Temporary Gantries and Lifting Frames
Cass Hayward’s designs for temporary gantries and lifting frames are almost always unique as such specialist techniques are only generally applied for unusual situations or repetitive processes. Some of our early projects of this type required dramatic engineering solutions such as the jacking frames used to relieve the deck load whilst the degraded RC crossheads of the M4 elevated motorway near Hammersmith were reconstructed. Also in London the heavy duty steel box girder portals designed by us for the 6m vertical strand jacking of the twin 1300te. and 1600te. girders of the old Primrose Street bridge demanded special attention to detail to retain sufficient clearance above and between the live tracks.
We designed special walkway units to receive the gantry rails used for the overhand demolition and installation of the 49 spans of Leven Viaduct as part of our design remit and special cradles for lifting out and preservation of one Brunel’s last remaining cast iron bridges over the canal at Paddington Station. For North Road Bridge reconstruction in Doncaster we arranged for the new permanent steel skeleton to be erected at high level to serve as a demolition gantry, and then lowered to its final position using high capacity long stroke telescope rams.