Project: Dartford Creek Barrier

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Qualter Hall were awarded this prestigious contract from the Environment Agency, via their National Framework Contractor Birse Civils Ltd, for the refurbishment of the Dartford Creek Barrier.

The barrier was built in 1981 to reduce flood risk from the Thames Estuary to Crayford and Dartford, and therefore protects thousands of homes in the area.

The refurbishment works carried out included the design and supply of new hydraulic drive and braking systems, new electrical and control systems and refurbishment of the hydraulic latch system including new hydraulic cylinders. Qualter Hall were also responsible for the on-site installation, testing and commissioning.

The barrier comprises of two gates that travel vertically, driven by a chain system. Each of the two gates is balanced by two water-filled counterweights. The complete gate system is supported on two towers in which the counterweights are suspended and guided. Each gate is approximately 30 metres wide x 5.1 metres high. The gate tracks on the outside of the towers are so arranged that when lowered, the gates are placed one on top of the other to form a 10.12 metre high barrier across the creek.

The project brought interesting logistics and challenges working in and around existing operating equipment, for example, a key feature of the upgrade was ensuring at all times that one gate was available in the event that operation was required.

Client: Birse Civils Ltd/Environment Agency