预应力碳纤维布加固钢筋混凝土梁的抗弯性能试验研究

Experimental study on flexural behavior of RC beams strengthened with prestressed CFRP sheets

通过9根预应力碳纤维布加固的钢筋混凝土梁在不同预应力水平和不同配布率下的抗弯性能试验,研究其开裂荷载、屈服荷载、极限荷载、曲率延性等受力性能。试验结果表明,梁的破坏形态均为碳纤维布拉断;梁的开裂荷载及屈服荷载随碳纤维布的预应力水平或配布率的提高而提高,但屈服荷载的提高幅度明显小于开裂荷载的提高幅度。另外,配布率较低、预应力水平较高的梁的开裂荷载与屈服荷载高于配布率较高而预应力水平较低的梁的开裂荷载与屈服荷载。梁的极限荷载随配布率的提高而提高。在较高配布率情况下,梁的极限承载力随预应力的提高而略有提高。加固梁的曲率延性系数随预应力和配布率的提高而减小。为保证加固梁破坏时具有一定的延性,建议预应力水平最高控制在40%~50%。

Nine RC beams strengthened with prestressed CFRP sheets are tested with different prestressing level and CFRP ratio,and cracking load,yielding load,ultimate load and curvature ductility of these beams are studied.It is observed that the failure modes of the beams are tensile failure of CFRP.The cracking load,yielding load increase with increase of prestressing level or CFRP ratio,but increase of yielding load is much less than that of cracking load.Beams with low CFRP ratio and high prestressing level have larger cracking load and yielding load than those with high CFRP ratio and low prestressing level.To improve CFRP ratio can increase the ultimate load,and there is small growth of ultimate load with the improvement of prestressing level under condition of high CFRP ratio.The curvature ductility factors of beams decrease with the increase of CFRP ratio or prestressing level.The the maximum of prestressing level is recommended to be between 40% to50% to guarantee the beam's ductility.