Abstract: In order to investigate the long-term performance of carbon fiber reinforced plastics (CFRP) reinforced bridge structures in service environment, the accelerated corrosion experiments of RC beams strengthened by CFRP under different load types coupled with hygrothermal environment were carried out. Under three working conditions of no-load, static load and alternating load coupled with hygrothermal environment, the stress, deformation, bending capacity and damage evolution law of the test beam were discussed, and the damage mode of the beam body and the bond interface was analyzed. The transfer rule of shear stress at CFRP bonding interface was revealed by microelement analysis. The results show that the plasticization of the adhesive layer and the hydrolysis of the matrix are the main causes of the deterioration of the bonding interface properties under the coupling action of load and hygrothermal environment. The coupling action of load and hygrothermal environment, especially the alternating load, promotes the deterioration of the adhesive layer and causes the further deterioration of the mechanical properties of the reinforced structure. The load coupling effect increases the transfer rate of shear stress from the bonding interface to the end of the beam. The coupling effect of alternating load and hygrothermal results in the reduction of ultimate bearing capacity, mid-span deflection and ultimate strain of CFRP strengthened RC beams by 16.8%, 38.3% and 28.3%, respectively.

Key words: bridge engineering; strengthened by CFRP; RC beam; coupling action; damage of bonding interface

摘要： 为探究服役环境下碳纤维复合材料（CFRP）加固桥梁结构的长期性能，开展了不同荷载类型与湿热环境耦合作用下CFRP加固RC梁的加速腐蚀试验，探讨了湿热环境+空载或静载或交变荷3种工况试验梁的受力、变形、抗弯承载力及损伤演化规律，分析了梁体及黏结界面的损伤模式，通过微元体揭示了CFRP黏结界面剪应力的传递规律。结果表明：湿热环境耦合荷载作用下，黏结胶层塑化与基体水解是黏结界面性能劣化的主要原因；荷载尤其是交变荷载与湿热环境的耦合作用促进了黏结胶层的劣化，导致加固结构的力学性能进一步下降；荷载耦合作用增大了黏结界面剪应力向梁体端部传递的速率；交变荷载与湿热环境的耦合作用导致CFRP加固RC梁极限承载力、跨中挠度、CFRP极限应变分别下降了16.8%、38.3%和28.3%。

关键词: 关桥梁工程；CFRP加固；RC梁；耦合作用；黏结界面损伤