[Extra Number] The Zhangjiajie Grand Canyon Glass Bridge was successfully closed, the first of its kind in the world!

Glass Bridge Steel Box Girder Successfully Joined

On the morning of December 3, on the cliff between Lishuya and Wuwangpo in the Zhangjiajie Grand Canyon Scenic Area in Hunan. With the precise lifting of the last 41-ton stiffening beam, the steel box girder of the Zhangjiajie Grand Canyon Pedestrian Glass Bridge, which has attracted worldwide attention, was successfully closed.

"Finally successful, Zhangjiajie created a world miracle"! Standing in the center of the Ganghelong Glass Bridge, overlooking the Grand Canyon under the Qianren cliff, Chen Zhidong, the initiator of the glass bridge and chairman of the Zhangjiajie Grand Canyon Scenic Area, was filled with emotions and relieved.

"One word, difficult! Two words, difficult!" Chen Zhidong said that it took more than four years from conception to realization of this long-cherished wish, during which inspection, survey, design, demonstration, material selection, review, testing, construction... experienced countless "contests" and twists and turns.

Design Overcomes Multiple Technical Challenges

Wan Tianbao, deputy chief engineer of the China Railway Bridge Institute Group, the bridge design unit, said that the Zhangjiajie Grand Canyon Glass Bridge has the functions of spanning, tourism and landscape. The design of the glass bridge has overcome many technical problems such as construction material selection, glass technology, wind resistance, anti-skid, compression resistance, wind resistance, and frost resistance. In particular, in view of the technical problem that when many pedestrians walk in unison on the bridge, it is easy to cause resonance and cause the bridge structure to deform. A total of 72 glass balls weighing 750 kilograms are irregularly placed on the glass bridge with a total length of 430 meters and a width of 6 meters. This objectively disrupts the pace of many pedestrians walking in unison and effectively curbs pedestrian vibrations. At the same time, for the selection of bridge deck glass, almost all influential glass manufacturing companies in the world have been screened, and load rolling tests have been repeatedly conducted. The current bridge deck glass has the characteristics of "large size, high hardness, high thickness, wear-resistant, anti-freeze, ultra-pure, explosion-proof, high load It has many characteristics such as load carrying, mildew resistance, and temperature drop resistance. According to the design, the maximum visitor capacity of the bridge deck is 800 people. Visitors do not need to worry about the pressure of the bridge deck glass. In addition, after the glass bridge is opened, a health monitoring system will be established to ensure the durability of the bridge.

The on-site construction of the glass bridge is also a worldwide technical problem. Guo Kun, the constructor and project manager of the China Construction Sixth Engineering Bureau Bridge Company, said that the load-bearing steel beams on the bridge deck are steel-concrete composite structures with a cross-sectional width that gradually changes from 15m at both ends to a standard section of 6m, with a total of 37 segments. Cable cranes were used to erect the bridge from both ends to the middle of the span. During the construction process, the elevation of the main cable in the middle of the span changed "first up and then down". It was very difficult to control the linearity of the bridge. The construction workers were hoisting on a 300-meter-high "catwalk", which made the operation very difficult. At the same time, the cable system of this project has a spatial cable plane structure, making it difficult to control the spatial linearity of the main cable and install cable clamps and slings. During the construction process, the main cables were pulled horizontally and the cable clamp and sling installation processes were optimized to better solve the difficulties in the construction of the spatial cable surface. Guo Kun also introduced that the environmental protection of the construction site and reducing the normal operation of the scenic spot are also the key points of the project. The tunnel anchors and pile foundation excavation did not use blasting construction, which reduced the damage to the ecology of the scenic spot. Next, there are many steps including linear adjustment of the whole bridge, bridge welding, wire wrapping of the main cable for anti-corrosion, and installation of bridge deck glass and railings. What is even more worth mentioning is that the on-site construction is undertaken by a young technical team with an average age of only 28 years old.

Ten World Records and Opening Time

After closing, the Zhangjiajie Grand Canyon Glass Bridge will be a world-class bridge and tourist landscape project. At the same time, it has become a model for international bridge construction with ten "best in the world" including the world's longest, the world's highest, and the world's first large-scale bridge with glass as the main stress-bearing structure.

The Zhangjiajie Grand Canyon Glass Bridge will be opened to the public before May Day in 2016, when tourists at home and abroad can experience "walking in the sky". The Zhangjiajie Grand Canyon Scenic Area is located close to Wulingyuan, the core scenic spot of Zhangjiajie, a world natural heritage. After more than 6 years of development and construction, it has become a boutique scenic spot for Zhangjiajie's east-line tourism. So far, it has received a total of 4.3769 million Chinese and foreign tourists.