波形钢腹板混凝土组合箱梁纯扭性能全过程分析

Whole process analysis on pure torsional behavior of concrete composite box girders with corrugated steel webs

为获得波形钢腹板混凝土组合箱梁在纯扭矩作用下全过程的扭矩-扭率曲线,基于混凝土开裂前后2个阶段,建立了组合箱梁纯扭性能全过程分析模型.针对混凝土开裂前阶段,考虑截面宽高比和波形钢腹板形状的影响,提出了组合箱梁弹性扭转刚度的修正公式,同时引入普通钢筋和预应力筋的影响,修正了组合箱梁开裂扭矩计算公式.对于混凝土开裂后阶段,针对RASTM T中混凝土已开裂和忽略混凝土拉应力的不合理假定,提出了考虑扭率计算值修正的组合箱梁纯扭转非线性分析方法.然后,利用C++语言编制了组合箱梁纯扭性能全过程分析计算程序.分析结果表明,模型计算值与试验值吻合良好.该模型可准确预测波形钢腹板混凝土组合箱梁纯扭转受力全过程的扭矩-扭率曲线.

To obtain the whole torque-twist curve of the concrete composite box girders with corrugated steel webs under pure torsion,a whole process analytical model for the pure torsional behavior of the composite box girders is established on the basis of two stages,before and after concrete cracking.As for the stage before concrete cracking,a correction formula for the elastic torsional stiffness of the composite box girders is proposed with considering the impacts of the cross-sectional aspect ratio and the shape of the corrugated steel webs.Moreover,a calculation formula for the cracking torque of the composite box girders is corrected through considering the effects of the steel bars and the prestressed tendons.As for the stage after concrete cracking,a nonlinear analytical method for the composite box girders under pure torsion considering the correction of the calculation values of twists is proposed to correct the unreasonable assumptions that the concrete is cracked and the concrete tensile stress is ignored in RASTMT(rotating angle seftened truss model for torsion).Then,a calculation program for whole process analysis on the pure torsional behavior of the composite box girders is developed basedon C++.The analytical results exhibit the good agreement between the calculated values and the experimental values.This analytical model can accurately predict the whole torque-twist curve of the concrete composite box girders with corrugated steel webs under pure torsion.