The Effects of Sequential Aftershocks on the Behavior of the Irregular RC Buildings

Studies show that design codes did not provide a reliable way to consider the effects of successive earthquakes on the behavior of the RC buildings. A lot of research are underway in this field, but the effect of shear wall placement in the regular and irregular structures under the seismic sequences and the imposing the vertical acceleration component to them has not been considered. For this purpose, in this study, the Christchurc earthquakes have been employed to observe the effects of seismic sequences on the location of the shear wall in the regular and irregular 3- and 8-story structures. The studied reinforced concrete structures have a dual system of flexural frames with shear walls. In this study, the designed shear wall with ACI code 318-14 is located in the different openings of structures. To model the frame of the structures of concrete flexural frame with wall, the Ibarra and Krawinkler concentrated joint behavioral model has been considered. The Hazus code is utilized to provide the fragility curves and also to indicate the failures based on the four drift-based performance levels. The IDA analysis is then performed on the models and the results are acquired. The failure index is considered as the maximum drift between the floors of the structures. The IR_3S_MO structure under main earthquakes at the three performance levels (Slight, Moderate, Complete) can withstand 11%, 14% and 88% spectral acceleration more than the IR_3S_LO structure, respectively. This ratio is approximately 10%, 12% and 42% for the IR_3S_RO structure, respectively.