后成型端部缺口梁抗剪加固试验探究.docVIP

后成型端部缺口梁抗剪加固试验探究摘 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。 关键词：缺口梁；加固；抗剪强度；桁架比拟 中图分类号：TU375.1 文献标志码：A 文章编号：1674-4764（2012）04-0038-08 Experimental Analysis on Shear Strengthening Capacity of Secondary Dapped-end Beams LI Yuechena, LU Yiyanb, CHEN Mingxiangb, GAO Zuopinga (a.School of Water Resource and Hydropower;b.School of Civil and Architectural Engineering, Wuhan University, Wuhan 430072, P. R. China) Abstract: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. Key words:dapped-end beam; reinforcement; shear strength; truss analogue  针对工程实践中常出现的需大幅度提高梁构件抗弯承载力的情况，文献［1］提出了粘接型钢加固的新方法，该方法在被加固梁底粘接焊接成型的钢梁并采用化学锚栓以