Lift, launch and lower - replacing the Bishop's Bridge Road Bridge at Paddington Station

The works to replace and widen the Bishop’s Bridge Road Bridge whilst maintaining normal operation of Paddington station presented significant engineering challenges. The bridge crosses 13 rail tracks (eight with 25kV overhead electrification) and two LUL surface lines at the platform ends on the approach to Paddington Station and the Paddington branch of the Regents canal. Quite apart from the physical constraints of the site, both above and below ground, the design was required to allow for future developments including links to the new deck. The contractor’s novel solution of lifting the existing 800t, 65m span Bowstring Bridge before launching the new, 3200t deck beneath it and then lowering the old bridge onto the new structure to take it away on a transporter, required additional transitory phases during construction to be addressed in the design of the structure. This paper describes the development of the project concept, the various constraints identified and the effect these and the innovative construction method, imposed on the final design for the main bridge structures.

Jo’ Kenward, BEng (Tech) Hons, CEng, FIStructE, MICE, MIHT
Technical Director, Hyder Consulting Ltd

Alan Monnickendam, BSc (Hons), CEng, MICE
Partner, Cass Hayward LLP