(Shaanxi National Games) Opening Ceremony of the National Games: How was the giant "Pomegranate Flower" built?
China News Service, Xi'an, September 15 (Ma Chihai, Liang Xiaohui) The 14th National Games opened on the 15th in Xi'an, Shaanxi. A splendid opening ceremony was held that night at the largest stadium in the northwestern region-Xi'an Olympic Sports Center Stadium.
The biggest highlight of the stadium is its metal roof architectural style based on the flower of Xi'an-pomegranate flower.
According to the builders of the China Construction Second Bureau who participated in the construction, they completed the construction of 58,000 square meters of metal roof in only 90 days, making the "Pomegranate Flower" stunning the world.
28 pieces of "petals" make "urban symbols"
The architectural form of the Xi’an Olympic Sports Center Stadium is inspired by Xi’an’s flower pomegranate flower, with a building area of 152,000 square meters, which can accommodate 60,000 spectators.
At the same time, the stadium is the first smart stadium in China to achieve full coverage of 5G.
Viewed from the air, the stadium is like a huge "pomegranate flower" composed of 28 petals, meaning "the silk road sets sail, the flower of flourishing age".
The installation company project team of China Construction Second Engineering Bureau used 28 "petal" units to form the abstract form of flowers.
Behind the well-conceived shape is a complex and strict design.
The 28 "petals" have 7 different shapes, some of the roofs have a height difference of 10 meters, and the entire stadium has as many as 6,020 special-shaped structures.
The unique roof design creates a rich and gorgeous fifth facade effect.
In May 2021, StadiumdB, a world-renowned professional stadium data website, released the selection results of the "World's Best Stadium in 2020".
The Xi'an Olympic Sports Center Stadium won the "Top 10 World's Best Stadiums in 2020" and became the only stadium in China on the list.
Millimeter-level fine-tuning to build a high-altitude "operating table"
The metal roof area of 58,000 square meters is equivalent to the size of 10 standard football fields, and the whole is a special-shaped space curved structure. Only 4 of the 6,020 panels are identical.
The project introduces "BIM+3D scanning" technology to achieve tailored tailoring in three steps.
An aerial view of Xi'an Olympic Sports Center Stadium.
Photo courtesy of China Construction Second Bureau
The first is BIM modeling.
The metal roof deepening design team of the installation company built a three-dimensional model for the project's metal roof system with 18,000 purlins and more than 6,000 panels based on the building shape model.
The second is 3D scanning.
Through the 3D scanning robot, the main steel structure of the scene is scanned, the point cloud data of the entity is extracted, noise reduction and reverse processing are performed, and the basic entity point cloud model is obtained.
Finally, the analysis of mold clamping.
Import the point cloud model and the original design model into BIM as a whole for comparison, and determine the deviation between the structural design and the actual installation structure on site.
"Our work is like putting together a big picture at an undulating height of 58 meters," explained Zhao Huan, the chief engineer of the project.
In June 2020, the project won the Yu Prize, the highest prize in the field of waterproofing in China's construction.
The 90-day tackling reappears "Xi'an speed"
"After working on projects for more than ten years, I have never encountered such a rush!" This is the deepest memory of Xiao Yong, the project production manager.
During the peak period of construction, nearly 600 operators and 11 large-scale machines worked in an orderly manner on the same site to achieve full coverage of the roofing area.
The traditional metal roof modeling work takes several months. The project introduces the Grasshopper parametric design, so that the computer automatically generates the model results according to the proposed algorithm.
Compared with manual data entry, it can save 30 days of modeling time, shorten the construction period by 15 days, and save 10 million yuan in materials and installation costs.
The highest point of the cornice roof is about 58 meters. The project team uses "modular" assembly technology to divide the components into hundreds of units for ground assembly, segmented hoisting, and high-altitude docking, and then use large hoisting equipment to hoist them in place as a whole, which makes the construction more efficient. High-altitude construction increased by 30%.
On October 20, 2019, the project team came to the construction site to observe the installation of the last roof panel together.
This aluminum-magnesium-manganese alloy plate with a thickness of only one millimeter is the last process of roof installation, and it also proves the courage and wisdom of the two bureaus to overcome difficulties and vowed to fulfill the contract.
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