Investigation of potential damage to bridge infrastructure from induced earthquakes

Abstract

This paper evaluates the fragility of bridges in areas exposed to induced seismic hazards, including human-caused earthquakes commonly associated with the petroleum industry and wastewater disposal. Recently, the rate of such ground motions has significantly increased, especially in areas with high levels of hydraulic fracturing oil extraction in the Central U.S. Induced earthquakes are generally small-to-moderate in magnitude; however, they typically happen in places with historically negligible seismicity, where the structures are designed considering no-to-low seismic demands. Therefore, the increased seismic activities in the region raise concerns about the safety of the infrastructure in that area. This study investigates the fragility of bridge portfolios subjected to induced earthquakes considering major sources of uncertainty in ground motions, bridge geometry, and material properties. Fragility curves are developed with respect to different intensity measures such as peak ground acceleration and velocity, as well as spectral accelerations. In addition, developed fragility curves are compared with those associated with other seismic hazards to evaluate the influence of ground motion characteristics on bridge fragility. The comparison includes similar magnitude natural earthquakes in the Western U.S., New Madrid seismic hazards (i.e., the historical seismic hazard of interest in the Central U.S.), and fragility estimates from HAZUS.