Seismic diagnosis for rehabilitation and upgrading of steel gymnasiums

摘要

In this paper we describe an improvement of an existing method of seismic diagnosis for steel gymnasiums used in Japan. This improvement is made so that the results of diagnosis match the actual seismic damage of steel educational facilities (mostly gymnasiums) caused by the great Hanshin--Awaji earthquake, which occurred on 17 January 1995. The strategies for rehabili- tation and upgrading including decision making as to which struc- ture, where in the structure and how much to improve, are determ- ined in consideration of the results of seismic diagnosis for the present (or damaged) state as well as the retrofitted state of the structure. In this paper, seismic performance indices are calculated for the pre--damaged state of the educational facilities by use of the existing seismic diagnosis method and compared with the actual damage observed. An index of seismic performance should have strong negative correlation with the damage level observed in the facilities after severe earthquakes. The index used herein is calcu- lated from two other indices, one for load carrying capacity and one for deformability. The latter index is similar in its role to the R--factor in the US and the q--factor in the European seismic regu- lations. By revising the manner of calculation of the deformability index only, the correlation between the seismic performance index and the damage level has been much improved.