Civil Engineering
Britain's longest elevated highway
SEC
ECHON
CTION:
SECTION 6
ROAD
-WESTBOURNE PARK
STATION,
LADBROKE GROVE
STATION
SECTION
WHITE CITY
STADIUM
PADDINGTON
STATION
SECTION,
THE 4 km long Western Avenue Ex- tension from Paddington to White City provides a motorway link between Central London and the A.40 trunk road to South Wales. It is the longest elevated highway in Britain, completed recently at a cost of £15.25 million.
A feature of the highway was that its main prestressed concrete structure necessitated the design by John Laing Construction Ltd., the contractors, of special temporary works and construc- tion equipment.
For one 1200m long section, con- taining an elevated roundabout at White
Far East BUILDER, November 1970
City, the 35m spans of the highway were constructed in precast concrete units weighing up to 45.7t each. The spans take the form of longitudinally post-tensioned hollow spine boxes with reinforced concrete cantilevers on each side.
Construction, which was either from precast concrete units or in situ concrete, fell into four distinct sections separated by gaps:
1. The western in-situ transition structure and dual 11m carriageway, six spans of which are formed by two spine box units side by side, joined
-
Route of highway looking east from White City
together after completion of the longi- tudinal stressing.
2. Dual 7.3m carriageway, of which nine spans are constructed from single units.
3. The cast in-situ roundabout and its adjacent slip roads formed from single units.
4. The eastern in-situ transition structure and dual 12.5m carriageway, five spans of which are formed by a combination of three spine-box units side by side, again joined together after completion of the stressing.
This separation and the provision
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