Cracking behavior of prestressed CFRP strengthened RC beams subjected to wetting/drying cycling under flexural load

Abstract

The cracking pattern and spacing are essential for the structural durability of RC structures strengthened by prestressed CFRP plates. In this study, the effects of prestressing levels and wetting/drying cycling (WDC) on the cracking behavior of RC beams strengthened by prestressed CFRP plates were investigated. A modified model for calculating the average crack spacing was developed by incorporating the interfacial stress between adjacent cracks, the prestressing levels, and the WDCs. The effects of interfacial properties and prestressing levels on the average crack spacing were analytically studied. Besides, four-point bending tests were conducted on seventeen strengthened beams subjected to WDC. The results show that cracking propagation was restrained by prestressing forces but facilitated by WDCs. Moreover, WDC and prestressing force lead to an increase in the average cracking spacing of the strengthened beams. The average cracking spacings calculated by different equations were compared to the experimental results, and it can be found that the modified modelprovides the closer prediction of the average crack spacing for CFRP-strengthened beams under WDC and prestressing.