裂缝对简支梁结构静力特性影响研究

发布时间：2018-05-20 03:10

本文选题：裂缝 + 简支梁　；参考：《重庆交通大学》2014年硕士论文

【摘要】：本文首先概括了桥梁裂缝分类并对引起裂缝的原因进行了分析，然后对4片有机玻璃简支T梁和一片钢筋混凝土简支矩形梁进行了室内模型试验并与ANSYS有限元模型的计算结果进行了对比，重点关注裂缝对简支梁底应变的影响；在模型试验的基础上，，对桥梁工程中常用的中小跨简支梁进行了数值模拟，以此研究裂缝对简支梁静力特性的影响；最后通过实例工程对含裂缝结构进行了分析和研究，并得到了如下结论： ①在有限元软件ANSYS中采用分离式裂缝模型对简支梁裂缝进行模拟是合理可行的，能准确的描述其静力特性； ②在集中荷载作用下，主梁结构上已有的裂缝附近区域存在很大的应变梯度，应变在裂缝位置接近为0，离开裂缝位置应变迅速增大到无裂缝时的正常应变值； ③理想情况下，裂缝对应变影响区域的大小与所施加静力荷载的大小无关； ④简支梁在出现裂缝前后的挠度差值不能作为裂缝位置定位的一个有效参数； ⑤理想情况下，对于截面形式相同，梁跨径不同的简支T梁，裂缝对应变影响区域的大小与梁跨径的大小无关； ⑥简支空心板梁纵向裂缝对沿梁跨径方向上的应变值影响很小，可以忽略不计； ⑦简支空心板梁跨中横向应变值的大小与沿跨径方向上的纵向裂缝长度无关，只与裂缝深度有关。
[Abstract]:This paper first summarizes the classification of bridge cracks and analyzes the causes of the cracks. Then, four polyglass-supported T-beams and a reinforced concrete simply supported rectangular beam are tested in laboratory and compared with the results of ANSYS finite element model, focusing on the effect of cracks on the bottom strain of simply supported beams. On the basis of model test, numerical simulation is carried out to study the influence of cracks on static characteristics of simply supported beams with small and medium span, which is commonly used in bridge engineering. The conclusions are as follows: 1 in the finite element software ANSYS, it is reasonable and feasible to use the split crack model to simulate the crack of simply supported beam, and can accurately describe its static characteristics; (2) under concentrated load, there exists a large strain gradient in the area near the cracks in the main beam structure, where the strain is close to zero, and the strain increases rapidly from the crack position to the normal strain value without crack; (3) under ideal conditions, the size of the area affected by the crack strain is independent of the size of the static load applied; (4) the deflection difference of simply supported beam before and after crack can not be regarded as an effective parameter of crack location; (5) under ideal conditions, for simply supported T-beams with the same cross section and different spans, the size of the area affected by the crack strain is independent of the size of the beam span; (6) the longitudinal crack of simply supported hollow slab beam has little effect on the strain value along the span direction of the beam, which can be ignored; (7) the magnitude of transverse strain in the span of simply supported hollow slab beam is independent of the longitudinal crack length along the span direction, but only related to the crack depth.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441

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