This study evaluates the effects of amount and balance of repair in a gymnasium typical of Japanese schools. Several combinations of main shocks and aftershocks were evaluated. This study showed that a repair using partially retightened anchor bolts is not effective on the short span of the building, but it is effective in the long span, as long as the aftershocks are smaller than 25% of the main shock. The balance of repair does not reduce or amplify the out-of-plane deformation of the walls in the gymnasium, but it causes amplification of the in-plane deformation of the walls in the long span. Therefore, when repair by retightening of anchor bolts is performed, all column bases should be fully retightened as much as possible.
HERNANDEZ et al. (Thu,) studied this question.