预制拼装桥梁节段间接缝抗剪性能试验研究

发布时间：2018-01-22 15:51

本文关键词： 节段预制拼装接缝模型试验抗剪性能直剪承载力直剪破坏模式　出处：《东南大学》2015年硕士论文　论文类型：学位论文

【摘要】：节段预制拼装混凝土桥梁具有以下优点：施工速度快,对周围交通影响小,质量控制易于实现及跨径适应范围大等。节段预制拼装混凝土桥梁适应当代建设施工快节奏的要求,与体外预应力技术相结合,具有良好的技术合理性、耐久性和经济性。接缝是节段预制拼装混凝土桥梁的薄弱部位,其受力性能对于节段预制拼装混凝士桥梁在正常使用极限状态和承载力极限状态下的受力性能均有重要的影响。接缝处的局部剪切破坏在工程实践中发生的概率较高,但是关于接缝局部剪切破坏机理及接缝抗剪承载力的研究较少,目前还没有统一的认识。本文选取正应力水平(2MPa、3MPa、4MPa)、接缝类型(干接、胶接)、接缝构造(平接缝、键齿接缝)、键齿尺寸和接缝插筋(普通钢筋插筋、FRP插筋)为试验参数,设计了14个试件进行节段式混凝土梁接缝抗剪试验,通过试验得出了不同参数条件下试件接缝附近裂缝产生和发展的规律、接缝的破坏模式及抗剪承载力,通过将试验结果进行比较分析,得出了几种参数对接缝抗剪性能的影响。本文对现有的接缝局部抗剪承载力计算公式进行了归纳和总结,并将本文试验所得的接缝抗剪承载力实测值与现有主要计算公式计算值进行了对比。在试验研究和理论分析的基础上,总结出了各种类型接缝的局部剪切破坏机理。对于平接干接缝,基于摩擦理论给出了其抗剪承载力计算公式;对于平接胶接缝,基于M. M. Bakhoum和Xiangming Zhou平接胶接缝试验所获得数据,采用回归分析的方法,得到了平接胶接缝抗剪承载力的半经验半理论公式。对于键齿接缝,以键齿在局部剪切作用下的破坏模式一斜压破坏为基础,结合摩尔应力圆理论,推导出了键齿破坏时的竖向剪切抗力τ的理论计算式,进而提出了键齿干接缝和键齿胶接缝的局部抗剪承载力计算公式。对于插筋加强接缝,根据剪力摩擦理论提出了插筋加强接缝的抗剪承载力计算公式。最后采用本文以及其他学者所进行的接缝局部剪切试验的试验结果对所提出的公式进行了验证,证明了本文所提出的公式具有良好的适用性。本文采用ABAQUS通用有限元分析软件,建立了各个主要模型试验试件的ABAQUS有限元分析模型。通过将有限元分析结果与本文的试验结果进行对比,证明了采用ABAQUS能够较好对试验过程进行模拟。本文对键齿接缝抗剪承载力公式实际应用于节段预制拼装体外预应力桥梁中时可能遇到的一些问题进行了研究。探讨了在实际工程中由于桥梁梁体整体弯曲和预应力损失造成的预应力筋内应力的变化,针对由此引起的接缝面正应力增量,对键齿干接缝和键齿胶接缝分别进行了研究。最后,对于键齿干接缝和键齿胶接缝,分别给出了修正后的接缝抗剪承载力公式。
[Abstract]:Segmental prefabricated concrete bridges have the following advantages: fast construction speed and small impact on the surrounding traffic. The quality control is easy to realize and the span adaptability is large. The segmental precast assembled concrete bridge adapts to the requirement of the fast rhythm of the contemporary construction and combines with the external prestressing force technology, which has good technical rationality. Durability and economy. Joints are weak parts of segmental prefabricated concrete bridges. Its mechanical performance has important influence on the mechanical behavior of segmental precast assembled coagulant bridges under both normal service limit state and bearing capacity limit state. Probability of Local Shear failure at joints in Engineering practice. Higher. However, there are few researches on the mechanism of local shear failure and shear bearing capacity of joints, so far there is no unified understanding. In this paper, the normal stress level of 2MPa / 3MPa / 4MPa is selected. Type of joint (dry joint, glued joint, joint construction (flat joint, key tooth joint, key tooth size and joint insertion (ordinary steel bar / FRP insertion)) are test parameters. Fourteen specimens were designed for joint shear tests of segmental concrete beams. The rules of crack generation and development, failure mode and shear bearing capacity of joints were obtained under different parameters. Through the comparison and analysis of the test results, the influence of several parameters on the shear resistance of butt joint is obtained. In this paper, the existing formulas for calculating the local shear capacity of joint are summarized and summarized. In addition, the measured values of shear bearing capacity of joints obtained in this paper are compared with the calculated values of existing main calculation formulas, on the basis of experimental research and theoretical analysis. The local shear failure mechanism of various types of joints is summarized. The formulas for calculating the shear capacity of flat joints are given based on the friction theory. For the flat seams, the regression analysis method was adopted based on the data obtained from the parallel seams test of M. Bakhoum and Xiangming Zhou. The semi-empirical and semi-theoretical formula of shear capacity of flat joint joint is obtained. For the bond tooth joint, it is based on the failure mode of bond tooth under the local shear action-baroclinic failure, combined with the theory of molar stress circle. The formula of vertical shear resistance 蟿 is derived, and the formula of local shear bearing capacity of joint tooth dry joint and bond tooth adhesive joint is put forward. Based on the shear friction theory, a formula for calculating the shear capacity of reinforced joints is proposed. Finally, the formula is verified by the experimental results of the local shear tests carried out by this paper and other scholars. It is proved that the formula presented in this paper has good applicability. The ABAQUS general finite element analysis software is used in this paper. The ABAQUS finite element analysis model of each main model test specimen is established, and the finite element analysis results are compared with the test results in this paper. It is proved that the test process can be well simulated by using ABAQUS. In this paper, some problems that may be encountered in the practical application of the shear bearing capacity formula of key tooth joints in the precast assembly of externally prestressed bridges are discussed. The change of internal stress of prestressed tendons caused by the whole bending of bridge beam and the loss of prestress is discussed. According to the normal stress increment of the joint surface caused by this, the key tooth dry joint and the bond tooth glue joint are studied respectively. Finally, the key tooth dry joint and the key tooth glue joint are studied. The modified formula of shear bearing capacity of joint is given respectively.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446

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