A Comparative Study on the Effects of Earthquakes on Seismic Base Shear Force, Based on Indonesian Seismic Code 2012 and 2019 (Case Study of UNSRAT Building)

Indonesia is a high-seismic-risk region, requiring structural design to be regularly updated in line with seismic data developments. This study aims to compare the effects of applying Indonesian Seismic Code 2012 and Indonesian Seismic Code 2019 on the seismic base shear force of a six-story Civil Engineering Department Building at Sam Ratulangi University (UNSRAT) in Manado, Indonesia. The analysis was conducted using equivalent static and dynamic response spectrum methods with ETABS software. The results of the study show an increase in response spectrum parameters (SDS & SD1) and an increase in basic shear force of approximately 56.7% in the 2019 Indonesian Seismic Code. In addition, displacement and inter-story drift increased by approximately 5%, with some stories exceeding the allowable drift limit, indicating unsafe structural performance according to Indonesian Seismic Code 2019. These findings emphasize the importance of implementing the updated seismic code in structural design for buildings in earthquake-prone regions to ensuring adequate stiffness and strength within the prescribed safety limits.