The Performance Assessment of the Structural Bracing Model for Multi-Story Building

Earthquakes are a severe issue for construction. The building collapsed due to the earthquake because it could not bear the earthquake load. Even more so, it was constructed using outdated and different building regulations that do not comply with modern building codes that account for seismic loads. As a result, disaster mitigation methods, such as retrofitting, must be implemented. Retrofitting procedures are commonly used in many developed countries. The bracing system is a typical retrofitting method used on building structures. In this study, a retrofitting program was carried out on The State Finance Building II Semarang, which was built in the 1980s, one of the old buildings in Semarang City, using a reinforced portal structure. This study's bracing system is a Concentrically Brace Frame (CBF) with Inverted V Brace and V Brace variations. The structural analysis software ETABS V.18.2.0 analyzes the building's structure. The structural review includes story drift, the P-Delta effect, and horizontal torsion irregularities. According to the results, steel bracing can minimize the period and displacement associated with story drift, making the structure more stable, with a maximum displacement reduction of 59.66% for inverted V-type steel bracing. Aside from that, steel bracing also can minimize the occurrence of torsion in the building. As a result, steel braces can be used to strengthen the structure.