In mid-2003, Nuttall’s subsidiary John Martin, was commissioned to replace 117 roller bearings in the structure of the Thelwall Viaduct on the M6, which stretches 1,500 metres over the River Mersey and an adjacent canal. During the test phase in the months preceding, 23 roller bearings had already been replaced. One function of the bearings is to allow the bridge deck to freely expand and contract with fluctuating temperatures.
To replace the roller bearings, hydraulic jacks are used to lift the bridge deck slightly. Carrying out this operation requires reinforcing the bridge deck with extra steel beams. All necessary materials have to be winched up onto the pier head. John Martin Construction is well on the way to complete bearing replacement works to allow reopening the viaduct by spring 2005. The company still has until September 2005 to add extra reinforcement to the pier heads and install new drainage pipes which form part of the additional phases of the work.