Study of Seismic Design of Lifeline System Considering System Performance after an Earthquake

本研究探讨地震后供水系统之系统表现，以及改善之优先顺序。1995年兵库县南部（科比）地震后，科比市的供水系统完全中断，失去了主要功能。大约花了三个月的时间才完全恢复供水。在1995年的科比地震中，由于地震的破坏是不现实的，所以应该在生命线系统中引入基于性能的设计。此外，由于管道长度巨大，从系统性能的角度来看，在系统加固中需要优先进行改造。首先，为了估计网络在地震后的供水点，对供水管道进行了流量分析。本研究以日本金泽市的供水管网为例进行研究。从系统性能的角度评估了地震后暂停供水和供水不足对公民社会的影响。根据1995年科比大地震的资料，分析了震后天数与主要用水目的的关系，给出了最小供水量目标。定义了水资源短缺损失的概念，用以评价水资源短缺对城市生活的影响程度。缺水损失是指供水量与最低目标之间的差额，用货币价值来评估。为减少地震后因停水、供水不足造成的供水损失，对供水管道进行了加固研究。结果表明，缺水总损失可作为评价改造优先性的指标之一。

This study deals with a system performance of water supply system after an earthquake and prioritization of the retrofit. After the 1995 Hyogoken Nambu (Kobe) earthquake, the water supply system of Kobe City was completely disrupted and its principal functions were lost. It took about three months for complete recovery of water supply. Since it is not realistic that the earthquake damages were perfectly prevented against very rare but great earthquake like the 1995 Kobe earthquake, performance based design should be introduced into the lifeline system. Moreover, the retrofit prioritization is required in the system strengthening From the point of system performance because of the enormous piping length.First, a flow analysis of water supply pipelines was conducted in order to estimate under water supply points of a network after a scenario earthquake. The water supply pipeline network of Kanazawa City in Japan was adopted as a case study in this study. An effect of suspension and under supply of water on a civil society after an earthquake was estimated from the point of system performance. Based on the data in the 1995 Kobe earthquake, the relation between the day after the event and main purpose of water was shown and the minimum objective of water supply volume was given. Then a loss for water shortage was defined to evaluate the degree of effects of water shortage on a civic life. A loss of water shortage, which was a difference between supplied water volume and the minimum objective was evaluated by the value of money. The strengthening of water supply pipelines was studied to reduce the loss for water shortage due to the suspension and under supply of water after an earthquake. The results revealed that the total loss for water shortage seems to be one of the indices for evaluation of retrofit prioritization.