Site: Various locations along Macclesfield Canal
Date: January to March 2018
Value: £135,000
Introduction
The Rothen Group were asked by Canal & River Trust and Kier to assist with repairing several sections of piling and washwall that lay within a Heritage Area. Several separate sections of washwall had either collapsed or rotated with sections of stone coping having fallen into the canal along with sandbag walling. Over 220m of washwall needed to be repaired, whilst the towpath and canal remained open. The project involved:
On site meetings to establish best plant/equipment and methodology for undertaking works in heritage areas in a sensitive manner
Versatile kit to get plant & materials to site where access was very awkward
Managing boat & towpath users during the works
Recovering stone copers out of the canal with crane barge for reuse
Experienced team due to sandbag walling element and heritage training
Undertaking piling works including all marine plant & experienced team
Laying of copers
The Project
Several sections of heritage washwall had rotated and collapsed into the canal creating navigational problems and towpath safety concerns. The site was remote and access tricky with all materials and plant having to be floated to/from site. In addition a range of civil engineering methods were needed, from sheet piling to removal of debris to heritage sand bag walling. All of these were problems that we could overcome with both of experienced staff and versatile plant.
Our specialist 70ft crane boat was ideal for these works as it is not only powered but has a carrying capacity of 20t as well as a 15t/metre crane which can lift 1.6t at 8metres allowing for self loading/unloading of materials. It was fitted with a clamshell to salvage the stone copers from the canal, storing them in the hold for use at the end of the works. It could then have a piling hammer attached and work with a hopper to undertake the installation of L8 sheet piles.
Once the initial clearance and piling works were undertaken, the sandbag walling could then begin. This had to be undertaken by hand, standing in the water. Hessian bags were hand filled with a mix of lime, sand & cement and then carefully laid by hand in an ‘English Bond’ to create a stable and structurally sound washwall. The stone copers were then laid on top and a lime cement mortar used to grout them in place.
The verge was then blended into the stone copers and seeded to create a natural look in keeping with the area and history.
Throughout all of the works, the towpath and navigation remained open which the team managed with banksman.