predict accurately the shear strength of the bare and rehabilitated joints. The CFRP strengthening enhanced further the joint strength by up to 69%, achieving a shear strength comparable to that of joints designed according to modern seismic provisions. Therefore, the rehabilitation/strengthening method is very effective for postearthquake strengthening of typical substandard structures of developing countries.
American Society of Civil Engineers
2013-11-26
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78009/7/WRRO_78009.pdf
Garcia, R., Jemaa, Y., Helal, Y. et al. (2 more authors) (2013) Seismic strengthening of severely damaged beam-column RC joints using CFRP. Journal of Composites for Construction, 18 (2). ISSN 1090-0268
http://dx.doi.org/10.1061/(ASCE)CC.1943-5614.0000448
10.1061/(ASCE)CC.1943-5614.0000448
oai:eprints.whiterose.ac.uk:78236
2014-09-15T01:41:04Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78236/
A modelling study of long term green roof retention performance
Stovin, V
Poe, S
Berretta, C
This paper outlines the development of a conceptual hydrological flux model for the long term continuous simulation of runoff and drought risk for green roof systems. A green roof's retention capacity depends upon its physical configuration, but it is also strongly influenced by local climatic controls, including the rainfall characteristics and the restoration of retention capacity associated with evapotranspiration during dry weather periods. The model includes a function that links evapotranspiration rates to substrate moisture content, and is validated against observed runoff data. The model's application to typical extensive green roof configurations is demonstrated with reference to four UK locations characterised by contrasting climatic regimes, using 30-year rainfall time-series inputs at hourly simulation time steps. It is shown that retention performance is dependent upon local climatic conditions. Volumetric retention ranges from 0.19 (cool, wet climate) to 0.59 (warm, dry climate). Per event retention is also considered, and it is demonstrated that retention performance decreases significantly when high return period events are considered in isolation. For example, in Sheffield the median per-event retention is 1.00 (many small events), but the median retention for events exceeding a 1 in 1 yr return period threshold is only 0.10. The simulation tool also provides useful information about the likelihood of drought periods, for which irrigation may be required. A sensitivity study suggests that green roofs with reduced moisture-holding capacity and/or low evapotranspiration rates will tend to offer reduced levels of retention, whilst high moisture-holding capacity and low evapotranspiration rates offer the strongest drought resistance.
Elsevier
2013-12-15
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78236/7/WRRO_78236.pdf
Stovin, V, Poe, S and Berretta, C (2013) A modelling study of long term green roof retention performance. Journal of Environmental Management, 131. 206 - 215.
http://dx.doi.org/10.1016/j.jenvman.2013.09.026
10.1016/j.jenvman.2013.09.026
oai:eprints.whiterose.ac.uk:78237
2018-03-29T01:10:07Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78237/
Configuring maximum entropy deconvolution for the identification of residence time distributions in solute transport applications
Sonnenwald, F.
Stovin, V.R.
Guymer, I.
The advection-dispersion equation (ADE) or aggregated dead zone (ADZ) models and their derivatives are frequently used to describe mixing processes within rivers, channels, pipes, and urban drainage structures. The residence time distribution (RTD) provides a non-parametric model that may describe mixing effects in complex mixing contexts more completely. Identifying an RTD from laboratory data requires deconvolution. Previous studies have successfully applied maximum entropy deconvolution to solute transport data, with RTD sub-sampling used for computational simplification. However, this requires a number of configuration settings which have to date not been rigorously investigated. Four settings are investigated here: the number and distribution of sample points, the constraint function, and the maximum number of iterations. Configuration options for each setting have been systematically assessed with reference to representative solute transport data by comparing the goodness-of-fit of recorded and predicted downstream profiles using the Nash-Sutcliffe Efficiency Index, evaluating RTD smoothness with a measure of entropy, and through consideration of the mass-balance of the RTD. New methods for defining sample point distribution are proposed. The results indicate that goodness-of-fit is most sensitive to constraint function and that smoothness is most sensitive to the number and distribution of sample points. A set of configuration options that includes a new sample point distribution is shown to perform robustly for a representative range of laboratory solute transport data.
ASCE
2013-10-24
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78237/8/WRRO_78237.pdf
Sonnenwald, F., Stovin, V.R. and Guymer, I. (2013) Configuring maximum entropy deconvolution for the identification of residence time distributions in solute transport applications. Journal of Hydrologic Engineering. Oct. 24, 2013. ISSN 1084-0699
http://dx.doi.org/10.1061/(ASCE)HE.1943-5584.0000929
10.1061/(ASCE)HE.1943-5584.0000929
oai:eprints.whiterose.ac.uk:78238
2014-04-23T08:42:32Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78238/
A generic hydrological model for a green roof drainage layer
Vesuviano, G.
Stovin, V.R.
A rainfall simulator of length 5 m and width 1 m was used to supply constant intensity and largely spatially uniform water inflow events to 100 different configurations of commercially available green roof drainage layer and protection mat. The runoff from each inflow event was collected and sampled at one-second intervals. Time-series runoff responses were subsequently produced for each of the tested configurations, using the average response of three repeat tests. Runoff models, based on storage routing (dS/dt = I–Q) and a power-law relationship between storage and runoff (Q = kSn), and incorporating a delay parameter, were created. The parameters k, n and delay were optimized to best fit each of the runoff responses individually. The range and pattern of optimized parameter values was analysed with respect to roof and event configuration. An analysis was performed to determine the sensitivity of the shape of the runoff profile to changes in parameter values. There appears to be potential to consolidate values of n by roof slope and drainage component material.
IWA Publishing
2013-10-01
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/78238/7/WRRO_78238.pdf
Vesuviano, G. and Stovin, V.R. (2013) A generic hydrological model for a green roof drainage layer. Water Science and Technology, 68 (4). 769 - 775. ISSN 0273-1223
http://dx.doi.org/10.2166/wst.2013.294
10.2166/wst.2013.294
oai:eprints.whiterose.ac.uk:78239
2017-04-18T00:24:37Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78239/
Experimental analysis of green roof detention characteristics
Yio, M.N.H.
Stovin, V.R.
Werdin, J.
Vesuviano, G.
Green roofs may make an important contribution to urban stormwater management. Rainfall-runoff models are required to evaluate green roof responses to specific rainfall inputs. The roof's hydrological response is a function of its configuration, with the substrate – or growing media – providing both retention and detention of rainfall. The objective of the research described here is to quantify the detention effects due to green roof substrates, and to propose a suitable hydrological modelling approach. Laboratory results from experimental detention tests on green roof substrates are presented. It is shown that detention increases with substrate depth and as a result of increasing substrate organic content. Model structures based on reservoir routing are evaluated, and it is found that a one-parameter reservoir routing model coupled with a parameter that describes the delay to start of runoff best fits the observed data. Preliminary findings support the hypothesis that the reservoir routing parameter values can be defined from the substrate's physical characteristics.
IWA Publishing
2013-10-01
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/78239/8/WRRO_78239.pdf
Yio, M.N.H., Stovin, V.R., Werdin, J. et al. (1 more author) (2013) Experimental analysis of green roof detention characteristics. Water Science and Technology, 68 (7). 1477 - 1486. ISSN 0273-1223
http://dx.doi.org/10.2166/wst.2013.381
10.2166/wst.2013.381
oai:eprints.whiterose.ac.uk:78240
2014-07-01T00:38:07Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78240/
A practical model to describe temporal variations in total suspended solids concentrations in highway runoff
Stovin, V.R.
Guymer, I.
Techniques to predict temporal variations in concentrations and loads of suspended solids from highway runoff are required to estimate impacts on receiving water ecology and to inform the design of interception/treatment devices. A recent UK study included the collection of rainfall, highway runoff rates and sediment load and quality data from six different sites where motorway runoff drained directly into a receiving watercourse. This data set is used to critically evaluate a previously-published model (Kim et al. 2005) aimed at predicting temporal variations in runoff quality. The comparisons, based on discrete samples collected during 21 storm events, suggest that a simplification of the model, requiring just two parameters, provides a robust estimate of temporal variations in total suspended solids (TSS). Generic parameter values are provided, and the model’s application is illustrated. The model captures first flush effects well, but the identified generic parameters fail to fullypredict the variation in absolute TSS values that are observed in practice.
SP Versita
2013-06
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78240/14/WRRO_78240.pdf
Stovin, V.R. and Guymer, I. (2013) A practical model to describe temporal variations in total suspended solids concentrations in highway runoff. Acta Geophysica, 61 (3). pp. 706-731. ISSN 1895-6572
http://dx.doi.org/10.2478/s11600-013-0101-9
10.2478/s11600-013-0101-9
oai:eprints.whiterose.ac.uk:78241
2017-10-19T21:35:56Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78241/
Absence of a hydraulic threshold in small-diameter surcharged manholes
Stovin, V.
Bennett, P.
Guymer, I.
Previous research into surcharged manholes has highlighted the existence of a threshold surcharge level that separates two distinctly-different hydraulic regimes. Sharp changes in manhole energy loss and solute transport characteristics occur when the surcharge depth passes through the threshold level. With respect to solute transport, two scale-independent cumulative residence time distributions (CRTDs) have been identified, corresponding to the below-threshold and above-threshold hydraulic regimes. However, previous studies focused on large diameter manholes, in which the manhole diameter (Φm) was at least 4.4 times greater than the pipe diameter (Φp). This paper utilizes a validated computational fluid dynamics (CFD) modeling approach to explore the hydraulic behavior and mixing processes in small-diameter surcharged manholes (1.5<Φm/Φp<4.4). It is shown that the hydraulic threshold does not exist in the small diameter manholes; instead, the flow field is characterized by short-circuiting throughout the full range of surcharge depths. Data generated at low surcharge levels suggest that the mixing effects in the below-threshold region are not independent of surcharge level, as had previously been suggested. The absence of the threshold in small-diameter manholes is explained with reference to jet theory. Several previous studies that have characterized mixing and/or energy losses in surcharged manholes are revisited, allowing findings to be generalized across a broader range of manhole configurations, including effects attributable to benching and change in outlet angle.
American Society of Civil Engineers
2013-09-01
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/78241/7/WRRO_78241.pdf
Stovin, V., Bennett, P. and Guymer, I. (2013) Absence of a hydraulic threshold in small-diameter surcharged manholes. Journal of Hydraulic Engineering, 139 (9). 984 - 994. ISSN 0733-9429
http://dx.doi.org/10.1061/(ASCE)HY.1943-7900.0000758
10.1061/(ASCE)HY.1943-7900.0000758
oai:eprints.whiterose.ac.uk:78242
2014-04-16T14:23:28Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78242/
The potential to retrofit sustainable drainage systems to address combined sewer overflow discharges in the Thames Tideway catchment
Stovin, V.R.
Moore, S.L.
Wall, M.
Ashley, R.M.
Experience of retrofitting sustainable drainage systems (SuDS) in the United Kingdom is limited, and there are no well-established procedures for evaluating the feasibility, value or cost-effectiveness of doing this, particularly at the catchment scale. This paper demonstrates a two-phase process for evaluating the potential to retrofit SuDS to address combined sewer discharges in three subcatchments within the Thames Tideway catchment of London. The first phase evaluates what might be achieved with various levels of disconnection (‘global’ disconnection scenarios) using hydraulic models, while the second phase considers how disconnection might practically be achieved. High levels of disconnection are technically possible but practicably difficult. In selected cases, and with aggressive implementation of SuDS, combined sewer overflow CSO discharges could potentially be eliminated or reduced to acceptable levels without the need for any modifications to underground assets. However, retrofit SuDS could not eliminate the requirement for some form of sewer modification in any subcatchments.
John Wiley & Sons
2013-06
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78242/8/WRRO_78242.pdf
Stovin, V.R., Moore, S.L., Wall, M. et al. (1 more author) (2013) The potential to retrofit sustainable drainage systems to address combined sewer overflow discharges in the Thames Tideway catchment. Water and Environment Journal, 27 (2). 216 - 228. ISSN 1747-6585
http://dx.doi.org/10.1111/j.1747-6593.2012.00353.x
10.1111/j.1747-6593.2012.00353.x
oai:eprints.whiterose.ac.uk:78295
2017-11-01T01:50:35Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78295/
The Negative Phase of the Blast Load
Rigby, S.E.
Tyas, A.
Bennett, T.
Clarke, S.D.
Fay, S.D.
Following the positive phase of a blast comes a period where the pressure falls below atmospheric pressure known as the negative phase. Whilst the positive phase of the blast is well understood, validation of the negative phase is rare in the literature, and as such it is often incorrectly treated or neglected altogether. Herein, existing methods of approximating the negative phase are summarised and recommendations of which form to use are made based on experimental validation. Also, through numerical simulations, the impact of incorrectly modelling the negative phase has been shown and its implications discussed.
Multi-Science Publishing
2014-03-26
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78295/8/Rigby%20et%20al.%20-%202014%20-%20The%20Negative%20Phase%20of%20the%20Blast%20Load.pdf
Rigby, S.E., Tyas, A., Bennett, T. et al. (2 more authors) (2014) The Negative Phase of the Blast Load. International Journal of Protective Structures, 5 (1). 1 -20. ISSN 2041-4196
http://dx.doi.org/10.1260/2041-4196.5.1.1
10.1260/2041-4196.5.1.1
oai:eprints.whiterose.ac.uk:78408
2018-03-29T03:00:55Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78408/
The influence of migrating bed forms on the velocity-intermittency structure of turbulent flow over a gravel bed.
Keylock, C.J.
Singh, A.L.
Foufoula-Georgiou, E.
Modeling turbulent flows at high Reynolds number requires solving simplified variants of the Navier-Stokes equations. The methods used to close the resulting Reynolds-averaged, or eddy simulation equations usually follow classical theory and, at small enough scales, postulate universal scaling for turbulence that is independent of the velocity itself. This may not be the best way to conceptualize geophysical turbulence. Turbulent intermittency may be defined in terms of the local “roughness” of the velocity signal as measured by pointwise Hölder exponents. This study investigates the joint velocity-intermittency structure of flow over a gravel-bed surface with migrating bed forms. We report clear velocity-intermittency dependence and quantify its nature above the moving bed form profile. Our results imply differences in energy transfer close to bed forms at shorter wavelengths than those forced directly. Hence, progress in modeling flows of geophysical relevance may require a reconsideration of the principles on which turbulence closures are based.
American Geophysical Union
2013-04-16
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/78408/1/GRL50337_published.pdf
Keylock, C.J., Singh, A.L. and Foufoula-Georgiou, E. (2013) The influence of migrating bed forms on the velocity-intermittency structure of turbulent flow over a gravel bed. Geophysical Research Letters, 40 (7). pp. 1351-1355.
http://dx.doi.org/10.1002/grl.50337
http://dx.doi.org/10.1002/grl.50337
oai:eprints.whiterose.ac.uk:78409
2018-03-28T11:34:06Z
7374617475733D707562
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78409/
High resolution radar measurements of snow avalanches
Vriend, N.M.
McElwaine, J.N.
Sovilla, B.
Keylock, C.J.
Ash, M.
Brennan, P.V.
Two snow avalanches that occurred in the winter 2010–2011 at Vallée de la Sionne, Switzerland, are studied using a new phased array FMCW radar system with unprecedented spatial resolution. The 5.3 GHz radar penetrates through the powder cloud and reflects off the underlying denser core. Data are recorded at 50 Hz and have a range resolution better than 1 m over the entire avalanche track. We are able to demonstrate good agreement between the radar results and existing measurement systems that record at particular points on the avalanche track. The radar data reveal a wealth of structure in the avalanche and allow the tracking of individual fronts and surges down the slope for the first time.
American Geophysical Union
2013-02-28
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/78409/1/GRL50134.pdf
Vriend, N.M., McElwaine, J.N., Sovilla, B. et al. (3 more authors) (2013) High resolution radar measurements of snow avalanches. Geophysical Research Letters, 40 (4). pp. 727-731.
http://dx.doi.org/10.1002/grl.50134/
http://dx.doi.org/10.1002/grl.50134
oai:eprints.whiterose.ac.uk:78410
2018-03-29T03:01:13Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78410/
Temporal trends in avalanche activity in the French Alps and subregions: from occurrences and runout altitudes to unsteady return periods.
Eckert, N.
Keylock, C.J.
Castebrunet, H.
Lavigne, A.
Naaim, M.
We present an analysis of temporal trends in ∼55 000 avalanches recorded between 1946 and 2010 in the French Alps and two north/south subregions. First, Bayesian hierarchical modelling is used to isolate low-, intermediate- and high-frequency trends in the mean avalanche occurrence and runout altitude per year/winter. Variables are then combined to investigate their correlation and the recent evolution of large avalanches. Comparisons are also made to climatic and flow regime covariates. The results are important for risk assessment, and the development of new high-altitude climate proxies. At the entire French Alps scale, a major change-point exists in ∼1978 at the heart of a 10 year period of high occurrences and low runout altitudes corresponding to colder and snowier winters. The differences between this change-point and the beginning/end of the study period are 0.1 avalanche occurrences per winter and per path and 55 m in runout altitude. Trends before/after are well correlated, leading to enhanced minimal altitudes for large avalanches at this time. A marked upslope retreat (80 m for the 10 year return period runout altitude) accompanied by a 12% decrease in the proportion of powder snow avalanches has occurred since then, interrupted from about 2000. The snow-depth and temperature control on these patterns seems significant (R = 0.4–0.6), but is stronger at high frequencies for occurrences, and at lower frequencies for runout altitudes. Occurrences between the northern and southern French Alps are partially coupled (R∼0.4, higher at low frequencies). In the north, the main change-point was an earlier shift in ∼1977, and winter snow depth seems to be the main control parameter. In the south, the main change-point occurred later, ∼1979–84, was more gradual, and trends are more strongly correlated with winter temperature.
International Glaciological Society
2013-03
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/78410/1/j12J091_paper.pdf
Eckert, N., Keylock, C.J., Castebrunet, H. et al. (2 more authors) (2013) Temporal trends in avalanche activity in the French Alps and subregions: from occurrences and runout altitudes to unsteady return periods. Journal of Glaciology, 59 (213). 93 - 114. ISSN 0022-1430
http://dx.doi.org/10.3189/2013JoG12J091
http://dx.doi.org/10.3189/2013JoG12J091
oai:eprints.whiterose.ac.uk:78411
2018-03-29T03:00:17Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78411/
A classification scheme for turbulence based on the velocity-intermittency structure with an application to near-wall flow and with implications for bedload transport
Keylock, CJ
Nishimura, K
Peinke, J
Kolmogorov's classic theory for turbulence assumed an independence between velocity increments and the value for the velocity itself. However, recent work has called this assumption in to question, which has implications for the structure of atmospheric, oceanic and fluvial flows. Here we propose a conceptually simple analytical framework for studying velocity-intermittency coupling that is similar in essence to the popular quadrant analysis method for studying near-wall flows. However, we study the dominant (longitudinal) velocity component along with a measure of the roughness of the signal, given mathematically by its series of Hölder exponents. Thus, we permit a possible dependence between velocity and intermittency. We compare boundary layer data obtained in a wind tunnel to turbulent jets and wake flows. These flow classes all have distinct characteristics, which cause them to be readily distinguished using our technique and the results are robust to changes in flow Reynolds numbers. Classification of environmental flows is then possible based on their similarities to the idealized flow classes and we demonstrate this using laboratory data for flow in a parallel-channel confluence. Our results have clear implications for sediment transport in a range of geophysical applications as they suggest that the recently proposed impulse-based methods for studying bed load transport are particularly relevant in domains such as gravel bed river flows where the boundary layer is disrupted and wake interactions predominate.
American Geophysical Union
2012-03
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/78411/1/JGR%202012%20published%20version.pdf
Keylock, CJ, Nishimura, K and Peinke, J (2012) A classification scheme for turbulence based on the velocity-intermittency structure with an application to near-wall flow and with implications for bedload transport. Journal of Geophysical Research, 117 (F1).
http://dx.doi.org/10.1029/2011JF002127
http://dx.doi.org/10.1029/2011JF002127
oai:eprints.whiterose.ac.uk:78412
2017-08-17T05:12:17Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78412/
The application of computational fluid dynamics to natural river channels: Eddy resolving versus mean flow approaches
Keylock, C.J.
Constantinescu, G.
Hardy, R.J.
In the last decade, as computing power has increased, there has been an explosion in the use of eddy-resolving numerical methods in the engineering, earth and environmental sciences. For complex geomorphic flows, where accurate field investigations are difficult to perform and where experiments may be difficult to scale, these numerical approaches are beginning to give key insights into the nature of these flows. Eddy-resolving methods such as Large and Detached Eddy Simulation (LES/DES) may be contrasted with the time-averaged, three-dimensional simulations that only really began to be applied seriously in geomorphology fifteen years ago. While the potential of LES for geomorphology has been examined previously, DES is a relatively recent method that deserves further consideration. In this paper, we explain the method and then utilise examples from meander and confluence flows, as well as flow near the bed of a gravel bed river, to highlight the improvements to both the representation of the mean flow, and to the representation of time-varying processes, that result from the use of LES/DES. Some suggestions are provided for the future use of such techniques in geomorphology.
Elsevier
2012-12-15
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78412/7/WRRO_78412.pdf
Keylock, C.J., Constantinescu, G. and Hardy, R.J. (2012) The application of computational fluid dynamics to natural river channels: Eddy resolving versus mean flow approaches. Geomorphology, 179. 1 - 20. ISSN 0169-555X
http://dx.doi.org/10.1016/j.geomorph.2012.09.006
10.1016/j.geomorph.2012.09.006
oai:eprints.whiterose.ac.uk:78413
2017-04-11T05:23:47Z
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https://eprints.whiterose.ac.uk/78413/
The flow structure in the wake of a fractal fence and the absence of an "inertial regime"
Keylock, C.J.
Nishimura, K.
Nemoto, M.
Ito, Y.
Recent theoretical work has highlighted the importance of multi-scale forcing of the flow for altering the nature of turbulence energy transfer and dissipation. In particular, fractal types of forcing have been studied. This is potentially of real significance in environmental fluid mechanics where multi-scale forcing is perhaps more common than the excitation of a specific mode. In this paper we report the first results studying the detail of the wake structure behind fences in a boundary layer where, for a constant porosity, we vary the average spacing of the struts and also introduce fractal fences. As expected, to first order, and in the far-wake region, in particular, the response of the fences is governed by their porosity. However, we show that there are some significant differences in the detail of the turbulent structure between the fractal and non-fractal fences and that these override differences in porosity. In the near wake, the structure of the fence dominates porosity effects and a modified wake interaction length seems to have potential for collapsing the data. With regards to the intermittency of the velocities, the fractal fences behave more similarly to homogeneous, isotropic turbulence. In addition, there is a high amount of dissipation for the fractal fences over scales that, based on the energy spectrum, should be dominated by inter-scale transfers. This latter result is consistent with numerical simulations of flow forced at multiple scales and shows that what appears to be an “inertial regime” cannot be as production and dissipation are both high.
Springer
2012-06
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78413/7/WRRO_78413.pdf
Keylock, C.J., Nishimura, K., Nemoto, M. et al. (1 more author) (2012) The flow structure in the wake of a fractal fence and the absence of an "inertial regime". Environmental Fluid Mechanics, 12 (3). 227 - 250. ISSN 1567-7419
http://dx.doi.org/10.1007/s10652-011-9233-0
10.1007/s10652-011-9233-0
oai:eprints.whiterose.ac.uk:78520
2014-04-24T12:51:09Z
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https://eprints.whiterose.ac.uk/78520/
Robust classification for the joint velocity-intermittency structure of turbulent flow over fixed and mobile bedforms
Keylock, CJ
Singh, A
Foufoula-Georgiou, E
Venditti, JG
Two datasets of turbulence velocities collected over different bedform types under contrasting experimental conditions show similarity in terms of velocity-intermittency characteristics and suggest a universality to the velocity-intermittency structure for flow over bedforms. One dataset was obtained by sampling flow over static bedforms in different locations, and the other was based on a static position but mobile bedforms. A flow classification based on the velocity-intermittency behaviour is shown to reveal some differences from that based on an analysis of Reynolds stresses, boundary layer correlation and turbulent kinetic energy. This may be attributed to the intermittency variable, which captures the local effect of individual turbulent flow structures. Locations in the wake region or the outer layer of the flow are both shown to have a velocity-intermittency behaviour that departs from that for idealized wakes or outer layer flow because of the superposition of localized flow structures generated by bedforms. The combined effect of this yields a velocity-intermittency structure unique to bedform flow. The use of a time series of a single velocity component highlights the potential power of our approach for field, numerical and laboratory studies. The further validation of the velocity-intermittency method for non-idealized flows undertaken here suggests that this technique can be used for flow classification purposes in geomorphology, hydraulics, meteorology and environmental fluid mechanics. © 2014 The Authors.
Wiley
2014-03-26
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78520/1/Robust_Classification.pdf
Keylock, CJ, Singh, A, Foufoula-Georgiou, E et al. (1 more author) (2014) Robust classification for the joint velocity-intermittency structure of turbulent flow over fixed and mobile bedforms. Earth Surface Processes and Landforms. ISSN 0197-9337
http://dx.doi.org/10.1002/esp.3550
10.1002/esp.3550
oai:eprints.whiterose.ac.uk:78697
2014-04-25T14:32:26Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78697/
Real-Time Gamma Imaging of Technetium Transport through Natural and Engineered Porous Materials for Radioactive Waste Disposal
Corkhill, CL
Bridge, JW
Chen, XC
Hillel, P
Thornton, SF
Romero-Gonzalez, ME
Banwart, SA
Hyatt, NC
American Chemical Society
2013-12-03
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78697/1/Realtime_Gamma.pdf
Corkhill, CL, Bridge, JW, Chen, XC et al. (5 more authors) (2013) Real-Time Gamma Imaging of Technetium Transport through Natural and Engineered Porous Materials for Radioactive Waste Disposal. ENVIRONMENTAL SCIENCE & TECHNOLOGY, 47 (23). 13857 - 13864. ISSN 0013-936X
http://dx.doi.org/10.1021/es402718j
10.1021/es402718j
oai:eprints.whiterose.ac.uk:78702
2014-07-01T11:01:20Z
7374617475733D707562
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https://eprints.whiterose.ac.uk/78702/
Identification of rotational failure mechanisms in cohesive media using discontinuity layout optimization
Smith, C.C.
Gilbert, M.
Discontinuity layout optimisation (DLO) is a generally applicable numerical limit analysis procedure that can be used to identify critical plastic collapse mechanisms in geotechnical problems. Previous research has focused on using plane-strain DLO to identify mechanisms that are purely translational, or which involve rotations only along predefined boundaries. In this paper a more general formulation, capable of identifying mechanisms that can involve arbitrary rotations and/or translations in cohesive media, is presented. The formulation is then verified through investigation of the yield surface and evolution of the collapse mechanism associated with a footing under combined vertical and moment (V, M) loading, and through study of the well-known anchor uplift problem. It is shown that results of very high accuracy can be obtained, in terms of the collapse load and of the predicted failure mechanism. In the light of the new results, the Bransby design formula for combined vertical and moment loading has been modified to improve its accuracy. Additionally, the more general DLO formulation presented is shown to have several inherent advantages compared with existing numerical limit analysis approaches.
ICE Publishing
2013-07
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78702/1/smith_gilbert_2013.pdf
Smith, C.C. and Gilbert, M. (2013) Identification of rotational failure mechanisms in cohesive media using discontinuity layout optimization. Geotechnique: International Journal of Soil Mechanics, 63 (14). 1194 - 1208. ISSN 0016-8505
http://dx.doi.org/10.1680/geot.12.P.082
10.1680/geot.12.P.082
oai:eprints.whiterose.ac.uk:78780
2014-05-09T12:43:56Z
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https://eprints.whiterose.ac.uk/78780/
Application of discontinuity layout optimization to three-dimensional plasticity problems
Hawksbee, S
Smith, C.C
Gilbert, M
A new three-dimensional limit analysis formulation that uses the recently developed discontinuity layout optimization (DLO) procedure is described. With DLO, limit analysis problems are formulated purely in terms of discontinuities, which take the form of polygons when three-dimensional problems are involved. Efficient second-order cone programming techniques can be used to obtain solutions for problems involving Tresca and Mohr–Coulomb yield criteria. This allows traditional ‘upper bound’ translational collapse mechanisms to be identified automatically. A number of simple benchmark problems are considered, demonstrating that good results can be obtained even when coarse numerical discretizations are employed.
ROYAL SOCIETY
2013-04-24
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78780/1/WRRO_78780.pdf
Hawksbee, S, Smith, C.C and Gilbert, M (2013) Application of discontinuity layout optimization to three-dimensional plasticity problems. Proceedings Royal Society A, 469 (2155). 20130009. ISSN 1364-5021
http://dx.doi.org/10.1098/rspa.2013.0009
10.1098/rspa.2013.0009
oai:eprints.whiterose.ac.uk:78781
2018-03-24T23:28:59Z
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78781/
Influence of backfill on the capacity of masonry arch bridges
Callaway, P.
Gilbert, M.
Smith, C.C.
The influence of the presence of backfill on the load-carrying capacity of a masonry arch bridge can be considerable. The backfill is responsible for transmitting and distributing live loads from the road or rail surface through to the arch barrel and also for laterally stabilising the arch barrel as it sways under load. However, it can be difficult to separate these two distinct effects, and hence also difficult to ascertain whether existing assessment code recommendations are realistic. To address this, a series of experiments designed to separate these two effects have been performed. A total of 27 small-scale bridge tests were undertaken and the experimentally obtained peak loads then compared with results from limit analysis software of varying complexity. It was confirmed that passive restraint and live load distribution both contribute significantly to bridge-carrying capacity, and that, when failure involves a four-hinge failure mechanism, even comparatively simple limit analysis software can model the various effects remarkably well.
ICE Publishing
2012-09-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78781/1/Callaway_et_al_2012.pdf
Callaway, P., Gilbert, M. and Smith, C.C. (2012) Influence of backfill on the capacity of masonry arch bridges. Proceedings of the Institution of Civil Engineers: Bridge Engineering, 165 (3). 147 - 157. ISSN 1478-4637
http://dx.doi.org/10.1680/bren.11.00038
10.1680/bren.11.00038
oai:eprints.whiterose.ac.uk:78782
2017-08-25T13:34:30Z
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https://eprints.whiterose.ac.uk/78782/
A locking-free stabilized kinematic EFG model for plane strain limit analysis
Le, C.V.
Askes, H.
Gilbert, M.
An element free Galerkin (EFG) based formulation for limit analysis of rigid-perfectly plastic plane strain problems is presented. In the paper it is demonstrated that volumetric locking and instability problems can be avoided by using a stabilized conforming nodal integration scheme. Furthermore, the stabilized EFG method described allows stable and accurate solutions to be obtained with minimal computational effort. The discrete kinematic formulation is cast in the form of a second-order cone problem, allowing efficient interior-point solvers to be used to obtain solutions. Finally, the performance of the stabilized EFG method is illustrated by considering several numerical examples.
Elsevier
2012-09
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/78782/7/WRRO_78782.pdf
Le, C.V., Askes, H. and Gilbert, M. (2012) A locking-free stabilized kinematic EFG model for plane strain limit analysis. Computers and Structures, 106. 1 - 8. ISSN 0045-7949
http://dx.doi.org/10.1016/j.compstruc.2012.03.012
10.1016/j.compstruc.2012.03.012
oai:eprints.whiterose.ac.uk:78783
2016-11-16T06:27:26Z
7374617475733D707562
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https://eprints.whiterose.ac.uk/78783/
Potential use of structural layout optimization at the conceptual design stage
Park, P.
Gilbert, M.
Tyas, A.
Popovic-Larsen, O.
Despite recent developments in computer-aided design in architecture, both in terms of form generation techniques and performance-based design tools, there still appears to be polarization between the 'visual' and the 'technical' elements of design. Two causes of this are discussed: long-standing tradition within the discipline and perception of design as primarily a visual exercise. Structural layout optimization is a technique which enables automatic identification of optimal arrangements of structural elements in frames. As the technique appears to have the potential to help reduce the polarization between the visual and the technical elements of design, it can be considered as an 'integrative' form generation tool. Applications of the technique are considered via three design examples, demonstrating both its potential and areas where refinement is required before it is suitable for application in practice.
Multi-Sciences Publishing
2012-03-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78783/11/fulltext.pdf
Park, P., Gilbert, M., Tyas, A. et al. (1 more author) (2012) Potential use of structural layout optimization at the conceptual design stage. International Journal of Architectural Computing, 10 (1). 13 - 32. ISSN 1478-0771
http://dx.doi.org/10.1260/1478-0771.10.1.13
10.1260/1478-0771.10.1.13
oai:eprints.whiterose.ac.uk:78784
2016-11-04T02:18:54Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
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https://eprints.whiterose.ac.uk/78784/
On the optimality of Hemp’s arch with vertical hangers
Pichugin, A.V.
Tyas, A.
Gilbert, M.
In 1974 W. S. Hemp constructed a prototype structure to carry a uniformly distributed load between two pinned supports. Although Hemp’s structure had a significantly lower volume than a parabolic arch with vertical hangers, it was shown to fail the Michell optimality criteria, and therefore to be non-optimal. In this paper we demonstrate that if limiting compressive and tensile stresses are unequal then Hemp’s structure is optimal for the half-plane provided the ratio of limiting tensile to compressive stresses falls below a certain threshold. An analytical proof is presented and the finding is confirmed by results from large scale numerical layout optimization simulations.
Springer
.
2012-07
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78784/11/WRRO_78784.pdf
Pichugin, A.V., Tyas, A. and Gilbert, M. (2012) On the optimality of Hemp’s arch with vertical hangers. Structural and Multidisciplinary Optimization, 46 (1). 17 - 25. ISSN 1615-147X
http://dx.doi.org/10.1007/s00158-012-0769-5
10.1007/s00158-012-0769-5
oai:eprints.whiterose.ac.uk:78869
2014-05-08T13:52:42Z
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https://eprints.whiterose.ac.uk/78869/
Integrated modelling for Sustainability Appraisal of urban river corridors: Going beyond compartmentalised thinking
Kumar, V
Rouquette, J.R
Lerner, D.N
Elsevier
2013-12-15
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78869/1/WRRO_78869.pdf
Kumar, V, Rouquette, J.R and Lerner, D.N (2013) Integrated modelling for Sustainability Appraisal of urban river corridors: Going beyond compartmentalised thinking. Water Research, 47 (20). 7221 - 7234. ISSN 0043-1354
http://dx.doi.org/10.1016/j.watres.2013.10.034
10.1016/j.watres.2013.10.034
oai:eprints.whiterose.ac.uk:78884
2014-05-08T15:17:41Z
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https://eprints.whiterose.ac.uk/78884/
The bacteriological composition of biomass recovered by flushing an operational drinking water distribution system.
Douterelo, I
Husband, S
Boxall, J.B
This study investigates the influence of pipe characteristics on the bacteriological composition of material mobilised from a drinking water distribution system (DWDS) and the impact of biofilm removal on water quality. Hydrants in a single UK Distribution Management Area (DMA) with both polyethylene and cast iron pipe sections were subjected to incremental increases in flow to mobilise material from the pipe walls. Turbidity was monitored during these operations and water samples were collected for physico-chemical and bacteriological analysis. DNA was extracted from the material mobilised into the bulk water before and during flushing. Bacterial tag-encoded 454 pyrosequencing was then used to characterize the bacterial communities present in this material. Turbidity values were high in the samples from cast iron pipes. Iron, aluminium, manganese and phosphate concentrations were found to correlate to observed turbidity. The bacterial community composition of the material mobilised from the pipes was significantly different between plastic and cast iron pipe sections (p < 0.5). High relative abundances of Alphaproteobacteria (23.3%), Clostridia (10.3%) and Actinobacteria (10.3%) were detected in the material removed from plastic pipes. Sequences related to Alphaproteobacteria (22.8%), Bacilli (16.6%), and Gammaproteobacteria (1.4%) were predominant in the samples obtained from cast iron pipes. The highest species richness and diversity were found in the samples from material mobilised from plastic pipes. Spirochaeta spp., Methylobacterium spp. Clostridium spp. and Desulfobacterium spp., were the most represented genera in the material obtained prior to and during the flushing of the plastic pipes. In cast iron pipes a high relative abundance of bacteria able to utilise different iron and manganese compounds were found such as Lysinibacillus spp., Geobacillus spp. and Magnetobacterium spp.
Elsevier
2014-02-05
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/78884/1/WRRO_78884.pdf
Douterelo, I, Husband, S and Boxall, J.B (2014) The bacteriological composition of biomass recovered by flushing an operational drinking water distribution system. Water Research, 54C. 100 - 114.
http://dx.doi.org/10.1016/j.watres.2014.01.049
10.1016/j.watres.2014.01.049
oai:eprints.whiterose.ac.uk:79209
2018-03-29T02:18:42Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/79209/
Experiments on reverse-channel connections at elevated temperatures
Huang, S.S.
Davison, B.
Burgess, I.W.
This paper reports on an experimental investigation of the behaviour of reverse-channel connections between steel beams and concrete-filled tubular (CFT) columns in fire conditions. The objectives of the tests were to assess the behaviour of beam-to-column connections subject to the combinations of significant tying and shear forces and large rotations, which can arise during a building fire, and to provide test data to characterise and validate simplified temperature-dependent component-based connection models. It has been found that the reverse-channel connections not only provide a practical solution for connecting steel beams to composite columns but they also possess high ductility and strength. Such high ductility allows greater beam deformations in fire while reducing the magnitudes of the induced axial forces, thereby enhancing the fire resistance of the connections without requiring them to be stronger.
Elsevier
2013-04
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/79209/9/WRRO_79209.pdf
Huang, S.S., Davison, B. and Burgess, I.W. (2013) Experiments on reverse-channel connections at elevated temperatures. Engineering Structures, 49. 973 - 982. ISSN 0141-0296
http://dx.doi.org/10.1016/j.engstruct.2012.12.025
http://dx.doi.org/10.1016/j.engstruct.2012.12.025
oai:eprints.whiterose.ac.uk:79210
2018-03-27T03:02:09Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
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https://eprints.whiterose.ac.uk/79210/
A structural fire engineering prediction for the Veselí fire tests, 2011
Huang, S-S.
Burgess, I.W.
Davison, B.
Fire hazards and full-scale structural tests have provided evidence that the beam-column connections of building frames are the weakest structural elements, which are vulnerable to fracture in fire. Connection fractures may lead to extensive damage or even progressive collapse. However, current design methods for connections are solely based on ambient-temperature behaviour, the additional forces and rotations generated in fire are not taken into account. The Structural Fire Engineering Research Group of the University of Sheffield is involved in a European-collaborative project which concerns the behaviour and robustness in fire of practical connections to composite columns. This includes two natural fire tests in a full-scale composite structure in Veselí, the Czech Republic. The Sheffield team was responsible for predicting the structural behaviour in the tests before they were conducted. This assessment was conducted using the specialist structural fire engineering FEA program Vulcan. This paper reports the results of this predictive analysis.
Multi Science Publishing
2013-03-01
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/79210/1/SSH3.pdf
Huang, S-S., Burgess, I.W. and Davison, B. (2013) A structural fire engineering prediction for the Veselí fire tests, 2011. Journal of Structural Fire Engineering, 4 (1). 1 - 8. ISSN 2040-2317
http://dx.doi.org/10.1260/2040-2317.4.1.1
http://dx.doi.org/10.1260/2040-2317.4.1.1
oai:eprints.whiterose.ac.uk:79211
2018-03-20T11:02:36Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
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https://eprints.whiterose.ac.uk/79211/
High-temperature tests on joints to steel and partially-encased H-section columns
Huang, S-S.
Davison, B.
Burgess, I.W.
This paper reports on a series of tests at elevated temperatures on connections between steel beams and H-section columns, both unfilled and partially-concrete-encased. Reverse-channel connections to both types of column, as well as flush endplate connections to partially-encased H-section columns, were studied. The experiments aimed to investigate the behaviour of beam-to-column connections subject to significant tying forces and large rotations in fire situations, and to provide test data for development and validation of simplified component-based connection models. It has been found that reverse-channel connections provide not only high strength, but also the high ductility which is required to reduce the possibility of connection fracture and to improve the robustness of buildings in fire.
Elsevier
2013-01
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/79211/8/WRRO_79211.pdf
Huang, S-S., Davison, B. and Burgess, I.W. (2013) High-temperature tests on joints to steel and partially-encased H-section columns. Journal of Constructional Steel Research, 80. 243 - 251.
http://dx.doi.org/10.1016/j.jcsr.2012.09.006
http://dx.doi.org/10.1016/j.jcsr.2012.09.006
oai:eprints.whiterose.ac.uk:79212
2018-03-29T01:38:17Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/79212/
Effect of transient strain on strength of concrete and CFT columns in fire – Part 1: Elevated-temperature analysis on a Shanley-like column model
Huang, S.
Burgess, I.W.
This paper presents elevated-temperature analysis on a Shanley-like column model, as part of a study on the effect of transient strain on the strength of concrete and concrete-filled tubular columns in fire. Three high-temperature concrete material models are applied and the structural behaviours of the Shanley-like model using these three material models are compared. The effects of transient strain of concrete have been investigated by comparing the results of the analyses with and without considering this property, under the assumption that the temperature distribution within the model is uniform. The model has been evaluated against the tangent-modulus and reduced-modulus critical buckling loads at elevated temperatures. Numerical analyses have been carried out under both steady-state and transient heating scenarios, in order to investigate the influence of each on high-temperature structural analysis of the type described in this paper. It is seen that considering transient strain causes a considerable reduction of the buckling resistance, irrespective of the concrete material models and loading–heating schemes used.
Elsevier
2012-11
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/79212/9/WRRO_79212.pdf
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