预应力混凝土梁抗剪承载能力上限值研究

Study on the Upper Limit of Shear Capacity of Prestressed Concrete Beams

根据《公路钢筋混凝土及预应力混凝土规范》(以下简称《公路桥规》)计算出的预应力混凝土梁式桥的抗剪承载能力上限值明显偏小,且未考虑预应力对抗剪承载能力上限值的有利影响,这对大跨度梁式桥的经济指标影响很大。采用类比及理论分析方法研究后认为,可将《公路桥规》中抗剪承载能力上限值计算公式前面的系数提高至0.62,且应根据预应力度对结构的抗剪能力上限值考虑1~1.25的放大系数。

The upper limit value of shear bearing capacity of prestressed concrete beam bridge calculated according to “Specifications for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts”(hereinafter referred to as “Highway Bridge Code”) is obviously small, without considering the favorable influence of prestress on the upper limit value of shear bearing capacity, which has a great impact on the economic index of long-span beam bridge. By analogical and theoretical analysis, it is considered that the coefficient in front of the calculation formula of the upper limit of shear bearing capacity in “Highway Bridge Code” can be increased to 0.62, and the improvement coefficient in the range of 1 to 1.25 should be considered for the upper limit value of shear capacity of the structure according to the degree of prestress of the structure.