CFRP加固组合石梁受剪性能试验研究

进行了2根素石梁和6根组合石梁的单调加载试验,研究在弯剪段环形包裹CFRP条带对于提高组合石梁受剪性能的作用.2根组合石梁加载至弯剪段开裂即停止加载并采用环形包裹CFRP条带进行抗剪修复,作为断损修复试件;2根组合石梁加载前即进行抗剪加固,作为加固试件,以此对比断损修复和加固的效果.试验中,加固试件和断损修复试件均发生变形明显的弯剪破坏,同时伴随CFRP条带断裂.试验结果表明,环形包裹CFRP条带可以有效防止组合石梁弯剪段开裂后突然发生剪切断裂,提高试件的受剪承载力和变形能力,且加固的效果好于断损后修复.此外,提出了环形包裹CFRP条带加固组合石梁的受剪承载力计算公式,计算结果与试验结果吻合良好.

Experimental investigation on shear behavior of composite stone beams strengthened with CFRP strips

Monotonically loading tests were conducted on two plain stone beams and six NSM prestressed CFRP-stone composite beams to investigate the effect of CFRP wrapping on the shear strength of specimens. Two unstrengthened composite stone beams, serving as the control specimens, were loaded until the initial flexure-shear crack occurred, then they were unloaded and strengthened in shear with CFRP strips and served as strengthened damaged specimens. The other two beams were strengthened in shear before loading and served as strengthened undamaged specimens. The strengthening effect between damaged and undamaged beams was studied. All the specimens strengthened in shear failed in the mode of flexure-shear failure, accompanied by the rupture of CFRP strips. Experimental results show that, CFRP wrapping could effectively prevent the abrupt shear failure of composite stone beams when cracking occurred in the flexure-shear zone, and significantly enhanced the bearing capacity and deformation capacity. The strengthening effect in strengthened undamaged specimens was more remarkable than that in strengthened damaged specimens. In addition, a model to predict the shear resistance of strengthened beams was promoted, and the computed results showed good agreement with the experimental results.