Performance-Based Seismic Design Code for Buildings in Japan

The seismic design code of buildings in Japan was revised in June 2000 to implement a performance-based structural engineering framework. The code provides two performance objectives: life safety and damage limitation of a building at two corresponding levels of earthquake motions. The design earthquake motions are defined in terms of the acceleration response spectra specified at the engineering bedrock in order to take into consideration the soil conditions and soil-structure interaction effects as accurately as possible. The seismic performance shall be verified by comparing the predicted response values with the building’s estimated limit values. The verification procedures of seismic performance in the new code are in essence a blend of the equivalent single-degree-of-freedom modeling of a building and the site-dependent response spectrum concepts, which make possible the prediction of the maximum structural response against earthquake motions without using time history analysis.