Shake Table Seismic Performance Assessment of Auxiliary Battery Power Systems Using the FEMA 461 Protocol

Auxiliary batteries and battery rack systems are widely used as a risk mitigation strategy in several critical facilities to supply power following loss of external power from the grid. Although these systems might fail during earthquakes, causing cascading catastrophic economic and life losses, they have received little attention in terms of investigating their seismic performance. However, after recent extreme events (e.g., the Fukushima nuclear disaster), such risk mitigation systems have been attracting more attention to ensure their functionality during extreme events. This paper investigates the seismic performance and modes of failure of battery rack systems that are currently used in several critical facilities. Shake table tests were performed at different ground motion levels, following the recommendations of the FEMA 461 guidelines. The results demonstrated that the design guidelines and fragility curves currently assigned to battery rack systems in the FEMA P-58 prestandards do not encompass all possible failure mechanisms. This paper not only enlarges the experimental database of the seismic performance of battery rack systems, but also facilitates the adoption of these systems within the next generation of performance-based seismic design standards.