U形CFRP条带混锚加固混凝土梁抗剪试验

摘要

为解决纯粘贴 U形纤维增强聚合物基复合材料(FRP)加固钢筋混凝土梁中 FRP 端部容易发生剥离破坏等问题,自主研发了对纤维布条带端部进行自锁锚固的方法和锚板,提出了端锚与粘贴并用的混锚U形条带抗剪加固方法.通过2根未加固梁、1根纯粘贴和2根混锚 U形碳纤维增强聚合物基复合材料(CFRP)带抗剪加固梁的对比试验,证实了混锚抗剪加固的有效性:混锚能够对纤维带端部进行可靠锚固,阻止端部剥离破坏的发生,实现纤维拉断破坏,大幅度提高材料强度利用率.混锚加固在抑制混凝土梁斜裂缝开展、延缓箍筋屈服、提高箍筋和CFRP的极限应变以及提高抗剪承载力等多个方面的表现均明显优于纯粘贴加固.%In order to prevent the premature end-debonding of externally bonded fiber reinforced polymer (FRP) composite used for shear strengthening of reinforced concrete (RC)beams,a novel self-locking anchorage for FRP sheet was developed and a hybrid-anchoring method for FRP U-sheet was proposed,which was bonding the FRP to the surfaces of a beam and anchoring the FRP ends by anchor plates.Five specimens were tested to validate the fea-sibility of the new method,including two control specimen,one specimen strengthened by externally bonded (EB) U-sheets of carbon fiber reinforced polymer(CFRP)and two specimens strengthened by hybrid-anchored U-sheets. The results show that hybrid anchorage can shift the end-debonding of CFRP to the rupture failure and greatly im-prove the fiber-strength utilization.It performs much better than the conventional method of externally bonding in the aspects of restraining the propagation of the diagonal crack,improving the strain behavior of steel stirrups and CFRP,and increasing the shear capacity of RC beam.