品質事故事例からみる建築生産システムの実態とその脆弱性

摘要

日本の建築物の品質は、他の製品と同様に高い評価を受けてきた。 しかし、近年、品質に関係するトラブルが数多く散見されるように なってきている。品質事故は、様々な原因が重なり合って起こるが、 これらの品質事故の原因はどのようなものなのか。また、それを誘 引する背景は何なのか。品質事故の再発防止のためにはどうしたら いいのか。これらを明らかにすることが求められている。%Today, there are many construction failures in many parts in Japan. This is attributed to the fact that there are some problems in the building construction system. The authors assume that the quality assurance system in construction is composed of four levels. The first level is "law" such as the building standard law. The second level is "standard" such as JIS, JAS, JASS, or the standard specification. The third level is "plans in a particular project" such as drawings, particular specifications, working drawings, construction plans, or working instructions. The fourth level is "the technology/skill of the engineer/craftsman". The quality is to be assured by the complementary relationship among these four levels. These days, projects are getting bigger and more complicated, the procurement system is diversifying, and the technology is advancing. However, "law" doesn't correspond to these changes, and "plans in a particular project" which formerly complemented "law" are not enough now. Therefore, this study focuses on the following aspects. 1. Clarify the quality assurance system from the view points of the four levels. 2. Clarify the actual conditions of the quality assurance system. 3. Clarify the mechanism of the construction failures by using descriptive models.