Novel Method for Retrofitting Superstructures and Piers in Aged Steel Railway Bridges

Deterioration of aging bridges is a serious problem that affects their serviceability and durability. Appropriate repair, strengthening, or replacement work should be performed on aged bridge structures to ensure they remain in good condition. A novel strengthening method using rubber-latex mortar, glass-fiber-reinforced polymer plates, lightweight rapid-hardening concrete, and reinforcement bars is proposed in this article. The strengthening method can be used to strengthen both steel railway bridge superstructures and piers. To confirm the effectiveness of the strengthening method, field tests on a short-span railway bridge and laboratory tests on longitudinal-lateral beam connections and steel piers were performed. Because the structural stiffness of aged steel structures is directly related to the fatigue performance and the seismic behavior of steel piers, the applied load versus displacement and strain responses of the test specimens were of primary interest in the tests. Strain results at key sections were experimentally measured and are reported in this paper. According to the experimental results, the present renovation method can significantly enhance the rigidity and reduce the stress levels in bridge girders, connections, and piers, resulting in the extension of the residual service life of such structures.