端部机械锚固FRP-混凝土黏结界面承载力试验研究

采用胶-机械混合锚固体系可以有效防止纤维增强复合材料 (FRP)与混凝土之间的早期剥离破坏，提高FRP材料的强度利用率。为明确端部锚固对黏结界面性能及破坏形式的影响，进行了不同锚固形式的FRP-混凝土黏结结点的单面剪切试验，对比分析了纯外贴锚固（EB）、普通混合锚固（HB）和自锁混合锚固(SLHB)三种不同端部锚固形式的锚固性能。对于HB-FRP加固方法，探究了FRP黏贴长度和机械锚固扣件施加扭矩大小对加固效果的影响。结果表明：采有EB、HB、SLHB锚固形式的FRP加固构件破坏形式分别为界面剥离、FRP滑动拉出和FRP拉断（强度利用率为1.0）；采用SLHB-FRP和HB-FRP加固方法的试件相比采用EB-FRP加固方法的加固构件在15N·m的扭矩下可以提高承载力约122.9%和56.4%，采用EB-FRP和HB-FRP加固方法试件的FRP强度利用率分别为0.448和0.702；随着扭矩的增大，采用HB-FRP加固方法的试件极限荷载也有不同程度的提升，且失效荷载与扭矩线性相关；对于自锁混合锚固形式，在15kN·m的扭矩作用下，FRP强度均能得到100%利用，失效荷载均为FRP拉断荷载，与黏结长度无关。

Experimental study on bearing capacity of FRP-concrete bonding interface with mechanical end anchorage

The adhesive-mechanical hybrid bonding system can effectively prevent the premature debonding failure of interface of fiber reinforced polymer (FRP) and improve the strength utilization rate of FRP material. In order to identify the effect of end anchorage system on the bond behavior and failure mode, a series of single shear tests of FRP-concrete bond joints with different anchorage types were carried out. The anchoring behavior of three different anchorage types, respectively named as external bonded (EB), normal hybrid bonded (HB) and self-locked hybrid bonded (SLHB), were studied in the test. For HB-FRP reinforcing method, the influence of bond length of FRP and the torque applied to the mechanical anchorages was investigated. The test results show that the failure modes of FRP to concrete interface were respectively interfacial debonding for EB specimens, FRP pulling out from anchorage system for HB specimens, and FRP fracture for SLHB specimens (strength utilization ratio is 1.0). Compared with EB specimens, HB and SLHB anchorage types can increase the bearing capacity at 15 N·m by 122.9% and 56.4%, respectively. The FRP strength utilization ratios for EB and HB-FRP specimens are 0.448 and 0.702，respectively. For the HB specimens, the ultimate load is increased with the increase of torque. The failure load is linearly dependent on the torque. For SLHB specimens, the FRP strength can be fully utilized by 100% under the torque of 15 kN·m. It is also showed that the failure load is tensile load, and has nothing to do with bond length.