边界条件对高桥墩稳定性及有效长度的影响分析与研究

发布时间：2018-01-09 13:10

本文关键词：边界条件对高桥墩稳定性及有效长度的影响分析与研究　出处：《重庆交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着公路交通运输事业的发展,山区修建的桥梁日益增多。由于山区地形特点为沟深、坡陡,桥梁的桥墩往往较高。但是《公路钢筋混凝土及预应力混凝土桥涵设计规范》(JTG D62-2004)第5.3.1条第(2)款,仅给出理想边界条件下计算长度系数的取值。事实上桥墩的边界条件比较复杂,墩底桩土作用非理想固结;墩顶有支座纵横向的约束,其边界条件既非固结、也非铰接。本文主要是从以下两个方面来研究桥墩的稳定性及桥墩计算长度系数的取值:①当桥墩桩基作用于刚性地基时,认为墩底的边界条件为固结;桥墩墩顶有普通板式橡胶支座时,认为墩顶的边界条件是弹性连接。在这种边界条件下把桥墩简化为一理想中心受压杆,用静力法进行桥墩稳定方程的推导。然后用有限元软件求解数值解并与公式解进行对比分析。最后根据数值解得到的桥墩计算长度系数,并获得其与桥墩墩高、桥墩墩径的关系曲面图,由该曲面图可以拟合出一个简化公式。②当桥墩桩基作用于不同地基系数的弹性地基中时,认为墩底的边界条件为弹性连接;桥墩施工阶段或作用有普通板式橡胶支座时,把墩顶的边界条件当做是墩顶自由或墩顶弹性连接。在这种边界条件下把桥墩简化为一理想中心受压杆,用静力法进行稳定方程的推导;最后应用有限元软件求得数值解并与公式解进行对比分析。通过本文的研究,推导了桥墩墩底固结而墩顶为弹性连接,墩底为弹性连接而墩顶自由或墩顶弹性连接状态下桥墩的临界力求解公式,并用数值验证了其正确性。该公式是一个关于临界荷载的超越稳定方程,借用Excel软件就可以得出临界力从而得出计算长度系数。
[Abstract]:With the development of highway transportation, more and more bridges are built in mountainous areas. The piers of bridges tend to be high. But the Code for Design of reinforced concrete and Prestressed concrete Bridges and culverts on Highway (JTG D62-2004) Article 5.3.1 (2). In fact, the boundary conditions of bridge piers are quite complex, and the pile-soil action at the bottom of the piers is not ideal consolidation. The top of the pier is constrained by the vertical and horizontal direction of the support, and the boundary condition is neither consolidated. In this paper, the stability of the pier and the value of the calculated length coefficient of the pier are studied from the following two aspects: 1. When the pile foundation of the pier acts on the rigid foundation, the boundary condition of the pier bottom is considered as consolidation; When the top of the pier has a common plate rubber bearing, the boundary condition of the pier top is considered as elastic connection. Under this boundary condition, the pier is simplified as an ideal central compression rod. The static method is used to deduce the stability equation of the bridge pier. Then the numerical solution is solved by finite element software and compared with the formula solution. Finally, the length coefficient of the pier is calculated according to the numerical solution, and the height of the pier is obtained. A simplified formula .2 when the pier pile foundation acts on the elastic foundation with different foundation coefficients, the boundary condition of the pier bottom is considered to be elastic connection. In the stage of bridge pier construction or when the ordinary plate rubber bearing is used, the boundary condition of the pier top is regarded as the free connection of the pier top or the elastic connection of the pier top. Under this boundary condition, the pier is simplified as an ideal central compression rod. The stability equation is derived by static method. Finally, the numerical solution is obtained by the finite element software and compared with the formula solution. Through the research of this paper, the consolidation of the pier bottom and the elastic connection at the top of the pier are deduced. In the case of elastic connection at the bottom of the pier and free at the top of the pier or elastic connection at the top of the pier, the critical solution formula of the pier is verified by numerical results. The formula is a transcendental stability equation for critical loads. By using Excel software, the critical force can be obtained and the calculated length coefficient can be obtained.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U443.22

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