Seismic Performance Evaluation of Flat Slab vs. Grid Slab Systems in Multistoried Buildings: A Comparative Study

This study compares the seismic performance of three distinct slab systems in multi-story buildings: flat slab, grid slab, and conventional slab. The study focuses on assessing their structural efficiency under seismic loading circumstances, specifically for buildings of varying heights (2-, 5-, and 8-storey) in seismic Zone III. To examine characteristics such as bending moment, shear force, base shear, storey drift, and displacement, static analysis was done using IS 875 (Part 1 and 2): 1987 and IS 1893: 2016. The findings show that, although flat slabs provide architectural freedom and reduce floor-to-floor height, they have higher bending moments and shear forces than grid and conventional slabs, making them more prone to punching shear failure. Grid slabs, although being physically robust, exhibit higher displacement and drift, particularly in taller buildings. Conventional slabs, on the other hand, display higher performance in seismic circumstances because of their beam-supported structure, resulting in improved lateral stability. The study reveals that, although flat slabs are appropriate for low-rise structures with open spaces, grid and conventional slabs are better suited for taller buildings in seismic zones owing to their increased seismic resistance and structural efficiency. Major Findings: Flat slabs have higher bending moments, shear forces, and base shear compared to grid and conventional slabs, making them more susceptible to punching shear failure, especially in seismic zones. Grid slabs, while providing structural strength, exhibit higher displacement and drift, particularly in taller buildings. Conventional slabs offer better seismic resistance and lateral stability due to their beam-supported structure, making them more efficient for high-rise buildings in seismic zones.