Method Led Design - Reconstruction of UB 278 Newark Dyke
This new long-span railway bridge for the East Coast Main Line was designed with new piled foundations out-with the existing bridge footprint and the brick substructure modified to accommodate a unique slide process for removal of the old bridge and installation of the new. New bridge bearings were mounted on permanent crossheads that spanned between the remote pile caps and that were installed as “needle beams” passing through new openings mined through the existing abutments. The needle beam crossheads were designed also (with temporary extensions) to act as a slide paths for jacked skids traversing the old trusses out and the new bridge deck in. The superstructure steelwork was designed to allow off-line launch erection of single girders and deck assembly over the river. A key feature of the integrated demolition and installation method was the opportunity to create a new square twin-track span in place of the existing pair of single track truss bridges. These had been in a complex staggered arrangement to accommodate the skewed alignment of the tracks over the river.
The new bridge deck was completed, including with ballast and tracks, alongside the existing live tracks and then slid into position in a single 72 hour possession during which time the existing trusses were also removed to a safe remote position for subsequent dismantling. Completed superstructure design for transverse slide erection over river in possession.