Seismic behavior of RC moment resisting structures with concrete shear wall under mainshock–aftershock seismic sequences

Abstract

A structure may subject to several aftershocks after a mainshock. In many seismic design provisions, the effect of the seismic sequences is not directly considered or underestimated. This paper studies the seismic behavior of RC moment-resisting structures with concrete shear wall under seismic sequences. Two three-dimensional structures of short and medium height were designed and analyzed. The former models were studied under a group of real mainshock-aftershock seismic sequences. The models were loaded and designed according to the fourth edition of the Iranian seismic code of standard no. 2800 and ACI-318 respectively. Furthermore, the non-linear dynamic time-history finite element analysis of models was performed via the explicit method. The parameters of maximum displacement, inter-story drift ratio, residual displacement, and finally the effect of the ratio of aftershock acceleration to mainshock acceleration were investigated and assessed. Due to the high lateral stiffness of shear walls, parallel with the complete elastic behavior, aftershocks cause no growth in inter-story drift ratio and relative displacement in the short structure model. In contrast, compared to the structure under the solely mainshock, the medium height structure model under seismic sequences showed significant growth in the amount of relative displacement (even more than 50% growth), inter-story drift ratio, plastic strain, and residual displacement (almost 30% growth). Furthermore, unlike the moment-resisting frame structures, models showed no significant growth in the drift ratio with the height. Assessments indicated that the ratio of aftershock to mainshock acceleration is a determinative parameter in structural behavior under seismic sequences.

Seismic Assessment of RC Shear Wall Structure under Real Seismic Sequences Using Equivalent Shell-Wire Model

“…The experimental shear wall used was the RW1 model as tested by Thomson and Wallace [11], the details of which are shown in Figure 4a. According to previous studies, there is a good agreement between the experimental test and the 3D solid model [25]. The capacity curves of the 3D solid model and the equivalent shell-wire were obtained using monotonic load and nonlinear FE analysis (∆target = 6.5 cm).…”

“…The computational costs of the models also were compared. The accuracy of the 3D solid model has been previously investigated and the results have shown good agreement between the complex 3D solid and experimental models [25].…”

“…The initial damage criteria of the material (concrete or steel rebars) depended on the specific strength. For ductile material (steel rebars), when the stress reached its limits, the evolution of the damage variable took an exponential form according to the fraction strain, strain rate, and displacement at failure [18,[25][26][27]. Experimental studies have shown that brittle material (concrete) under either compression or tension, the initial damage, damage evolution, or cumulative damage could be linked to the model provided by Lubliner et al [28].…”

“…Thus, it was assumed that the compressive stiffness recovered entirely when the load changed from tension to compression. Under tensile loading, however, the stiffness did not recover because of the existence of small cracks [25,26,29,30].…”

Structural Response and Damage Evaluation of a Typical Highrise Rc Building in Dubai Under an Earthquake With Single and Multiple Peaks

“…The analyses of wooden structures to include the influence of seismic sequences of smaller-magnitude events on damage and seismic losses for light-frame wood buildings has been also conducted (Chase et al, 2019). Soureshjani and Massumi (2022) investigated the behavior of RC moment-resisting buildings with shear walls to seismic sequences employing explicit time-history analysis. The developed structural models of the buildings were of three and six stories.…”