The national stadium located at Beijing Olympics park central area south, is in 2008 the 29th Olympics games's main stadium. Project total area 21 hectares, floor space 258,000m2. In the field the audience attends a banquet approximately is 91000, attends a banquet temporarily approximately 11000. Will hold the Olympic Games, Paralympic Game to hold the closing ceremony, the track and field competition and the football competition finals. After Olympic Games, will become Beijing residents widely to participate in the sports and to enjoy the sports entertainment's large-scale specialized place, and becomes has the terrestrial reference sports architecture with the Olympic Games inheritance. National stadium project for top grade sports architecture, main body structural design service life 100 years, fireproof rank for first-level, earthquake resistance fortification intensity 8 degrees, understructure work waterproofing rank 1 level. The project main body construction assumes the spatial saddle ellipse, the north and south length 333 meters, the thing width 294 meters, height 69 meters. The main body steel structure forms the whole the giant spatial saddle-shaped steel truss knitting type “the bird nest” the structure, the steel structure always uses the steel quantity is 42,000 tons, the concretes stand divides into upper, middle and lower three, the stand concrete structure for underground 1, ground 7 reinforced concrete frame - shearing force wall structure system. On the steel structure and the concretes stand withdraws completely, is not mutually connected, formally assumes encircles mutually gathers, the foundation sits on a connected foundation mat. In the national stadium roof steel structure has covered the double-decked membrane structure, namely fixes between the steel structure top chord the transparent upper formation ETFE membrane and fixes under the steel structure last quarter and the inner rim sidewall translucent lower level PTFE acoustics suspended ceiling.