钢管混凝土拱肋脱空受力性能分析

发布时间：2019-01-05 02:19

【摘要】：钢管混凝土材料由于其强度高,塑性、韧性好,施工方便,耐火性能强,以及经济等优点,被广泛地应用于拱式体系桥梁结构中。然而,由于核心混凝土泵送不到位、外界温度的变化以及结构自身的收缩徐变等因素,钢管混凝土拱肋不可避免地出现脱空现象,使得脱空成为钢管混凝土拱桥的典型病害之一。因此,分析拱肋脱空后钢管混凝土拱桥受力性能的变化,掌握其变化规律,可为该类桥梁的设计和施工提供理论指导。论文基于钢管与核心混凝土完全脱粘的假定,运用结构力学方面的知识,通过理论推导的方法定性地探讨了脱空对单圆管拱肋和哑铃型拱肋抗弯刚度及内力的影响,并借助有限元软件对相关算例进行验证分析。在考虑拱肋材料非线性和几何非线性的基础上,分别建立了单圆管拱肋和哑铃型拱肋的有限元模型,研究了拱肋脱空后,不同的脱空率、含钢率、矢跨比、荷载作用形式等参数对单圆管拱肋和哑铃型拱肋的极限承载力影响。并以跨径125m的钢管混凝土拱桥为工程背景,建立了全桥的ANSYS有限元模型,分析拱肋不同的脱空率、含钢率、荷载作用形式对其自身刚度及全桥承载力的影响。结果表明:对于单圆管拱肋而言,完全脱粘不会引起结构抗弯刚度的降低;而对于哑铃型拱肋,完全脱粘会引起结构抗弯刚度的降低,当核心混凝土沿径向发生部分脱空后,哑铃型钢管混凝土拱桥的刚度和极限承载力均会发生不同程度的降低,且降低的程度与脱空率、矢跨比、含钢率、荷载作用方式等参数有关。
[Abstract]:Concrete-filled steel tube (CFST) material is widely used in arch system bridges because of its high strength, plasticity, toughness, easy construction, strong fire resistance and economy. However, because the core concrete pump is not in place, the outside temperature changes and the shrinkage and creep of the structure itself, the concrete filled steel tube arch rib inevitably appears the phenomenon of void. It is one of the typical diseases of concrete-filled steel tubular arch bridge. Therefore, it can provide theoretical guidance for the design and construction of this kind of bridge by analyzing the change of mechanical performance of concrete-filled steel tubular arch bridge after arch rib detachment and mastering its changing law. Based on the assumption of complete debonding between steel tube and core concrete, the influence of void on bending stiffness and internal force of single circular pipe arch rib and dumbbell arch rib is discussed qualitatively by using the knowledge of structural mechanics. With the help of finite element software, the related examples are verified and analyzed. On the basis of considering the material nonlinearity and geometric nonlinearity of arch rib, the finite element models of single circular tube arch rib and dumbbell arch rib are established, respectively. The ultimate bearing capacity of single circular pipe arch rib and dumbbell arch rib is affected by the loading form and other parameters. Taking the CFST arch bridge with a span of 125m as the engineering background, the ANSYS finite element model of the whole bridge is established, and the influence of different void ratio, steel content and load form on the stiffness and bearing capacity of the whole bridge is analyzed. The results show that complete debonding will not decrease the flexural stiffness of single circular pipe arch rib. For dumbbell arch rib, complete debonding will reduce the flexural stiffness of the structure. When the core concrete is partially removed along the radial direction, the stiffness and ultimate bearing capacity of the dumbbell-shaped concrete-filled steel tube arch bridge will be reduced in varying degrees. The degree of reduction is related to the void ratio, rise-span ratio, steel content, load mode and so on.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU398.9

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