Consideration of subsurface layer to evaluate site amplification effect in the response and limit strength calculation design method, the building standard law

Abstract

Buildings in Japan must be designed and constructed according to Building Standard Law, the Enforcement Order and the Notiˆcation by Ministry of Construction and the Ministry of Land, Infrastructure and Transport notiˆcation. The buildings in our country are suŠered the extensive damages cause by earthquake, typhoon, andˆre, etc. Then, earthquake is adopted as one of forces/loads that should be endured by the buildings. Through these valuable experiences, we learned that the ground condition strongly in-‰uences earthquake ground motion and earthquake damage. By conventional Allowable stress design method, seismic design force level is deˆned taking into account the surface geological condition at construction site. In addition, by the Response and Limit Strength Calculation design method newly adopted for performance-based design concept by the revised Building Standard Law in June, 1998 the seismic force is deˆned at engineering bedrock as an acceleration response spectrum corresponded to the seismic activity in a region concerned with the site ampliˆcation eŠect by subsurface layers and soil-structure interaction eŠect. In this paper, I would like to introduce the consideration of subsurface layers to evaluate site ampliˆcation eŠect under the Building Standard Law and relating regulation especially with relation to the Response and Limit Strength Calculation design method.

Japanese attitudes toward risk control in seismic design in light of observation, prediction, and actual performance of building structures

“…However, the intensity levels of the design earthquakes stipulated in the 2000 BSL were adjusted to be comparable to those defined in the 1981 BSL to ensure the continuity in design practice. The new Level 2 design spectrum (specified at the engineering bedrock) was derived from the R t ‐ T relationship for intermediate subsoil type II using the average level of soil amplification ( G s ) of 1.5 for short periods and 2.0 for long periods 28,29 …”

“…The new Level 2 design spectrum (specified at the engineering bedrock) was derived from the R t -T relationship for intermediate subsoil type II using the average level of soil amplification (G s ) of 1.5 for short periods and 2.0 for long periods. 28,29 Although several large earthquakes hit the territory of Japan in the 2000s, there have been no further revisions in the building code since 2000. This indicates that the seismic load prescription in the Japanese building code has been fundamentally unchanged since 1981, particularly with respect to the site specificity, characterized by the zone factor (Z).…”