Long-span and pre-stressed is a new combinition form of steel structure by high-strength steel, corrosion-resistant, anti-fatigue and a variety of space struction, with perfect integration together of the flexible steel cables and rigid steel struction, for the architect to provide a means of building that both functional and economic and coverage of large areas and space. Beijing Olympic Games in 2008 to adopt this structure in seven venues.
Get into the venues of Beijing 2008 Olympic Games, you can not but pay attention to their unique external form: the wave curves of National Stadium elegant appearance and beautiful gesture; the dome of Badminton Hall likely sky, it shows a round-sky and side-earth the traditional universe view between quiet and movement; "Chinese ridge" of the Table Tennis Hall stretched wings and with a 100-year-old history Beijing University complement each other, it would rather charm of Chinese traditional architecture ... ...
The originality of these patterns are emerging with a closely related form of the structure, that is now the first selected type of structure:long-span pre-stressed steel in stadiums, airports, mainframe database, the Convention and Exhibition Center and other large-scale construction..
According to the contract that all Olympic venues large-span prestressed steel breakdown of the design, construction and monitoring of the Beijing Construction Engineering Group, vice president of the Institute of Construction Zhang Ran, long-span pre-stressed by high-strengthsteelcorrosion-resistant, anti - Fatigue and a variety of cable space in the form of a combination of the steel structure of a new form of flexible steel cable with the rigid perfect blend together for the architect to provide both functional and coverage of large areas of the economy, The means of building large space, they won the favor of the Beijing Olympic Games in 2008 to adopt this structure in seven venues.
93 m span- the world's largest, the outer ring to the pre-stressed cable tension value of 250 tons, the steel roof arch camber value of more than 110 mm, the design and structure difficulty of the Olympic Badminton Hall is rare in the world . The project has adopted a string-dome steel structure system, mainly constitute by the network of single-layer shell, and pre-stressed cables. One of the pre-stressed cables is the most significant feature of this project and difficulty.
In response, Beijing Construction Engineering Group to build NARL Dr. Qin Jie given such a vivid metaphor: "We have the usual hand power Wo Wo-lap course of the other way around, that is, in the string-dome structure imposed by the process of pre-stressed. We are forced to grip Grip ring, rubber ring contraction, then hand-eminence. Faso to the ring like rubber circle, back to our network is single-shell, the finger is the pole. In the works, we first of all to the 'rubber ring' (to the Central cable) the inside of a rally, through the force 'finger' (pole) passed to the 'back'(single-layershelnetwork)on the arch so slowly.
Due to the huge roof and the complex structure, to the Central cable tension of the process difficulty. The first difficulty is how to maintain post-tensioned vertical pole. NARL built with a solid edge computing, in the simulation of force to carry out accurate analysis and guidance for the project; The second is due to the large-span, a single pre-stressed cable tension to achieve the maximum value of 250 tons (of the world's largest two-way string The structure of the National Stadium individual pre-stressed cable tension value of 120 tons), construction risks.
According to the designers tension with the situation of-the-art equipment such as hydraulic jacks, at the same time mechanical engineer from the tension on the set of equipment specifically designed to address this problem; Third, the form of flexible control. Since the final structure of the arch by Zhang pulled out of child support aircraft, construction of the security challenge. Therefore, the layout designer for monitoring more than 50 points for Lasso, and the steel rod to monitor stress and deformation of the structure to monitor to ensure the safety and quality of the structure.
National Stadium steel roof truss structure in the form of "single face a two-way pre-stressed steel truss string", the main hall 144.5 meters long from north to south and 114 meters wide things, for its two-way span truss string of pre-stressed steel in the world. National Stadium project as a whole steel roof truss Pin 14, of the total volume of 2800 tons of steel, how to complete such a huge scale of pre-stressed steel structure design and construction so that really to build pre-stressed NARL's engineers made difficult.
After 26 demonstration programs and optimization of the designers to finalize the single-Pin high-altitude sub-assembly, pre-cable wear, slip cumulative, pre-stressed tension of the construction of the installation of new technology. Tongsudeshuo, the truss is to be assembled in the high-altitude, wear steel cables into the "Shang Jin stretched", and then a north-south through the East-West Rail in batches of them from the west to the eastern side of the slide into the final overall tension, so Significantly reduce construction costs.
In addition to the completion of pre-stressed breakdown of the National Stadium in the design and construction, Beijing Construction Engineering Group to build NARL also act as a permanent steel structure health monitoring. Through 83 monitoring equipment to Taiwan, the whole wireless monitoring system and advanced laboratory equipment poses a set of strict monitoring system, the National Stadium on the steel structure for real-time monitoring, which is the first time in our country.
Olympic table tennis hall at the top of a table similar to the shape of the shell structure of the network, extending the wings, "Ridge China" very dynamic, forming a whirlwind hold up the table a unique style. Beijing Construction Engineers NARL Lu Jian Li Qing: "pre-stressed by a circular truss network began to shell, the radial was to shoot around, which makes Beijing University Table Tennis Hall of space has become extremely complex string, can be the most domestic. Because it is Irregular, uneven, when the tension is easy in the middle of the 'ball' pull side. "To this end, NARL take to build a "multi-step and more small-class" symmetrical tension. 32 Pin Tongsudeshuo is carried out under the pre-stressed truss tension, at 8 symmetrical points, a total of 4 times, and at many times, gradually pulling imposed in order to ensure the stability of the structure.
However, Zhang said: "Although China has built many in the international span of a leading long-span prestressed steel structure, but design and construction process, there are still many unresolved issues, the development is the 'theory of scientific research in advanced engineering applications ',' Practical application of scientific research behind the project ',' the speed of technological innovation is greater than the speed of the accumulation of research '. In the future, Beijing Construction Engineering Science Summer Camp will be built in the design and construction methods to improve, the node full-scale pilot study to monitor the construction and health Monitoring the theory, methods and practical technology to do research on issues such as more in-depth exploration.