考虑基础刚度影响的超长混凝土结构温度应力分析

发布时间：2018-02-09 03:43

本文关键词： 超长框架结构温度应力基础刚度等效温差弹簧约束　出处：《苏州科技学院》2015年硕士论文　论文类型：学位论文

【摘要】：由于建筑功能与美观的需要,要求建筑物不设置或者较少设置伸缩缝,从而导致结构的伸缩缝间距远大于规范规定的间距要求。对于超长混凝土结构,通常要研究的是结构由于温度变化所引起的应力与变形。实际工程中常采用设置后浇带、施加预应力等措施来解决温度应力,然而设计中通常采取上部结构嵌固的假定,从而忽略了基础的实际刚度对超长混凝土结构性能的影响。如果考虑基础对结构的有限约束刚度,则结构设计更加接近实际,其受力性能将有所改善,也将使超长结构的设计更具经济性、安全性。本文在大量理论支撑及分析的基础上,借助有限元软件ABAQUS做了以下几个方面的研究,并得出了相应成果。1.考虑有限基础刚度,结构楼板中温度应力与柱底嵌固假定模型相比有很大降低,应力集中现象有所改善,底层柱底内力明显减小。通过改变基础刚度调节结构侧移刚度也是缓解超长结构温度效应的一种方法。2.根据现行桩基规范的方法计算桩基水平刚度与转动刚度;运用有限元方法模拟桩-土共同作用,计算桩基基础的水平刚度与转动刚度。有限元数值模拟结果误差较小,并可用于后续考虑基础刚度的超长结构温度应力分析;在基础刚度有限元数值计算时,可取50倍桩径的桩周土体参与共同模拟。3.研究超长混凝土结构在季节温差作用下结构变形及内力分布,分析超长结构温度应力的影响因素。数据表明,结构侧移刚度对其温度效应影响较大,设计中要考虑底层层高对减小温度应力的有利作用。4.结合实际工程-苏州轨道交通2号线太平车辆段上盖平台D2区工程,利用长期的现场监测数据与有限元数值模拟结果对比,分析该超长结构在使用阶段有限元数值模拟与监测数据的异同。分析中考虑混凝土徐变收缩时效特性,考虑有限基础刚度。研究表明,有限基础刚度对于超长结构温度应力的有利影响不可忽略。
[Abstract]:Because of the need of building function and beauty, it is required that no or less expansion joints are set in the building, which leads to the space between expansion joints of the structure being much larger than the spacing required by the code. For super-long concrete structures, The stress and deformation of the structure caused by temperature change are usually studied. In practical engineering, measures such as setting post-pouring belt and applying prestress are often used to solve the thermal stress. However, the supposition that the superstructure is embedded is usually adopted in the design. Therefore, the influence of the actual stiffness of the foundation on the performance of the super-long concrete structure is neglected. If the finite restrained stiffness of the foundation on the structure is considered, the design of the structure is closer to the actual situation, and the mechanical performance of the structure will be improved. It will also make the design of super-long structure more economical and safe. Based on a large amount of theoretical support and analysis, this paper has done the following research with the help of finite element software ABAQUS, and has obtained the corresponding results. 1. Considering the stiffness of finite foundation, The temperature stress in the structure floor is much lower than that in the column bottom inlaid model, and the stress concentration phenomenon is improved. The internal force at the bottom of the bottom column is obviously reduced. Adjusting the lateral stiffness of the structure by changing the foundation stiffness is also a method to alleviate the temperature effect of the super-long structure. 2. The horizontal stiffness and rotational stiffness of the pile foundation are calculated according to the current method of pile foundation code. Using finite element method to simulate pile-soil interaction, the horizontal stiffness and rotational stiffness of pile foundation are calculated. The error of finite element numerical simulation results is small, and it can be used in the thermal stress analysis of super-long structure considering foundation stiffness. In the finite element calculation of foundation stiffness, the soil around the pile with 50 times the diameter of the pile participates in the simulation. 3. The structural deformation and internal force distribution of the super-long concrete structure under seasonal temperature difference are studied. The influence factors of the temperature stress of super-long structure are analyzed. The data show that the lateral stiffness of the structure has a great influence on the temperature effect. In the design, the beneficial effect of the height of the bottom layer on reducing the temperature stress should be considered. 4. Combining with the actual project, the D _ 2 area of the upper cover platform of Taiping depot of Suzhou Rail Transit Line 2 is compared with the finite element numerical simulation results by using the long-term monitoring data. The similarities and differences between the finite element numerical simulation and the monitoring data of the super-long structure are analyzed. The creep and shrinkage aging characteristics of concrete and the finite foundation stiffness are considered in the analysis. The favorable effect of finite foundation stiffness on the temperature stress of super long structure can not be ignored.
【学位授予单位】：苏州科技学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU755

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