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Andun were appointed to undertake the demolition engineering for the dismantling of Darby House footbridge. This project was particularly complex due to the articulation of the structure.
Client: Telford & Wrekin Council
Principal Contractor: Balfour Beatty
Demolition Contractor – EDR
Overview
The dismantling was part of the Station Quarter redevelopment to connect Telford town centre and the railway station.
Built in the 1980’s, it had reached the end of its design life due to the impact of corrosion on the structure and the need to treat and repair the bridge bearings.
Structural Design
Understanding how the footbridge worked was key to planning its dismantling. This allowed us to design an effective demolition scheme that minimised the temporary works.
The footbridge was characterised by pin joints, fixed bearings, and rollers, which allowed for thermal movement.The difficulty was that the pin joints’ lack of moment capacity meant that the tower could rotate during dismantling if it wasn’t properly supported.
The design required careful consideration, as cutting the supporting cables without stabilising the structure could lead to uncontrolled collapse.
Demolition Methodology
The demolition started by the stripping of the footway construction, and timber deck. A temporary propping system was then installed beneath the bridge deck. This allowed the first section of the structure to be removed.
The pier above the deck level was the next item to be removed. However, a prop was required to ensure the stability of the remaining section of the pier.
The remaining section of the deck was removed in two pieces before the remaining section of the pier was lifted out.
Temporary Works
As part of the demolition, there was also a range of supporting temporary works that were designed:
- Propping
- Lifting Arrangement
- Mobile crane design and positioning
- Road protection
Demolition Overview
The demolition of Darby House footbridge was completed in 2024.
Whilst the demolition was not in itself complex or challenging, the structure’s articulation made understanding it and its impact on the proposed demolition methodology vital to designing a safe and effective scheme that minimised the required temporary works.