Title: New Seismic Design Provisions in Japan
Author(s): S. Otani, H. Hiraishi, M. Midorikawa, and
Publication: Symposium Paper
Appears on pages(s): 87-104
Keywords: capacity curve; capacity spectrum; damage initiation;
demand spectrum; life safety; limit states; performance-based
design; pushover analysis; SDF system; seismic design
The seismic design requirements in the Building Standard Law of Japan were revised in June 2000 toward a performance-based design framework. The performance objectives are (a) life safety and (b) damage control of a building at two corresponding levels of earthquake motions. The design earthquake motion is defined in terms of acceleration response spectrum at engineering bedrock. The amplification of ground motion by surface geology and the soil-structure interaction must be taken into consideration. The response is examined by so-called capacity spectrum method by comparing the linearly elastic demand spectrum of design earthquake motions and the capacity curve of an equivalent single-degree-of-freedom (ESDF) system. The structure as designed is reduced to an ESDF system using a nonlinear static analysis under monotonically increasing horizontal forces. Equivalent damping is used to modify the demand spectrum taking into account the energy dissipation capacity of a structure at the prescribed limit states.