Seismic Performance and Recovery Modeling of Natural Gas Networks at the Community Level Using Building Demand

Earthquakes can substantially disrupt the operation of critical lifelines in a community, particularly water, gas, and other below-ground infrastructure. The damage that occurs to lifelines in a community from an earthquake can, in turn, have a substantial impact, resulting in social and economic disruption. Furthermore, the duration of the loss in functionality of lifelines is a key factor in the economic disruption that results from an earthquake. In this study, a virtual community known as Centerville was subjected to earthquakes of varying intensity, each having the same assigned point source location, using a well-known attenuation model in order to examine the restoration of communities in the aftermath of an earthquake. The virtual community model being studied has the essential physical components that describe a community, but the focus of this paper is the natural gas network, which is composed of a processing plant, compressor stations, city gate stations, district regulating stations, and buried pipelines. Based on the level of damage that occurred to the network components and their connectivity (topology) throughout the community, the functionality of supplier nodes is assessed using Monte Carlo simulation, and functionality curves are presented for the community's natural gas network. Notably, the effect of the industrial makeup of a community on its natural gas recovery following an earthquake, as well as the influence of replacing conventional steel pipes with high-density polyethylene (HDPE) ductile pipelines, is examined. As expected, the ability of the HDPE pipe to reduce the network recovery time is substantial and is quantifiable at the community level using the approach presented herein.