On October 11, the staff introduced the double-layer circular tube glass on the ice ribbon (small picture). At the National Speed Skating Museum site, 90% of the curtain wall glass has been completed. Photographed by Wang Jianing, a journalist of the New Beijing News
3360 pieces of glass to assemble ice ribbon curved curtain wall
The construction of the National Speed Skating Hall, the venue of Beijing 2022 Winter Olympic Games, is accelerating. At present, the venue is carrying out the construction of two main projects, roof and curtain wall. The complete shape of the ice ribbon has been preliminarily presented.
The National Speed Skating Hall, known as Ice Ribbon, is the competition venue for speed skating in Beijing 2022 Winter Olympic Games. Recently, a reporter from the Beijing News visited the National Speed Skating Hall located on the southern side of the Tennis Center of the Olympic Forest Park.
Reporters learned at the construction site that the construction of the exterior curtain wall of the venue has reached the end stage, 3360 pieces of exterior curtain wall glass have been installed more than 3000 pieces, about 90% of which will be completed by the end of this month. The ice ribbon on the outer curtain wall is also being installed tightly. It is expected that by the end of the year, the entire venue will be sealed to achieve ribbon flying.
The National Speed Skating Hall is the landmark venue of Beijing Winter Olympic Games. The project is contracted by Beijing Urban Construction Group. Its main venue has a construction area of about 80,000 square meters and a height of 33.8 meters. It can accommodate about 10,000 spectators. Ice Ribbon is the largest single-layer, bidirectional orthogonal saddle-shaped cable net roof in the world, the largest ice surface in Asia of 12,000 square meters, and the free-flowing surface of the Temple of Heaven is spliced with 3360 pieces of glass.
After completion, the Ice Ribbon of the National Speed Skating Hall will work with the Birds Nest of the National Stadium and the Water Cube of the National Swimming Center to form the worlds first symbolic complex of Two Olympic Cities. After the Winter Olympic Games, the National Speed Skating Gymnasium will be a comprehensive stadium which integrates sports events, mass fitness, cultural leisure, exhibition and social welfare.
How to install the temple of heaven curved curtain wall?
On October 11, a reporter from the Beijing News reported that the glass curtain wall of the National Speed Skating Hall, which resembles the shape of the Temple of Heaven, has been installed in a large area. The continuous curved glass curtain wall of the external facade extends with the height of the roof contour.
Zhang Yi, executive manager of the General Contracting Department of the National Speed Skating Hall Project of Beijing Urban Construction Group, introduced to reporters that the curved glass curtain wall of the National Speed Skating Hall has a large volume. 3360 pieces of glass units need to be mechanically operated with workers and seamlessly embedded in the frame made of S-shaped steel keel.
Before glass installation, an important construction procedure is to install 160 S-shaped steel keels, which is the skeleton of the whole curved curtain wall. Curtain wall steel structure engineering includes curtain wall S-shaped steel keel, arc connecting beam, ribbon support rod, ribbon circular steel pipe processing and field installation. Each S-shaped steel keel is made of four pieces of steel plate tailor-welded, the longest is 32.7 meters, the weight is about 6 tons, and the shortest is 16.1 meters.
Compared with general planar curtain wall, S-shaped steel keel has complex shape, difficult die making, high installation accuracy and difficult construction. Each S-shaped steel keel has different sizes, different positions and different curvatures, which requires us to adjust repeatedly in the field construction to ensure accurate positioning, and then the curved glass can be inserted into each space without error. Zhang Yi said.
According to its introduction, the curved curtain wall is made of super white, double silver, low-radiation and semi-toughened glued hollow (low-e) glass, none of which is of the same size, including convex and concave curved-arc glass, flat glass, large flat facade glass and ice ribbon semi-circular tube glass. The unit radius is 1.5 meters. The glass-glued layer is advanced SGP film, and the middle hollow layer is filled with inert gas. Can play the effect of heat preservation.
How can these glass of different shapes be fitted to the outer curtain wall of the National Speed Skating Hall? Zhang Yi told reporters that many convex and concave glasses need to be pushed a little bit into the frame composed of two ice ribbon shafts and S-shaped steel keel, and the angle of installation needs to be studied and pondered over and over again. This is much more difficult than the installation of ordinary flat glass. Over the past year, the R&D team has been researching on-site installation technology and constantly improving and adjusting it.
How does Ice Ribbon fly?
Reporters at the construction site saw that in addition to large areas of curved glass, in the North-South side of the venue, several ice ribbons have successfully surrounded the curved curtain wall. Close observation shows that the tube glass, which is the body of the ice ribbon, consists of a block of semi-cylinders, and the transparent glass is decorated with white patterns like ice crystals.
Zhang Yi told reporters that these circular tube glasses are specially made for the stereotyping and processing of the National Speed Skating Hall. There are more than 3500 pieces of them. They are joined together to form an ice ribbon distributed from top to bottom on the outer curtain wall. The average circle is about 640 meters, and all of them are connected up to about 14,000 meters. Each unit is made of two layers of 6mm glass, which needs to be bent into a 350mm diameter radian. It is very difficult to process.
The ice crystal pattern we see is made on the surface of glass by special glaze technology, showing the effect of ice and snow crystal. For curved glass, the smaller the radius, the more difficult it is to process. It is more difficult to bend two pieces of glass into the same radian and fit them firmly together.
More distinctive is that the lighting of ice ribbon will be installed on the intersection of two pieces of glass glued together in a millimeter. More than 90 small bulbs will be installed intensively every meter. Through the light guide effect of the color glaze film, the light will be introduced into the glass, so that the light presents a special soft effect. The whole ice ribbon will become a luminous glass body. Twenty-two ice ribbons are wrapped around the surface of curved glass curtain wall like the track of speed skaters. When the lighting is opened at night, the beautiful ribbon flying effect will be formed.
How to build a two-way orthogonal saddle-shaped cable net roof?
In the construction of the National Speed Skating Hall, it is more difficult than the construction of the external curtain wall, which is the installation of roof engineering. The ice ribbon of the national speed skating museum is designed as the largest single-layer two-way orthogonal saddle shaped cable net roof at present, with a long span of about 200m from north to south, a short span of about 130m from east to west, and only a quarter of the steel consumption of the traditional roof. Because the cable net structure on the roof of the stadium is bidirectional and orthogonal saddle-shaped, the constructors need to complete many complicated construction procedures, such as cable net ground laying, lifting and installation, tension, roof unit installation and so on.
The roof currently under construction can still be seen in the shape of an open cable net, like a giant tennis racket hanging over the stadium. The role of the cable net is the whole roofsskeleton. When the roof unit is installed, low-radiation membrane material will be suspended at the bottom of the cable net, and theskeletonwill be hidden entirely. Zhang Yi said.
Zhang Yi explained that because the spatial form of cable net roof is very complex, every square space form after tension is different, so the size of each unit filled is different, and it needs to be processed and customized after measured data. At the construction site, there are piles of units to be installed on the roof. Each block is marked with a dimension table accurate to millimeters, batches and detailed numbers representing the installation area, and each corner corresponds to the orientation of southeast and northwest. According to reports, this is to ensure that the installation will not be misaligned, once the misalignment can not fit the hyperboloid saddle curve.
In addition, the reporter also saw a number of special-shaped units with different shapes, many with different slopes of grooves. These grooves are roof drains. Siphons will be installed in the grooves. When it rains, the rainwater will converge and then drain out. Our builders need to install one piece by one on the cable net roof at the designed angle like building blocks. It is reported that there are about 600 complex special-shaped units, accounting for more than half of the total number of roof units. At the construction site inside the speed skating hall, hundreds of large square buckets are still suspended from the roof in the center of the site, which is one of the ingenious ideas in the installation process of the cable net roof of the National Speed Skating Hall. According to reports, these buckets are designed to simulate units that will be installed on roofs in the future. The roof cable net has certain flexibility. During the installation of the roof unit, the cable net will be constantly deformed. In order to keep it in the state of completion in the future, we simulate the weight of the roof by hanging the counterweight, so that thegrid framecan be locked in, and then gradually remove the counterweight with the installation of the roof, and constantly replace it, so that the whole roof can be maintained all the time. In a stable state of deformation. New Beijing News reporter Wu Jiaoying, source of this article: New Beijing News responsible editor: Wang Muqing_NB12712
In addition, the reporter also saw a number of special-shaped units with different shapes, many with different slopes of grooves. These grooves are roof drains. Siphons will be installed in the grooves. When it rains, the rainwater will converge and then drain out. Our builders need to install one piece by one on the cable net roof at the designed angle like building blocks. It is reported that there are about 600 complex special-shaped units, accounting for more than half of the total number of roof units.
At the construction site inside the speed skating hall, hundreds of large square buckets are still suspended from the roof in the center of the site, which is one of the ingenious ideas in the installation process of the cable net roof of the National Speed Skating Hall. According to reports, these buckets are designed to simulate units that will be installed on roofs in the future. The roof cable net has certain flexibility. During the installation of the roof unit, the cable net will be constantly deformed. In order to keep it in the state of completion in the future, we simulate the weight of the roof by hanging the counterweight, so that thegrid framecan be locked in, and then gradually remove the counterweight with the installation of the roof, and constantly replace it, so that the whole roof can be maintained all the time. In a stable state of deformation.