预应力CFRP联合横向增强法在空心板梁桥加固中的应用研究

Research on application of prestressed CFRP combined with transverse reinforcement method in hollow slab girder bridge reinforcement

针对空心板梁桥预应力碳板加固后各梁板间横向传力不畅的问题,提出了预应力碳板联合横向增强的加固方法,开展了采用横向增强前后的实桥验证试验,确立了结合梁板强度、刚度以及整跨横向传力状态的综合评定体系。试验选取某3×16m简支空心板梁桥进行横向增强前后的试验研究,测试在试验荷载作用下各片梁的应变和挠度,探讨采用横向增强前后各片梁的应变、挠度校验系数、相对残余以及横桥向应变、挠度变化规律。得出如下结论:提出了针对空心板梁桥横向传力状态的评价指标-偏离系数标准差σp,得出σp小于15%时,横向传力状态良好;σp大于15%时,横向传力不畅,需增强横向联系;经预应力CFRP加固并横向增强后,荷载试验结果校验系数小于1,相对残余小于20%,偏离系数标准差小于15%,表明结构强度、刚度、恢复原状态能力及横向联系均处于安全状态。

Aiming at the problem of poor transverse force transfer between beams and plates after the reinforcement of prestressed carbon plates of hollow slab girder bridge,the reinforcement method of prestressed carbon plate combined with transverse reinforcement is proposed,the real bridge verification test before and after transverse reinforcement is carried out,and the comprehensive evaluation system for beam-slab strength,rigidity and transverse force transmission state across the entire span is established.In the experiment,a 3×16m simply hollow slab girder bridge is selected for the experimental study before and after transverse reinforcement,the strain and deflection of each beam under the test load are tested,and the variation laws of strain,deflection check coefficient,relative residual and transverse bridge strain and deflection of each beam before and after transverse reinforcement are discussed.It is concluded that:the deviation coefficient standard deviationσp,an evaluation index for the transverse force transfer state of hollow slab girder bridge,is proposed,draw the following conclusions whenσp is less than 15%,the state of transverse force transmission is good;whenσp is greater than 15%,the transverse force transmission is not smooth,and the transverse connection needs to be strengthened;After prestressed CFRP reinforcement and transverse reinforcement,the load test result verification coefficient is less than 1,the relative residual is less than 20%,and the standard deviation of the deviation coefficient is less than 15%.It shows that the structural strength,rigidity,ability of restoring to the original state and transverse connection are all in a safe state.