Coffle End near Bedford

The aim of this project was to protect a railway bridge from scouring of foundations due to flood event river flows. Suttle Projects were engaged, as a full scope tier 2 contractor, to complete the scour protection scheme for AMCO on behalf of Network Rail, LNE zone.

The mobilisation involved an extended crossing of agricultural land, with heavy equipment and materials, across a low-lying flood plain, adjacent to the Great River Ouse.

To facilitate excavations around the existing bridge foundations we created two watertight piled cofferdams using 8m Larrsen piles.  The piling was achieved with marine equipment, including a unifloat pontoon.  As each phase of cofferdams were set up, we installed a double level of D500 limestone rock.  A 65 tonne class long reach excavator enabled us to service the cofferdam on the bank furthest from the compound, without requiring further expensive access from the north river bank, or the cost and programme implication of shipping a large volume of rock armour by pontoon.

The service on site offered by our team included daily structure monitoring to high accuracy parameters to ensure work was moving forward without introducing any structural movement or settlement. This helped to offer the client a level of reassurance that allowed the operational railway to remain entirely unaffected by our working scope.