An Evaluation Framework For Fire Following Earthquake in Seattle: Water Network Performance and Deep Basin Seismic Effects

Abstract

Historic fire following earthquake (FFE) events show that the damage caused by fire after a seismic event can match or outstrip the damage caused by the earthquake itself in terms of scale. Effectively mitigating the damage caused by FFE events and investing in more resilient communities requires a better understanding of how the multiple, interlaced infrastructure systems that make up our communities respond when exposed to seismic and fire hazards. The analytical framework defining these structure/infrastructure dependencies should be modular, allowing for component models to be updated and improved within the existing set of rules, and allowing for new and unique communities and hazards to be investigated. This dissertation aims to better understand the threat of FFE, especially in the North American Pacific Northwest (PNW), and identify some infrastructure parameters that contribute to a community's resilience to this hazard. It does this by developing software and a framework methodology for analyzing water distribution network (WDN) performance following earthquake. It then applies this FFE analysis framework to a specific community by creating a multi-infrastructure system computational model of a portion of Seattle, WA's downtown area. Finally, it measures the sensitivity of fire spread in a steel moment resisting frame (MRF) to earthquake effects, including the effects of sedimentary basins found in the PNW. The dissertation identifies a number of critical parameters for resilience to FFE. These include the importance of WDN pressurization following earthquake; the dependence of the WDN on the power network for pressurization in non-gravity-fed systems; the shape of water storage tanks; and the additional risk that sedimentary basins pose to fire protection systems in steel MRFs. Other outcomes include the development of an WDN analysis application; the development of a general, modular FFE analysis framework; the application of this framework to virtual and real communities; a series of FFE risk mitigation suggestions for Seattle; an intrabuilding fire spread model that explicitly accounts for sprinkler performance and seismic damage to non-structural fire protection systems (FPSs); and a discussion of best practices for community resilience data collection.