大跨度空间网格结构常用安装方法及新思路

Common Installation Methods and New Ideas of Long-Span Spatial Grid Structures

近年来,大跨度空间网格结构在航站楼、会展中心、体育馆等城市大型公建项目中得到了广泛的应用。伴随着新型结构形式的不断涌现,现场安装也面临着巨大挑战。通过对近年来空间网格结构典型案例梳理及几种常用安装方法的优、劣势分析,发现现有安装方法在实际应用中均存在一定的局限性。因此,亟需对更高效的安装技术展开深入研究。以国际FIFA标准建设的广州10万座足球场项目,是国内罕见的球场与商业结合、场心下设地下室的体育文化综合体项目。项目设计灵感来源于“并蒂莲”,取其“含苞待放又紧紧相拥”的优美形态,造型别致。钢罩棚最高点标高为88.600 m,最大悬挑长度约91 m,自上而下布置3层菱形花瓣状体块,每层花瓣造型由12个单元构成,单根杆件长度可达40~64 m,形成巨型带肋空间折板网格结构。在分析现有的高空原位安装、累积滑移安装等方法后,发现存在临时措施量大、交叉作业多、质量控制难等问题。借鉴桥梁竖转安装思路,提出空间网格结构的负角度竖转安装方法。其核心步骤为:低位拼装—竖转到位—嵌补合龙—同步分级卸载。而后,对竖转界面及单元划分、竖转系统设计、转铰构造等关键节点进行分析。基于此,利用MIDAS/Gen大型结构有限元分析软件,对竖转过程关键施工阶段的变形及受力进行施工模拟验算,并与设计施工阶段的结果进行对比,以此验证竖转安装方法的可操作性。分析结果表明:卸载后的钢罩棚整体变形模拟值与设计值基本吻合;竖转法安装技术在安全、质量、临时措施量及进度控制等方面相较于常规的安装方法均具有一定优势,在大跨度空间网格结构的安装中具有广泛的应用前景和实用价值。

Spatial grid structure is widely used in large-scale public construction projects in recent years,such as terminal buildings,convention and exhibition centers and gymnasiums,etc.With the growing emergence of new structural form,on-site installation is also facing great challenges.Through combing the typical cases of spatial grid structure in recent years and analyzing the advantages and disadvantages of several common installation methods,it is found that the existing installation methods have certain limitations in practical application.So it is urgent to carry out in-depth research on the new installation technology.Guangzhou football field is built in accordance with international FIFA standards with 100000 seats.It is a rare sports and cultural complex project in China that combines stadium and business and has a basement under the center of the field.The project design inspiration comes from“twin lotus flowers on one stalk”,take its“bud and tightly embrace”beautiful form,unique shape.The highest point elevation of the steel canopy structure is 88.6 m,and the maximum cantilever length is about 91 m.Three layers of diamond petal shaped blocks are arranged from top to bottom and the petal shape of each layer is composed of 12 units.The length of a single member is 40~64 m,forming a giant ribbed space folded plate grid structure.After the preliminary analysis of the existing methods of high-altitude in-situ installation and cumulative sliding installation,it was found that there were many problems,such as large amount of measures,many cross operations and difficult quality control.Referring to the idea of bridge vertical rotation installation,a negative angle vertical installation method of spatial grid structure was proposed.The core steps were as follows:low position assembly-vertical turning in place-nesting and closing-synchronous and graded unloading.Then the key points such as vertical rotation interface and unit division,vertical rotation system design and hinge structure were analyzed.From this,MIDAS/Gen software was used to carry out construction simulation calculation of deformation and force in key working conditions of vertical rotation process,and compared with the results of design conditions,so as to verify the operability of vertical rotation installation method.The results showed that the simulated deformation values of steel canopy after unloading were basically consistent with the design values.Compared with conventional installation methods,vertical rotating installation technology had certain advantages in safety,quality,quaitity of temporary measures and schedule control,and had a wide application prospect and practical value in the installation of large-span spatial grid structures.