This study investigates the seismic performance of reinforced concrete flat slab buildings strengthened with conventional structural elements, including drop panels, edge beams, shear walls, and coupled shear walls. Unlike previous works that examined these elements independently, this research provides an integrated comparative evaluation of several common strengthening approaches under identical modeling and seismic loading conditions, offering clear guidance for practical design optimization. A comparative finite element analysis was conducted using ETABS v20 in accordance with ACI 318-19 and ASCE 7-22 seismic design provisions. Five ten-story building models were developed to assess key response parameters such as story displacement, inter-story drift, column axial forces, diaphragm deformation, and punching shear resistance under gravity and earthquake loading. Results reveal that models incorporating coupled shear walls achieve the greatest improved seismic performance, with up to 50% reduction in story displacement compared to other configurations, while also minimizing column over-compression and lateral drift. Drop panels alone showed a localized improvement in punching resistance, but their global impact on lateral stiffness was limited. However, the combination of drop panels and edge beams produced a synergistic effect, significantly enhancing overall stiffness and controlling drift. Coupled shear walls efficiently redirected lateral forces away from critical slab–column joints, thereby mitigating the risk of punching shear failure. These findings offer practical guidance for structural engineers seeking to optimize the seismic design of flat slab buildings, emphasizing the importance of integrated strengthening strategies in achieving both stiffness and ductility in seismic regions. The findings underline the significance of systematically evaluating conventional strengthening techniques within a unified modeling framework, offering engineers practical insights for improving the seismic behavior of flat slab buildings at the early stage of design.
Hadwan et al. (Thu,) studied this question.