Abstract: This study presents a seismic analysis of square and U-shaped buildings with re-entrant corners, evaluating their performance under earthquake loading using two distinct base conditions rubber base isolation and fixed base. The presence of re-entrant corners introduces complex static behavior, which can significantly impact the building's seismic response. The analysis compares the effectiveness of rubber base isolation in mitigating earthquake-induced forces and vibrations in contrast to the fixed base condition, which represents traditional structural support. A three-dimensional model of both building shapes was developed in ETABS 2022 to simulate earthquake excitations, and various seismic parameters such as displacement, acceleration, and structural stresses were assessed. The results highlight the potential benefits of rubber base isolation in reducing seismic responses, especially in structures with irregular geometries like those with re-entrant corners.

Keywords: Seismic Analysis, Re-entrant Corner, Pushover Analysis, Base Isolator

| DOI: 10.17148/IARJSET.2025.12728