Cost-benefit Analysis of Seismic Retrofitting Strategies for Residential Buildings in Surabaya, Indonesia

Surabaya has potential vulnerability to a seismic activity as it has residential buildings with unreinforced confined masonry structures. This building structure is vulnerable to the massive destruction during the earthquake. Retrofitting existing unreinforced masonry structures is necessary as a mitigation strategy. However, the lack of funding and the high cost of retrofitting adaptation have become major obstacles. This study discussed a cost-benefit analysis of the seismic retrofitting strategies in confined masonry buildings in Surabaya. We added practical column, structural beams and a combination of practical column and structural beams as the retrofitting model. The model was then compared to normal buildings for a cost-benefit analysis. The results demonstrated that adding practical columns could significantly reduce the building damage by 4.75 %. The additional combination of a practical column and structural beams shows zero damage to the building after the earthquake. The reinforcement of structural beams represents the highest cost-benefit ratio (44.44) due to the lowest retrofitting cost with 30.73% of damage. The cost-benefit calculation is expected to give the community remarkable information regarding the critical value of seismic retrofitting to achieve the sustainable development.