The ICCP-SS technique for retrofitting reinforced concrete compressive members subjected to corrosion

Reinforced concrete (RC) stub columns are commonly featured in the construction industry, used in structures such as buildings and bridges. In coastal areas, bridge piers are subjected to serious corrosion damage, which may result in safety issues and huge economic losses. Currently, one of the most widely used retrofitting methods is the application of fiber reinforced polymer (FRP) sheets. This strengthening method can effectively improve the column capacities. However, as time goes by, the corrosion of re-bars will continue, leading to less force resistance. Impressed current cathodic protection (ICCP) is a well-known, efficient method to prevent further corrosion of the re-bars. Therefore, this study uses both ICCP and structural strengthening (SS) techniques to strengthen corroded RC columns. An experimental program consisting of 10 stub columns was carried out, including a 100-day accelerated corrosion process and 100-day ICCP protection and compression tests. Results show that the proposed ICCP-SS retrofitting method is not only effective in retarding the corrosion of steel but also capable of recovering the compression capacity of the corroded RC columns. In addition, comparisons between the test results and the predictions for RC column strengths by existing international design codes are made. The existing design methods were found to be conservative for the compression design of retrofitted columns.