Mablethorpe Outfall

As part of the Environment Agency’s Asset Refurbishment Programme of Work, JBA Bentley were commissioned to undertake repairs to a tidal outfall in Mablethorpe, Lincolnshire. The coastal outfall is constructed of a sequence of concrete box culverts with a pitched stone haunching. The old concrete pitched stone haunching along the outfall tunnel had badly deteriorated resulting in loss of pitching, exposing the box section units and creating a health and safety issue for members of the public on the beach.

The objective of the project was to replace the haunching, increasing the asset life and reducing the risk to the general public. The preferred option was to remove the stone pitching and replace with fibre reinforced concrete dowelled into the box culvert sections. Using fibres eliminated the need for steel reinforcement. A concrete mix was specified with additives to reduce the curing time which enabled the concrete to reach the required strength within a tidal window. The new haunching had a brushed finished to provide a non-slip surface for the public.

Good planning of the works allowed us to do the construction works quickly despite the tidal constraints and working closely with the local authority helped us to plan the construction to have minimal disruption to the public, avoiding school holidays and public events.