钢桁腹组合桥力学模型及其对比

发布时间：2018-10-13 20:24

【摘要】：钢桁腹组合桥采用钢桁腹杆替代传统箱梁混凝土腹板，与混凝土顶底板共同构成组合截面，不仅解决普通腹板易开裂的问题，同时使结构有良好通透性，，造型美观。钢桁腹组合桥具有受力明确、自重轻、施工快且造价低的特点，在国外已经得到广泛应用，但在国内尚处于研究阶段，没有对应的规范体系和工程界通用的分析方法。基于此，本文主要研究、总结钢桁腹组合桥的力学模型，提出适用于工程实际的钢桁腹组合桥有限元分析模型，同时对其力学特性做简要分析，为其在工程上的应用提出合理可行的建议。本文结合有限元分析软件Ansys及Midas Civil建立了三个模型，分别为实体模型、简单梁格模型及精细化梁格模型。以实体模型为参考，对比分析两种梁格模型的计算精度，并通过设置两个代表性荷载工况来分析其力学特性。通过在位移、最大挠度以及混凝土顶底板和钢桁腹杆应力等结构参数的对比来验证钢桁腹组合桥在工程设计中采用空间梁格分析模型的可行性。计算与分析对比表明空间梁格模型具有足够精度，可在钢桁腹组合桥设计中采用。此外，本文采用实体模型分析了钢桁腹组合桥剪力滞后效应。选取三个参数，即钢桁腹杆件壁厚、混凝土顶板厚度及混凝土底板厚度，进行了参数分析；采用了不同的几何特征值，分析其对钢桁腹组合桥有效宽度比的影响。分析结果表明，钢桁腹组合桥在全桥范围内均存在剪力滞后现象，靠近支座处现象更为明显。同时，不同的截面几何参数对有效宽度均有不同程度的影响，在工程设计中有必要进行参数分析来确定钢桁腹组合桥合理尺寸。
[Abstract]:The steel truss web bar is used to replace the traditional box girder concrete web plate, which forms the combined section with the concrete top and bottom slab, which not only solves the problem that the ordinary web is easy to crack, but also makes the structure have good permeability and beautiful shape. Steel truss bellows composite bridge has been widely used in foreign countries because of its clear force, light weight, fast construction and low cost. However, it is still in the research stage in China, and there is no corresponding standard system and general analysis method in engineering field. Based on this, this paper mainly studies, summarizes the mechanics model of steel truss bellows composite bridge, puts forward the finite element analysis model of steel truss composite bridge suitable for engineering practice, and makes a brief analysis of its mechanical characteristics. Some reasonable and feasible suggestions are put forward for its application in engineering. In this paper, three models are established with finite element analysis software Ansys and Midas Civil, which are solid model, simple beam model and refined beam lattice model, respectively. Taking the solid model as the reference, the calculation accuracy of the two models is compared and analyzed, and the mechanical properties of the two models are analyzed by setting two representative load conditions. By comparing the structural parameters such as displacement, maximum deflection and stress of concrete roof and bottom slab and steel truss web bar, the feasibility of using spatial beam lattice analysis model in engineering design of steel truss web composite bridge is verified. The calculation and analysis show that the spatial girder lattice model has enough precision and can be used in the design of steel truss girders combined bridge. In addition, the shear lag effect of steel truss composite bridge is analyzed by using solid model. Three parameters, that is, the wall thickness of steel truss member, the thickness of concrete roof and the thickness of concrete floor, are selected to analyze the parameters, and the effect of different geometric eigenvalues on the effective width ratio of steel truss abdominal composite bridge is analyzed. The results show that there is shear lag in the whole bridge, especially near the support. At the same time, different section geometry parameters have different influence on the effective width, so it is necessary to analyze the parameters in engineering design to determine the reasonable size of steel truss girders.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441

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