混凝土梁抗剪承载力加固新方法的试验研究

Experimental study on a new method to improve the shear capacity of concrete beams

提出了在混凝土梁抗剪承载力不足时的一种加固新方法,即采用钢筋后锚固于混凝土梁的受剪区域,使之起到箍筋或弯起钢筋的抗剪作用,并制作试件对此进行了试验研究。研究结果表明,对比未加固的试件,采用本方法加固后,后锚固筋的存在迟滞了裂缝的发展,提高了开裂荷载,减小了相同荷载作用下的裂缝宽度,使裂缝由宽而稀变为细而密,表现出了良好的受力状态,并大幅度地提高了梁的抗剪能力。考虑到后锚固筋受力相对滞后的试验现象,在计算方法上,本加固方法采用了混凝土梁中弯起钢筋抗剪的计算公式并稍加改进后进行承载力估算,计算结果与实测值较为接近,并具有一定的安全储备。

A new method of post-installed bars through concrete beam in shear region is proposed,and the bars will play the role of shear reinforcement.Three specimens were made and tested.The results indicate that the anchoring tendons can delay cracking,narrow the width of the crack,and improve the shear capacity of the beam.Because of stress hysteresis of the post-installed bars,the formula of bend bar in beams can be used in this method with little improvement.The calculation result is closed to that of experiment,and has safety margin.The anchorage of the reinforcement material is effective.