预制混凝土预留孔灌浆钢筋粘结性能梁式试验研究

Beam Test of Bond Behavior of the Steel Bars in Grouted Hole of Precast Concrete

通过考虑钢筋直径、混凝土强度、灌浆料强度、钢筋锚固长度以及螺旋箍筋的配箍率5个影响因素,共设计了33个梁式试件来研究混凝土预留孔灌浆钢筋的粘结锚固性能。结果表明:试件发生了钢筋屈服和粘结破坏两类破坏形式,其中,采用C50与C60灌浆料、锚固长度为5倍钢筋直径的梁式试件均发生了粘结破坏,其余试件均为钢筋屈服破坏;钢筋直径越小、灌浆料强度越高、螺旋箍筋配箍率越高、钢筋锚固长度越长、混凝土强度越高,钢筋的粘结锚固性能越好。此外,根据试验结果拟合得到了预制混凝土预留孔灌浆钢筋极限粘结强度的经验公式,与实测结果的误差约为4.7%,吻合良好。

Considering the following five influencing factors,such as the diameter of steel bar,the strength of concrete, the strength of grouting material,the anchorage length of steel bar and the stirrup ratio of spiral stirrup,a total of 33beam specimens were designed to study the bond and anchorage performance of grouted rebar.The test results show that two kinds of failure modes,yielding and bonding failure,occur in the specimens.Among them,the specimens with C50and C60 grouting materials and the anchoring length of 5times the diameter of steel bar specimens all suffered from bond failure. All of them are yielding failure of steel bar.The smaller the diameter of steel bar is,the higher the strength of grouting material is.The higher the stirrup ratio of spiral stirrup is,the longer the length of bar anchorage and the higher of concrete strength is.In addition,based on the test results,the empirical formula of the ultimate bond strength of the precast concrete grouting rebar was obtained,which is in good agreement with the measured result of about 4.7%.