Experimental Investigation of Seismic Vulnerability of Braces under Hazard Consistent loading sequences

Abstract

In the last ten years, Chile and Japan have experienced several subduction earthquakes that lasted for extended periods of time. These occurrences have emphasized the need for a thorough examination of how the duration of ground motion impacts the performance of the components of the lateral load resisting system. In the present study, three large‐scale experiments were conducted on the wide‐flange brace member to evaluate the seismic vulnerability of the braces under the hazard consistent loading protocol. The loading sequences consider in the study are standard symmetric cyclic loading sequences, collapse‐consistent loading sequences representing subduction zone tension dominated and collapse‐consistent loading sequences representing subduction zone compression dominated. The subassemblage test‐set‐up was taken in the study to consider the effect of the end‐protect zone on the seismic assessments of the brace members. The evolution of strain at the mid‐section of the brace member is observed to be higher in case of the standard loading sequences as compared to the subduction zone loading sequences. The post yielding stiffness and the collapse resistance of the brace member under the subduction zone earthquake are present. The damage state of the open section brace member and evolution of the local bucking at the mid of the brace member were discussed. It is observed that open section delays the accumulation of strain at brace member and delay the fracture initiation. The ductility of the different brace members is compared to highlight the influence of the cross‐section properties of the brace on the ductility of the braced system.