变截面波形钢腹板组合梁桥的剪切变形及剪切屈曲研究

The composite girder bridge with corrugated steel webs is a competitive solution in the bridge design. Variable cross-sections, cantilever construction and partially encased composite webs are commonly adopted to fit the increase of the bridge span. Owing to these structural characteristics, there exists remarkable difference between uniform girders and non-uniform girders in the aspects of shear stress distribution, shear deformation and shear buckling. This project is devoted to the systematical study of shear behavior and shear analysis of long-span composite girder bridge with corrugated steel webs, especially considering the effect of variable cross-section, the phase of cantilever construction, and the use of partially encased composite webs. First of all, a general approach for shear stresses of arbitrary non-uniform composted beams will be derived, for the purpose of capturing the shear force distribution between the concrete slabs and steel webs along the bridge span. After that, analytical shear-deformation approaches for the conditions of bridge construction and bridge completion will be respectively explored, in order to provide a theory basis for the bridge deflection prediction. Finally, by means of strut-and-tie modelling and model testing, the shear transfer mechanisms of specimen girders with corrugated steel webs and/or encased composite webs will be disclosed. In a word, this project will provide analytical solutions to shear stresses, shear deformation, and shear buckling of non-uniform composite girder bridges. Moreover, practical approaches for the bridge design will also be suggested, such as the refined analysis of shear stresses, the prediction of bridge deflection, the calculation of shear buckling strength, and the design of encased composite webs.

波形钢腹板组合梁桥是一种有竞争力的桥型，随跨径不断加大，需采用"变截面、悬臂施工、复合腹板"等建造技术，由此产生的剪应力分布、剪切变形、剪切屈曲问题与等截面梁差异较大。本课题拟针对这些特点，系统开展受剪行为及其分析理论的研究。 首先，研究任意变截面波形钢腹板组合梁的剪应力解析计算方法，以揭示组合截面剪力在翼板和腹板间的分配比例沿桥跨的变化规律；在此基础上，针对悬臂施工状态和成桥状态，探讨考虑变截面效应的剪切变形解析计算方法，为变形精确预测提供理论依据；最后，还将结合拉压杆模型理论和模型试验，研究波形钢腹板和支点附近内衬混凝土复合腹板的剪力传递机制和剪切屈曲承载力计算方法。 本课题旨在攻克变截面波形钢腹板组合梁的"剪应力分布、剪切变形、剪切屈曲"三个关键科学问题，为该类大跨径桥梁的剪应力精细化分析、变形预测、剪切屈曲承载力计算、内衬混凝土构造等关键设计技术问题提供理论依据。

波形钢腹板组合梁桥是一种有竞争力的桥型，随跨径不断加大，需采用“变截面、悬臂施工、复合腹板”等建造技术，由此产生的剪应力分布、剪切变形、剪切屈曲问题与等截面梁差异较大。本课题针对这些特点，系统开展受剪行为及其分析方法的理论和试验研究。. 首先，研究了任意变截面波形钢腹板组合梁的剪应力解析计算方法，以揭示组合截面剪力在翼板和腹板间的分配比例沿桥跨的变化规律；在此基础上，针对悬臂施工状态和成桥状态，探讨了考虑变截面效应的剪切变形解析计算方法，为变形精确预测提供理论依据；最后，还结合模型试验，研究了波形钢腹板和支点附近内衬混凝土复合腹板的剪力传递机制和剪切屈曲承载力计算方法。. 本课题在变截面波形钢腹板组合梁的“剪应力分布、剪切变形、剪切屈曲”三个方面的研究成果，为该类大跨径桥梁的剪应力精细化分析、变形预测、剪切屈曲承载力计算、内衬混凝土构造等关键设计技术问题提供了理论依据。