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Large-span spatial steel structure creating the innovation of construction technology

Along with the continuous renewal of architectural ideas, many new type of structure in large span spatial steel structure are mainly cable structure and shell structure and the spatial grid structure, etc which used in Gymnasium ,Exhibition hall ,Bus Station, Hangar, workshop,and other roof structure, Building for aesthetic and functional diversification caused the transformation of construction technology. This change has given rise to new construction technology. The manufacturing technology of steel structure curve slip Asymmetric overall improvement of construction technology, let the construction beyond traditional to a higher level.

Large-span spatial steel structure is more and more complicated

Modern large-span steel structure is not limited to the traditional form of a single structure, the new structure and the various forms of composite structures are emerging. Structure more complex. “Bird’s Nest” distorted use of complex space truss structure, the “Water Cube” with a rigid frame structure is based on the theory of polyhedral space bubble, Olympic badminton hall is using the world’s largest suspendome span structure, the Guangzhou International Convention and Exhibition Centre with a truss string structure.

Such as the “Bird’s Nest”, “Water Cube” building such a large span space, difficult to construction , as the three-dimensional structures form and spatial structure of the system. “Bird’s Nest” is hyperbolic saddle type , the highest point is 68.5m , the lowest point is 40.1m , oval shaped in plane view , the long axis is 332.3m ,short axis is 297.3m . It is composed of a complex consisting of box-distorting elements and a lot of secondary structure intertwined together on space , with 4.2 million tons of steel structure , connected by a 300 km long welds. “Water Cube” in the form of structure is based on the theory of foam, cut from the 14-side and 12-side dodecahedron and the body is made of a combination of polyhedral steel structure, side length 177 m, height 30 meters, the roof thickness 7.2 m, the wall thickness of 3.5 m and 5.9 m .The whole structure consists of 29,979 members and 9,309 nodes, about 7,000 tons of steel, connected by a 100 km long welds.
Construction process embodies the “space” changes

For a large span steel structure which have several construction solution , each construction method has its own characteristics and different scope, the construction method of choice is reasonable or not will directly affect the project Quality, construction schedule, construction costs and other technical and economic indicators.

In recent years, a large number of engineering practice and honing, construction technology of large-span spatial structures has been a huge improvement. “Collapse Expand” construction technology is a method of construction fully reflect the large span space structure construction process, “space” change. It is the large-scale structure can become a sports agency, close to the ground in the first place “folding” the assembly, and then gradually expand to enhance and change the shape of the construction occurs constantly, until the shape of the design requirements. This method is similar collapsible people use the process of opening. “Cumulative slip” construction technology has been applied in many large projects, two-way beam string structure of the National Stadium on the use of the “cumulative slip with cable, bi-tensioned prestressed symmetric” technical solutions. 120 m span steel truss space bidirectional Lenticular the Wukesong Indoor Stadium is also used aerial cumulative slip technology. “Water Cube” is taken in combination, supplemented by bulk-based installation methods, components and shaped like a hollow ball combination “lollipop”, then as the center of a hollow sphere, lifting the lower rod connects with the ball in place , a “multi-mast Ball” state, consisting of a polyhedron welded, outside the polyhedron is “inflated pillow” membrane support frame. “Bird’s Nest” large and heavy components, truss column uses “lying spelling” main truss using “flat spelling” large tonnage units of hoisting and “stand up”, distorting components and high-altitude precision butt weld are enormous technical challenges . Installation of large-span spatial structure has a strong spatial association of any one component mounting position is not accurate, will lead to other elements difficult to install.

Information technology needs innovation
As the application of computer technology, information technology and advanced CNC equipment, space steel structure require a comprehensive application of information technology, design technology, manufacturing technology and management techniques to improve productivity and achieve customized goals to improve space steel structure innovation and management level. Steel structure CAD design and CAM manufacturing technology is computer-aided manufacturing technology areas, including the overall three-dimensional solid modeling, and optimization of sheet metal rod cutting, design and various types of steel tubular shaped nodes nodes, analysis, and manufacturing.

Continued large-scale projects, thus enabling the construction phase structure of security issues have become increasingly prominent. Some structural engineering force status in the construction process is completely different from the using phase, even the most unfavorable force structure some stage in the project during construction. Steel construction and installation simulation technology mainly consists of five areas: a large component of the lifting process simulation; various stages of the construction process conditions for each simulation; pre-distortion technology structure installation, including bagging and pre-displacement member; ultimately structure installation Upon completion of the correct geometry; pre-assembled structural elements simulation; uninstall process simulation. Through simulation analysis, can pre-construction process to fully discover the weak links and key control positions, can intuitively realize the structure of the entire construction process control and ultimately achieve the correct shape and size.

As the large increase in engineering practice, people will develop new systems to meet China needs a large span steel structures, new technologies, new materials, to more fully reflect the nature of large-span spatial structure, economy and rationality, to promote China’s large span steel structures positive, healthy development.