Where will the badminton match of Beijing Olympic Games be held?

Venue: Gymnasium of Beijing University of Technology

Venue: Beijing University of Technology

Venue Type: Newly-built competition venue

Uses during the Olympic Games: badminton, rhythmic gymnastics.

Used during Paralympic Games: None.

Building area (m2): 24383

Fixed number of seats: 5,800

Number of temporary seats: 1700

Commencement date: June 30, 2005

Planned completion time: the second half of 2007

Post-game function: the cultural and sports activity center of teachers and students; Provide training bases for badminton teams of the International Badminton Federation and the State Sports General Administration; At the same time, it is moderately open to society.

A badminton court with 60 kilograms of steel per square meter.

Walking into the gymnasium of the University of Technology, the dome is like the sky, and the cage covers all fields. Inadvertently, people feel peaceful. Under this sense of belonging, the reporter saw such a set of data: the dome with an inner diameter of 93 meters and an outer diameter of 98 meters, plus the two wings hanging on both sides, the steel consumption is less than 1200 tons, equivalent to 60 kilograms per square meter. The steel used in the Bird's Nest is about 400 kilograms per square meter, and the water cube is also 200 kilograms per square meter.

Comparatively speaking, the steel used in the gymnasium of Polytechnic University is only a fraction of other venues. This makes people wonder: compared with other Olympic venues, the difference in steel consumption is so great. Is the dome structure of badminton hall strong or not?

In fact, both at home and abroad, the theory of suspen-dome structure has been verified and achieved quite ideal results. Professor Kawaguchi, president of the International Space Structure Association and director of the Japanese Architectural Society, once designed a suspen-dome stadium, which he thought was a proud work. Since then, a small community gymnasium in Tianjin Development Zone has also tried this style. The dome structures of these two buildings are only over 30 meters in diameter. The challenge of the Gymnasium of the University of Technology is to need a giant with five circles and a diameter of 93 meters. What is the support of such a large dome structure?

"Prestressed" system realizes lightweight.

With people's eyes on badminton courts, the word "prestress" has entered people's field of vision more and more. Zhang Ailin, vice president of the University of Technology, said that "prestress" refers to the pre-application of force in the member to cope with the load of the steel structure itself, including roof self-weight, wind load, snow load and earthquake load. The prestressed system is mainly used in the truss string dome structure, which transforms the vertical load of the roof into tension.

If you have a bow at hand, put it vertically on the table, and the bowstring is close to the desktop. Then turn 180 degrees on the horizontal plane. The shape of the arch back is the dome of the badminton hall. Because the bowstring pulls both ends of the bow back, giving it an upward force to counteract its own gravity. This upward force is prestress. 1, the 200-ton dome is supported by this four or two kilograms of prestress.

As early as 2002, the University of Technology had done a similar experiment of prestressed system. At that time, the University of Technology was busy with two applications, one was to apply for the construction of an Olympic Games venue on campus, and the other was that Zhang Ailin, the academic leader, was applying for the national scientific research project of prestressed system. Some people say that happiness will last until tonight, and both wishes of Beijing University of Technology have come true. When bidding, the design of the Architectural Design Institute of South China University of Technology firmly caught the eye of the judges, and also had an appetite for Beijing University of Technology. Needless to say, the prestressed system will be integrated into the suspen-dome structure, and the gymnasium of the University of Technology will definitely win with "lightness".

Experiments show that the dome bears 3.2 times the design load.

Liu, a doctoral student who is still studying at Beijing University of Technology, still remembers the experiment last spring and summer. In mid-April, 2006, a dome model with the scale of 1 to 10 was built in the laboratory, and a model was built for one and a half months. Later, Liu followed Zhang Ailin and six or seven students into the laboratory. In order to verify the theoretical calculation and carry out safety tests, complex dynamic and static tests were started.

Before the experiment begins, Liu and his classmates should first connect the important nodes and components to the "sensors", and then connect them to the two computers at the experimental site. Although there are only five cycles, because there is a steel pipe connection in the middle, it will affect the whole body, and every small adjustment needs to be cautious. After that, it will be aggravated three times, and the static and dynamic experiments will be interspersed. It will take at least a week for a round of tests.

During the test, Liu kept a close eye on the future "Dome of the Gymnasium of Polytechnic University" and compared the subtle differences between the data. Indeed, they stayed in the experimental field all day. Liu recalled that they entered the field at 8: 00 every morning and often came out at 12 in the evening. Two months later, they ate 1, 000 yuan for lunch.

Let's take a look at the figures of the Gymnasium of Polytechnic University: the ultimate bearing capacity coefficient of the dome reaches 3.2, which means that it can bear the weight of 3.2 times the design load. The ultimate bearing capacity coefficient of general buildings is 1, which is safe. The verified data show that taking "light" can also achieve better results.

Ingenuity in detail, ingenuity in precision thinking

Badminton hall is not as grand as the National Stadium or as beautiful as the Water Cube, but it can reflect the originality of Polytechnic University everywhere.

In the dome structure, five ring cables are connected by steel pipes woven like fishing nets. In this braided structure, there are 102 universal expansion joints. The so-called universal expansion joint is to change the "dead buckle" at the intersection of the ring cable and the "fishing net" into a "live buckle".

The practice of "movable buckle" is to divide the fixed node into two halves, the fixed part at the top is slotted, and the part at the bottom is made into a hemisphere, similar to human joints. Two sets, better mechanical performance, safer for buildings. This split "snap button" was patented last year.

You may not see this universal expansion joint, but if you pass by the south gate of the University of Technology now, you can still see the steel pipe "fishing net" covered above the main stadium. In the previous dome structure, all the ring cables were connected by a radial cable. Considering that the strength of the ring cable itself is 4 to 5 times higher than that of the steel pipe, in order to make the dome safer and match the materials better, two tie rods are connected at each joint to form a more stable V-shaped structure. This is why the architect said that the gymnasium of Polytechnic University is "not flexible, but both rigid and flexible".

With the development of badminton hall, there is also a booklet called "Technical Specification for Prestressed Steel Structures". From 2004 to 2006, this technical specification lasted for three years and was finally released at the end of last year.

Prior to this, there was no technical specification for prestressed structural system in China. In the construction of Shenzhen Convention and Exhibition Center, prestressed structures were also adopted, but only general steel structure specifications were adopted, and there were not enough technical specifications.

Zhang Ailin has always had the idea of making up this rule. Taking advantage of the rare opportunity of the University of Technology to build a gymnasium, he and another University of Technology professor Lu started work together and sent the first draft of the regulations to more than 40 experts across the country. Unexpectedly, they got unanimous evaluation, and experts used "just in time" to describe the gaps filled by technical regulations and the great promotion they brought.

On June 5438+065438+ 10, 2005, steel structure experts gathered at the annual meeting of China Steel Structure Association, and invited Zhang Ailin to give a special report on the gymnasium of University of Technology. At the meeting, he introduced the first draft of this technical specification and the idea of universal expansion joint. Zhong, an 86-year-old expert, patted Zhang Ailin on the shoulder excitedly and said, "Your Beijing University of Technology has done two decent things for the development of steel structure in China. It's really not easy. "

Say it's applying for a patent, say it's filling a gap. In fact, all this is just because of the intelligence of Beijing University of Technology.