某大跨度拱结构环梁基础设计分析

Analysis of Circular Beam Foundation of a Super-Span Arch Structure

某体育场是目前国内跨度最大的开闭式结构,其屋盖采用拱支单层网壳钢管结构,通过拱脚支座将上部荷载传递至基础,基础采用整体式环梁加预应力管桩承台的形式,预应力管桩承受竖向荷载,环梁承受水平荷载并且协调上部结构水平方向的变形。文中介绍了环梁基础的截面选取、配筋设计及应用有限元方法的受力分析,并结合施工过程中的环梁侧土应力现场监测数据,对环梁基础抵抗大跨度拱结构上部传来的水平荷载的性能进行了研究,探讨了梁侧回填土压力对环梁基础受力的贡献。研究表明,回填土压力的作用受到诸多因素的影响,表现出较大的离散性,回填土的侧阻力能够优化环梁基础的受力性能,但在控制较小位移的前提下作用有限,环梁基础作为一种自平衡体系,是抵抗上部结构巨大水平推力的一种有效的结构形式。

The dome of a stadium, which is one of the biggest span among the existing opening-closing structures in China, is an arch supporting steel tube structure. The structural loads are transferred to the foundation through the arch bearing. The foundation of the stadium is made up of circular beam foundation which resists horizontal force and prestressed pipe piles which resist vertical load. The section selection for the circular beam and its reinforcement are introduced in the paper. By analyzing the circular beam foundation of the stadium using finite element method together with the testing data of soil pressure during construction, the research was conducted to analyze the characteristics of circular beam foundation when the superstructure loads were applied to the foundation, and the contribution of the filled soil near the beam to the circular foundation was investigated. The results show that the effects of the filled soil which has large discrepancies, are affected by diverse factors. The resistance of filled soil can optimize the performance of circular beam and has little effects under the condition of small displacement control. As a self-balanced system, it is verified that the circular beam foundation is an effective structure to resist tremendous horizontal force.