Forward directivity near-fault and far-fault ground motion effects on the responses of tall reinforced concrete walls with buckling-restrained brace outriggers

Abstract

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 ber 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.

Outrigger and Belt‐Truss System Design for High‐Rise Buildings: A Comprehensive Review Part II—Guideline for Optimum Topology and Size Design

“…(i) Placing the outriggers at lower levels increases the acceleration [43,47]. (ii) According to reference [183], the maximum floor acceleration belongs to the far-fault records and occurs near the outrigger level.…”

Effect of damped outriggers arrangement on the seismic response of high-rise steel structures

“…As mentioned before, one-outrigger systems located at two adjacent stories labeled with their lower story numbers are depicted in the following gures. According to the ASCE/SEI 7{10 [21] for buildings with a long period, the allowable drift ratio is assumed to be equal to 0.02.…”

“…To increase the damping of the outrigger system, other passive energy dissipators, such as Buckling-Restrained Brace (BRB), are also implemented [18][19][20][21]. This element limits the maximum force that the outrigger can develop [18].…”

“…It was observed that the location of the plastic hinges in the core wall was in uenced by the BRB outriggers [20]. Moreover, a response modi cation factor of 5 is recommended for the Reinforced Concrete (RC) core-wall with BRB [21].…”

Effect of record scaling on the behavior of reinforced concrete core-wall buildings subjected to near-fault and far-fault earthquakes

“…The damage observed from the recent earthquakes illustrated that structures located within the NF area su ered more severe damage than structures located outside of this zone [15]. Strong (NF) ground motion is usually characterized by a longperiod pulse-like motion in the horizontal direction that includes large displacement and large velocity amplitude [16].…”