Earthquake scaling method on the seismic responses of reinforced concrete core walls with outrigger subjected to near fault earthquakes

The present study examines the seismic behavior of reinforced concrete core-walls with outrigger systems exposed to near-fault (NF) and far-fault (FF) strong ground motions using two different record scaling techniques: spectrum-matching (SM) and amplitude scaling (AS). The outrigger uses buckling restrained braces (BRB). The systems are first designed with seismic codes and the conventional response spectrum analysis (RSA) process. Nonlinear fiber element models for the core walls and nonlinear BRB elements for the outrigger are generated in order to conduct nonlinear time history analysis. The SM and AS methods are used to obtain appropriate records for nonlinear time history analysis. When compared to the SM approach, the AS procedure resulted in a greater requirement for curvature ductility at the upper level of the core-wall, and this problem is particularly significant for the near-fault ground motions. The reason for this difference is the changes in the ground motion characteristics due to SM procedure. For near-fault ground motions, changes in the ground motion characteristics are more severe. According to the obtained results, due to the change and reduction of responses of tall core-wall with outrigger by SM process in time history analysis, it is not recommended to use this scaling method in this structural system.