An Investigation of Building Seismic Design Parameters in Mataram City Using Lombok Earthquake 2018 Ground Motion

Abstract

Mataram City is the capital of West Nusa Tenggara Province. West Nusa Tenggara consists of two islands namely Lombok and Sumbawa islands. Major earthquakes which have occurred in Lombok in 2018 are definitely making a difference in spectral acceleration. This becomes an important factor to be addressed in structural building design. Spectral acceleration in the short period, S S increases by 18,323% compared to the value listed in existing seismic code, SNI 1976:2012 corresponding to a return period of 2475 years. However, even though the S S value increases, the building design category has not changed, which remains in the D category. In general, the acceleration value in this study is found relatively greater than that of the existing code for periods of less than 0.462 s for site class D, and in periods of less than 0.830 s in site class E. Furthermore, the seismic response coefficient, C S increases by 10.782% compared to C S calculated using current code for medium soil. This impact is more severe in soft soil areas, where the increase reaches 13.168%. Improving of the existing code with the new building seismic design parameters affected by recent strong earthquake ground motion, leads to be more preparedness and becomes an important part of disaster risk reduction for the region.