The Bird's Nest is the main stadium of the 28 Beijing Olympic Games. The design of the giant stadium, which was jointly completed by Plic Prize winners Herzog and De Mellon in 21 and China architects, looks like a "nest" that breeds life, more like a cradle, and
entrusts mankind with hope for the future. The designers didn't 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 and covers the stadium with 91, people. Sightseeing stairs naturally become an extension of the structure; The columns have disappeared, and the evenly stressed net 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 the sunlight into a diffuse inflatable membrane, so that the stadium bid farewell to the sunshine shadow; The whole terrain rises 4 meters, and the interior is used as an auxiliary facility, which avoids the huge investment consumed by the excavation.
The Bird's Nest is a long-span curved structure with a large number of curved box-shaped structures. The design and installation are very challenging, and scientific and technological support is indispensable everywhere in the construction process. The "Bird's Nest" adopts the advanced building technology today, 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, tons, and the maximum span is 343 meters. Moreover, the structure is quite complex, and its three-dimensional distortion is processed like a twist. After construction, problems such as settlement, deformation and hoisting 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 concrete construction of "Bird's Nest" has been completed, and the steel structure construction has begun. In order to effectively control the maximum wall thickness of the member, reduce the welding workload and make the connection structure more reasonable, high-strength Q46 steel is used in the design.
speaking of Q46 steel, most people may not know it. The structural design of "Bird's Nest" is strange and novel, and Q46, the steel structure that built it this time, has many unique features: Q46 is a kind of low-alloy high-strength steel, which will only undergo plastic deformation when the stress intensity reaches 46 MPa, which is greater than that of ordinary steel, so it is very difficult to produce. This is the first time that Q46 steel has been used in building structures in China. The thickness of the steel plate used this time is 11 mm, which is unique in the past. In the national standard, the maximum thickness of Q46 is only 1 mm. In the past, this kind of steel was generally imported from Luxembourg, Korea and Japan. In order to provide a "fit" Q46 for the "Bird's Nest", from September, 24, researchers from Wuyang Special Steel Plant in Henan Province began to tackle key scientific and technological problems for more than half a year, and three trial-productions were finally successful. Nowadays, Q46 steel for the "Bird's Nest" has started mass production. In 28, 4 tons of domestically produced Q46 steel with independent innovation and intellectual property rights will support the "Bird's Nest".
-Birds build nests
From East Congo to the tropical savannah in South Africa, you can often see a weaver bird called the grey-headed finch. They use grass and many fibers with different flexibility to weave nests, hanging from branches like strange fruits. Weavers choose strong animal hair-most commonly zebra or antelope hair, tie their nests firmly to branches, and wrap their 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 several young birds living in it, and it will not fall off regardless of wind and rain.
At the beginning of this century, a natural science enthusiast, Irving Murray, found that young birds did not imitate their older partners when building nests. In order to rule out the possibility of young birds being trained, Yi Yen took some eggs from the weaving nest and secretly put them in the nest of canaries 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 suitable materials for nesting, but they are allowed to lay their 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 up their nests hanging in cages, and their styles were no different from those built by their free previous generations. They are familiar with construction technology, and their knowledge in this field is by no means inferior to that of their great-grandparents. They also know how to pad the bottom of the cage with soft but not strong horse hair, and will never weave it into the nest wall by mistake. If there is leftover material, they will use the leftover material to reinforce the connection between the nest and the tree strips on the cage, and use it to tie a special knot with a "trademark".