Client: Bournemouth Borough Council
Contractor: Dyer & Butler
Duration: 12 Weeks
Date posted: 06-11-2014
After recent surveys conducted by MMC's dive team and their engineers, more scour had been detected below the beautiful stone of Iford Old Bridge.
Previous attempts at protecting these scour holes using rock armour and soluform bag work had failed, and last Christmas day saw over 100 residents in the area being evacuated when the river Stour burst its banks.
Bournemouth Borough Council therefore made the decision to address this on a sustainably bigger scale.
A series of core plugs were taken to establish the depth of the foundations in the hope that the concrete inverts could be demolished and lowered to allow more water to pass between the four arches.
Unfortunately data obtained confirmed that the current slab was at the lowest it could be without undermining the structure.
MMC broke up and removed 100's of tons of concrete along with excavating the river bed an excavator which was positioned on our ex nato road transportable steel modular pontoons.
MMC divers used hydraulic and pneumatic underwater breakers to brake up the vast concrete slabs, grading the seabed and then lining the entire downstream riverbed with four Proserve mattresses, each one 50m by 8.0m and filled with 46 tonns of underwater grout this was pumped from x2 site silos down to the diver.