Proposal of repair index and strategy for recovery of reinforced concrete buildings damaged by earthquakes

Abstract

Restoration of damaged buildings is an important issue for achieving smooth recovery of society after a devastating earthquake disaster. In general, in past earthquake disasters in Japan, demolition or repair judgement was made based on damage level of the target building using the “Japanese Damage Level Classification Standard (2015)”. However, as cost effectiveness is not considered in the judgement, all the damaged parts of the structure are generally repaired. In this regard, a reasonable evaluation methodology and judging criteria is necessary for strategic decision making of repair and recovery of damaged buildings. This research develops and proposes a “Repair Index” to estimate the effectiveness of different repair schemes for damaged reinforced concrete (RC) buildings for selection of most reasonable scheme. The basic concept of the “Repair Index”, which consist of (1) structural capacity recovery, (2) repair cost and (3) economic loss indices, is introduced. Firstly, recovery ratio of structural capacity was investigated based on previous research and experiments, and a database was developed. Secondly, an evaluation method of repair cost and economic loss considering expected cost and loss in future earthquakes was proposed. and applied to a prototype RC building. Finally, Repair Index was applied to a prototype RC building and the most reasonable and cost effective repair strategy was discussed.