The Bird's Nest is the main stadium of the 2008 Beijing Olympic Games. 200 1 The design of the giant stadium, jointly completed by Plic Prize winners Herzog and De Mellon and China Architects, looks like a "bird's nest" that breeds life, more like a cradle.
With human hope for the future. The designer did not do any unnecessary treatment to the National Stadium, but frankly exposed the structure, thus naturally forming the appearance of the building.
The "Bird's Nest" is surrounded by a huge steel net, covering the stadium of 9 1 000 people. Sightseeing stairs naturally become an extension of the structure; The pillars are gone, and the net with uniform stress has no clear direction like branches, which makes people feel that every seat is equal, and being in it is like returning to the forest; Filter sunlight into a diffusion inflatable membrane, so that the stadium bid farewell to the shadow of sunlight; The whole terrain rises by 4 meters, and the interior is used as an auxiliary facility, which avoids the huge investment consumed by excavation.
Bird's Nest is a long-span curved structure with a large number of curved box structures. Design and installation are extremely challenging, and scientific and technological support is indispensable everywhere in the construction process. The "Bird's Nest" adopts today's advanced construction technology, and there are twenty or thirty technical problems in the whole project, among which the steel structure is unique in the world. The total weight of the "Bird's Nest" steel structure is 42,000 tons, and the maximum span is 343 meters. And the structure is quite complicated, and its three-dimensional distortion is treated like a twist. Problems such as settlement, deformation and hoisting after construction are gradually being solved, and related construction technical problems are also listed as key research projects of the Ministry of Science and Technology.
Now, the "Bird's Nest" has completed the concrete construction and started the steel structure construction. In order to effectively control the maximum wall thickness of members, reduce the welding workload and make the connection structure more reasonable, high-strength Q460 steel is adopted in the design.
Speaking of Q460 steel, most people may not understand it. The structural design of "Bird's Nest" is strange and novel, and the steel structure Q460 built this time has many unique features: Q460 is a low-alloy high-strength steel, which will only undergo plastic deformation when the stress intensity reaches 460 MPa, which is greater than that of ordinary steel, so it is very difficult to produce. This is the first time that Q460 steel has been used in building structures in China. The thickness of the steel plate used this time is 1 10 mm, which is unique in the past. In the national standard, the maximum thickness of Q460 is only100 mm. In the past, this kind of steel was generally imported from Luxembourg, South Korea and Japan. In order to provide a "suitable" Q460 for the Bird's Nest, from September 2004, the researchers of Henan Wuyang Special Steel began to tackle scientific and technological problems for more than half a year, and the trial production was finally successful three times. Nowadays, mass production of Q460 steel for "Bird's Nest" has begun. In 2008, 400 tons of domestic Q460 steel with independent innovation and intellectual property rights will support the "Bird's Nest".
-Birds build nests
From the eastern Congo to the savanna of South Africa, we can often see a weaver bird called the grey-headed finch. They weave nests with grass and many fibers with different elasticity and hang them on branches like strange fruits. Weavers choose strong animal hair-most commonly zebra or antelope hair, tie the nest firmly to the branches, and tie the hair into a knot with their mouths as a sign. Such a bird's nest can bear the full weight of a pair of adult birds and a few young birds living in it, and will not fall off no matter whether it is windy or rainy.
At the beginning of this century, a natural science enthusiast, Eryenne Murray, found that young birds do not imitate their older partners when building nests. In order to rule out the possibility of young birds being trained, Yi Yan took some eggs from the woven nest and secretly put them in the canary nest raised by his family to hatch. When the chicks hatch and grow up, they are moved to another specific place, where they can form "partners" and have children. At the same time, they are not allowed to get any materials suitable for nesting, but are allowed to lay eggs directly at the bottom of the cage. The laid eggs were taken away again, and then the canary was hatched ... This repeated experiment made the fourth generation of weaver birds not only cut off contact with their predecessors and nature, but also be completely domesticated by human beings.
Now, he puts a handful of grass, some slender branches and fibers in the birdcage. The weaver bird began to work with these materials in the cage. Soon, the birds made their nests in cages, and their styles were no different from those built by their free predecessors. They are familiar with construction technology, and their knowledge in this field is no less than that of their great-grandparents. They also know how to pad the bottom of the cage with soft but not strong horsehair, and they will never weave it into a nest wall by mistake. If there are scraps, they will use them to reinforce the connection between the nest and the tree bars on the cage and tie a special knot with a "trademark".