混凝土薄壁箱开裂对挠度的影响研究
发布时间：2019-05-19 19:07
【摘要】：混凝土箱梁桥的开裂现象普遍存在，，被认为是混凝土箱梁的“癌症”。其裂缝的开展，不仅严重影响结构的耐久性，而且加剧了箱梁桥的挠度。因此，本文对混凝土薄壁箱梁的开裂与挠度之间的关系进行理论研究，探寻相关规律，具有重要的理论意义和工程应用价值。本文主要完成了以下几个方面的工作： （1）对国内外箱梁挠度计算的研究历程和发展现状进行综述，结合混凝土薄壁箱梁裂缝现象的相关研究，提出了本文研究的主要内容。 （2）考虑了钢筋混凝土箱梁的材料非线性，采用大型分析软件ANSYS，基于Drucker-Prage五参数破坏准则和随机强化模型，建立了简支钢筋混凝土箱梁的有限元模型。 （3）对箱梁模型分级加载至裂缝宽度达到预测值。研究箱梁模型正截面裂缝和斜截面裂缝的开展情况、分布规律，以及各级荷载作用下的钢筋应力变化情况和挠度变化情况。将上述结果与相应的箱梁试验测试值对比发现两者数值吻合的较好。验证了通过采用本文所建立的有限元模型研究混凝土薄壁箱梁开裂对挠度的影响是可行的。 （4）在既有文献的基础上，对影响挠度的各因素，如开裂后的弯曲变形、剪力滞效应、剪切变形等，对挠度的影响进行定量的分析。在分析剪切变形导致的挠度增大过程中，依据变角桁架模型，考虑了斜截面裂缝的开展对剪切变形的影响。
[Abstract]:The cracking phenomenon of concrete box girder bridge is common and is considered to be the "cancer" of concrete box girder. The development of cracks not only seriously affects the durability of the structure, but also aggravates the deflection of the box girder bridge. Therefore, this paper makes a theoretical study on the relationship between cracking and deflection of concrete thin-wall box girder, and explores the relevant laws, which is of great theoretical significance and engineering application value. This paper mainly completes the following aspects: (1) the research course and development status of box girder deflection calculation at home and abroad are summarized, combined with the related research of concrete thin-wall box girder crack phenomenon, The main contents of this paper are put forward. (2) considering the material nonlinear of reinforced concrete box girder, the finite element model of simply supported reinforced concrete box girder is established by using the large-scale analysis software ANSYS, based on Drucker-Prage five-parameter failure criterion and random strengthening model. (3) the predicted value is obtained from the graded loading of the box girder model to the crack width. The development and distribution of normal section cracks and oblique section cracks in box girder model, as well as the stress variation and deflection variation of steel bars under various loads are studied. By comparing the above results with the corresponding box girder test values, it is found that the two values are in good agreement with each other. It is verified that it is feasible to study the influence of cracking of concrete thin-wall box girder on deflection by using the finite element model established in this paper. (4) on the basis of the existing literature, the influence of deflection, such as bending deformation after cracking, shear lag effect, shear deformation and so on, is analyzed quantitatively. In the process of analyzing the increase of deflection caused by shear deformation, according to the variable angle truss model, the influence of oblique section crack development on shear deformation is considered.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441;U448.213
本文编号：2480986
[Abstract]:The cracking phenomenon of concrete box girder bridge is common and is considered to be the "cancer" of concrete box girder. The development of cracks not only seriously affects the durability of the structure, but also aggravates the deflection of the box girder bridge. Therefore, this paper makes a theoretical study on the relationship between cracking and deflection of concrete thin-wall box girder, and explores the relevant laws, which is of great theoretical significance and engineering application value. This paper mainly completes the following aspects: (1) the research course and development status of box girder deflection calculation at home and abroad are summarized, combined with the related research of concrete thin-wall box girder crack phenomenon, The main contents of this paper are put forward. (2) considering the material nonlinear of reinforced concrete box girder, the finite element model of simply supported reinforced concrete box girder is established by using the large-scale analysis software ANSYS, based on Drucker-Prage five-parameter failure criterion and random strengthening model. (3) the predicted value is obtained from the graded loading of the box girder model to the crack width. The development and distribution of normal section cracks and oblique section cracks in box girder model, as well as the stress variation and deflection variation of steel bars under various loads are studied. By comparing the above results with the corresponding box girder test values, it is found that the two values are in good agreement with each other. It is verified that it is feasible to study the influence of cracking of concrete thin-wall box girder on deflection by using the finite element model established in this paper. (4) on the basis of the existing literature, the influence of deflection, such as bending deformation after cracking, shear lag effect, shear deformation and so on, is analyzed quantitatively. In the process of analyzing the increase of deflection caused by shear deformation, according to the variable angle truss model, the influence of oblique section crack development on shear deformation is considered.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441;U448.213
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