大跨度混凝土拱壳声屏障结构设计研究

Structural design and research of large-span concrete arch shell in enclosed sound barrier

北京朝阳站至五环路段(里程DK14+400~DK15+050)封闭式声屏障垂直轨线方向的结构跨度约40m,采用大跨度混凝土拱壳结构形式。结构拱形由斜线+圆弧+抛物线组成,满足建筑限高和景观要求;在拱顶抛物线段设置预应力平衡拉索,以平衡高位局部拱结构的推力,显著改善主拱结构和拱脚基础的受力状态。主拱之间的混凝土薄壳采用预制装配式壳板,通过优化SP预应力空心板和主拱结构的连接节点构造,提升主体结构施工效率的同时保证结构连接的可靠性。设计过程中,充分考虑施工组织方案,按照多个施工阶段进行包络设计;主拱结构各阶段的变形验算均满足规范要求,进行了拱结构的整体稳定性分析。主拱基础采用设反倾角的重力式混凝土条形基础形式,基础设计过程中充分考虑各种不利设计工况,充分保证基础设计的安全性。

Large-span concrete arch shell structure during the Beijing ChaoYang Railway Station to the Fifth Ring Road(mileage DK14+400~DK15+050)with a structure span of about 40m in the derection perpendicular to the tracks.The arch was composed of oblique lines,arcs and parabola to meet the building height limit and landscape requirements.Prestressed balance cables was set in the parabolic section of the arch to balance the horizontal internal force in the local arch structure,which significantly improve the stress state of the main arch structure and the arch foot foundation.Prefabricated shell plates was applied in the thin concrete shells between the main arches.By optimizing the connection joint between the prefabricated shell plates and arch structure,the construction efficiency of project was improved while ensuring the reliability of the structural connection.During the design process,the envelope design was carried out according to multiple construction stages.The deformation of the main arch structure at each stage meets the requirements of the specification.Overall stability analysis of the arch structure was carried out.Gravity concrete strip foundation with inclination angle was adopted in the arch foundation.Various unfavorable design conditions were fully considered in the foundation design process to ensure the safety of the foundation design.