不同方法加固足尺寸RC梁的抗弯性能

对4种常用加固方法加固的矩形截面钢筋混凝土梁的抗弯性能进行了对比试验研究.通过10根混凝土梁的抗弯加固试验,研究碳纤维布(carbon fiber sheet,CFS)、非预应力与预应力钢绞线和黏钢加固RC梁的受弯破坏特征,探讨4种加固方法对梁开裂荷载、屈服荷载、极限承载力和延性的影响,比较各种加固梁的裂缝扩展、挠度和刚度变化.研究表明:1)相比未加固梁,CFS、非预应力与预应力钢绞线和黏钢加固梁的开裂荷载分别提高了27.8%、59.7%、94.4%和73.6%;屈服荷载分别提高了12.4%、26.1%、36.2%和37.6%;极限承载力分别提高了48.0%、71.1%、74.6%和75.6%;极限挠度分别减小了23.6%、21.0%、31.1%和19.6%.2)正常使用状态下,预应力钢绞线加固效果优于非预应力钢绞线.3)钢绞线对提高梁二次刚度作用明显,而钢板作用较小.

Flexural Properties of Full-scale RC Beams Strengthened With Different Methods

Experiments were conducted to investigate the flexural behaviors of eight simply-supported RC beams strengthened with carbon fiber sheets,steel stands,prestressed steel stands,and steel plate individually and two comparative beams.Base on the experimental results,the flexural properties,failure characteristics,and the effect of different rehabilitation methods are analyzed.The cracking load,yielding load,ultimate load,ductility,development of cracks,deflection and rigidity are discussed.Experimental results show that 1) Compared with un-strengthened beams,the cracking load of RC beams strengthened with four different methods mentioned above are improved by 27.8%,59.7%,94.4% and 73.6%,respectively;yielding load are improved by 12.4%,26.1%,36.2% and 37.6%,respectively;ultimate load are improved by 23.6%,21.0%,31.1% and 19.6%,respectively;and ultimate deflection declines by 23.6%,21.0%,31.1% and 19.6%,respectively.2) From the angle of the normal use,the strengthening effect of beams strengthened with prestressed steel stands is better than that of un-prestressed.3) Steel stand can effectively improve the post-yielding stiffness of strengthened beams,while that of steel plate is not very effective.