安全性診断を考慮した木造家屋の更新システムに関するモデル分析

Abstract

阪神・淡路大震災における主な死亡原因の一つとして, 老朽木造家屋の倒壊が挙げられる。震災以降, 老朽家屋の更新(修繕)の促進を目的として, 自治体による安全性診断の補助制度が導入されている。本研究では木造家屋を所有かつ居住する者の家屋更新に関する意思決定モデルを構築し, 安全性診断が意思決定に及ぼす影響について分析する。さらに政府による補助政策が所有者の意思決定に与える影響についても分析を行う。

In Hanshin-Awaji earthquake, many old wooden houses collapsed, and the number of people died from it.It is becoming critical to check the safety of such houses and improve the quality of them. In order to help owners to obtain the information on safety of their own houses, some local governments in Japan have founded safety diagnosis scheme. In this paper, the decision making model on diagnosis and renewal of old houses is constructed, based on the hypothesis that owners try to maximize their lifelong expected utilities. The effect of deterioration of houses is also taken into account. That results in that temporal factors, such as lifetime of owner or history of houses, will affect owner's decision on renewal. It is also shown that safety diagnosis has positive worth for the part of owners. Finally, the effectiveness of government's intervention to owners' decision, such as subsidies, is also discussed.