基于多种徐变模型下钢—混组合桥梁徐变效应分析

发布时间：2018-10-10 12:33

【摘要】：近年来，由于钢-混凝土结合梁具有自重轻、强度高、刚度大等特点，在我国桥梁建设的应用中已日趋广泛。但是随着时间的推移，徐变作用导致其内力重分布，同时使结构产生较大的附加变形，因此充分合理分析大跨径组合梁桥的长期徐变效应具有重要的意义。而目前对于徐变效应的分析预测都是基于现有的混凝土徐变模型，研究表明，不同的徐变模型由于其考虑因素的不同以及实验条件和侧重点的不同，导致各种模型之间存在较大的差异性，因此为了充分分析大跨径组合连续箱梁桥的长期徐变效应，同时又考虑到港珠澳大桥6×85m组合连续箱梁桥重大工程特殊的社会意义和地位以及120年的超长设计使用寿命，因此本文针对港珠澳大桥6×85m组合连续箱梁桥，考虑上部混凝土桥面板预制存放180天，运用桥梁专业软件MIDAS/CIVIL建立大跨径组合梁桥空间计算模型，分别选取中国JTG-2004模型、欧洲CEB-FIP(1978)模型、CEB-FIP(1990)模型以及美国ACI-209模型，对大跨径组合连续箱梁桥进行长期徐变效应对比分析。主要研究成果包括以下几个部分： 1、以港珠澳大桥6×85m组合连续箱梁桥为工程背景，运用桥梁专业软件MIDAS建立全桥空间有限元模型，进行有限元仿真分析。 2、研究混凝土徐变对组合梁桥运营10年结构变形的影响，研究结果表明：在10年的计算运营时间里，在不同的徐变模型下，大跨径组合连续箱梁桥变形发展规律基本一致，各跨跨中徐变挠度都在不断增加，徐变变形增长速率逐渐减小，10年时间徐变基本全部完成，但是在不同的计算模型下，在不同的计算时间里，分析计算得到的徐变挠度各不相同； 3、随着时间的推移，徐变作用使混凝土板的截面应力逐渐减小，，但是变化幅度较小，其中上翼缘减小最大值为2.21MPa，下翼缘最大减小值为0.21MPa；对于钢梁而言，钢主梁上翼缘位置是受徐变作用影响最大的位置，运营10年后，JTG-2004模型、CEB-FIP(1978)模型、ACI209模型、CEB-FIP(1990)模型下的钢主梁上缘应力分别达到了钢材允许应力设计值的33.65%、35.67%、30.54%、30.88%，不同徐变模型下钢主梁应力相差达到10.77MPa，而钢主梁下翼缘由于徐变作用，导致其下缘拉应力出现一定程度的降低，但是降低幅度不大。
[Abstract]:In recent years, steel-concrete composite beams have been widely used in the construction of bridges in China due to their characteristics of light weight, high strength and large stiffness. However, with the passage of time, creep results in the redistribution of internal force and large additional deformation of the structure. Therefore, it is of great significance to analyze the long-term creep effect of long-span composite beam bridges. At present, the analysis and prediction of creep effect are based on existing concrete creep models. The research shows that different creep models are different because of their different factors, experimental conditions and emphases. Therefore, in order to fully analyze the long-term creep effect of long-span composite continuous box girder bridge, At the same time, considering the special social significance and status of the 6 脳 85m composite continuous box girder bridge and the 120 years' long design life of the bridge, this paper aims at the 6 脳 85m composite continuous box girder bridge of the HongKong-Zhuhai-Macao Bridge. Considering the prefabricated storage of upper concrete deck slab for 180 days, the spatial calculation model of long-span composite beam bridge was established by using the bridge professional software MIDAS/CIVIL. The Chinese JTG-2004 model, European CEB-FIP (1978) model, CEB-FIP (1990) model and American ACI-209 model were selected respectively. The long-span composite continuous box girder bridge is analyzed by comparing the long-term creep effect. The main research results include the following parts: 1. Taking the 6 脳 85m composite continuous box girder bridge of HongKong-Zhuhai-Macao Bridge as the engineering background, the spatial finite element model of the whole bridge is established by using the bridge professional software MIDAS. 2. The influence of concrete creep on the structural deformation of composite beam bridge for 10 years is studied. The results show that: in the 10 years of operation time, under different creep models, The deformation development law of long-span composite continuous box girder bridge is basically the same, the creep deflection of each span is increasing, the creep deformation growth rate is gradually decreasing, and the creep is almost complete in 10 years, but under different calculation models, In different calculation time, the calculated creep deflection is different. 3, with time, the creep effect makes the section stress of concrete slabs decrease gradually, but the variation range is small. The maximum value of reduction of upper flange is 2.21MPa, and that of lower flange is 0.21MPa. for steel beam, the position of upper flange of steel main beam is the most affected by creep. After 10 years of operation, the upper edge stresses of steel main beams under JTG-2004 model, CEB-FIP (1978) model, ACI209 model and CEB-FIP (1990) model have reached 33.65 ~ 35.67 and 30.88A of the design value of allowable stress of steel, respectively. The stress difference of steel main beam under different creep models is 10.77 MPa, while the lower flange of steel main beam is due to creep. The lower edge tensile stress decreases to a certain extent, but the decrease is not significant.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441

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