Developing method for repairing and strengthening i-section steel-concrete composite beams with HM-CFRP.

There are two options to solve problems of steel bridges, which are suffering from loss in cross section due to corrosion or those whose cross sections are insufficient as a result of increasing traffic loadings: either to change the beam with a new one or to strengthen the beam. To change the beam is disadvantageous for strengthening as it blocks the traffic flow for a long time and it is uneconomical.Fiber Reinforced Polymer (FRP) materials are preferred in strengthening processes as these materials are resistive against corrosion, thin and light, i.e., they do not cause a significant increase in the weight of the system, and good for preventing the fatigue cracks. As the steel has high strength, FRP material used for strengthening should also have high strength. It is thought that High Modulus Carbon Fiber Reinforced Polymer (HM-CRFP) produced in recent years shows a high performance in strengthening of steel beams.The aim of this study is to increase the rigidity, durability and strength of steel beams by strengthening them with HM-CFRP, to find the correct amount of HM-CFRP to have the required increase in durability of beam, and to determine the useful length of connection in order to achieve a good working condition for HM-CFRP with steel cross section. For this purpose, loading studies were performed on a number of beams and the behaviors of those beams under loading conditions were investigated. The numeric models of beams were made by ABAQUS finite element program and the solutions were verified by experimental results in close proximity. The necessary data were obtained by using the verified numeric model and having many numbers of solutions for beams of different sizes.