Seismic Resistance and Sustainable Performance of Retrofitted Buildings by Adding Stiff Diaphragms or Seismic Isolation

Abstract

This study focused on lifecycle assessment (LCA) and evaluation of the sustainable performance of structures retrofitted by adding stiff diaphragms or by using seismic isolation systems. To analyze the mitigation measures, methodological options addressing LCA uncertainties were used. For this purpose, a two-stage, nested, mixed, and balanced ANOVA test was applied. The following four cases were evaluated: nonretrofitted building (baseline), use of concrete diaphragms for strengthening, application of high-damping rubber bearings, and use of seismic isolation columns. Four natural ground-motion records were used for analysis: El Centro, Kobe, Hachinohe, and Northridge. The reduction in environmental damage, relative to the nonretrofitted alternative, was evaluated. It was found that the environmental impact of the four mitigation measures was approximately 10% of the total building impact. According to the results obtained in the frame of the present study, the use of seismic isolation columns resulted in damage reduction of approximately three times more than that achieved by high-damping rubber bearings.