贵阳某体育场大跨度悬挑罩棚结构设计研究

Research on structural design of a large-span cantilever canopy stadium in Guiyang

贵阳某超大型复杂体育商业综合建筑的大跨度悬挑罩棚,最大悬挑长度83.2 m。为了明确其受力机理及性能,对若干设计要点开展研究。根据建筑效果、施工条件及材料用量等多角度多方案比选,对结构体系下部采用钢筋混凝土框架-剪力墙结构,悬挑罩棚采用空间悬挑桁架与环桁架结构,经验算受力与变形均满足要求。对整体结构的地震行波效应进行了分析,设计最终采用视波速1100 m/s下的影响系数作为各层的地震作用放大系数。通过结构抗震性能化设计,对关键构件的性能目标予以加强,并对罕遇地震作用下结构的弹塑性性能进行验算,结果均满足要求。对罩棚进行整体稳定性研究,通过对整体模型进行线弹性屈曲分析,得到了竖向平面桁架杆件的计算长度系数,并补充采用直接分析法所得的结构受力状态,进行包络设计;通过考虑双非线性的屈曲分析,对结构的塑性发展进行研究。结果表明,结构塑性发展顺序合理,具备一定的安全储备。为考虑偶然荷载作用下,传力路径上发生重要构件失效的工况,采用拆除构件法研究了罩棚抗连续倒塌的能力,得到罩棚结构具备可靠的备用传力路径,满足设计要求。结合实际施工方法,对结构进行了相较一次成型态的分区分步施工模拟分析,得到主体结构的竖向位移与最大应力差异较小,施工方案可行。

This paper conducted research on some key design points of a large-span cantilever canopy(the maximum cantilever length is 83.2 m)of a large complicated sports and commercial complex building,to clarify its force mechanism and structural performance.Comparisons were made in terms of architectural performance,construction conditions and material quantities,etc.The lower part of the structural system adopts a reinforced concrete frame-shear wall structure,and the cantilever canopy adopts a spatial cantilever truss and ring truss structure.The forces and deformations meet the design requirements.The seismic travelling wave effect of the overall structure was analyzed and the influence coefficient at 1100 m/s wave speed was used as the seismic effect amplification coefficient.By means of performance-based design of the structure,the performance targets of key elements were strengthened and the elastic-plastic performance of the structure under rare earthquakes was verified.The overall stability of the canopy was investigated by performing linear elastic and double non-linear buckling analysis on the overall model.The former obtained the calculated length coefficients of the vertical plane truss bars,and the structural force state analysis was supplemented for envelope design using the direct analysis method;the latter investigated the plastic development mechanism of the structure,and the results show that the structure has a reasonable sequence of plastic development and a certain level of safety reserve.Considering the failure of important elements in the force transmission path under accidental loading,this paper adopted the method of removing elements to study the ability of the canopy to resist continuous collapse,and the results show that the canopy structure has a reliable alternate force transmission path and meets the design requirements.In combination with the actual construction method,the structure was simulated in a zoned and step-by-step construction analysis compared to the one-step forming state,and the differences in vertical displacements and maximum stresses in the main structure were slight,which proves the feasibility of the construction solution.