2006 Yogyakarta Synthetic Time History Response Spectrum versus SNI 1726:2019: Building Response

Abstract

This study investigates how a response spectrum derived from a synthetic acceleration time history representing the 2006 Yogyakarta earthquake compares with the SNI 1726:2019 design spectrum and influences the seismic response of a five-story reinforced concrete building. A 5%-damped event-based spectrum was developed through linear-acceleration analysis of single-degree-of-freedom systems and applied alongside the SNI spectrum to a three-dimensional ETABS model for Site Class SD. The developed spectrum reached a peak pseudo spectral acceleration of 1.011 g at 0.34 s, exceeding the SNI plateau of 0.78 g (0.155–0.777 s) by 29.62%. At the building's fundamental period of 1.086 s in X, the developed and SNI spectra gave 0.58 g and 0.56 g, a difference of 3.51%. At 1.385 s in Y, they gave 0.32 g and 0.44 g, a difference of 31.58%. The corresponding differences in unscaled base shear, elastic roof displacement, maximum inter-story drift, and P-Delta stability coefficients were small in X (2.28–3.05%) but greater in Y (27.35–31.34%), where SNI generally produced higher demands. Force scaling brought all cases to 2961.020 kN, although story-level force distributions remained different. All drift and stability checks met the adopted limits. These findings indicate that period-dependent spectral differences are reflected in structural responses but remain specific to the synthetic input and building examined. Further studies using additional ground motions and different building configurations are recommended.