Seismic Performance and Collapse Safety Assessment of Post-Tensioned Hybrid Precast Concrete Infill Wall-Frames and Comparison with Reinforced Concrete Infill Wall-Frames

Post-tensioned hybrid (PH) precast concrete wall-frame buildings provide excellent seismic performance, by reducing structural damage and residual drifts. In the present study, the use of PH precast concrete walls, as partial infill walls in low-rise reinforced concrete (RC) moment-resisting frames is evaluated and compared with RC infill wall (RIW) frames with a similar structural configuration. For this purpose, the seismic performance and collapse safety of 4-story post-tensioned hybrid precast concrete infill wall (PIW) frames and RIW frames with different frame shear ratios beta(F) are studied. Following the FEMA P695 methodology, fragility curves are generated, the collapse margin ratio (CMR) is determined, and then the adjusted collapse margin ratio (ACMR) of each frame is compared with acceptable adjusted collapse margin ratio ACMR(10%). The results indicate that, peak normalized floor displacements, inter-story drifts, and the column chord rotation demand of the PIW frames are for the most part slightly larger than the corresponding RIW frames but the PIW frames show better seismic performance in reducing the residual inter-story drifts than RIW frames, under design earthquake (DE) level and risk-targeted maximum considered earthquake (MCER) level ground motions. Although a slight decrease in the ACMR is observed with increasing beta(F), for both PIW and RIW frames, ACMR exceeds the ACMR10% indicating that the PIW frames show satisfactory collapse performance.