Earthquake is one of the natural disasters causing huge economic and social losses. Particularly, the seismic damages cause significant impact on critical lifelines such as water and sewerage, electricity, bridges, and transportation systems. The lifelines are very important infrastructures that may...
Earthquake is one of the natural disasters causing huge economic and social losses. Particularly, the seismic damages cause significant impact on critical lifelines such as water and sewerage, electricity, bridges, and transportation systems. The lifelines are very important infrastructures that may cause long-term failure of social system when they are damaged by the natural disasters. In this regard, related researches on the reliability assessment of water supply networks for seismic hazard have been carried out over the past 30 years. However, only few researches have studied methodologies for enhancing system reliability. Most of recent researches have focused on development of techniques enhancing system’s ability to recover after seismic damage. Studies on strategic plans for improving system reliability against seismic damage are insufficient. The final goals of this study are development of reliability evaluation model for seismic hazard and suggestion of reliability enhancement plans by optimal system design and pre-reinforcement. In order to achieve these final goals, four detailed strategies are suggested as follows. First, Reliability EVAluation model for Seismic hazard for water supply NETwork (REVAS.NET) is developed. In this model, probabilistic seismic hazards are produced in target area and hydraulic reliability is quantified by suitable indices. Second, the developed model is applied to real water supply networks in Korea. Seismic reliability is evaluated using historical seismic data. The results are analyzed and compared according to size, shape, and components of the systems. A sensitivity analysis is performed for each component (e.g. pipes and tanks) to investigate how they affect the seismic reliability. Third, the system is optimally designed to maximize the seismic reliability under a limited budget. The proposed method is applied to a real water transmission system and the system reliability of the original and optimal systems are compared. Fourth, rehabilitation priority model is developed considering seismic damages. In this model, the deterioration rate of pipes and single and multiple pipe failures are considered to determine system’s rehabilitation priority. As a result, not only system serviceability as well as the reliability distribution of system components can be identified under seismic hazard. From the application results of REVAS.NET of J transmission line, there are potential dangers of seismic damages about existing water supply systems. Therefore, some preparedness should be needed. In this point of view, simple durability enhancement of system components is conducted, but it has a marginal effect. So, strategic design approaches and increasing of connection paths among components also can be taken into account. From the comparison results of J and I city water networks, service area per tank, degree of loop, and distribution rate of pipe size have a strong influence on seismic reliability. Unlike the results of simple and uniform durability enhancement, duplicated construction of pipe has a major effect. Therefore, connectivity enhancement has to be considered as one major option. The optimal design results show that reliability as well as construction cost can be improved over the original design. However, in order to verify the optimal design results, more objective comparisons with original and optimal design have to be conducted such as some post-analysis. The developed rehabilitation model is quite simple and easy to apply in real system for practical use. Therefore, it can be used for reasonable and realistic rehabilitation strategy in case of directed proactive measures cannot be applied because risk of seismic damage is not relatively important to government authorities, but there is always a danger.
Earthquake is one of the natural disasters causing huge economic and social losses. Particularly, the seismic damages cause significant impact on critical lifelines such as water and sewerage, electricity, bridges, and transportation systems. The lifelines are very important infrastructures that may cause long-term failure of social system when they are damaged by the natural disasters. In this regard, related researches on the reliability assessment of water supply networks for seismic hazard have been carried out over the past 30 years. However, only few researches have studied methodologies for enhancing system reliability. Most of recent researches have focused on development of techniques enhancing system’s ability to recover after seismic damage. Studies on strategic plans for improving system reliability against seismic damage are insufficient. The final goals of this study are development of reliability evaluation model for seismic hazard and suggestion of reliability enhancement plans by optimal system design and pre-reinforcement. In order to achieve these final goals, four detailed strategies are suggested as follows. First, Reliability EVAluation model for Seismic hazard for water supply NETwork (REVAS.NET) is developed. In this model, probabilistic seismic hazards are produced in target area and hydraulic reliability is quantified by suitable indices. Second, the developed model is applied to real water supply networks in Korea. Seismic reliability is evaluated using historical seismic data. The results are analyzed and compared according to size, shape, and components of the systems. A sensitivity analysis is performed for each component (e.g. pipes and tanks) to investigate how they affect the seismic reliability. Third, the system is optimally designed to maximize the seismic reliability under a limited budget. The proposed method is applied to a real water transmission system and the system reliability of the original and optimal systems are compared. Fourth, rehabilitation priority model is developed considering seismic damages. In this model, the deterioration rate of pipes and single and multiple pipe failures are considered to determine system’s rehabilitation priority. As a result, not only system serviceability as well as the reliability distribution of system components can be identified under seismic hazard. From the application results of REVAS.NET of J transmission line, there are potential dangers of seismic damages about existing water supply systems. Therefore, some preparedness should be needed. In this point of view, simple durability enhancement of system components is conducted, but it has a marginal effect. So, strategic design approaches and increasing of connection paths among components also can be taken into account. From the comparison results of J and I city water networks, service area per tank, degree of loop, and distribution rate of pipe size have a strong influence on seismic reliability. Unlike the results of simple and uniform durability enhancement, duplicated construction of pipe has a major effect. Therefore, connectivity enhancement has to be considered as one major option. The optimal design results show that reliability as well as construction cost can be improved over the original design. However, in order to verify the optimal design results, more objective comparisons with original and optimal design have to be conducted such as some post-analysis. The developed rehabilitation model is quite simple and easy to apply in real system for practical use. Therefore, it can be used for reasonable and realistic rehabilitation strategy in case of directed proactive measures cannot be applied because risk of seismic damage is not relatively important to government authorities, but there is always a danger.
Keyword
#지진재해 신뢰성 REVAS.NET 상수관망 상수관망 설계 관로개량 우선순위
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