超高性能混凝土梁正截面承载力

Normal Section Bearing Capacity of Ultra High Performance Concrete Beam

对超高性能混凝土（UHPC）的单轴受压应力—应变全曲线和UHPC梁的受力性能进行试验研究及理论分析。试验结果表明：UHPC具有良好的受压变形性能,其应力峰值点应变达0.003 5,极限应变可达0.0045;UHPC梁具有良好的受拉变形能力及裂缝分布,其极限变形达梁跨径的1/30.1-1/71.8,梁体的混凝土应变基本符合平截面假定。基于UHPC的初裂抗拉强度得到的UHPC梁截面塑性影响系数为1.53,并据此建立UHPC受弯构件的开裂弯矩计算公式和极限承载能力计算公式,预测UHPC梁的破坏模式、开裂弯矩以及极限弯矩。计算结果具有较高的精度。

The experimental investigation and theoretical analyses were carried through on the uniaxial compressive stress-strain complete curve of Ultra High Performance Concrete （UHPC） and the mechanical behavior of the prestressed UHPC beams. Results show that the UHPC has good compressive deformation performance. The strain at the peak stress of UHPC UHPC beams have good tensile deformation capacity is about 0. 003 5 and the ultimate strain is 0. 004 5. and crack distribution. The ultimate deformation of UHPC beams is 1/30.1-1/71.8 of the beam span, and the concrete strain distribution of the beam body basically accords with the plane section assumption. The plastic influence coefficient of UHPC beam section is 1.53, which is obtained based on the tensile strength of the initial cracking. Accordingly, formulae for calculating the cracking moment of UHPC flexural member and the ultimate bearing capacity are established to predict the failure mode, the cracking moment and the ultimate moment of UHPC beams. The computed values are of high precision.