Fatigue life prediction of RC beams strengthened with externally bonded FRP sheets

Abstract

Based on the failed criterion of steel reinforcement fracture, an analytical model is presented for predicting the fatigue life of reinforced concrete (RC) beam strengthened with fiber reinforced polymer (FRP) sheets. In this model, the load cycle is divided into some loading blocks evenly and the stress amplitude of the tensile steel reinforcement is thought to be invariable in each loading block. Considering the degradation of material performance, including concrete creep, the stress amplitude of the tensile steel reinforcement is obtained by using the traditional sectional analysis method. Therefore, the fatigue life of the strengthened beam is carried out by using the well-known Palmgren-Miner rule. The reliability of the proposed analytical model is validated through comparisons with previous test results reported by the relative research groups. The compared results show that the proposed models can predict the fatigue life of the strengthened beam with an acceptable degree of accuracy.