WEST LINK BRIDGE AND MOTORWAY CONTRACTS NO'S ONE & TWO
The extent of the works included the construction of a 400m long, 40m high prestressed concrete box girder form of bridge in balanced cantilever construction together with associated 3km of motorway and three minor bridges.
The bridge has five spans, one 90m long, and the box is of a constant depth single cell. Piers are of a hollow concrete section. The deck was cantilevered out, using the balanced cantilever method from special sections at the top of each pier to near the middle of each span.
Deck construction from each pier started off from a pier table. The pier table was cast on formwork supported on a system of steel beams fixed to the pier, and on temporary props of concrete blocks next to each pier to carry the extra forces caused because of the differing lengths of cantilever to one or other side of the pier.
The deck was constructed in segments using two sets of formwork travellers or carriages consisting of a shutter the shape of the concrete, an A-frame superstructure from which the shutter was hung and a set of rails fixed to the deck on which the frame moved.
The dolphins we supported by 26 No. 914mm diameter and 24 No. 762mm diameter
vertical and raking tubular piles approximately 30M long. The piles were driven by a HH9 Hydraulic Piling
Hammer supported by a 160 tonne crawler crane operating from a 1000 tonne flat top floating crane barge.
The sheet piled retaining wall, with an area of 2100m2 was installed from
afloat using a PVE 25M Piling Hammer supported by a 60 tonne crawler crane operating from another crane
barge.
The approach bridges were installed using a combination of land based and
marine based cranes.
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