The complex contract at Chieveley interchange has involved work on four bridges 2 either side of the roundabout carrying the M4. Geodetic monitoring has been employed to monitor any movements in the bridge decks resulting from piling or pier removal. The abutments have been propped and the new bearings preloaded . The new piers, sitting on 48 off 100 tonne jacks, have been propped during renovation work and the decks have been weighed using 24 of 200 tonne load cells.