Damage Analysis of Concrete Open-Spandrel Deck Arch Bridges under Seismic Loads

Abstract

Risk assessment of arch bridges can be beneficial for making informed choices following an earthquake by addressing the most vulnerable components. Although several researchers have studied the seismic vulnerability of ordinary bridges, there is a scarcity of in-depth investigation of the seismic performance of arch bridges for both the capacity and demand sides. This paper studies the component- and system-level vulnerability of concrete open-spandrel deck arch bridges by identifying significant geometrical and design attributes through the application of parametric screening. A strain-based approach is presented to determine the component damage state thresholds owing to the insufficiency of detailed information on different component damage levels of open-spandrel deck arch bridges. Two categories of arch bridges with different superstructure-substructure connection types, including monolithic and non-monolithic connections, together with four rise-to-span ratios for each bridge category were considered. Detailed nonlinear three-dimensional analytical models representing the vulnerability of major bridge components as well as the uncertainty in modeling parameters were developed, and fragility analysis was performed by applying nonlinear time history analysis. Results exhibited the predominant role of the connection type between the deck and substructure as well as the rise–span ratio on the failure probability of arch bridges. Arch bridges with a non-monolithic superstructure–substructure connection type revealed more vulnerability at lower damage levels compared with arch bridges with the monolithic connection, while an opposite trend is observed in higher damage states. In summary, arch bridges with the non-monolithic connection type demonstrated enhanced seismic performance regarding the functionality and vertical stability of the bridge.