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2023

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05

Glass bridge keeps brittle materials from being 'fragile'


Due to its unique transparency and aesthetics, glass materials are favored in the field of construction and have been used for nearly a thousand years. However, due to the natural brittleness of glass materials, its application in the field of construction has been greatly restricted.

The Zhangjiajie Grand Canyon "Yuntiandu" glass bridge project is the world's first space cable plane large-opening suspension bridge, and it is the first large-scale landscape bridge using glass as a force-bearing structural member. The whole bridge uses glass as the bridge deck. There are 99 pieces of glass on the bridge deck. Glass load-bearing is facing challenges. This is the first time that glass structural products are used in non-curtain wall fields under the condition of horizontal load-bearing, as a part of the load-bearing structure. Elastic rubber gaskets are installed under and on the side of the glass structure to ensure that the glass structure has sufficient clearance and deformation coordination under various loads, so that it only bears local loads and does not participate in the overall force of the whole bridge structure.
However, the processing and construction of glass is facing huge challenges. Under the condition of horizontal installation, glass has been used as a load-bearing structural unit for a long time. In addition to conventional common loads, it also has to bear unconventional loads such as people and falling rocks. Overcoming brittleness is the first time that glass has been used in such a large quantity as a suspension bridge deck. The "brittleness" of glass makes it difficult to ensure its good durability, stability and reliability during installation and service.
 
Brittle materials are used as load-bearing materials. Once an uncontrollable and accidental falling object occurs, how to ensure that it will not be damaged after being impacted, or will not fall after being damaged? This is also a test of whether it has a strong rear bearing performance, and it is necessary to ensure that the bridge deck personnel are foolproof.
 
In recent decades, with the emergence of laminated glass and the improvement of its laminating process, the use area and application range of glass in the construction field have been greatly increased and expanded. The laminated glass builds a "bridge" between the glass sheets through the bonding effect of the polymer interlayer film, forming a "sandwich" structure, which enhances the integrity of the laminated glass components, improves the overall bearing capacity, and can also be used in the glass layer. Adhere to glass fragments after breaking, and maintain a certain residual bearing capacity. High performance and high requirements for safety When selecting materials for the glass bridge, the form of multi-layer tempered glass + film was adopted, and ultra-clear glass containing as little nickel sulfide and heterogeneous particles as possible was selected for processing and manufacturing. The film uses SGP material with high shear resistance and excellent post-failure bearing performance.
 
It is worth mentioning that, considering the high requirements of the glass bridge on weather resistance, we have done repeated tests and comparisons to ensure that the deflection deformation of the glass and the film and the change of the structural strength of the glass under different weather conditions meet the design safety requirements. demand, so as to ensure the safety of the bridge deck load.
 
Finally, there is the construction link. Because the location of the glass bridge is a suspended valley, the weight of a single piece of glass is very heavy. In structural materials, and ensure that the glass is not in direct contact with metal or non-metal hard materials.