Corrosion induce loss of cross section and section stiffness. We usually repair this damage with high strength bolted steel patch plates. However, the repair work is often carried out under dead load and also conducted by one side depending on working space and the corrosion extent. In this study, the experiment and FEM analysis is carried out to confirm the effect of preload such as dead load on the mechanical behavior of one / both side repaired member. In result, Preload and eccentric bending moment of one-side repair decrease yield strength and load sharing ratio of patch plate after yield limit state. The load sharing ratio of patch plate can be calculated with beam theory considering eccentric bending moment and improved by constraint out-of-plane displacement.
