3.4.6 Wing traveller machines
Two wing traveller machines were used on the project
– one for each of the approach viaducts.
One wing traveller machine was used to build the
outer road lanes on either side of the North approach
viaduct in Widnes. It followed the project’s movable
scaffold system (MSS), which constructed the central
part of the carriageway. The second was used for the
South viaduct.
The wing traveller - sometimes called the
Construct ion Cantilever Traveller - weighed 280
tonnes and was around 48m wide and 20m tall. It
worked in a similar way to the MSS and the form
traveller machines, acting as a movable concrete
mould to complete the full deck width, which, at just
over 43.5m at its widest point, carries six lanes of
traffic.
Completion of the bridge and viaduct decks involved
water-proofing the deck, installing fascias along its
sides, and laying the road surface.
3.4.7 Ancillary items - Windshields
To confirm aerodynamic stability and wind speeds on
the bridge wind tunnel testing was used. Windshields
are provided to reduce overturning moments on high
sided vehicles. On the West side of the deck the
windshields are significantly higher than those on the
East side reflecting the prevailing wind direction.
Testing was undertaken on a representative high
sided vehicle, see Figure 21.
The machine was fixed onto two railway tracks that sit
on top of the deck section that had already been cast
by the main section MSS. To maintain balance
concrete was poured into both sides of the machine
at the same time, enabling workers to cast 12 metre
sections of the outer deck on each side of the viaduct.
Once the concrete had set, hydraulic jacks pushed the
machine forward to the next position and the cycle
was repeated.
Figure 21: Windshield testing on high sided vehicle
References and sources:
KNIGHT, Martin – HALACZEK, Bartlomiej: Securing visual
quality and architectural intent while aiming for an
affordable tender design – the procurement of the
Mersey Gateway Crossing. Knight Architects, High
Wycombe, United Kingdom. 39th IABSE Symposium –
Engineering the Future. September 21-23 2017,
Vancouver, Canada
SANDERS, Paul – BRENNAN, G. – WOOD, H. – BANKS, J.
– ROMO MARTIN J.: Mersey Gateway Bridge (UK) –
Design for Construction. 19th IABSE Congress.
Stockholm 2016
Figure 20: The wing traveller machine in its starting
position at the North approach viaduct in Widnes
http://www.merseygateway.co.uk/
Sixty-two concrete pours were needed to create the
outer deck of the North approach viaduct, while 47
pours took place for the outer deck of the South
approach viaduct. Each pour consisted of around
80m 3 of concrete (40m 3 each side).
https://www.peri.com/en/projects/civil-
engineering/mersey-gateway-bridge-runcorn-to-
widnes-great-britain.html
3/2017