Two new FRP bridges have been designed, manufactured & supplied by Lifespan over the Droitwich Canal near Worcester.
- North Bridge – 18.3m length by 2.4m wide
- South Bridge – 18.3m length by 1.2m wide & a 9m long by 1.2m wide ramp
Our General Manager Martin Richardson commented that ‘The project was a technical and geometric puzzle which needed to be solved, which required early manufacturing involvement to define a solution’.
A detailed topographical survey was carried out using 3D scanning technology to obtain accurate information on the position, levels and dimensions of the existing structures.
Lifespan solve a technical & geometrical puzzle with FRP
Steve Dunn & Martin Richardson
10/06/24
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Utilising the tightest longitudinal radius for a Lifespan Bridge (60m) and positioning the soffit of the bridge just above the minimum soffit requirement allowing for tolerances, the end levels of the bridge decks could be calculated.
The modifications to the existing foundations and the ramp approaches required could then be identified.
The existing foundations needed to be reused to prevent the need to do any works near to the canal banks & the new bridges needed to fit on the footprint of the existing bridges, and reduce weight, whilst keeping the width of the new structure the same as the old one.
A minimum soffit level needed to be maintained for clearance under the bridges for canal traffic & the new structures needed to be DDA compliant.
During the outline design process detailed discussions needed to be held with the Clients Engineering team to define standards for the design of the new structures with a view to minimising weight. The discussion concluded that the full requirements of CD368 (Part of the DMRB) would be adopted and that an aluminium parapet would be used.
Early contractor involvement meant that it was identified that the wider of the bridges would best be installed using a barge mounted crane, and the deck was split into two sections with a longitudinal joint to minimise the weight to be lifted by the barge.
Lifespans flexible approach meant that they worked within the Clients Framework arrangements, Lifespan were employed by the Frameworks Contractors (Alun Griffiths) Designer (Burroughs) to carry out the survey work and initial sizing and positioning of the bridge decks. Once the design was agreed Lifespan worked directly with the Framework Contractor to manufacture and supply the decks and parapet. The decks were installed by the Framework Contractors Team including the Rothen Group who supplied the lifting expertise for the difficult installation. The work was carried out within the tight constraints of a Canal and River Trusts possession of the canal.
The modifications to the existing foundations and the ramp approaches required could then be identified.
The existing foundations needed to be reused to prevent the need to do any works near to the canal banks & the new bridges needed to fit on the footprint of the existing bridges, and reduce weight, whilst keeping the width of the new structure the same as the old one.
A minimum soffit level needed to be maintained for clearance under the bridges for canal traffic & the new structures needed to be DDA compliant.
During the outline design process detailed discussions needed to be held with the Clients Engineering team to define standards for the design of the new structures with a view to minimising weight. The discussion concluded that the full requirements of CD368 (Part of the DMRB) would be adopted and that an aluminium parapet would be used.
Early contractor involvement meant that it was identified that the wider of the bridges would best be installed using a barge mounted crane, and the deck was split into two sections with a longitudinal joint to minimise the weight to be lifted by the barge.
Lifespans flexible approach meant that they worked within the Clients Framework arrangements, Lifespan were employed by the Frameworks Contractors (Alun Griffiths) Designer (Burroughs) to carry out the survey work and initial sizing and positioning of the bridge decks. Once the design was agreed Lifespan worked directly with the Framework Contractor to manufacture and supply the decks and parapet. The decks were installed by the Framework Contractors Team including the Rothen Group who supplied the lifting expertise for the difficult installation. The work was carried out within the tight constraints of a Canal and River Trusts possession of the canal.