Non-linear Analysis of Multi-hazard Performance of Cylindrical Concrete Filled Steel Tubes Bridge Piers

Advanced finite element techniques are used to investigate the multi-hazard (earthquake and blast) performance of Concrete-Filled Steel Tubes (CFSTs) and Concrete Filled Double Skinned Tubes (CFDSTs) for bridge engineering applications. Specimens of both sections are analyzed using the finite element package LS-DYNA under similar seismic and blast loading. First, behavior of CFSTs recorded in seismic and blast tests are reproduced using the finite element program and compared to experimental results for accuracy and adequacy, then the techniques developed for this analysis are carried over to the modeling and analysis of CFDSTs. LS-DYNA captured generally well the behavior of CFSTs in both hazards, particularly the non-cyclic inelastic behavior under blast loads. Although the techniques used for the seismic analysis can be refined, the main features established experimentally are present. Also it is proven here that CFDSTs can develop their full strength over longer yield plateau than their CFSTs counterparts. Together, these two composite systems constitute valuable alternatives to conventional column piers of bridges that need be designed for multiple hazards.