Effects of Shear Wall Ratio and Location on Earthquake Performance of Reinforced Concrete Buildings Having Different Ribbed Slab Configurations

Abstract

This study investigates the earthquake performance of reinforced concrete buildings designed with ribbed slab system. Analyses were performed on hypothetical models representing residential buildings in Gaziantep/Islahiye region. In this study, a total of 18 shear wall-frame structure models with three different shear wall placements in accordance with TBEC-2018 were analyzed. Wall density index (0.003, 0.005 and 0.008), shear wall locations defined as M1 (vertically placed on the outer axes), M2 (center-mounted), and M3 (parallel to the outer axes), and ribbed slab placements (parallel and staggered) are considered as variable parameters. The seismic performance of the structures was evaluated using linear and nonlinear analyses. Nonlinear static pushover analyses were used to compare capacity curves, overstrength factor, interstory drift ratios, base shear forces, overturning moments, and second-order effects for each model. As the wall density index increased from 0.003 (%25) to 0.008 (%75), the initial stiffness increased by 158 %, but this increase decreased the plastic deformation capacity and modal displacement values. Models M1 and M3 with walls positioned on the outer axes provided 20.53 % more load carrying capacity than Model M2 with the central wall. The uncracked section shell exhibited 19 %-83 % stiffer behavior, while the cracked sections absorbed more energy. No significant effect of the slab rib arrangement (parallel/staggered) on the stiffness and period was observed. As the shear wall ratio increased, the torsional period decreased by up to 55 %, and the highest torsional strength was achieved in Model M3. Low shear wall ratio models exceeded code drift limits and showed increased interstory drift differences. The results showed that shear wall placement and ratios are critical to seismic performance, and that TBEC-2018 effectively enhances safety in ribbed slab systems.