Seismic Performance Evaluation of Low-Strength Precast Reinforced Concrete Arch Bridge Columns

Precast reinforced concrete (RC) columns are widely used in arch bridge construction due to their efficiency and modularity. However, many columns built in the 1990s, prior to the implementation of modern seismic codes, were constructed with low-strength concrete and lacked adequate detailing, raising concerns about their seismic performance. This study investigates the cyclic behavior of such aging columns through quasi-static tests on three full-scale specimens: an original precast column, a cast-in-place (CIP) reference, and a precast column with L-bar joints and prism-shaped connections. While the precast column exhibited moderately reduced load-bearing capacity compared to the CIP specimen, its ductility remained comparable. Notably, the presence of prism-shaped joints was observed to shift the plastic hinge region upward during testing, potentially reducing the risk of interface shear failure. These findings provide experimental insights into the seismic vulnerabilities of aging precast bridge columns and offer practical references for developing targeted retrofitting strategies.