Located at the southern part of the Olympic Green in Beijing, the National
Stadium is the main stadium of the 29th Olympiad in 2008. Occupying an area of
21 hectares, it has a floor space of 258,000 square meters. Its seating capacity
amounts to 91,000, including 11,000 temporary seats.
The venue will host the opening and closing ceremonies of the Beijing Olympic
Games and Paralympic Games, the track and field competitions, and the football
finals. After the Olympics, the stadium will become a large-scale sports and
entertainment facility for the residents of Beijing -- an architectural landmark
and Olympic legacy.
The main body of the National Stadium has a design life of 100 years. Its
fire resistance capability is first-rate, and it can withstand an
eight-magnitude earthquake. The water-resistance capability of its underground
project is also first-rate.
The main body of the National Stadium is a colossal saddle-shaped elliptic
steel structure weighing 42,000 tons. It is 333 meters long from north to south,
294 meters wide from east to west, and 69 meters tall.
The main body's elements support each other and converge into a grid
formation, just like a bird's nest with interlocking branches and twigs. Being a
seven-story shear wall system, the stadium's stand has a concrete framework. The
upper part of the stand and the stadium's steel structure are separated from
each other, but both are based on a joint footing. The roof of the National
Stadium is covered by a double-layer membrane structure, with a transparent ETFE
membrane fixed on the upper part of the roofing structure and a translucent PTFE
membrane fixed on its lower part. A PTFE acoustic ceiling is attached to the
side walls of the inner ring.
The construction of the National Stadium followed the PPP mode (Private +
Public + Partnership ), and it is co-owned by the Beijing State-Owned Assets
Management Co. Ltd (BSAM), who shares 58 percent of the total assets, and the
China International Trust and Investment (CITIC) Consortium, who holds the rest
of the assets.
Composed of BSAM and CITIC, the National Stadium Co. is responsible for
financing, construction, operation and management of the project. CITIC has a
post-Games licensed operation right for 30 years.
The National Stadium is a complex structure, posing great difficulties for
its designers and constructors.
1. Large and heavy steel parts
The fracture surface of the largest truss column -- the major load-bearing
component of the roof structure -- measures 25m x 20m, with a height of 67m. The
maximum weight of a single column is 500 tons. The main truss is 12m tall. The
maximum span between and through the two columns amounts to 145.577+112.788m,
and the maximum span between the two trusses stands at 102.39m. Each truss
column is of great bulk and weight, and so are the main trusses.
2. Complex nodal joints
Because the structural elements in the project are box-typed, many elements
intersect spatially among the steel parts. Besides, the complex nature of
secondary structures has resulted in the diversity of nodal joints of the main
structures, requiring accurate and sophisticated manufacturing and
3. Tight schedule
In addition to the huge workload, the allotted construction period is short.
Having started on December 24, 2003, the project is expected to be completed by
the end of 2007, with the inauguration time scheduled for March 2008. Therefore
many operations have to be conducted on a limited terrain, causing a very tense
4. The hoisting work extended across the winter and spring, so the workers
have had to defy both rainy and cold conditions in the winter to continue their
The workers have overcome tremendous engineering and technical challenges in
the process of construction:
1. Difficult work arrangement
They need to do very detailed research of operations and follow meticulous
arrangements to complete various kinds of work within a limited workspace.
2. Difficult hoisting of steel parts
To facilitate the assembly of the steel parts, the workers have to use a
prone position to assemble the truss columns, which requires a turnover process
before they are hoisted. The choice of the hoist points and lug hooks pose great
difficulties in the face of bulky and cumbersome steel parts, and the change of
pulling stress from three directions must be taken into consideration. The
workers need to meticulously rectify angles and positions of the box-typed
sectional parts to ensure accurate abutment during the hoisting process.
3. Difficult stabilizing process
They also have to fight the heavy wind load and keep the stability of the
steel parts by following a strict working order and use lateral stability
measures including the use of anchoring method and wind-holding ropes.
4. Difficult welding
The welders not only face a huge work volume, but also have to work on both
the thin steel sheets and thick steel slabs, on high-strength and cast steel
elements, and take downward, vertical or overhead positions while welding. They
face temperature changes, steel deformation and intensive labor. They need to
work above ground, in winter rain and under windy conditions.
5. Difficult installation
The workers face difficulties in ensuring accurate installation as the steel
parts and the related gigs and fixtures can be deformed easily under their own
dead weight and the change of temperatures. The workers must take
pre-installation measures to rectify and relieve the errors that might occur in
the process of installation.