Black Potts Footbridge Structural Analysis and conclusions – with the assistance of a search engine and Ai (Claude).
The following images are recent and unchanged. All dimensions and loads are estimated because the footbridge is no longer accessible.
Below is a close-up image of the ‘Bay 9’ structural issue.
Below is the ‘Post 10’ block shear structural issue.
The footbridge design is identified as a subdivided Warren/Fink Truss – 10 Bay Configuration
Design Parameters & Assumptions:
• Truss Type: Subdivided Warren Truss / Fink Truss configuration
• Structure: 10 rectangular bays, approx. 1.5m high × 2m long each
• Total span: 20m
• Total dead load: 10 tonnes (1000 kg/m distributed)
• Live load: 5 kN/m² (pedestrian loading to BS EN 1991-2)
• Material: Timber construction
• Support conditions: Simply supported at ends
• Load combination: Dead Load + Live Load (critical case)
• Truss characteristic: Alternating diagonal pattern typical of Warren/Fink design
You will find additional notes, diagrams and a composite image using the link below
Black Potts joint images 22-8-2025
In conclusion – the structural forces diagram and calculations highlight the inability of the bay 9 posts and diagonal to transfer any loads. Consequently those forces are transferred (as significant increases) to the top and bottom horizontals.
END