快速施工钢—混组合小箱梁桥静力行为分析与试验研究

发布时间：2018-07-09 21:27

本文选题：快速施工 + 钢-混组合梁　；参考：《浙江大学》2017年硕士论文

【摘要】：围绕现有城市及交通基础设施建设中进行中小跨径桥梁更换、维护或新建桥梁存在的交通干扰大、施工易受气候影响及质量难以控制等问题,提出了一种面向工厂化预制生产、高度小、刚度大、能充分发挥钢材及混凝土材料的强度、适应快速施工的高性能钢-混组合小箱梁桥。在对其结构设计和施工方法的关键技术进行讨论后,设计制作了相应的试验模型梁,进行了不同群钉参数模型梁的试验研究、数值分析及整桥的有限元分析,主要工作及成果如下:(1)讨论了快速施工高性能钢-混凝土组合小箱梁桥的标准模数选取,横隔板的布置,桥面板的型式与划分,高性能混凝土的应用,纵、横向接缝的联接方式,群钉的设计与布置,预应力的配置,整体的设计、施工安装等关键技术问题。(2)模拟高性能钢-混组合小箱梁的快速施工,设计制作了四片快速施工高性能钢-混组合小箱梁模型梁。通过试验研究,得到了不同群钉的布置间距、数量和焊钉的几何尺寸对其受力行为的影响,给出了挠度、应力以及极限抗弯承载力的计算建议。(3)建立单梁精细有限元模型,分析了荷载作用下的挠度、承载力、滑移量、和应力结果,数值计算结果与试验结果吻合较好,研究得到了适合群钉组合梁的建模方法和理论计算公式。采用塑性设计方法能够很好的得到群钉组合梁的极限抗弯承载力;按照换算截面法计算得到的钢梁底板应力要比实测值和有限元分析得到的应力大。(4)根据群钉组合梁的劈裂机理,通过建立精细化的有限元推出试件模型,分析群钉和混凝土在复杂应力状态下的性能,并给出相应的改进建议。参数分析后发现,施加横弯力和预压应力后,焊钉的平均抗剪力和抗剪刚度均有显著提高;焊钉的高度大于其直径的4倍后,焊钉高度变化对群钉中焊钉的平均抗剪承载力和抗剪刚度影响不大。(5)采用壳单元模拟桥面板和薄壁钢梁,用弹簧单元模拟组合梁群钉联接的效应,建立了一座40m跨径的快速施工钢-混组合小箱梁桥的数值模型,分析了群钉刚度变化下结构的响应,并对该整桥结构的应力和挠度进行了验算。结果表明正常使用极限状态和承载能力极限状态均符合要求,且具有较高的安全储备。
[Abstract]:Around the existing cities and traffic infrastructure construction of small and medium-sized span bridge replacement, maintenance or new bridges exist in traffic interference, construction vulnerable to climate impact and difficult to control the quality, and so on. This paper presents a kind of high performance steel-concrete composite small box girder bridge with low height and large stiffness, which can give full play to the strength of steel and concrete materials and adapt to rapid construction. After discussing the key techniques of the structural design and construction method, the corresponding test model beam is designed and made, and the experimental research, numerical analysis and finite element analysis of the whole bridge are carried out. The main work and results are as follows: (1) the selection of standard modulus, the arrangement of transverse partition, the type and division of deck slab, the application of high performance concrete, and the longitudinal of high performance concrete composite small box girder bridge are discussed. The key technical problems such as the connection mode of transverse joints, the design and arrangement of group nails, the allocation of prestress, the whole design, the construction installation, etc. (2) simulating the rapid construction of high performance steel-mixed composite small box girder, Four model beams of high performance steel-concrete composite box girder are designed and manufactured. Based on the experimental study, the effects of the arrangement spacing, the number of nails and the geometric size of welded nails on their mechanical behavior are obtained. The calculation suggestions of deflection, stress and ultimate flexural bearing capacity are given. (3) the fine finite element model of single beam is established. The results of deflection, bearing capacity, slip and stress under load are analyzed. The numerical results are in good agreement with the experimental results. The plastic design method can be used to obtain the ultimate flexural bearing capacity of composite beams with group nails. The stress of the steel beam bottom plate calculated by the conversion section method is larger than that obtained by the measured value and the finite element analysis. (4) according to the splitting mechanism of the composite beam with group nails, the detailed finite element model is established. The properties of group nails and concrete under complex stress state are analyzed, and corresponding improvement suggestions are given. After parameter analysis, it is found that the average shear force and shear stiffness of the welded nail are significantly improved after applying transverse bending force and precompression stress, and the height of the welded nail is more than 4 times of its diameter. The variation of nail height has little effect on the average shear bearing capacity and shear stiffness of welded nails in group nails. (5) the shell element is used to simulate the bridge deck plate and thin-walled steel beam, and the spring element is used to simulate the effect of composite beam group nail connection. The numerical model of a 40m span fast construction steel-concrete composite small box girder bridge is established. The response of the structure under the change of the stiffness of the group nail is analyzed, and the stress and deflection of the whole bridge structure are checked and calculated. The results show that both the normal use limit state and the bearing capacity limit state meet the requirements and have a high safety reserve.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441

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