Time-varying Flexural Reliability Analysis of RC Beams Strengthened with SNSM CFRP under Environment Effects

Abstract In order to evaluate the influences of environmental effects on the reliability of reinforced concrete (RC) beams strengthened with side near surface mounted (SNSM) carbon fibre-reinforced polymer (CFRP), combined with the relevant research results and the actual parameters of strengthened beams, the time-varying functions of the flexural capacity of the strengthened beams considering environmental effect was established. Then, based on the JC methods, the time-varying flexural reliability of RC strengthened beams under different ratios of standard values of dead load and live load was calculated. The results showed that the flexural reliability of RC beams decreased slowly with service time in the early period, and decreased rapidly in the later period. Compared with unstrengthened beams, the reliability of strengthened beams had been improved to a certain extent. When the unstrengthened beams were serviced 70% of the base period T, and then it could continue to be serviced about 16% of the base period T after been strengthened with SNSM CFRP. In general, the SNSM CFRP technique could improve the service time of RC beams. According to the analysis results, it was recommended that the RC beams should be strengthened in the early period to better improve the service time.