Derivation of dynamic properties of steel perforated ultra shallow floor beams (USFB) via finite element modal analysis and experimental verification

In recent years, the incorporation of asymmetric perforated ultra shallow floor beams (USFBs) constructed from advanced UB and UC profile beams in various composite floor systems has been extensively considered in practice. To date, limited research effort has been devoted to the detailed investigation of the dynamic properties of USFBs. In this paper, modal analyses of detailed FE models of various USFBs commonly used in composite floor systems developed in ANSYS are conducted to extract their dynamical properties (i.e. natural frequencies and mode shapes). Furthermore, experimental data pertaining to the standard impact test is also considered to validate the accuracy of the aforementioned FE results. In particular, a six meter long USFB beam is subject to impulsive excitation by means of an appropriately instrumented hammer. The dynamic properties obtained by processing the recorded response signals compare well vis-a-vis the corresponding results from the FE modal analysis. Finally, effective properties of USFBs which can be readily used in the definition of beam elements of constant cross-section along their longitudinal direction are derived. This constitutes an important step to facilitate the analysis and design of USFBs against dynamic loads at the serviceability limit state using standard commercial structural analysis software.