Near-fault ground motion effects on the responses of tall reinforced concrete walls with buckling-restrained brace outriggers

In this paper, responses of reinforced concrete core-wall structures connected to the outside columns by buckling-restrained brace (BRB) outriggers in tall buildings were investigated. These buildings are subjected to forward directivity near fault (NF) and ordinary far-fault (FF) ground motions. According to the current codes for the DBE level, the response spectrum analysis procedure was applied to analyze and design the structures. The nonlinear fiber element approach was used to simulate the reinforced concrete core-walls. Nonlinear time history analysis was implemented using 14 NF as well as 14 FF records at MCE level. In the core-wall, the results show that the mean moment demand envelope as well as the mean shear demand envelope obtained from the NF records are approximately similar to the corresponding demand envelope from FF records. The reason has to do with extending plasticity all over the RC core-wall which is subjected to both sets of records. The overall responses of the reinforced concrete core-wall with BRB outrigger system is in acceptable range both for NF and FF earthquakes. In this study, the largest curvature ductility demand in the reinforced concrete core-wall took place at levels just above the outriggers.