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.
Innovative BIM Methodology Applications Optimize a Complicated Design
Sichuan Road & Bridge discovered that Bentley applications could provide the BIM methodology and 3D visualization that they needed to overcome their design challenges. With ContextCapture, MicroStation, and OpenBridge Modeler, they determined a stable footprint for the bridge towers. Then, they used ProStructures to optimize the bridge design and ensured the proper placement and orientation of 158 cable clamps. Lastly, they modeled the construction process with LumenRT and MicroStation to determine how to keep workers safe and minimize the amount of land needed during construction, particularly when hoisting steel truss segments into place. Throughout the project the interoperability of Bentley applications improved data exchange among teams, boosted decision-making, and prevented mistakes before construction started.
Saving Time and Costs with Bentley Applications
By using Bentley modeling applications for all aspects of the project, Sichuan Road & Bridge saved a total of CNY 14.3 million. They determined how to optimize their digital design workflow, allowing them to reduce the bridge tower foundation footprint by 30% and lower the amount of complicated earthworks needed in the mountainous region. With unified digital design and strong communications among specialist teams, they improved modeling efficiency by 30% and design efficiency by 10%. Additionally, digital design helped resolve 114 clashes before construction began. In total, Sichuan Road & Bridge saved 60 days of design time and 19 months of construction time and completed the Chishui River Bridge in late 2019.
- The Chishui River Bridge crosses a gorge to connect two steep, mountainous areas, which required a complicated truss design to facilitate a difficult construction scenario.
- Sichuan Road & Bridge used Bentley applications to help them reduce the tower foundation footprint by 30%, improve modeling efficiency by 30%, and resolve 114 clashes.
- Bentley’s road and visualization solutions helped Sichuan Road & Bridge save 60 days of design time and 19 months of construction time.
“The use of BIM for the Chishui River Bridge project brought many benefits to both the design and the construction team, greatly stimulating its further application for future infrastructure projects.”
Sichuan Road & Bridge