Comparative Analysis of Lateral Capacity between Open-Frame and Infill-Frame Systems in a Four-Story Reinforced Concrete Building Using Pushover Analysis

پوختە

This study aims to compare the lateral capacity and seismic performance of open-frame (OF) and infill-frame (IF) configurations in an existing four-story reinforced concrete residential building in Badung, Bali. A three-dimensional structural model was developed using SAP2000, with identical geometry, material properties, and loading conditions for both configurations. The OF model excluded the lateral contribution of masonry infill, whereas the IF model incorporated existing infill walls using diagonal compression struts. Nonlinear static pushover analysis was conducted to evaluate base-shear capacity, displacement response, interstory drift, and structural performance. The results show that the IF model achieved higher performance-point base shear than the OF model, increasing from 42,144 to 42,855 kN in the X direction and from 43,825 to 44,788 kN in the Y direction. Performance-point displacement also decreased from 98.421 to 94.399 mm in X and from 93.171 to 91.261 mm in Y. Incorporating infill walls reduced interstory drift by approximately 36–58% and improved lateral stiffness, while both configurations remained within the Immediate Occupancy performance level. However, the relatively similar pushover curves indicate that the contribution of infill walls to overall lateral capacity remains limited because of substantial wall openings. The findings demonstrate that infill modeling provides measurable but moderate improvements in structural seismic performance.