轻型钢桁网支架在拱桥施工中的应用与研究

发布时间：2018-10-15 17:45

【摘要】：轻型钢桁网支架是一种用在中小跨径拱桥施工中的新型支架,具有质量轻,取材广泛,制作工艺简单,施工便捷和造价低廉等优点,适用于对基础要求较高的中小跨径现浇混凝土拱或预制拼接钢筋混凝土拱。它的推广应用可以缩短施工时间,降低施工成本,带来巨大的社会经济效益。但是由于此施工方法属于较新的工艺,因此缺少相关的理论和实践经验作为指导,因此对轻型钢桁网架做较为深入的研究,对其推广应用是十分必要的。本文针对浙江省湖州市长田漾大桥的拱圈施工,对轻型钢桁网支架做了实践与理论相结合的研究,主要包括以下几个内容：(1)通过对结构进行理论分析,确定了检验结构是否能够满足施工要求的标准。结构检验包括强度验算,刚度验算与稳定性验算三个方面。其中由于支架是由单榀钢拱架通过横向支撑联系成一个整体,通过在节点处绑扎钢管,将拱圈施工荷载转化为钢拱架面内节点荷载,进一步将钢桁网架的强度验算简化为单榀钢拱架的强度验算。(2)通过对施工过程中的钢桁网架的主要节点和主要受力杆件分别进行位移监测和应力监测,同时利用大型有限元分析软件Midas Civil建立相应的有限元模型,将监测结果与有限元模型计算结果进行对比分析,结果表明,计算结果与监测结果拟合较好,该有限元模型可以反映用在该施工中的钢桁网架的受力状态,因此可以将该有限元模型作为进一步深入研究的理论模型。(3)利用校验正确的有限元模型进行完整结构的静力分析和屈曲分析,检验轻型钢桁网架的强度,刚度和稳定性是否能够满足施工要求,为轻型钢桁网架的推广应用提供了理论基础。(4)针对长田漾大桥施工过程中出现了由于现场施工偶然因素造成的结构中的个别杆件失去承载力的情况,为了防止由于杆件出现失效破坏,而导致结构发生倒塌,因此对结构进行倒塌分析。本文选择12种初始破坏状态进行倒塌分析,分析结果表明,在12种初始破坏状态下,针对长田漾大桥拱圈施工工序的轻型钢桁网支架不会发生倒塌破坏。但是由于钢桁网架的杆件众多,因此有必要对所有杆件进行深入分析,确保结构在现场施工偶然作用下不会发生倒塌破坏。经过以上分析,最后提出结论,轻型钢桁网支架可以在中小跨径拱桥施工中推广应用,本文的理论分析具有一定的针对性,可以作为钢桁网架推广应用理论分析的基础,但是对应不同的施工工序和施工参数,需要重新检验结构的安全性,并对结构进行适当的优化设计。
[Abstract]:Light steel truss mesh support is a new type of support used in the construction of medium and small span arch bridge. It has the advantages of light weight, wide selection of materials, simple manufacturing technology, convenient construction and low cost, etc. It is suitable for medium and small span cast-in-place concrete arch or prefabricated reinforced concrete arch. Its popularization and application can shorten construction time, reduce construction cost and bring huge social and economic benefits. However, because this construction method is a relatively new technology, it is lack of relevant theory and practical experience to guide it. Therefore, it is necessary to do more in-depth research on the light steel truss grid, and its popularization and application are very necessary. Aiming at the arch circle construction of Tianyang Bridge of Huzhou Mayor of Zhejiang Province, this paper studies the combination of practice and theory of light steel truss mesh support, which mainly includes the following contents: (1) through theoretical analysis of the structure, It is determined whether the structure can meet the construction requirements. Structural inspection includes strength check, stiffness check and stability check. Because the support is connected into a whole by a single steel arch frame through transverse bracing, the construction load of the arch ring is transformed into the in-plane joint load of the steel arch frame by binding the steel pipe at the joint. Furthermore, the strength checking calculation of steel truss grid is simplified as that of a single steel arch frame. (2) displacement monitoring and stress monitoring are carried out on the main joints and the main stress members of the steel truss grid in the construction process. At the same time, the finite element model is established by using the large-scale finite element analysis software Midas Civil, and the results of monitoring and finite element model calculation are compared and analyzed. The results show that the calculated results fit well with the monitoring results. The finite element model can reflect the stress state of the steel truss grid used in the construction. Therefore, the finite element model can be used as the theoretical model for further research. (3) static analysis and buckling analysis of the complete structure are carried out by using the correct finite element model to test the strength of the light steel truss grid. Whether stiffness and stability can meet construction requirements, It provides a theoretical basis for the popularization and application of light steel truss grids. (4) in view of the loss of bearing capacity of individual members in the structure caused by accidental factors in site construction during the construction of Changtian Yang Bridge, In order to prevent the structure from collapsing due to the failure and failure of the member, the collapse analysis of the structure is carried out. In this paper, 12 kinds of initial failure states are selected for collapse analysis. The results show that under 12 initial failure states, the light steel truss mesh support for the arch ring construction process of Changtian Yang Bridge will not collapse and destroy. However, due to the large number of members of the steel truss grid, it is necessary to make a thorough analysis of all the members so as to ensure that the structure will not collapse and destroy under the accidental action of the field construction. After the above analysis, the conclusion is put forward that light steel truss mesh support can be popularized and applied in the construction of middle and small span arch bridge. The theoretical analysis in this paper has some pertinence and can be used as the basis of the theoretical analysis for the popularization and application of steel truss grid. However, for different construction procedures and construction parameters, it is necessary to re-examine the safety of the structure and carry out appropriate optimization design of the structure.
【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】：U445.4;U448.22

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