波形钢腹板预应力混凝土曲线组合梁弯扭作用机理及计算理论研究

The prestressed concrete composite beam with corrugated steel webs has some advantages such as lighter weight, higher shear strength of web, and more efficient of prestressing, but when it is used in curved beam bridge, the stress behavior and structural details will be changed due to the bending-torsional coupling effect. At present, the research on the bending-torsional mechanism and calculating theory of the curved PC composite beam with corrugated steel webs is still rather lack. In this project, the whole-process static model test of the simple and continuous curved PC composite beams with corrugated steel webs will be conducted, the change law of the bending-torsional effect with the design parameters will be obtained; The analytical results of the bending-torsional stress behaviors of the curved PC composite beam with corrugated steel webs will be deduced by energy-variational principle in elastic stage; Based on the analysis of the distortional effect, the strengthening mechanism of the diaphragms on the distortional stiffness of the curved PC composite beam with corrugated steel webs will be discovered, and the calculation method of the diaphragms space will be given; By analyzing the influence of the torsional effect on the stress increment of the curved external prestressed tendon, and combined with the test data, the stress increment of the curved external prestressed tendon will be given; According to the experimental results of the continuous curved PC composite beam with corrugated steel webs, the redistribution law of the internal force and the bending-torsional correlativity will be studied. The experimental and theoretical results developed in this project would reveal the bending-torsional mechanism of the curved PC composite beam with corrugated steel webs, give the practical design advices, and provide theoretical basis and technical support for design theory, popularization and application of this type of structure.

波形钢腹板PC组合梁具有自重轻、腹板抗剪强度大、预应力效率高等优点，但应用于曲线桥时会由于弯扭耦合效应引发受力机理和构造细节上的相应改变，而目前关于波形钢腹板PC曲线组合梁弯扭作用机理及计算理论的研究还相对缺乏。本项目通过波形钢腹板PC简支及连续曲线组合梁的全过程静载模型试验，得到各种弯扭效应随设计参数的变化规律；采用能量变分法获得弹性阶段波形钢腹板PC曲线组合梁弯扭受力性能的解析解；通过畸变效应分析明确横隔板对该类结构抗扭刚度的增强机制，并给出横隔板间距的计算表达式；分析扭转效应对曲线体外预应力筋应力增量的影响，结合试验结果，给出其应力增量的计算方法；根据波形钢腹板PC连续曲线组合梁的试验结果，研究内力重分布规律，给出弯扭相关关系表达式。项目成果可从试验及理论两个角度揭示波形钢腹板PC曲线组合梁的弯扭作用机理，给出实用设计建议，为此类结构的计算理论和推广应用提供理论依据和技术支撑。

波形钢腹板PC组合梁具有自重轻、腹板抗剪强度大、预应力效率高等优点，但应用于曲线桥时会由于弯扭耦合效应引发受力机理和构造细节上的相应改变，而目前关于波形钢腹板PC曲线组合梁弯扭作用机理及计算理论的研究还相对缺乏。本项目通过波形钢腹板PC简支及连续曲线组合梁的全过程静载模型试验，得到了荷载-挠度和荷载-扭转角曲线、混凝土板开裂机制、应变分布规律、曲线预应力增量、连续梁荷载重分布特征及极限弯扭相关关系，补充和积累了波形钢腹板PC曲线组合梁的弯扭试验数据；采用能量变分法对弹性阶段单箱单室和单箱双室任意截面波形钢腹板PC曲线组合梁的弯扭效应进行了理论推导，采用伽辽金法进行了数值求解，通过参数分析从理论上揭示了波形钢腹板曲线组合梁的弯扭作用机理；通过弹性阶段刚性扭转及畸变效应的理论分析，获得了应力比（弯曲正应力和扭转正应力的比值）的敏感影响参数，并以其为控制条件，给出了横隔板间距的计算表达式；分析了扭转效应对曲线体外预应力筋应力增量的影响，引入曲线内、外侧力筋应力增量沿截面横向的变化梯度η，并结合试验结果给出了η的经验表达式，在其基础上确定了曲线预应力筋应力增量的计算方法；根据波形钢腹板PC连续曲线组合梁的试验结果，研究了正、负弯矩和扭矩的内力重分布规律，给出了不同受力阶段内力重分布系数计算方法；结合模型试验和有限元全过程非线性分析，研究了弯扭效应下波形钢腹板曲线组合梁开裂弯矩和开裂扭矩的折减系数，以及极限弯矩和极限扭矩的计算方法，并给出了弯扭相关关系表达式。项目成果从试验及理论两个角度揭示了波形钢腹板PC曲线组合梁的弯扭作用机理，给出了实用设计建议，为此类结构的计算理论和推广应用提供了理论依据，对其施工及使用过程中的安全与稳定性提供了技术支持，提高了该领域的研究水平。

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