Development of Hybrid Monitoring System for Early Detection of Earthquake Damage to Lifeline

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This study deals with development of hybrid monitoring system of ground motion and lifeline facilities for early detection of their earthquake damage. First, the monitoring of ground failure, especially soil liquefaction was studied because liquefaction was one of the most crucial geotechnical hazards during an earthquake. In this study, strong ground motion records were used for detection of liquefaction. Amplitude characteristics of strong ground motion records were investigated. The time histories of the ratio of vertical ground acceleration to horizontal one was calculated from the strong ground motion records in liquefied and non-liquefied areas. As the ratio increased after the liquefaction occurred, the ratio seems to be one of the indices of detection of liquefaction. Frequency characteristics of the strong ground motion records were also studied. The running spectra and time histories of the predominant fequency of the strong ground motion records in liquefied and non-liquefie … More d areas were calculated. The decrease rate of the predominant frequency is the one of indices of detection of liquefaction.Next, the methodology for estimation of spatial liquefaction potential was proposed. The method was a geostatistical procedure which was called as Kriging technique using semi-variogram. This method was applied to estimation of liquefied sites by using the data obtained from boreholes at limited sites in Niigata, Noshiro and Kobe cities. The areas where the liquefaction occurred during the 1964 Niigata, 1983 Nihonkai Chubu and 1995 Hyogoken Nambu earthquakes, respectively, could be predicted relatively well.Furthermore, the optimum monitoring sites for lifeline facilities were investigated by case study of Kanazawa city. The critical points of pipeline network were clarified by the flow analysis after an earthquake, then the important sites for monitoring were determined in considering the crucial bases after an earthquake such as a general hospital, shelter, and so on. Less