后成型端部缺口梁抗剪加固试验研究  

Experimental Analysis on Shear Strengthening Capacity of Secondary Dapped-end Beams

作　　者：李曰辰[1] 卢义焱[2] 陈明祥[2] 高作平[1] 

机构地区：[1]武汉大学水利水电学院,武汉430072 [2]武汉大学土木建筑工程学院,武汉430072

出　　处：《土木建筑与环境工程》2012年第4期38-45,共8页Journal of Civil,Architectural & Environment Engineering

基　　金：湖北省重点科学技术发展计划项目(20001P2104)

摘　　要：采用粘型钢法对钢筋混凝土简支梁进行抗弯加固时,由于底部型钢不能伸到支座中去,端部形成缺口,称为后成型缺口梁,缺口使梁端部的应力状态更加复杂。通过对21个梁试件的试验,研究了缺口梁粘钢板抗剪加固的变形过程、受力性能和破坏特征。结果表明,粘贴横向和45°斜向钢板2种方式加固效果均良好,明显推迟了梁上裂缝的出现,极限承载力最大分别提高了102%和93%。由于受缺口处应力集中的影响,破坏主要模式为混凝土拉坏或剪坏并导致钢板粘接失效,破坏具有一定的过渡过程。改变粘贴钢板的宽度,研究不同粘钢量时的加固效果,并在此基础上,运用桁架比拟理论建立缺口梁端部的力学模型,并根据试验数据回归出相应的抗剪加固承载力计算公式。Because section steel can only be extended to the edge of the support,when a simple-support RC beam is reinforced by bonded section steel,a notch comes into being at the end of the beam which is called a secondary dapped-end beam,making the stress state of the beam more complex.Through experimental analysis on 21 dapped-end beam specimens shear reinforced by steel plate bonded,the deformation process,performing characteristics and failure mechanism of the specimens were investigated.The result shows that two steel bonded forms,including horizontal steel plate and oblique steel plate with angle 45° bonded,delay the appearance of cracks significantly and improve the maximum bearing capacity by 102% and 93%.Due to the impact of stress concentration at the notch,the main modes of damage include concrete tensile or shear failure with the result of bonding failure of a steel plate.By changing the width of steel plates and analyzing different reinforcement effects,formula of bearing capacity of shear reinforcement was proposed based on the method of truss analogue,which provides a reference for engineering application.

关 键 词：缺口梁 加固 抗剪强度 桁架比拟 

分 类 号：TU375.1[建筑科学—结构工程]