Study of G+20RCC Building in Seismic Zone V Using Soil Structure Interaction

Abstract

This thesis investigates the impact of Soil-Structure Interaction (SSI) on the seismic performance of re-inforced concrete (RCC) building. The study focuses G+20 storey RCC buildings located in Seismic Zone V, modelled using ETABS software. A three-layer soil profile, including soft clay (0–5 m), me-dium-dense sandy silt (5–15 m), and dense sand/gravel (15–30 m), is incorporated to simulate realistic soil behavior. The analysis compares buildings with flexible base condition, examining base shear, lateral displacements, storey drifts, overturning moments, and performance points. Results show that considering SSI increases the building’s natural period, leading to a reduction in base shear and overturning moments, but causing increased lateral displacements and storey drifts. The study also compares drift values with allowable limits as per IS 1893:2016, confirming that all models comply with seismic deflection requirements but may approach wind deflection limits in flexible-base models. The findings highlight the importance of considering SSI for a more accurate seismic design, as fixed-base assumptions may lead to unsafe or inefficient designs. This research provides insights into incorpo-rating realistic soil conditions in seismic design, particularly for high-rise buildings in seismic zones.

Keywords: Soil-Structure Interaction (SSI), ETABS, RCC Buildings, Seismic Zone V, Base Shear, Storey Drift, Performance Point, Seismic Design.