Analisis Statik Non-Linear (Pushover) Gedung dengan Ketidakberaturan Horizontal Terhadap Perilaku Seismik Menggunakan Software Midas Gen dan Etabs

Abstract

Indonesia's seismically active condition necessitates safe building design. However, modern architectural trends often result in irregular plan layouts that can degrade seismic performance. This study aims to comparatively analyze the seismic performance of a regular building against three irregular models (L, T, and Z-shaped). The research methodology is a nonlinear static (pushover) analysis on a 6-story reinforced concrete hotel building model located in Medan, designed with a Special Moment Resisting Frame (SMRF) system. The analysis was performed using Midas Gen software and validated against ETABS. Structural performance was evaluated based on the capacity curve, which serves as the basis for determining ductility, overstrength, the collapse mechanism, and the performance point. The results indicate that the regular structure exhibits superior ductility and strength. Plastic hinge formation occurred more extensively in the beams of the compliant structure, resulting in greater energy dissipation. Conversely, the irregular structures were more vulnerable with a non-ideal collapse mechanism, failing to adhere to the strong-column weak-beam (SCWB) principle, which was characterized by premature column failure before other elements reached further yielding levels. However, after increasing the dimensions of critical columns, the collapse mechanism of the irregular structures was significantly improved. Despite the behavioral differences, all models achieved the Damage Control performance level. In conclusion, horizontal irregularity significantly degrades a structure's seismic performance. This study demonstrates that design interventions, such as column strengthening, are crucial for ensuring the safe and ductile behavior of irregular structures. These findings provide technical guidance for designing seismic-resistant buildings with more efficient configurations.