BFRP加固重度预裂钢筋混凝土梁受弯承载力试验研究

Experimental study on flexural capacity of severely pre-cracked RC beams reinforced with BFRP

为了研究外贴BFRP加固重度预裂RC梁的受弯承载力,通过设置2组试件,对比分析了BFRP加固重度预裂RC梁的破坏形态、承载力、荷载-挠度曲线和荷载-纤维布应变曲线等。研究结果表明：重度预裂RC梁经BFRP加固后,在加载过程中,跨中混凝土沿原裂缝开裂和扩展,达到极限荷载后,受压区混凝土被压碎,BFRP未发生明显破坏;重度预裂RC梁的受弯承载力可达到同BFRP层数加固基准梁的107.99%（1层BFRP）、95.07%（2层BFRP）和99.34%（3层BFRP）;BFRP加固重度预裂RC梁的荷载-挠度曲线及荷载-纤维布应变曲线的变化规律与基准梁存在差异。根据BFRP加固重度预裂RC梁的破坏特点,并考虑受压区混凝土抗压强度的折减,提出了适用于BFRP加固重度预裂RC梁的受弯承载力计算公式,经过验证,计算值与试验结果吻合良好。

To study the flexural capacity of severely pre-cracked RC beams reinforced with externally bonded BFRP, the failure modes, flexural capacity, load-deflection curves and load-BFRP strain curves of the beams were analyzed by comparing two groups of test specimens. The results show that the concrete in the mid-span of the severely pre-cracked RC beams reinforced with BFRP cracks and propagates along original cracks. The concrete in compressive zone is crushed and the BFRP is not destroyed obviously after reaching the ultimate loads. The flexural capacity of the severely pre-cracked RC beams reinforced with BFRP could achieve 107.99% （one layer of BFRP） , 95.07% （two layers of BFRP） and 99.34% (three layers of BFRP） of the benchmark beams reinforced with the same BFRP layers. The load-deflection curves and the trends of the load-BFRP strain responses of the severely pre-cracked RC beams reinforced with by BFRP are different from the benchmark beams. According to the failure characteristics and considering reduction of the compressive strength of the concrete in the compressive zone, a formula for calculating the flexural capacity of severely pre-cracked RC beams reinforced with BFRP is presented and the calculated values are in good agreement with the experimental results.