NORTH BERWICK HARBOUR WALL

Project details

During Storm Babet, severe weather resulted in a breach through the main pier at North Berwick Harbour. The breach measured 20m in length. Southbay were awarded a contract to reconstruct the damaged section in a sympathetic manner, recognising the Grade B listed status. The contract was delivered in two distinct phases so as to recover the collapsed wall material and clear the harbour and install temporary protection in the form of rock bags to the structure, allowing harbour operations to continue, whilst planning of the permanent works was undertaken. Rapid site mobilisation was critical when installing temporary protection.

The harbour wall has been reconstructed using recovered material to maintain its original appearance.

Phase 1 of the contract involved recovering stone from within the harbour and relocating the material to the site compound. This involved tracking plant into the harbour, utilising restricted tidal windows which coincided with low spring tides. The recovered stone was then assessed, with any deemed as being in good condition processed for re-use when reconstructing the wall. Specialist stone was sourced to make up any shortfall in required quantities. This initial phase also involved the installation of temporary rocks bags using a mobile crane positioned on top of the harbour wall.

 

Phase 2 involved reconstruction of the harbour wall. Works to the lower wall included utilising traditional masonry methods to provide a bespoke mortar mix in keeping with the historic structure. Using experienced stone masons, mortar beds were laid, prior to the placement and levelling of blocks. The area behind the blocks was backfilled with concrete. By reconstructing the lower wall, the plant required to reconstruct the main wall could then be positioned on the structure.

 

When reconstructing the main wall, the recovered blocks were transported from the site compound using a telehandler, ready for installation to the seaward side. Using an 8t excavator with grab attachment, the blocks were lifted onto a mortar bed and grouted into position. A concrete foundation was then formed on the landward side of the wall, prior to the installation of the recovered blocks. Once the wall was reconstructed to the required level, dowels were drilled into the seaward side of the wall. A concrete pump was then used to discharge concrete into the core between the newly built walls. The wall was reconstructed using this sequential method in 5 separate lifts. Further works included the construction of a new deck slab, incorporating cobbled stone. Further works included the construction of a new deck slab, incorporating cobbled stone.

 

The project involved a significant public interface, with the operational harbour used to berth both tourist and fishing vessels. Significant planning of the works was required due to complex and narrow access restrictions, with the damage located on the outer harbour wall. The project was successfully completed with minimal disruption caused to harbour users.

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