大跨径钢管混凝土拱桥几何非线性及徐变效应数值研究

发布时间：2018-01-20 16:04

  本文关键词： 钢管混凝土 拱桥 徐变效应 几何非线性 耦合　出处：《长沙理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：钢管混凝土作为一种组合材料其核心混凝土处于三向受压状态,材料抗压强度和抗变形能力得到了增强,凭借着材料的稳定可靠性及便于安装生产等优越性,钢管混凝土拱桥正在朝着大跨径乃至超大跨径的趋势发展。由于核心混凝土密闭于钢管内,因此钢管混凝土材料的徐变与普通混凝土不同。钢管对内部密闭的混凝土起着约束的作用,同时混凝土也制约着钢管,在徐变的影响下,两者之间会发生应力重分布的现象,随着时间的增加,钢管应力会呈明显上升的趋势而混凝土应力则会相应降低。本文在叙述了徐变产生原理及其认识的基础上,比较分析了目前国内外常用的几类徐变模式,并介绍了徐变计算的基本原理和方法,对比分析了徐变产生过程中的各项影响因素,然后以某中承式钢管混凝土系杆拱桥为工程背景,利用ANSYS通用有限元软件实现了对其主拱肋模型的徐变效应分析。结构计算中,多采用线性理论,随着钢管混凝土拱桥跨径日益加大,其几何非线性特点也日趋明显。本文在阐述几何非线性的基本计算方法及其理论的基础上,利用ANSYS对某钢管混凝土拱桥有限元模型进行了考虑几何非线性影响下与线性影响的对比计算分析。对于同时考虑几何非线性及徐变耦合作用影响的研究目前还较少见,本文在采用微分法导出了平面梁单元几何非线性切线刚度矩阵的基础上,结合徐变效应计算的初应变法,利用FORTRAN语言编制了同时考虑几何非线性及徐变耦合分析程序,并使用该程序进行了某桥塔悬臂梁模型的算例分析验证。
[Abstract]:Concrete-filled steel tubular (CFST) as a composite material its core concrete is in a three-direction compression state the compressive strength and deformation resistance of the material has been enhanced by virtue of the material stability reliability and ease of installation and production and other advantages. Concrete-filled steel tubular arch bridge is developing towards the trend of long span and even large span, because the core concrete is confined to the steel tube. Therefore, the creep of concrete-filled steel tube is different from that of ordinary concrete. The steel tube plays a restraint role on the inner confined concrete, and the concrete also restricts the steel tube, under the influence of creep. Stress redistribution will occur between the two, with the increase of time. The stress of steel pipe will increase obviously and the stress of concrete will decrease accordingly. Based on the description of the principle and understanding of creep, several kinds of creep modes commonly used at home and abroad are compared and analyzed in this paper. The basic principle and method of creep calculation are introduced, and the influencing factors in the process of creep are compared and analyzed. Then, a through concrete filled steel tubular tied arch bridge is taken as the engineering background. The creep effect of the main arch rib model is analyzed by using ANSYS software. The linear theory is used in the structure calculation, and the span of concrete-filled steel tube arch bridge is increasing day by day. The characteristics of geometric nonlinearity are becoming more and more obvious. In this paper, the basic calculation method of geometric nonlinearity and its theory are expounded. The finite element model of a concrete-filled steel tubular arch bridge is analyzed by using ANSYS. The effects of geometric nonlinearity and creep coupling are considered in this paper. It's rare at the moment. Based on the derivation of geometric nonlinear tangent stiffness matrix of plane beam element by differential method, the initial strain method is used to calculate creep effect. A program for coupled analysis of geometric nonlinearity and creep is developed by using FORTRAN language, and an example of a cantilever beam model of a bridge tower is given.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441;U448.22
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本文编号：1448816