All the high-rise buildings in the world are swaying in the strong wind. Why can they live in peace?

Nowadays, there are more and more high-rise buildings in the world, one after another, constantly reaching new heights. Top World Skyscraper 10: Burj Khalifa, Dubai, 828 meters high; Shanghai Tower, China, 632 meters high; Royal Bell Tower Hotel in Mecca, 60 1 meter high; China Yin Gao Finance 1 17 Building, with a height of 596.6 meters; Korea Lotte World Building, 555 meters high; World Trade Center 1 Building, New York, USA, with a height of 541.3m; China Guangzhou East Tower (Chow Tai Fook Financial Center), 530 meters high; China Tianjin Chow Tai Fook Financial Center, 530 meters high; China Beijing CITIC Building, 528 meters high; China Taipei 10 1 Building, 508m high.

From the above ranking, we can see the rapid progress and development of China in recent years. Of the 65,438+00 top high-rise buildings, 6 are located in China. Among them? Chow tai fook? Having two buildings is noteworthy, but it is not discussed in this article.

Of course, this is just a list of high-rise buildings that have been built so far. In the near future, many new high-rise buildings will be erected and seats will be rearranged.

According to some data, the tallest building in the world will still be in Dubai in the future, and the World Tower under construction will reach 1600 meters! At that time, Burj Khalifa could only come second; South-central Suzhou Center in China will rank third at a height of 729 meters; China Wuhan Green Center ranks fourth with a height of 636 meters, and Shanghai Center can only rank fifth; Tianjin Yin Gao 1 17 Building will rank sixth with a height of 62 1 meter.

Among the top six, China accounted for four. Will China build the tallest building in the world in the near future? It is possible, but we won't talk nonsense until we have accurate information. In fact, there is still a tall building not listed, but it must be said that this is the Empire State Building in new york, USA. Built in 193 1, this building is 88 years old. It has occupied the position of the tallest building in the world for decades and is still one of the landmark buildings in new york.

Friends who have been to high-rise buildings know that these seemingly towering buildings are not static, but the higher they are, the more they shake. They swayed the willows in the wind and danced gracefully all the time. Why can't these tall buildings beat the wind and waves, but I can't stand? In fact, people did it on purpose. It's safer this way.

Because it is these graceful dances that can relieve the pressure brought by the strong wind at the top. Just like when we play Tai Chi, we have to stagger to understand the risks.

If you really build a tall building, it will be blown away. Tall buildings can't be better than rubble.

Because at high altitude, the wind is very strong, high-rise buildings will tilt when they are subjected to great force, but if they are too rigid, they will only bear more and more pressure, and finally they can only rely on it? Fold? To relieve stress. Willow swaying with the wind, swaying and dragging, but releasing and relieving the pressure, thus? No discount? .

This truth also tells us that in the journey of life, when you encounter some insurmountable obstacles, you can also take a detour and take a step back, just like a tall building swaying in the wind.

Therefore, when designing super high-rise buildings, the rocking coefficient of high-rise buildings must be considered. According to Article 3.7.3 of China's Technical Code for Concrete Structures of High-rise Buildings, according to different structures, the top displacement should be limited to 1/550~ 1000, and the displacement of buildings with a height of not less than 250m should be limited to 1/500.

The swing of tall buildings in this range is called safe swing.

In order to ensure the safety of high-rise buildings, buildings with a height exceeding 300 meters restricted by national codes need special design and professional audit, and the examination and approval procedures for demonstration are very strict.

Generally, each super high-rise building has a unique design, and the allowable shaking range is also different.

In order to solve the safety problem of high-rise building shaking, it is necessary to make a very professional choice in materials and design, such as selecting high-quality steel with good ductility and maintaining appropriate gaps in the curtain wall structure.

High-quality materials and design can ensure that the super-high-rise building is swaying in the wind, the structure is stable, and there will be no fracture and damage, and the corresponding coefficient should be retained in the design. For example, the Unified Standard for Reliability Design of Building Structures (GB 50068-200 1) stipulates that the safety factor of general building structures is 1.5, which requires the super high-rise building to have a greater coefficient guarantee.

Simply put, it only needs to bear the pressure of 100, and the design should be able to bear the pressure of 150 or higher. If the design can resist the typhoon 12, it can actually resist the super typhoon 18.

Of course, the shaking of buildings is inevitable, but the amplitude should be controlled. If it is allowed to swing freely in the wind without control, the amplitude is too large, or it causes vibration, it will destroy the building. At present, dampers are most commonly used in the world to control the swing of buildings. This damper belongs to a super high-rise building? Ding fengdan? .

Anyone who has seen Journey to the West knows that Tang hated his disciples and disciples crossing the Flame Mountain to go to the Western Heaven for Buddhist scriptures, and had to use a banana fan to put out the fire in the Flame Mountain. However, the banana fan is in the hands of Niu Wangmo's wife, Princess Tiefan. the Monkey King tried to borrow the banana fan with both carrot and stick, but Princess Tiefan flew a hundred miles with the banana fan.

When the Monkey King arrived at Mount Sumi, the Bodhisattva gave him one? Ding fengdan? When he returns, Princess Iron Fan will never slap him again.

Does this damper for handling wind pressure of high-rise buildings belong to high-rise buildings now? Ding fengdan? .

This? Ding fengdan? To put it bluntly, it's the heavy kind? Weighing? What is the standard name? Mass? It hangs in the middle of a high-rise building with complex technology, and the lower part is connected with a complex damping system.

When the building is blown by the wind, this? Weighing? Just like a pendulum, it shakes with the shaking of a building, but the shaking amplitude is smaller than that of the building, which will produce hysteresis effect and reverse swing.

Are you online? Ding fengdan? Under the pull of the building, the swing amplitude of the building is greatly reduced. The scientific explanation is that the mechanical energy of strong wind acting on high-rise buildings is converted into heat energy through damping system and dissipated.

Our Shanghai Tower? Ding fengdan? Call? Vortex mounted tuned mass damper? With a weight of 1000 ton, it is the heaviest damper in the world and an innovative technical achievement. According to the data provided by the construction party of Shanghai Tower, this damper can reduce the peak acceleration caused by wind by more than 43% and keep 90% of the space in the building comfortable.

Another famous damper is the 10 1 building in Taipei. The damper of this building used to be the heaviest in the world, but now it has been broken by Shanghai Tower.

The tuned mass damper of building 10 1 weighs 680 tons and looks like a golden sphere. Hanging on the 92nd floor of this 10 1 storey building, it is the only exposed damper in the world for tourists from all over the world to visit. In fact, the stability damper system of high-rise buildings can be designed according to different shapes and functions of buildings and different landing sites.

For example, Guang Zhouta, which is unknown in the list of Tall Buildings 10, is commonly known as this? Small waist? The actual height of the building has reached 600 meters, which should have ranked fourth, but this building is more of a tower structure, so it is generally not included in the ranking of high-rise buildings.

This tall building is located in Guangzhou where typhoons frequently occur. If the quality block scheme of Shanghai Center or Taipei 10 1 building is adopted, it is not applicable. Therefore, the active and passive compound tuned damping control system pioneered by China is added to the design, and two movable giant water tanks on the top floor are used to stabilize the building. These two water tanks are filled with 200,000 liters of water, and they move in the opposite direction when encountering a typhoon, which not only plays the role of stabilizing buildings, but also plays the role of high-rise fire water tanks.

But it is the tallest building in the world, Dubai? Burj Khalifa? (formerly Burj Khalifa) No damper. This tall building is 828 meters high, with a total of 162 floors, and its maximum swing in the wind exceeds 3 meters.

Burj Khalifa? The reason why dampers are not used is because the shape and design of this building have excellent wind resistance.

First of all, what is this called? Tower? Super high-rise buildings adopt triangular design, which will disperse the wind when attacked by strong winds; With the decrease of the area from the ground to the top of the tower, the width of the bottom enhances the foundation resistance, while the wind surface at the top of the tower is smaller, and the pressure at the top of the tower gradually decreases.

The foundation of this tower is also very solid. The reinforced concrete is poured 30 meters deep and the pile is 70 meters deep, reaching the depth of 20 floors.

Even so, many important wind-proof and earthquake-resistant measures have been taken in the building, such as the hexagonal core tube in the center of the building, which can resist shearing, bending and torsion; The shape of a three-petal flower is also called a scissors wall. When the wind blows from behind, it will form a vortex and weaken the influence of the wind.

In fact, even if the Shanghai Tower is equipped with a damping system, many measures have been taken in the design to reduce the sway of the building and enhance its ability to resist wind energy. For example, in the shape design, twist? DNA？ Images, this? The wind surrounds the building? When encountering strong wind, it will form vortex gyro effect, which will make the building sway, relieve wind energy and reduce the side force of strong wind by 24%; In order to ensure the stability of the low-rise building, 980 86-meter-deep foundation piles were drilled and 60,000 cubic meters of concrete was poured to form a 6-meter-thick foundation slab. Although this building is located in alluvium, it is the safest building in Shanghai.

For the safety of modern buildings, structural design and material selection are also very important, such as curtain wall. China's "Technical Specification for Concrete Structures of High-rise Buildings" points out that all kinds of building curtain walls should be used in high-rise buildings over150m. This shows that in high-rise buildings, the curtain wall should be given priority to the external structure, rather than the physical structure.

In fact, we are now in a metropolis, shuttling through towering buildings, and looking around casually, we see all kinds of curtain walls, most of which are glass curtain walls. Have we ever wondered why?

Some people may think that this is a fashion now, just follow the trend. Actually, it's not.

Modern super high-rise buildings are surrounded by curtain walls almost without exception. Mainly from the perspective of safety and economy, the most important thing is safety.

Some people will say that these curtain walls are thin and brittle, so how can they be as safe as infilled walls? Will it be stronger than cement bricks?

In fact, this understanding is wrong. The safety of curtain wall lies in its three main characteristics: first, curtain wall is a complete structural system composed of panels and supporting structures, with independent bearing capacity; Secondly, it can bear large deformation in its own plane and has sufficient displacement capacity relative to the main structure; Third, it does not share the load on the main structure and the impact outside the envelope.

This curtain wall has strong wind resistance, compression resistance and earthquake resistance.

The Institute of Structure of China Academy of Building Research has done shaking table tests on various types of building curtain walls. The results show that even when the input acceleration of the shaking table reaches 0.9g and the structural displacement reaches 1/60, which is equivalent to 10 degree earthquake, the curtain wall is still not damaged. The infilled wall will crack when the displacement is11000, and will be destroyed when the displacement is 1/300. If there is an earthquake, it will be destroyed by a small earthquake and destroyed by a medium earthquake.

This is because the solid infilled wall has poor in-plane deformation ability and is closely combined with the main structure, so it cannot realize relative displacement. When there is a fault, it will vibrate with the main body, leading to damage.

The special connection structure of the girth joint of building curtain wall panel is that it can bear the displacement of 65438+ 1/000 or even 1/60, and this ability to resist building deformation is amazing.

Therefore, the tall buildings are swaying in the strong wind, and the surrounding curtain walls are intact. Even in many large earthquakes, the curtain walls of high-rise buildings are intact. Moreover, only the curtain wall adopted in modern times can ensure that the towering buildings will not collapse or fall down during the strong oscillation of the earthquake, thus avoiding causing greater casualties.

Of course, curtain walls are not all glass, but also aluminum plates, slates and even ceramic plates. But the curtain walls of modern high-rise buildings are mostly glass, because the transparency and beauty of glass are unparalleled. Every coin has its two sides. On the negative side, the glass curtain wall has caused great light pollution to the city. How to overcome this problem is a subject that architects have been trying to solve, so I won't discuss it here.

Curtain wall is enough to save construction funds, so we won't discuss it here.

This is the main reason why the tallest building in the world can ensure safety.

The safety of modern high-rise buildings has many aspects, such as fire fighting and escape. Space-time communication believes that with the continuous progress of human scientific and technological civilization, building construction will become bigger, higher, more modern and safer.

That's it. Welcome to discuss.

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