钢板加固箱型混凝土梁受弯性能研究

Experimental study on flexural performance of box type concrete beams strengthened with steel plate

为研究钢板加固箱型混凝土梁的受弯性能及其影响因素,对8根不同混凝土强度、配筋率、钢板加固量、U型箍间距的箱型混凝土梁进行了受弯试验。结果表明:钢板加固能够很好地改善梁的受弯性能,未加固的箱型混凝土梁表现为超筋梁破坏现象,加固的箱型混凝土梁表现为受压区混凝土被压碎,受拉钢筋及钢板达到屈服且未发生钢板与混凝土剥离破坏现象;钢板加固使箱型混凝土梁的屈服荷载提高了45%~143%,使极限荷载提高了74%~183%,提高幅度明显;钢板加固属于被动加固,故对梁的开裂荷载影响不大;钢板加固箱型混凝土梁可以使刚度得到显著提高;箱型混凝土梁的屈服荷载、极限荷载、刚度均随着混凝土强度、配筋率、加固量、U形箍间距的增加而增加;钢筋屈服以后,钢板限制了钢筋应变,充分利用了加固材料,加固效果很好。

To study box type concrete beams strengthened with steel plate on flexural properties and influencing factors, eight box type concrete beams are designed with different concrete strength, reinforcement ratio, amount of reinforcement steel plate and U-shaped hoop spacing, corresponding bending tests are carried out. Results show that the flexural performance of the beams can be well improved by steel plate strengthened. The destruction phenomenon of unreinforced box type concrete beams manifests as over bar, reinforced concrete compression zone is crushed, tensile reinforcement and steel plate are yield, and debonding failure phenomenon does not occur between steel plate and concrete. The yield load is significantly improved by steel plate strengthened by 45%~143%, and ultimate load of beams improved by 74%~183%. Steel plate strengthened is a passive strengthened, which has little effect on the crack load, the stiffness of strengthened beams can be significantly improved by strengthened with steel plate. The stiffness, yield load and ultimate load of box type concrete beam are increased with the increase of concrete strength, reinforcement ratio, reinforcement ratio and U-hoop spacing. The strain of steel plate grows rapidly and strain of reinforcement is limited after reinforcement yielding. The strengthened material is useful so the steel plate strengthening may achieve good effects.