Experimental and Numerical Modeling on Fatigue Damage in FRP and PM Confinement Tilt’s Fulcrum RC Segments under Humid and Constant Amplitude Loading

It is a stringent challenge to swiftly rehabilitate and strengthen the concrete segments on the metro tunnel that are under the humid environment and vibration fatigue by the locomotives. By means of fatigue experiments under the constant amplitude loading, the repair materials (fiber reinforced polymer (FRP) and polymer matrix (PM)) which can be moisture proof and resist the cyclic load are introduced. Hereafter, a fatigue model of tilt’s fulcrum reinforced concrete (RC) segments under constant amplitude loading are proposed by the calibration of S-N curves through these fatigue test. The fatigue model explains for the (a) scope of pre-damage, (b) mechanical properties of the repaired concrete segments, such as the specific rupture times of cycle and stress-crack opening relation, and (c) effective plastic strain behavior of the RC segments. The results show that the purely PM is an excellent candidate for repairing the fatigue loaded damaged RC segment. It (L-4-2) had an average mechanical behavior for cyclic load bearing compared with the remaining specimens. On the other hand, the numerical model predictions had an approximately 96.00% of agreement with the corresponding test results.