Evaluasi Kinerja Seismik Struktur Hotel Bertingkat Tinggi dengan Denah Irregular Menggunakan Metode Multi Mode Pushover Analysis (Studi Kasus: Hotel XY di Kota Surabaya)

Abstract

The infrastructural growth of high-rise buildings in Surabaya often result in irregular plan configurations that are highly vulnerable to torsional effects due to eccentricity between the center of mass and the center of rigidity. This study aims to evaluate the seismic performance of the newly designed Hotel XY high-rise structure, featuring an L-shaped irregular plan, located in Surabaya—a region geologically close to the active Kendeng and Surabaya fault lines. The evaluation utilizes the Multi-Mode Pushover Analysis (MMPA) method to accurately account for higher mode effects. The procedure refers to the ASCE 41-17 standard, with the seismic hazard limited to BSE-1N (design-basis earthquake with 475-year return period). The analysis applied lateral loads based on selected mode shapes: Mode 1 (primary), Mode 5, and Mode 10 (higher modes) for the X-direction, and Mode 2 (primary), Mode 6, and Mode 11 (higher modes) for Y-direction. The conversion back of target roof displacement to the MDOF system yielded the largest peak displacement is Mode 1 (325,103 mm) and Mode 2 (313,366 mm). Through the Complete Quadratic Combination (CQC) method, the maximum roof displacement is found to be 469,135 mm (X-direction) and 423,653 mm (Y-direction). The total base shear obtained is 40.882,08 kN for the X-direction and 45.770,45 kN for the Y-direction. Globally, the performance level of the designed Hotel XY structure is categorized as Life Safety to Collapse Prevention (LS-CP) due to critical inter-story drifts at the 3rd floor (2,40% in X-direction) and 3rd-4th floors (2,05% in Y-direction). Based on ASCE 41-17 criteria, the proposed design does not meet the Life Safety target (>2,0%), but remains safe from sudden total collapse (<4,0%). Local component evaluation shows that critical elements are within the Immediate Occupancy to Life Safety (IO-LS) level with no risk of story mechanism.