Basic materials
The shape structure of "Bird's Nest" is mainly composed by the great gate type frame, a total of 24 truss column, has now completed 20 truss column of the whole column and two column lifting. The National Stadium top appear before the saddle-shaped, the long axis of 332.3 m, short axis of 296.4 meters, a maximum height of 68.5 meters, the lowest point height of 42.8 meters.

Design changes
Under the premise of maintaining the same architectural style of the "Bird's Nest", the new design, structure and layout, build the section type, material utilization, and other issues were more substantial adjustment and optimization.The roof can be opened in the original design was canceled and the roof opening to expand, greatly reducing the amount of steel and steel structure optimization.Large-span roof support above the 24 truss column spacing of 37.96 m. The main truss around the opening of the roof middle radial layout, with 22 specimens of the main truss through or close to straight. In order to avoid overly complex node, a small amount of the main truss truncated near the inner ring. Steel structure is a large number of box-shaped components made from sheet steel cross arrangement of the main truss and the roof and facade of the structure together to form a "nest" of special architectural shape. The main grandstand section reinforced concrete frame-shear wall structure with large span steel structure completely disengaged.

The use of the Q460 steel
Speaking of Q460 steel, most people may not understand.Structural design of the Bird's Nest "is strange and novel, while the structures of steel Q460, there are many unique: of Q460 is a high strength low alloy steel, it will occur in the force strength of 460 MPa plastic deformation,the strength than general steel, so the production is very difficult.This is the domestic steel Q460 specifications for the first time in the building structure; use of the plate thickness of 110 mm, previously only in the national standards of Q460 the maximum thickness of only 100 mm. This steel is generally imported from Luxembourg, Korea, Japan. From September 2004 to the "Bird's Nest" fit "of Q460, the researchers of Wuyang special steel for up to half a year of science and technology research, before and after 3 trial finally been successful. Now, prepare for the "Bird's Nest" Q460 steel has begun mass production. 2008, 400 tons of independent innovation, intellectual property rights of domestic Q460 steel will hold up the "nest" of steel frame reinforced.

Special structure
In addition, the roof of the inner ring main truss lifting and facade structure installation is in full swing. The steel used in the "Bird's Nest" Steel up to 11 cm thick, had never before produced in the country.In addition, the surface in the "Bird's Nest" at the top of the network structure will paste a layer of translucent membrane. Use of this film, the light is not shone in the stadium, but by the diffuse reflection, so that light is softer, thus the formation of diffuse light can also solve the venue lawn maintenance, but also for seats shelterfunction. The more unique is, "bird's nest" stadium the outdoor terrain slightly uplift, will be many affiliated facilities in the terrain, such already avoid to dig under the earth to the amount of huge investment, and uplift the slope in the edge of the outdoor plaza slowly to land, according to the potential of the 2000 field is built to warm up the pews, and the surrounding environment organic fusion, and save investment again.