钢管混凝土抛物线拱平面外稳定性能研究

发布时间：2019-01-23 11:24

【摘要】：在竖向荷载作用下,拱支承处产生的水平推力,使得拱肋截面弯矩显著减小,以承受轴向压力为主。钢管混凝土材料以受压为主,适合于在拱结构中应用。钢管混凝土拱兼具承载力高、施工方便、造型美观等优点,故在我国桥梁工程中取得了广泛的应用,并且近年来也得到了国外工程界的认可。随着施工技术的成熟,钢管混凝土拱的跨度不断增大,不利于拱肋的稳定;同时,现代桥梁结构的造型愈加新颖、独特,其平面外稳定问题尤为突出。在钢管混凝土拱的平面外稳定问题中,其失稳时是由轴力、平面内及平面外弯矩、扭矩等共同作用导致的,截面应力分布较为复杂,同时包括几何非线性的影响,导致问题进一步复杂,相关研究比较少见。因此,针对钢管混凝土拱的平面外稳定问题开展研究工作,显得迫切而必要。本文以工程中常见的钢管混凝土抛物线拱为研究对象,对其在竖向荷载作用下的平面外稳定性能展开研究,具体内容如下:(1)采用ABAQUS软件建立钢管混凝土抛物线拱的有限元模型,针对钢管混凝土拱的结构、材料特点,以及平面外稳定问题的受力特点,确定适合的单元类型、材料应力-应变关系及分析方法,并考虑几何-材料双重非线性及几何初始缺陷的影响。通过对比现有的钢管混凝土抛物线拱平面外稳定试验及钢管混凝土格构柱轴压试验结果,验证本文采用有限元模型的正确性。(2)通过对目前工程中单圆管截面钢管混凝土拱的统计分析,确定本文研究对象的几何参数,着重研究其平面外稳定问题的主要影响因素:含钢率、长细比及矢跨比。由荷载-位移全过程曲线的分析,得到其平面外稳定承载力;由拱肋截面的变形及内力分析,确定其发生平面外失稳过程中的受力特点,据此采用等效柱模型,确定其平面外稳定系数计算公式。(3)针对工程常见的桁式截面钢管混凝土抛物线拱,对其平面外稳定性能展开研究,截面形式有双肢、三肢及四肢截面,主要分析参数有含钢率、长细比及矢跨比。在单圆管截面钢管混凝土拱平面外稳定性能研究的基础上,针对桁式截面钢管混凝土拱的结构特点及受力特点,对其在单位剪力作用下的平面外剪切变形进行推导,并建立考虑剪切变形影响的平面外稳定设计公式。
[Abstract]:Under the vertical load, the horizontal thrust produced at the support of the arch makes the bending moment of the arch rib section decrease significantly, and the axial pressure is the main force. Concrete-filled steel tube material is mainly under compression, which is suitable for application in arch structure. Concrete-filled steel tube arch has the advantages of high bearing capacity, convenient construction and beautiful shape, so it has been widely used in bridge engineering in our country, and has been recognized by foreign engineering circles in recent years. With the maturity of construction technology, the span of concrete-filled steel tube arch is increasing, which is not conducive to the stability of arch rib. At the same time, the shape of modern bridge structure is more novel and unique, and the problem of out-of-plane stability is particularly prominent. In the out-of-plane stability of concrete-filled steel tubular arch, the instability is caused by the joint action of axial force, in-plane and out-of-plane bending moment, torque, etc. The problem is further complicated, and the related research is relatively rare. Therefore, it is urgent and necessary to study the stability of concrete-filled steel tubular arch. In this paper, the concrete filled steel tube parabola arch, which is commonly used in engineering, is taken as the research object, and its out-of-plane stability under vertical load is studied. The main contents are as follows: (1) the finite element model of concrete filled steel tubular parabola arch is established by using ABAQUS software. According to the structure, material characteristics and stress characteristics of the out-of-plane stability problem, the suitable element type is determined. The stress-strain relationship of materials and its analytical method are considered, and the effects of geometric material double nonlinearity and geometric initial defects are considered. By comparing the existing concrete filled steel tube (CFST) parabola arch external stability test and the axial compression test results of CFST lattice columns, The validity of the finite element model is verified. (2) through the statistical analysis of concrete filled steel tube arch with single circular pipe section in current engineering, the geometric parameters of the research object are determined. The main influencing factors of the out-of-plane stability are studied, such as steel content, aspect ratio and rise-span ratio. Based on the analysis of the load-displacement curve, the out-of-plane stability bearing capacity is obtained. Based on the analysis of deformation and internal force of arch rib section, the stress characteristics in the process of external instability of arch rib are determined, and the equivalent column model is adopted. The calculation formula of the out-of-plane stability coefficient is determined. (3) for the common truss section concrete-filled steel tube parabola arch, the out-of-plane stability of the arch is studied. The section forms are two-limb, three-limb and extremity section. The main analysis parameters are steel content ratio, aspect ratio and span ratio. Based on the study of the external stability of concrete filled steel tube arch with single circular section, the external shear deformation of concrete filled steel tube arch with truss section under the action of unit shear is deduced according to the structural characteristics and stress characteristics of concrete filled steel tube arch with truss section. The design formula of out-of-plane stability considering the influence of shear deformation is established.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU398.9
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本文编号：2413732