11.36: Influence of type of loading protocols and restraining parameters on cyclic response of steel BRB: Fid-Bau Portal

11.36: Influence of type of loading protocols and restraining parameters on cyclic response of steel BRB

Ghowsi, Ahmad Fayeq / Sahoo, Dipti Ranjan

Buckling‐restrained braces (BRBs) are the special type of braces capable of yielding in both tension and compression under axial loading. These BRBs provide the nearly symmetrical hysteretic response and the higher energy dissipation potential as compared to the conventional steel braces. However, the use of relatively slender core plates in BRBs results in the smaller elastic and post‐elastic axial stiffness and the possibility of end plate rotation at the transition zone resulting in the unexpected premature damages. One of the possible way to change the stiffness of BRBs is to change the yielding core slenderness ratio to an acceptable limit. The range of reduction of yielding core ratio of BRBs depends on the required magnitude of hysteric energy dissipation as well as maximum and cumulative displacement ductility levels. This research is focused on the influence of core cross‐sections, friction between the core and restrainers, gap between core and restrainers, loading protocols, and core slenderness ratio on the cyclic performance of steel BRBs. A numerical study has been conducted for a series of BRB elements using the finite element software ABAQUS. Numerical models are validated by comparing the predicted results with the findings of a past experimental study on six numbers of steel BRBs subjected to different types of loading protocols. The energy dissipation potential of BRBs did not change significantly with the nature of loading protocols. However, the cyclic response of BRBs was significantly influenced by magnitude of friction and gap between the core and restraining elements. Moreover, the strength adjustment factors are unaffected by the different types of loading and as core cross‐sections.