The "ice belt" roof system is designed as a saddle surface structure. It consists of 49 pairs of bearing cables and 30 pairs of stabilizing cables. For weaving saddle-shaped cable net, the long span 198m and the short span 124m. Each cable network weighs several tons. Only through accurate design can the ribbon be woven into a net.
Always observe the stress state of cable net during construction, and a slight negligence will affect the construction quality, which requires extremely high construction. In order to better understand the state of the steel cable, Luo Yaozhi's team installed a self-developed wireless sensor at the construction site to monitor the stress of the building in real time. From September, 20 18 to February, 2020, the team conducted data processing at the construction site, monitored all nodes of the threaded woven net at all times, and provided decision support for the construction scheme. The developer said: "The wireless sensor of Zhejiang University is like a pair of eyes, watching the whole process of engineering construction."
Wireless sensors have played an important role in the construction process, and the "ice belt" after construction is still measured remotely through monitoring. Professor Xu Xian of the team said that their team monitored six parameters of the National Speed Skating Gymnasium, including stress, displacement, acceleration, temperature, wind pressure and cable force. The number of test points reaches more than 1000, which is the largest single building structure.
The monitoring system of Luo Yaozhi team of Zhejiang University is independently developed and designed. Since 20 10, it has been applied to the operation monitoring of the National Stadium "Bird's Nest" and the construction monitoring of Beijing Daxing International Airport.
During the construction of "ice belt", the team used the scale model of 12: 1 to study the key construction technology and model test of large-span cable-net roof structure in ice belt, and solved the construction problem of roof.
Design is difficult. It is also difficult to build the' ice belt' into a landmark venue of the Winter Olympics from the drawings. How to smoothly lift the cable net laid on the ground, which cables need to be tensioned after reaching the height of the roof, and how much error they can bear in the end, these data need to be observed sensitively. The team created a simplified model of the National Speed Skating Hall to simulate the whole construction process of the cable net structure.
Dancing Beijing "Ice Ribbon", majestic steel structure "Bird's Nest" and flexible membrane structure "Water Cube" form the world's first "Double Olympic City" landmark building complex. Behind this, the scientific and technological wisdom and strength of the team of Zhejiang professors and experts have contributed.