纤维织物增强高延性混凝土加固受损RC梁受剪性能试验

为研究二次受力对纤维织物增强高延性混凝土(TRHDC)加固钢筋混凝土(RC)梁受剪性能的影响，对8根TRHDC加固梁和1根对比梁进行了静载试验，分析了纤维织物层数、损伤程度及持载水平对梁破坏形态、荷载-挠度曲线、荷载-箍筋应变曲线及荷载-织物应变曲线的影响。试验结果表明：所有梁均发生了剪压破坏，仅一根梁出现剥离现象；TRHDC可有效限制斜裂缝的发展，延缓箍筋屈服和刚度退化；TRHDC加固显著地提高了梁的受剪承载力和变形能力，最高分别达67%和54%；加固效果未完全随纤维织物层数的增大而提高，与TRHDC面层利用率有关；原梁箍筋屈服之前，损伤程度对加固梁受剪性能的影响不明显，原梁箍筋屈服之后，加固梁受剪承载力随损伤程度的增大而降低；加固效果随持载水平的提高而降低；两层纤维织物的TRHDC可有效修复完全受损RC梁的受剪性能；建立了考虑二次受力的TRHDC加固RC梁受剪承载力的计算公式，且计算值与试验结果吻合较好。

Experimental on the shear behavior of pre-damaged RC beams strengthened by textile reinforced highly ductile concrete

Static load tests were conducted on eight reinforced concrete (RC) beams strengthened by textile reinforced high ductile concrete (TRHDC) and one control beam to study the effect of secondary loading on the shear behavior of TRHDC-strengthened beams. The influence of the number of the textile layer, damage degree of beams, and different sustained loads on the failure mode, load-deflection curves, load-strain curves of stirrups, and load-strain curves of textile were analyzed. The results indicate that all beams fail in shear compression mode, and the debonding phenomenon is only observed in one beam. TRHDC can effectively restrain the development of shear cracks, delay the yielding of stirrups and the stiffness degradation. This strengthening method can significantly improve the shear strength and deformation capacity of RC beams by up to 67% and 54%, respectively. The strengthening effectiveness does not completely increase with the number of the textile layer increase, which is related to the utilization rate of the TRHDC layer. When the stirrup of the original beam does not reach its yielding strength, the damage degree has no obvious influence on the shear behavior of strengthened beams. On the contrary, the shear strength of strengthened beams decreases with the increase of the damage degree. The strengthening effectiveness decreases with the sustained load increasing. The completely damaged RC beams can be restored by the TRHDC with two numbers of the textile layer. A calculation formula for the shear strength of TRHDC-strengthened beams considering the secondary loading was proposed. The calculation values are in good agreement with the test results.