Performance-Based Design of a Three-Story Steel Special Moment Resisting Frame Using LRFD and Response Spectrum Analysis

Abstract

The design of steel building structures in high-seismic regions requires adequate strength, stiffness, and ductility to ensure structural safety during earthquake events. This study presents the performance-based design of a three-story office building employing a Special Moment Resisting Frame (SMRF) system in Padang, Indonesia, one of the country's most earthquake-prone regions. The structural design follows the Load and Resistance Factor Design (LRFD) approach in accordance with SNI 1726:2019 and SNI 1729:2020. Numerical modeling and structural analysis were performed using SAP2000 under gravity, wind, and response spectrum earthquake loading. The structural performance was evaluated based on the fundamental period, mass participation ratio, interstory drift, base shear, and member strength requirements. The analysis produced a fundamental period of 1.128 s, cumulative mass participation exceeding 90%, and a maximum interstory drift of 22.79 mm, which is significantly lower than the allowable limit of 88.46 mm. The selected steel sections, consisting of IWF 400×400×13×21 columns and IWF 350×175×7×11 and IWF 500×200×10×16 beams, satisfied all LRFD strength requirements. The total structural weight of 14,036.34 kN generated a design base shear of 1,754.54 kN, fulfilling the seismic design requirements for Seismic Design Category D. The study demonstrates that the proposed SMRF configuration using BJ 41 steel provides an effective structural solution for multi-story buildings in seismic regions and offers a practical design reference for future steel building applications in Indonesia.