A simplified fatigue model for CFRP-strengthened RC beams under the coupling action of a hot–wet/saline environment and cyclic loading

• Published in: International journal of fatigue Vol. 187; p. 108444
• Main Authors: Luo, Shanshan, Li, Wen, Chen, Zhanbiao, Guo, Xinyan, Li, Dongyang, Lin, Jiaxiang, Qin, Guang, Huang, Peiyan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2024
• Subjects: Carbon fiber-reinforced polymer; Fatigue life; Fatigue model; Hot–wet/saline environment; RC beam; Fatigue life; Hot–wet/saline environment; Fatigue model; RC beam; Carbon fiber-reinforced polymer
• ISSN: 0142-1123; 1879-3452
• DOI: 10.1016/j.ijfatigue.2024.108444

•A salt spray environment system capable of being coupled with cyclic loading was developed.•A linear simplified hot–wet/saline environmental fatigue model was developed.•Higher unit temperature and humidity reduced the fatigue limit similarly to the simplified model.•Higher unit salinity decreased the fatigue limit approximately 7.2 times more than temperature. Reinforced concrete (RC) structures in subtropical coastal areas are subjected to the combined influences of temperature, humidity, and salt exposure. Previous studies on the fatigue failure of fiber-reinforced polymer (FRP)-RC structures did not consider the coupling effect of the environment and loading. In this study, a simplified hot–wet/saline environmental fatigue model was developed to consider the linear influence of environmental parameters, including temperature, humidity, and salinity. Then, a closed environmental box was self-designed to provide the temperature–saline environment. By simulating a subtropical coastal environment with typical salinity levels (0, 3, and 5 wt% NaCl) and temperatures (10, 35, and 50 °C), fatigue tests were conducted on 38 typical carbon fiber-reinforced polymer–RC beams. In assessing the simplified model’s predictive accuracy, the average errors for estimating the fatigue limits and lives in the validation groups with or without saline conditions were 4.1 % and 33.7 %, respectively. The simplified model indicated that higher unit temperature and humidity similarly reduced the fatigue limit and that higher salinity decreased the fatigue limit by approximately 7.2 times greater than temperature or humidity. This research provides valuable insights into the strength design and life prediction of RC structures in the offshore or subsea regions of subtropical coastal areas.