钢筋混凝土连续梁抗剪强度研究

Study of shearing strength of R.C. continuous beams

现行《公路桥涵设计规范》（ＪＴＪ０２３－８５）［１］ 尚缺乏计算钢筋混凝土连续梁抗剪强度的计算公式。根据国内外大量的试验研究资料分析，提出了按极限状态法计算这种梁的建议公式、设计方法和构造要求；并通过４ 根较大尺寸（ｌ＝ ５ ｍ ＋ ５ｍ ）的等高度和变高度钢筋混凝土连续梁的试验梁验证，证明所建议的计算公式和设计方法是安全、适用和经济的。当标准跨径ｌ＞ １３ ｍ 时，较原《公路桥涵设计规范》［２］（按容许应力法）可节省抗剪钢筋约１０；当ｌ≤１３ ｍ 时，两者接近相等而略省。

There is still no shear formula in calculating the R.C. continuous beams in the present “Design Code of Highway Bridges and Culverts” (JTJ 023 85). In this paper, the formula of shearing strength in limit state, design method and construction needs for R.C. beams are proposed on the basis of plentful experimental data. The proposed formula are applied in the four larger R.C. continuous beams (l=5 m+5 m ) with constant depth and variable depth, which shows that the proposed formula and design method are safe, applicable and economical. In comparison with the former code (by the allowable stress method),the proposed formula can save about 10% shear reinforcement for the beam of normal span of l>13 m ,while the shear reinforcement by the proposed formula is nearly equal and less than that by the old formula with normal span of l≤13 m .