Earthquake effects on buried lifeline systems.

摘要

The research described in this work represents the first time that comprehensive geographic information system (GIS) analyses were performed for a large U.S. water supply with extensive earthquake damage and strong motion data. As part of the work, water supply repair records for the 1994 Northridge earthquake were assembled. The earthquake damage includes 15 transmission line, 74 trunk line (nominal pipe diameter {dollar}ge{dollar} 600 mm), and 1013 distribution lines (diameter {dollar}<{dollar} 600 mm) repairs. All of approximately 10750 km of distribution lines and 1000 km trunk lines were digitized and incorporated in a GIS database that also includes repair records and the corrected strong motion records of 165 seismograph stations.; Using this database, spatial relationships between pipeline damage and various seismic parameters are explored. The seismic parameters selected are peak ground acceleration (PGA), velocity (PGV), and displacement; spectral acceleration and velocity; spectrum intensity (SI); Arias intensity (AI), and Modified Mercalli Intensity (MMI). Damage correlations between cast iron (CI) distribution line damage and seismic parameters are developed. Reliable data from past earthquakes are also used in developing the correlations. Damage correlations with PGA and PGV have the highest r{dollar}sp2,{dollar} with PGV slightly better. Asbestos cement, steel, and ductile iron distribution line damage are evaluated with respect to both PGA and PGV. In addition, damage correlations between steel trunk line damage and both PGA and PGV are developed.; Current correlations used in GIS-based loss estimation procedures for buried lifelines do not distinguish between distribution and trunk lines. This study shows that there is a substantial difference at similar levels of PGA and PGV. The correlations developed show that repair rates (repairs/km of pipeline) for distribution pipelines are approximately 2 to 10 times higher than those for trunk lines for PGV up to 150 cm/s. When compared with regressions developed in previous research, the correlations in this work show that repair rates for distribution lines are approximately 1.5 to 15 times lower than those from previous regressions for PGV up to 150 cm/s whereas repair rates for trunk lines are approximately an order of magnitude lower than those from previous regressions. These large differences have important implications for earthquake loss estimation procedures applied to lifelines.; A framework of how to use GIS to analyze pipeline damage and display the results for best visualization of damage patterns was provided. A hyperbolic relationship between visual display of high pipeline damage zones and grid size was developed. The relationship is valid for a wide range of scales tried from approximately 1,200 km{dollar}sp2{dollar} to 1 km{dollar}sp2.{dollar} This relationship can be implemented in GIS software to get sufficiently refined, but easily visualized, damage patterns.; A case history evaluation of pipeline response to permanent ground deformation (PGD) that occurred in Balboa Blvd. and McLennon Ave. during the 1994 Northridge earthquake is presented. Analytical results from sliding block models of soil-pipeline interaction are compared with field observations, and shown to be in reasonably good agreement with field performance. Strain rate effects associated with rapid loading from TGD and PGD do not have a significant influence on steel pipeline performance.