Building the Fanli Bridge with vertical and horizontal BIM

Currently under construction, Yixing’s Fanli Bridge in Jiangsu Province, China, is a cable-stayed bridge with three lantern-shaped towers that cross the Dongjiu River and Fanli Avenue.

The total length of the bridge is 500 meters with six dual vehicle lanes, and the project’s total cost is approximately US$100 million. The Tongji Architectural Design and Research Institute designed the bridge and is involved in the construction planning. Due to the urban landscape requirements, the special lantern shape is adopted for the towers. The bridge’s unusual lantern-shaped towers adds to the complexity of the structure’s design and construction planning, but BIM processes and model-based design, analysis, and construction planning helped the team master the project’s intricacies and supported a significant schedule and cost savings (compared to traditional 2D design processes).

Design for vertical and horizontal BIM

Unique design challenges

1. Design the stiffeners and diaphragms to ensure safety of the tower, especially the lower crossbeam nodes and the cable anchorages
2. Decisions on how to divide the steel box girder (longitudinally and laterally) and steel towers (vertically) so that these sections can meet the highway transportation size limit and the maximum hoisting weight of the floating crane; at the same time, when designing longitudinal division and transverse diaphragms, positions of the anchorages in the box girder and towers must be considered.
3. Collaborative design is needed for the towers and the box girder especially where the tower legs cross the girder; collaborative design is needed between the cables and the girder and between the cables and the towers.
4. Maintain operating space for both welding and later maintenance.

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