Fatigue testing of corroded RC continuous beams strengthened with polarized C-FRCM plate under ICCP-SS dual-function retrofitting system

The paper presents an experimental investigation into fatigue behaviour of corroded reinforced concrete (RC) continuous beams strengthened by carbon-fabric reinforced cementitious matrix (C-FRCM) under a typical dual-function retrofitting system. The retrofitting system adopted impressed current cathodic protection (ICCP) technique, which is an electro-chemical anti-corrosion technique for anodic polarization to reduce or prevent oxidation of metal, together with structural strengthening (SS) technique, which can effectively restore or improve the bearing capacity of the structure. In the experimental programme, a total of ten RC continuous beam specimens were tested under fatigue loading. The influence of key structural parameters on the fatigue life of the RC beams was examined, including the corrosion degree of the steel bar, fatigue load level, and charge density of C-FRCM plate. The calculation theory based on the transformed-section method for the cyclic stress amplitude of steel reinforcing bar in RC beam strengthened by C-FRCM plate was determined. On this basis, the S-N (cyclic stress amplitude versus cycles to failure) curves of the corroded RC continuous beams strengthened by polarized C-FRCM under the ICCP-SS dual-function retrofitting system were obtained by fitting the relevant fatigue data for fatigue design guidance.