Component-Based Element of Beam Local Buckling Adjacent to Connections in Fire

An analytical model based on the yield line mechanism [1] has been proposed by the authors to predict the beam-web shear buckling and bottom-flange buckling in fire. This paper described the development of a component-based element considering both buckling phenomena at the beam-ends, based on this analytical model. The component-based buckling element consists of top springs and bottom springs, all of which are capable of dealing with loading-unloading-reloading cycles. This new component-based element has been implemented into the software Vulcan, adjacent to the existing component-based connection element. An example case using a single-span beam has been analysed in Vulcan. The modelling results have been validated against finite element modelling using ABAQUS, indicating that the newly developed component-based buckling element is of good accuracy to reflect the behaviour of local buckling phenomena. Comparison of the structural responses of the beams with and without the buckling element in Vulcan has been carried out. This comparison shows that with and without the buckling element does make a difference in the modelling results. This indicates the potential effects of the local buckling at beam ends on the connected joints and columns and on the entire frames at elevated temperatures.