The Zhuhai Banzhang Mountain Footbridge is a structural design with a 625m long footbridge, which consists of a 25m tall spiral walkway at Banzhang Mountain and a 230m bridge crossing over an existing highway (the longest span is 40m). Cundall provided multi-disciplinary consultancy including structural and bridge engineering, building services engineering, vertical transport, and lighting design.
The bridge and the observation tower are parts of the 9km long Banzhang Mountain Trail located in Zhuhai, China (as indicated in the image below). The bridge and tower act as a connection point between the eastern and western mountains of the Banzhang Mountain Trail.
The unique geometries of the footbridge and spiral walkway have been designed to satisfy the requirement of architectural, aesthetic, and structural performance from both static and dynamic aspects. It also complies with both local codes, regulations, and appropriate for international guidelines.
A conventional steel box girder was used for the footbridge and spiral walkway to provide lightweight and steady performance for curvey geometry. Due to the complex shape and higher workload of the footbridge piers, both steel composite and reinforced concrete are adopted as the materials.
The structure of the spiral walkway tower is designed using a system comprised of steel exoskeleton structure and internal reinforce concrete lift core. The structural configuration and size of the steel members are optimised and tied back to the internal concrete core wall, which houses the lifts, to achieve overall lateral stability. The exoskeleton pattern, strut, and cable anchorages are designed to follow the conical-spiral deck geometry. As a result, the structural design is more efficient and the appearance is more appealing. In addition, it also eases structural detailing, fabrication, and construction.
Given the long-span and lightweight design of the structure, a comprehensive dynamic time-history footfall analysis using Fourier series function has also been carried out. This is to assess the pedestrian comfort level of the design, under activities such as walking, running, and jogging, on top of the code-based static studies.