Earthquake Response and Damage Evaluation of a Heritage Masonry Arch Bridge in Türkiye

Historical masonry bridges in many developing countries are highly vulnerable to seismic damage due to their construction without consideration of regional earthquake risks. This study investigates the seismic behavior of a historical masonry arch bridge that remains in active use. A detailed Finite Element Model (FEM) of the structure was developed using ABAQUS software based on original architectural drawings. Nonlinear time-history analyses were performed using 110 ground motion records to determine seismic demands. Mid-span lateral displacements were used to define damage states under varying seismic intensity levels, based on multiple scaled ground motion records. Analytical fragility curves were derived to estimate the probability of exceeding specific damage levels under varying seismic intensities. To complement the global vulnerability assessment, the Concrete Damaged Plasticity (CDP) model was employed to evaluate localized damage patterns, including tensile and compressive failure mechanisms. Results revealed that damage tends to concentrate at the arch bases and span ends, aligning with stress concentrations under seismic loads. The study provides a comprehensive framework for assessing the seismic performance of historical masonry bridges and highlights the necessity of structure-specific evaluations. The methodology and findings are applicable to similar masonry bridge typologies in other earthquake-prone regions, supporting future conservation and retrofitting strategies.