Fragility curves for unanchored medical equipment accounting for building and content interaction

Abstract

Currently, construction codes and standards require nonstructural fragility information to define nonstructural performance objectives and expectations for low- and design-intensity earthquake motions. To address this knowledge gap, this study focuses on the development of analytical fragility curves for unanchored medical equipment commonly found in hospital critical rooms, taking into account the building’s performance, damage progression, and content interaction simultaneously. To achieve this goal, a fully equipped emergency room, intensive care unit, and operating room are simulated on the first, fourth, and fifth floors of a mid-rise hospital building, respectively, and subjected to service, design, and maximum considered earthquake levels under fixed-to-the-base (FB) and base-isolated (BI) support conditions. The building’s floor acceleration responses are used as input motions to assess the performance of several pieces of medical equipment using rolling and sliding nonlinear models. This study has included a comprehensive uncertainty analysis to propagate different sources of uncertainty into the fragility curves. Fragility results indicate that, under FB support conditions, equipment malfunctions and failures are expected to occur during low-intensity earthquake motions, even if the hospital building experiences minor structural damage. Furthermore, knowing the damaged condition of medical equipment (malfunction/failure) is crucial for determining its availability and subsequent use to stabilize critical condition patients or save their lives. Finally, these fragility curves can be used to plan post-disaster recovery and make risk-informed decisions in healthcare facilities.