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

Abstract

In this study, the responses of reinforced concrete core-wall structures connected to the outside columns by Buckling-Restrained Brace (BRB) outriggers in tall buildings were investigated. The buildings were 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 showed that the mean moment demand envelope and the mean shear demand envelope obtained from the NF records were approximately similar to the corresponding demand envelopes from FF records. The reason had to do with extending plasticity all over the RC core-wall, which was subjected to both sets of records. The overall responses of the reinforced concrete core-wall with BRB outrigger system were 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.