【作者】 熊红霞；

【导师】 刘沐宇；

【作者基本信息】 武汉理工大学 ， 桥梁与隧道工程， 2004， 硕士

【摘要】 钢管混凝土拱桥作为一种新兴的桥型，以它轻巧的结构、美观的造型、超强的跨越能力等优势，近十佘年来在我国得到了迅速的推广与应用．但目前对钢管混凝土拱桥设计理论的研究还相对落后于工程实践，尤其在钢管混凝土的收缩徐变特性、温度荷载与温度应力特性以及车辆荷载作用下的动力响应特性等方面的研究都有待进一步深化。 本文以中承式钢管混凝土刚架系杆拱桥为研究对象，借助大型通用有限元软件ANSYS分别建立了平面计算模型和空间计算模型，对钢管混凝土拱桥的收缩徐变性能、在温度荷载作用下的受力性能及其在车辆荷载作用下的动力响应特性等进行了模拟分析。论文的主要研究成果有： 1 考虑到钢管混凝土的收缩徐变性能的研究还很有限，本文建立了空间有限元计算模型对钢管混凝土刚架系杆拱桥的收缩徐变特性进行了数值模拟，分析了混凝土收缩徐变对拱桥受力特性及截面应力重分布的影响．研究表明混凝土收缩徐变对结构体系的全截面轴力基本上无影响，但对结构的全截面弯矩有较大的影响，且收缩徐变对拱桥内力、应力与位移的影响在成桥后的两年内基本趋于稳定。 2 建立平面有限元计算模型对钢管混凝土刚架拱桥在温度荷载和恒载作用下的受力情况进行了理论研究，详细地分析了不同矢跨比、拱轴系数、主拱拱肋含钢率等设计参数对拱桥各控制截面内力、应力、位移变化的影响。分析结果表明：对于大跨径的刚架系杆拱桥，改变矢跨比对恒载作用下结构的轴向力以及温度整体变化产生的结构内力影响较大；在不改变主拱拱肋截面尺寸的情况下，设计中可以提高矢跨比来减小主拱拱肋各截面的内力与应力：改变拱轴系数对各控制截面的全截面恒载弯矩影响很大，对在温度荷载作用下全截面的轴力也有较大的影响，并表现出一定的非线性；整体地加大拱肋钢管的壁厚可以解决拱顶截面上弦杆的应力集中现象。 3 建立空间有限元计算模型，采用时程分析法，进行了当移动荷载以不同速度通过桥面时的时间历程动力响应分析和动力放大效应分析。分析结果表明：荷载以1～20m／s的速度匀速移动通过桥面时，桥跨结构的动力响应非常明显．指出即使是理想的集中力以恒定的速度通过桥面时也会引起明显的动力放大效应。更多还原

【Abstract】 Concrete-filled steel tubular (CFST) arch bridge is a new-type structure of bridge, which has been popularized and developed rapidly in the past ten years in China because of its advantage: light structure, beautiful model and super crossing ability. The study on design theories of CFST arch bridges gets relatively behind the engineering practice at present. The research on the creep and shrinkage of concrete, the temperature stress under the temperature load, dynamic performance under the traffic load of the structer need to be deepened.On the basis of a CFST tied rigid frame arch bridge, by means of general software ANSYS, a space finite element model (FEM) and a plane FEM are built to analyze its temperature stress and dynamic behavior under the traffic load with an emphasis on analyses of creep and shrinkage of concrete. The research of this paper includes mainly several parts:1 Considering the analysis of creep and shrinkage is a basic problem of bridge structure analysis. However, the research of creep and shrinkage of CFST is very limited. In this paper, the creep and shrinkage of frame tied CFST arch bridge is discussed. The analysis results reflect that the creep and shrinkage has a great influence upon the structure force and stress of any control cross-section. The cross-stress redistribution is very obviously. The creep and shrinkage of concrete has few influence upon the structure axial force, but has great influence upon the bending moment. This influence goes to be steady within two years after completing construction of the bridge.2 According to the CFST tied riged frame arch bridge, a plane computing model is built to analyze its temperature effect theoretically. The different design parameters such as ratio of rise to span, coefficient of arch axis and ratio of steel of the arc ribs have different influence on internal force, tress and displacement of any control cross-section of arch bridges. The results is calculated and compared. It reflect that changing the ratio of rise to span has obvious influence on the axes force under invariant load and on the internal force under temperature load of long span CFST arch bridges. The internal force and stress of arch bridge ribs can be decreased by increasing the ratio of rise to span in its design. Changing the coefficient of arch axis has a certain extent nonlinear influence on its bending moment and the axes forcewith temperature load by increasing the thickness of the steel tube can avoid tip of the arc being a focus of stress. The analyses results can provide the design of such type bridge with reference.3 The natural vibration and the time history dynamic response of the structure under different velocity moving load are analyzed on the basis of the space computing model. The analysis reflect that the dynamic response of the structure is very obviously under uniform velocity moving load, even if under a given fixate. So choosing the impact coefficient is very important in the design of such type bridge.更多还原