有腹筋预应力超高强混凝土梁受剪承载力试验研究

为揭示有腹筋预应力超高强混凝土梁受剪性能,通过11根预应力超高强混凝土梁和4根预应力普通混凝土梁受剪性能试验,对比分析了不同参数对试验梁的破坏形态、荷载-挠度曲线、承载能力和钢筋应变的影响.结果表明:预应力超高强混凝土梁的破坏形态与预应力普通混凝土梁相似,且预应力超高强混凝土梁具有更好的刚度、承载能力和剪切延性.增大剪跨比和箍筋间距均可降低极限承载力,另外,当预应力度大于0.34时,提高预应力度对极限承载力才有积极贡献.建立了有腹筋预应力超高强混凝土梁斜截面受剪承载力的计算公式,计算结果与试验结果吻合较好.此外,利用现行规范(GB 50010-2010)计算有腹筋预应力超高强混凝土梁受剪承载力的计算结果离散性较大,计算结果不稳定.

Experimental Study of the Shear Capacity of Prestressed Ultra-high Reinforced Concrete Beams with Stirrups

In order to investigate the shear behavior of prestressed ultra-high reinforced concrete beams, a total of 11 prestressed ultra-high reinforced concrete beams and 4 prestressed ordinary reinforced concrete beams were tested. The experimental study addressed failure mode, load-delfection curve, ultimate load capacity and the steel strain. The test results have shown that failure mode of prestressed ultra-high reinforced concrete beams is similar with that of prestressed ordinary reinforced concrete beams. Generally, prestressed ultra-high reinforced concrete beams have better higher stiffness and ultimate load capacity, as well as shear ductility. An increase in the shear span-depth ratio or space of stirrups decreases ultimate load capacity. In addition, it has positive effect on the ultimate load capacity for degree of prestress of more than approximately 0.34. A calculating formula for shear capacity of prestressed ultra-high reinforced concrete beams with stirrups was offered. The calculation results agree well with the test conclusions. The current China code (GB 50010-2010) used for the design of prestressed ultra-high reinforced concrete beams is very unstable and the dispersion ratio is high.