Contractors World UK & Ireland Vol 6 No 1
between lifting positions.
DLT has developed and carried out detailed design
of the gantries, including the lifting tackle, deck anchor-
ages, deck segment adjustment and advancement M&E
There are 3 spans of 223 m, 104 m and 101.5 m be-
tween the north tower (NT) and the north abutment
(NA) passing over two piers N1 and N2. The transition
between single cable stayed box girder and the twin box
girders is located just to the north of the last pier N2.
The last 222 m of deck weighing 6400 t including this
transition is to be erected by launching from behind NA.
A king post and stay system is used to allow the deck
to cantilever the full span length. The launch support
bearings have to be changed during the launch to ac-
commodate the transition in deck form. An unusual
feature of the launch occurs towards the end when the
nose is lifted to pass over the last pier by sliding the rear
end down temporary ramp walls built in the north
DLT has developed and detailed the launch scheme,
including permanent works interfaces and all temporary
works, and will provide site support during launching.
Deck Support Falsework at Piers S1
Erection of the deck segments over the southern ap-
proach piers S1 and S2 requires extendable falsework
to support and adjust the position of the pier deck seg-
ments to allow closure between them and the main
After the pier segment has been lifted onto the false-
work, by the Erection Traveller, it is slid south over the
pier to generate sufficient space to lift a further
Subsequently, the pier segment is moved north to
connect it to the previously erected deck. The required
longitudinal movement range is approximately 5 m.
There is also a requirement for hydraulic vertical supports
to control the loading and in order to transfer the weight
of the segment from the temporary supports onto the
DLT has developed the concept and is now carrying
out detailed design of the temporary works, permanent
works interfaces and equipment specification.
© 2015 Dorman Long Technol
Top: Deck erection gantry manufacture model
Middle: Detail of lifting strand jacks and plan align-
Bottom: Detail of deck lifting frame with slope adjust-
Contractors World UK & Ireland