Present Condition of Seismic Retrofit of Buildings in Japan
by Masaya Hirosawa
Concrete Journal,Vol.35,No.10,Oct.1997
- Synopsis
- Since the 1995 Great Hanshin Earthquake, seismic retrofit of existing buildings are rapidly promoted mainly on public buildings. Objective buildings for retrofitting are medium-and lowrised reinforced concrete buildings such as school buildings, office buildings, hospitals etc. and gymnasiums of steel structure. Seismic diagnosis and seismic retrofit design are carried out by structural engineers conforming to technical guidelines compiled by the ministry, but shortage of the engineer is distinguished. Steel braces or concrete shear walls is mainly used as main retrofitting techniques for reinforced concrete buildings and the retrofit does not cause much functional drop in case of school. Retrofit construction cost corresponds to around from 10% to 20% of those for reconstruction of the building. However, seismic diagnosis and retrofit of private buildings are scarcely carried out. Retrofit of multi-stories buildings and buildings on use by the current techniques are generally difficult and new techniques such as retrofit by base isolation are now discussed.
- Keywords:
- seismic diagnosis, seismic retrofit, retrofit design, retrofit construction
