Retrofitting of Railroad Bridge Piers Using a Novel Hybrid Jacket

The objective of this study is to introduce and evaluate a new hybrid jacket for retrofitting plain concrete columns of railroad bridges subjected to the lateral and axial loadings. In a steel plate- FRP (STF) composite jacket, at first the steel strips are attached in the longitudinal direction to the concrete column using epoxy adhesive. Then, FRP jacket at the transverse direction is used to provide lateral confinement and to prevent buckling of attached steel plates. At the present paper, experimental study on the concrete cylinder specimens was performed to assess the effectiveness of the proposed jacketing method and also to compare with common retrofitting methods. A total of eleven concrete cylinders of 100 mm x 200 mm were fabricated with specified concrete strength of 27 MPa. An unreinforced specimen was benchmark, and the others were reinforced using different jacketing methods. All of the specimens are tested using universal testing machine (UTM). Some important parameters, such as axial strength, energy dissipation and elastic stiffness were obtained and compared for all specimens. Based on the obtained results, specimen jacketed using proposed method indicated the best performance among all the jacketed specimens and can be used for retrofitting of plain concrete railroad bridge piers.