Seismic Fragility of RC Wall-Frame Buildings Using the DDBD Approach for Vulnerability Assessment

In the most severe seismic zones, the majority of earthquake-resistant structures are constructed using in-plane shear walls with frames in India. RC wall-frame buildings exhibit an increase in structural stiffness resulting from the combined behavior of flexure and shear under seismic loading. In addition to this, the nonlinear behavior of RC wall-frame buildings is crucial to investigate. In the present study, 8- and 15-story RC wall-frame structures with various shear wall configurations were designed using the direct displacement-based design (DDBD) approach considering life safety (LS) performance state. The fragility curves were generated using the nonlinear static pushover analysis. The seismic vulnerability was calculated using fragility curves. The performance of RC wall frames under seismic loading was studied using the interstory drift ratio and the future collapse probability of the structure with reference to damage indexes. RC wall-frame building of shear walls located in the center of the inner panel performed exceptionally well in both mid- and high rise because the probability of severe damage is 0.4% for 8-story and 0.7% for 15-story buildings; and the probability of collapse is 0.1% for both, indicating that structures designed using DDBD satisfied the performance state. The present investigation contributes to quantifying the seismic fragility and vulnerability of RC wall-frame buildings and establishing an initiative for seismic fragility-based design of DDBD-designed RC wall-frame buildings using the fragility curves.