An important element of the work is a new steel footbridge, also known as the Transfer Deck, that has been built over the central portion of the station providing access to all of the platforms.
Because the structure is 100m-long and spans a functioning and busy railway station, it was constructed in three separate stages, adjacent to the northern entrance building.
“Erecting the bridge over the live railway lines was not an option so we devised a plan to build it in stages and then launch them into position,” explains Ben Binden, Cleveland Bridge Site Agent.
The first section of the bridge to be erected measured 50m x 30m and consisted of 550t of steelwork. It was site assembled on piers and then pulled by strand jacks towards its final position adjacent to the Western Gateline building. This then made room for the second section to be assembled in the same location.
Slightly smaller at 24m long, the second section was connected to the first and the combined structure was then launched a further 18m to connect the Transfer Deck to the western gateline building.
“Stage three of the bridge construction consisted of infilling the 23m long section between the second section and the northern entrance,” explains Peter Mullen, Tata Steel Projects Engineer.
This major reconstruction of a key hub on the rail network represented a considerable step for the client and its team. The deck structure itself presented challenges for construction above the operating rail lines, and steelwork was the appropriate material for the varied structural forms used.
The overall works at the station present a fairly dramatic environment for the travelling public.