HDC加固震损无腹筋混凝土梁受弯性能试验研究

An experimental study on bending behavior of damaged beams reinforced with high ductile concrete

利用高延性混凝土(high ductile concrete,HDC)良好的黏结性能和裂缝控制能力,对19根达到极限承载力的无腹筋混凝土梁进行加固处理,并对其进行四点弯曲性能试验,研究了HDC加固震损混凝土梁受弯的裂缝开展情况、破坏形态、承载力、挠度及应力变化的影响,分析了不同HDC厚度、配筋率对HDC加固震损混凝土梁的受弯性能影响。试验结果表明:利用HDC加固震损混凝土梁的承载能力得到了明显的提高,峰值荷载最高提升89%;破坏后的裂缝较原梁多且发展完全;提高加固层厚度的加固效果要明显优于提高配箍率;开裂荷载及破坏时的极限挠度分别最大提高了250%和189%,延性得到明显改善;最大裂缝没有发生在界面处,新旧混凝土之间黏结非常好,协同工作性能良好。

Using high ductile concrete(HDC)good adhesion properties and crack control ability,19 reinforced concrete beams with ultimate bearing capacity are strengthened.The four-point bending performance test was carried out to study the effects of HDC-reinforced broken concrete beams on the development of cracks,failure modes,bearing capacity,deflection changes,and stress changes.The effects of different HDC thickness and reinforcement ratio on the reinforcement performance of HDC reinforced concrete beams were analyzed.The results show that:the load-carrying capacity of the damaged concrete beam strengthened by HDC has been significantly improved,and the peak load is increased by up to 89%;the fracture after the failure is more than the original beam and the development is complete;the reinforcement effect of increasing the thickness of the reinforcement layer is obviously better than the improvement of the hoop ratio;the ultimate deflection at cracking load and failure was increased by 250%and 189%,respectively,and the ductility was significantly improved.The largest crack did not occur at the interface,the bonding between the old and new concrete was very good,and the cooperative work performance was good.According to the test results,the simplified calculation formula of the flexural capacity of the damaged concrete beams with high ductility was obtained.The calculated values agree well with the experimental results.