長期間の工事履歴に基づく部位・設備ごとの信頼度の算定及びこれを活用した最適な更新周期の推計

抄録

 In this research we conducted a long-term survey of the actual states of repair construction on buildings. From the investigation, we estimate the most suitable renewal cycle of the parts and equipment in buildings. If we know the appropriate renewal cycles of major parts and equipment in buildings, we can keep buildings in good conditions for long time.

 1) In the first half of the analysis, we surveyed the current situation of repairing works conducted on 668 buildings. Preventative repair works are periodically carried out, however it was understood that the number and the cost of reconstruction after the malfunction takes much more proportion than those of preventative repair works.
 2) In the middle stage, we researched the reliability and the failure rate of various part and equipment in buildings and estimated long-term tendencies. The rough life span of the building parts and the types of equipment were estimated from the calculated reliability functions. It was made clear that the life spans of them are almost about 30 years. The failure rate gradually increased a little around 15-20 years after completion.
 3) In the final section, we used the total maintenance costs, calculated by the failure rate and the failure risks, and estimated the most suitable renewal cycle of the parts and equipment in buildings. As a result, it turned out that the failure risk has a large impact on the determination of the optimal renewal cycle. As for the electrical equipment, the suitable optimal cycle is around 20 years when the failure risk increases threefold. It will be around 15 years if the failure risk increases tenfold.