SEISMIC PERFORMANCE OF HORIZONTALLY IRREGULAR CONCRETE BUILDINGS: A PUSHOVER ANALYSIS APPROACH

Irregular building configurations, both horizontally and vertically, are more vulnerable to seismic forces, requiring careful evaluation to reduce the risk of structural collapse. This study investigates the seismic performance of three horizontally irregular building models: Model A (U-shaped), Model B (L-shaped), and Model C (T-shaped). Nonlinear static pushover analysis is used to assess structural performance, covering collapse levels, displacement, drift ratio, and base shear, validated by SNI 1726-2019 and referencing FEMA 356 and ATC-40 for performance point evaluation. Pushover analysis simulates the building's behavior under lateral forces, identifying the performance point where the structure transitions to inelastic behavior. The results show that Model A (U-shaped) has the largest displacements (5.15% in the X-direction and 4.92% in the Y-direction) and the highest drift ratios (5.02% in the X and 4.61% in the Y) due to greater torsional eccentricity. Base shear values for Model A are also higher (5.32% for X and 7.60% for Y). According to FEMA 356, Model A achieves an "Immediate Occupancy" classification, while ATC-40 places it under "Damage Control." This study highlights the importance of detailed pushover analysis in designing seismic-resistant irregular buildings.