Building 350 Meters Above a River Gorge 

To improve economic development in the Sichuan and Guizhou provinces in China, as well as provide a reliable connection between the Guizhou Jiang Xi Gu and Sichuan Xugu expressways, local officials wanted to build a new bridge linking the two roads. The CNY 1.7 billion Chishui River Bridge would cross the river at a total length of 2,009 meters. Sichuan Road & Bridge is responsible for the design, production, and construction of the project. The winding, mountainous site posed complicated topographical and geological conditions, including a cliff on the Sichuan side and a maximum elevation of 350 meters, as well as collapse zones and rocky and karst areas that posed a danger to the project team. Consequently, they needed a design that provided a strong structural support system over the wide gorge above the river. Thus, a 1,200-meter section of the bridge would require a double-tower, single-span suspension design.

Rugged Terrain Makes Most Bridge Designs Impossible 

As the design of the Chishui River Bridge became increasingly complex, Sichuan Road & Bridge realized they needed a more flexible, digital workflow to ensure an accurate design, improve communication among teams, and avoid mistakes and clashes. This project was among the most challenging they had encountered over the decades, as the rugged terrain limited their use of heavy equipment, making it difficult to construct an access road. Since most bridge construction methods were impossible to implement as a result, the team had to determine how to construct the main bridge deck as a truss off-site and deliver segments to the gorge, as well as determine how to design a system of 158 cables to support the bridge deck. Therefore, traditional 2D design methods were not up to the task.