宽幅预应力混凝土连续箱梁桥施工裂缝控制研究

发布时间：2018-06-20 11:55

本文选题：连续箱梁桥 + 混凝土　；参考：《重庆交通大学》2016年硕士论文

【摘要】：预应力混凝土连续梁桥随着高速公路和市政工程等基础设施建设的发展而得到迅速发展和广泛应用。然而由于设计、施工等方面不合理因素的影响,部分桥梁在施工或运营阶段出现了各种形式的裂缝。尤其是在桥梁宽度增加后,施工过程中裂缝问题较为突出。为了解决依托工程施工过程中出现的裂缝问题,本文从以下方面展开研究:首先根据国内相关工程实例及本文所依托工程的施工现状,对宽幅箱梁桥悬臂施工所出现的裂缝进行了深入分析。通过现场对比试验,初步确定影响裂缝产生的重要因素。其次对混凝土早期力学性能进行分析,考虑混凝土弹性模量、抗拉强度随龄期的变化,分别从自重、环境温度、水化热、挂篮、预应力、箱梁截面宽度等方面进行仿真分析研究,重点分析箱梁纵、横桥向的应力分布,确定引起箱梁桥施工中裂缝出现的主要因素。分析表明环境降温、挂篮沉降、水化热、横向配筋、箱梁截面宽度是箱梁施工裂缝产生的主要因素。环境降温对裂缝的影响表现在降温时箱室顶板上下表面会出现纵向裂缝;水化热对混凝土裂缝的影响表现在在升温期,顶板上表面会出现横向裂缝;在降温期,顶、底板下表面会出现纵向裂缝;而梁截面宽度降低后以上各工况下均不会出现纵向裂缝。而其中水化热对箱梁施工裂缝的影响最大。最后为解决宽幅箱梁桥出现的施工裂缝,本文分别从挂篮、温度控制、施工工艺、横向配筋等方面提出相关的裂缝控制措施。为寻求经济、合理的防治措施,进行了现场对比试验,通过各方面对比确定宽幅箱梁桥施工裂缝的最终控制措施。对裂缝的处理措施进行总结,提出今后在类似桥梁的设计、施工过程中应注意的事项。
[Abstract]:With the development of highway and municipal engineering, prestressed concrete continuous beam bridge has been developed rapidly and widely used. However, due to the influence of unreasonable factors such as design and construction, some bridges appear various kinds of cracks in construction or operation stage. Especially after the bridge width increases, the crack problem is more prominent in the construction process. In order to solve the crack problem in the construction process of the relying engineering, this paper starts the research from the following aspects: firstly, according to the domestic relevant engineering examples and the construction situation of the project relied on in this paper, The cracks in cantilever construction of wide box girder bridge are analyzed in depth. Through the field contrast test, the important factors that influence the crack are preliminarily determined. Secondly, the early mechanical properties of concrete are analyzed, considering the variation of elastic modulus and tensile strength of concrete with age, from the aspects of self-weight, ambient temperature, hydration heat, hanging basket, prestress, etc. The section width of box girder is simulated and studied. The stress distribution in longitudinal and transverse direction of box girder is analyzed and the main factors causing cracks in construction are determined. The analysis shows that the main factors causing the cracks in the construction of box girder are cooling environment, settling of hanging basket, heat of hydration, transverse reinforcement and section width of box girder. The effect of environmental cooling on cracks is that longitudinal cracks appear on the upper and lower surface of the roof of the chamber, while the effect of hydration heat on the cracks in concrete is reflected in the temperature rise period, the transverse cracks on the top surface of the roof, and the transverse cracks on the top of the roof during the cooling period. Longitudinal cracks will appear on the bottom surface of the bottom plate, while longitudinal cracks will not appear under the above conditions when the width of the beam section is reduced. Among them, the heat of hydration has the greatest influence on the cracks in box girder construction. Finally, in order to solve the construction cracks of the wide box girder bridge, this paper puts forward the relevant crack control measures from the aspects of hanging basket, temperature control, construction technology, transverse reinforcement and so on. In order to seek economic and reasonable preventive measures, field comparative tests were carried out to determine the final control measures for construction cracks of wide box girder bridges. This paper summarizes the treatment measures of cracks and puts forward the matters needing attention in the design and construction of similar bridges in the future.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U445.57

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