Large span roof indeed & other; Can't afford to injury & throughout

Large span roof indeed & other; Can't afford to injury & throughout; ?

On March 9, encountered strong winds dust weather in Beijing, the Beijing capital international airport T3 terminal building roofs metal plates for the third time by wind, netizens have spit travel & other; Used throughout the &; . Large span roof of wind resistance ability, really so fragile?

Is not a structuredesignTo blame

Day 11, capital airport area winds of up to 30 meters per second, wind grade 11 or above, strong cyclone in the capital airport terminal 3 international area northeast corner of the roof plate local was torn. Since then, the airport is not a further interpretation on the the cause of the accident.

Is the scene of the accident description view, and on December 10, 2010 and 2010 on November 22, local swept up by the strong wind, T3 terminal building roof due to roof was pulled, the outermost cuticle plates made metal plate below the pale yellow rock heat preservation quilt the wind blows away.

According to understand, T3 is by the famous British architect Norman & middot; Foster design, as the design is the architectural design of BeijingresearchThe courtyard.

Beijing architectural design institute a spoke on condition of anonymityexpertsSaid, is this a few times the accident itself, does not involve the problem of structure design, because the T3 roofing structure part and didn't appear because the wind damage, the main reason or fixed roof skin, connection, especially sheet metal process method of sealing the side problem.

For reasons of cost control, "he said," domestic manufacturer imported from Germany to the originally a whole roof manufacturing method with some simplified processing, therefore, the performance, quality roofing could end up some deviation.

& other; Once the metal plate sealing side become loose, easy to open local winds. If can increase some bolt to reinforce joint, the roof fixed can be improved. Throughout the &; He thought.

Large span cantilever wind sensitivity is high

In fact, large public buildings roof damage, blown down phenomenon is not only the T3 alone, these buildings are often some of the large span structure, roof tend to weight, large flexibility, its ability to resist wind pressure is particularly important.

Capital airport with big span time three pyramid steel reticulated shell, roof shows herringbone, while in the three-dimensional space, the shape of the roof is not a piece of plate is the same, is typical of different buildings.

Swiss registered architects, engineers association representative in China, however, said zhang wan SAN: large span itself does not mean weak ability to resist wind load, but large-span structures have large area beyond the part of seg, cantilever, its surface have been up and down the wind effect, the actual wind is equal to the resultant force on the surface of the up and down, therefore, was part of the wind load mainly, is also the most sensitive part of the wind pressure.

& other; This is similar to open an umbrella, wind pressure, the greater the umbrella in front edge of the greater the negative pressure. Throughout the &; He explained that the area of the cantilever and the shape of the front would affect roof the size of the wind load.

Assuming that found in the experiment, cantilever local under wind pressure will be too large, or be able to improve building structure reinforcement andmaterialTo improve physical properties of the way.

Zhang wan said, local structure reinforcement can be for cantilever structure with steel bar reinforcement, or the strength of cantilever root structure and cross section area of a certain amount of reserve.

In addition, the roof structure of epidermis and adhesion area, location and strength of the adhesion as well as the method, also to be able to echo the former enough resistance to wind pressure of the design requirements. It is often through secondary design and manufacturerThe constructionrocess to ensure that mainly involves process method.

In his view, if the T3 terminal building structure does not appear problem, in general, the problem is most likely to appear on the surface of the fixed.

If the metal plate is screwed to theThe Steel Structure Project On, once have a piece of plate screw corrosion protection is not enough, the surface stress point no alignment, the fixed ability could be affected; Or between epidermis and structure, metal plate and metal plate between the flexible handle is not enough, not to local wind suction have very good weakening effect and so on.

Wind tunnel tests would be quite safe

It is easy to understand, in order to ensure the safety of long-span structures accurately calculating the wind load is very important. Wind load of the building, however, affected by many factors, for example, a once-in-a-century winds, terrain roughness of ground, roof height and slope, surrounding buildings etc. It is because of the wind load is difficult to estimate the influence of the civil engineering department of tsinghua university professor Qian Jiaru said, large and key construction must through building model wind tunnel test.

So-called architectural wind tunnel test is simply on the basis of movement principle of relativity, the building model in the duct of artificial, man-made air flow, simulation of air flow to pressure generated by the project structure, this also is the experiment building wind parameters. And simulation environment, mainly rely on meteorological department on areas in which architecture has long-term observation records, as well as mathematicalstatisticsAnalysis of the wind direction, wind speed, and so on and so forth.

After T3 terminal building for the first time by the wind waves, the official explanation, at present our country architectural designstandardIs to fight against the winds of 26.8 meters per second, which is 11 level wind, and T3 terminal building roof is in accordance with the higherstandardDesign construction, to fight against the winds of 28.3 meters per second, which is grade 12 in the wind.

Wind tunnel test, however, it is difficult to include special circumstances wind design, therefore, although it is wind parameters testing application architecture at present the most scientific method, still can't be sure.

Is presented in this paper, wind tunnel test and theoretical data, building can withstand wind ultimately be achieved through the construction process. Wind tunnel test, in short, once appear during the construction process, it may lose its original value.

Design and construction process

Zhang wan SangJieShao, in fact, the domestic construction industry standard of structure design is relatively high, the safety coefficient of reserved a certain extent, and even has caused waste. So, in theory should not have too many accidents.

& other; Problem is that the domestic architectural design, structural design, each detail of the second design is layer upon layer disjointed. Throughout the &; He said.

& other; We tend to spend a small amount of the cost foreign building, pleaseThe designerDo a beautiful concept design, and then by domestic structuresThe designerick up bar, in the process, the original design scheme is likely to go out of form. And once the manufacturer and the contractor's second design cohesion stage, architects will greatly to let it go, and dominated by manufacturer and the contractor. Finally, not only the construction is difficult to reflect architect's original intention, once an accident, also can cause the parties mutual buck-passing situation & throughout; .

Unlike domestic, western is architect shall assume overall responsibility for the building field, that is to say, the whole construction project was organized by the architect to form structure, detail structure, mechanical and electrical and other professional team, carry out design concept to the final implementation level.

The responsibility of general control mechanism, apparently, more emphasis on the whole process of project implementationmanagement. He says that while the current domestic began to attach importance to architectural designmanagementroblem, however, may not undertake the project management company is proficient in building design, process management, often only stay in control of the schedule.

To the face of luxury goods, not to the lining of luxury goods

In recent years, the domestic architectural aesthetic seems increasingly towards a personalized, exaggerated, if construction is largely a regional cultural carrier, so, they & other Do STH unconventional or unorthodox & throughout; This is understandable.

& other; But, at present, the domestic some new terminal in a paradox. Throughout the &; Zhang SAN think, behind those who pursue the form unique, is does not match with the not enough in-depth elaboration of design and construction. & other; Will this look and real, in the form of coarse, in many details. Throughout the &;

In fact, a simple architecture, if you have solid, perfect construction technology, you can give us to fully. Instead, a beautiful and different building structures, if you want to stand for long, even if they don't consider the loss of the architectural space, only consider cost, also will be more expensive than ordinary buildings, and even much more expensive, so, where is the necessity of the cost.

In his view, the more important is, if true to one and Steel Structure Project Luxury & throughout; Have strong desire, but the but again don't want to really get what it takes cost, so it can only be one and other High imitation goods & throughout; . And so large scale high copy product, finally only by using it to assume the risk of all its people.
A race against time
http://steelstructurewarehouse.blogspot.com/2013/06/a-race-against-time.html