【摘要】 为研究体外预应力超高性能混凝土（Ultra-high Performance Concrete,UHPC）无腹筋梁的抗剪性能，设计了3片体外预应力UHPC无腹筋梁，剪跨比分别为1.44、2.56、3.67，采用四点加载的方式进行抗剪性能试验，获得了试验梁的荷载-位移关系、荷载-应变关系、破坏形态以及极限抗剪承载力。试验结果表明：体外预应力UHPC无腹筋梁的抗剪破坏方式均表现为脆性破坏，随着剪跨比的增大，试验梁破坏形态依次表现为斜压破坏、剪压破坏、剪拉破坏；剪跨比越大，斜裂缝的数量越少、倾角越小，试验梁的极限抗剪承载力越小，且减小趋势变缓。基于极限平衡法推导了体外预应力UHPC无腹筋梁的抗剪承载力计算公式，验算了14片无黏结预应力UHPC梁的抗剪承载力，该公式适用性良好。更多还原

【Abstract】 In order to study the shear behavior of externally prestressed ultra-high performance concrete(UHPC) beams without stirrups, three externally prestressed UHPC beams without stirrups were fabricated. The shear behavior of the test beams was investigated by four-point loading with three shear span ratios of 1.44, 2.56 and 3.67,respectively.The load-displacement relationship, load-strain relationship, failure mode, and ultimate shear bearing capacity of the experimental beam were obtained. The experimental results show that the shear failure modes of externally prestressed UHPC beams without stirrups all exhibit brittle failure. As the shear span ratio increases,the specimens are failed by diagonal compression, shear compression and shear tension. The larger the shear span ratio, the less diagonal cracks and the smaller the angle of inclination. The ultimate shear capacity of the test beams also decreases with the increasing shear span ratio and the decreasing trend becomes slower. Based on the ultimate equilibrium method, the formulae for calculating the shear capacity of externally prestressed UHPC beams without stirrups are derived. The shear capacity of fourteen unbonded prestressed UHPC beams is verified, which is of good applicability.更多还原