大气腐蚀条件下中等跨径公路钢箱梁桥受力性能评估
发布时间：2018-09-18 21:06
【摘要】：钢箱梁桥随服役时间的增加将不可避免地出现各种结构损伤,会严重影响钢箱梁桥的使用性能,本文以绍兴一座匝道钢箱梁桥为依托工程,从腐蚀的角度出发,结合实地调研、理论分析和数值模拟等方法,研究大气均匀腐蚀和局部腐蚀对中等跨径公路钢箱梁桥受力性能的影响,为在役中等跨径公路钢箱梁桥承载能力的评估和检测提供科学依据,以便更好地弥补现有评估方法的不足。本文的主要研究工作和相关结论如下:(1)结合依托工程所使用钢材的化学成分和所处地区的环境因素,得出了依托工程中钢箱梁外部和内部的腐蚀深度预测公式分别为0.762C?0.036t外和0.587C?0.049t内。随后,以依托工程为背景,采用有限元数值模拟技术,定量分析了在大气均匀腐蚀作用0~100年内,钢箱梁桥受力性能随服役时间增长的变化规律。研究结果表明:大气均匀腐蚀会造成钢箱梁各部件厚度减小,但一直能保持较好的整体性,且满足刚度与强度的设计要求;大气均匀腐蚀会造成钢箱梁桥的极限承载能力成线性减小,当腐蚀时间为100年时,下降为无损伤阶段的87.5%左右。(2)在分析以往钢桥腐蚀损伤作用下实际检测数据的基础上,结合依托工程所处的具体环境,得出腹板两端和底板跨中为严重腐蚀区域,并指定每种区域最大腐蚀深度分别为原有部件厚度的50%,然后采用数值模拟技术定性分析了不同腐蚀区域在不同腐蚀程度的情况下对钢箱梁桥整体受力性能的影响。研究结果表明:在指定腐蚀深度范围内,局部腐蚀状态下的钢箱梁桥能满足刚度与强度的设计要求;局部腐蚀对钢箱梁桥极限承载能力影响较为明显,当腐蚀深度为原有部件厚度的50%时,极限承载力下降到无损伤阶段的60%~70%之间。(3)通过对钢箱梁桥在各种腐蚀作用下应力和位移进行分析,研究了钢箱梁桥在遭受均匀腐蚀和局部腐蚀过程中的应力关键区域和位移变化规律。研究结果表明:顶板在与腹板相接位置出现了明显的剪力滞后现象;底板跨中区域以及底板边缘与腹板相接位置应力较大;腹板两端靠近横梁区域为应力和变形的关键区域;横隔板在弯扭耦合作用下,在过人通道的角点处易发生应力集中现象。
[Abstract]:With the increase of service time, various kinds of structural damage will inevitably appear in the steel box girder bridge, which will seriously affect the performance of the steel box girder bridge. In this paper, based on a ramp steel box girder bridge in Shaoxing, from the point of view of corrosion, combined with field investigation, Theoretical analysis and numerical simulation are used to study the effect of uniform and local corrosion of atmosphere on the mechanical performance of medium span highway steel box girder bridge, which provides a scientific basis for the evaluation and detection of the bearing capacity of medium span highway steel box girder bridge in service. In order to better compensate for the shortcomings of existing evaluation methods. The main research work and related conclusions are as follows: (1) combined with the chemical composition of the steel used in the supporting project and the environmental factors in the region, The external and internal corrosion depth prediction formulas of the steel box girder in the backing engineering are obtained respectively in 0.762C?0.036t and 0.587C?0.049t. Then, based on the engineering background, finite element numerical simulation technique is used to quantitatively analyze the variation of the mechanical behavior of steel box girder bridges with the increase of service time during the 0-100 years of uniform atmospheric corrosion. The results show that uniform atmospheric corrosion will reduce the thickness of the components of the steel box girder, but it can keep a good integrity and meet the design requirements of stiffness and strength. Uniform atmospheric corrosion will reduce the ultimate bearing capacity of steel box girder bridge linearly. When the corrosion time is 100 years, it will decrease to 87.5% of the non-damaged stage. (2) on the basis of analyzing the actual detection data of steel bridge under the action of corrosion damage, Combining with the concrete environment of the supporting project, it is concluded that the two ends of the web and the middle span of the bottom plate are the seriously corroded areas. The maximum corrosion depth of each region is designated as 50 of the original component thickness, and then the influence of different corrosion zones on the overall mechanical performance of steel box girder bridge is analyzed qualitatively by numerical simulation technique. The results show that the steel box girder bridge under local corrosion can meet the design requirements of stiffness and strength in the specified corrosion depth range, and the local corrosion has a more obvious effect on the ultimate bearing capacity of the steel box girder bridge. When the corrosion depth is 50% of the original component thickness, the ultimate bearing capacity decreases to between 60% and 70% of the non-damage stage. (3) the stress and displacement of the steel box girder bridge under various corrosion conditions are analyzed. The stress critical region and displacement variation of steel box girder bridge under uniform and local corrosion are studied. The results show that the shear lag appears in the joint position of the roof and the web, the stress in the middle region of the bottom plate and the edge of the bottom plate is large, and the two ends of the web are the key areas of stress and deformation near the cross beam area. Under the coupling of bending and torsion, the stress concentration is easy to occur at the corner of the passage.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441;U448.213
本文编号：2249101
[Abstract]:With the increase of service time, various kinds of structural damage will inevitably appear in the steel box girder bridge, which will seriously affect the performance of the steel box girder bridge. In this paper, based on a ramp steel box girder bridge in Shaoxing, from the point of view of corrosion, combined with field investigation, Theoretical analysis and numerical simulation are used to study the effect of uniform and local corrosion of atmosphere on the mechanical performance of medium span highway steel box girder bridge, which provides a scientific basis for the evaluation and detection of the bearing capacity of medium span highway steel box girder bridge in service. In order to better compensate for the shortcomings of existing evaluation methods. The main research work and related conclusions are as follows: (1) combined with the chemical composition of the steel used in the supporting project and the environmental factors in the region, The external and internal corrosion depth prediction formulas of the steel box girder in the backing engineering are obtained respectively in 0.762C?0.036t and 0.587C?0.049t. Then, based on the engineering background, finite element numerical simulation technique is used to quantitatively analyze the variation of the mechanical behavior of steel box girder bridges with the increase of service time during the 0-100 years of uniform atmospheric corrosion. The results show that uniform atmospheric corrosion will reduce the thickness of the components of the steel box girder, but it can keep a good integrity and meet the design requirements of stiffness and strength. Uniform atmospheric corrosion will reduce the ultimate bearing capacity of steel box girder bridge linearly. When the corrosion time is 100 years, it will decrease to 87.5% of the non-damaged stage. (2) on the basis of analyzing the actual detection data of steel bridge under the action of corrosion damage, Combining with the concrete environment of the supporting project, it is concluded that the two ends of the web and the middle span of the bottom plate are the seriously corroded areas. The maximum corrosion depth of each region is designated as 50 of the original component thickness, and then the influence of different corrosion zones on the overall mechanical performance of steel box girder bridge is analyzed qualitatively by numerical simulation technique. The results show that the steel box girder bridge under local corrosion can meet the design requirements of stiffness and strength in the specified corrosion depth range, and the local corrosion has a more obvious effect on the ultimate bearing capacity of the steel box girder bridge. When the corrosion depth is 50% of the original component thickness, the ultimate bearing capacity decreases to between 60% and 70% of the non-damage stage. (3) the stress and displacement of the steel box girder bridge under various corrosion conditions are analyzed. The stress critical region and displacement variation of steel box girder bridge under uniform and local corrosion are studied. The results show that the shear lag appears in the joint position of the roof and the web, the stress in the middle region of the bottom plate and the edge of the bottom plate is large, and the two ends of the web are the key areas of stress and deformation near the cross beam area. Under the coupling of bending and torsion, the stress concentration is easy to occur at the corner of the passage.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441;U448.213
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