Bridges
All structures over 40m
long are being built
with steel
Bridges improve
major artery
24 NSC
July/Aug 18
Highways England’s £1.5 billion
A14 improvement scheme
between Cambridge and
Huntingdon aims to relieve
congestion, unlock economic growth,
improve safety and enhance the local
environment.
The existing road is notoriously congested
and suffers from numerous delays as it is
used by almost 85,000 vehicles every day,
far more than it was originally designed to
accommodate.
The improvements include a new bypass
to the south of Huntingdon, widening
sections of both the existing A14 and A1
trunk roads, the creation of new local access
roads, and improved junctions.
A total of 34 bridge structures will be
required for the scheme, crossing roads,
railways and waterways. Working on behalf
of the A14 Integrated Delivery Team, six
of these structures are being fabricated,
supplied and installed by Cleveland Bridge.
Steelwork for two of these bridges – the
A14 Brampton Interchange Bridge and
the East Coast Mainline Bridge - has been
completed, while the viaduct over the River
Great Ouse is currently ongoing and due to
complete by early August. The final three
bridges (see box) will all be completed by
early 2019.
Commenting on the use of steel, A14
Integrated Delivery Team Construction
Director Jim McNicholas says: “Prior
to coming to site we carried out a value
engineering exercise and from this we
decided that any structure that was 40m or
longer would be built with steel.”
Completed in January, the A1 Brampton
Interchange Bridge is an 80m-long curved
bridge spanning the A1. The bridge was
constructed from 30 curved and cambered
girders, each up to 34m long and weighing a
total of 1,400t.
Cleveland Bridge says the major
challenge on this bridge was the curved and
cambered nature of the structure. It had to
use advanced modelling software to enable
the manufacture of the girders for the deck,
which had a high skew and a tight radius.
The complex geometry meant the girders
had to be transported singly and then spliced
and braced together on site. To achieve the
total bridge length of 80m, ten lines of three
girders, weighing up to 55t each, were used
to span between abutments and piers.
Cleveland Bridge says it developed a
jacking system on top of the piers which
allowed the girders to cantilever out beyond
the central pier. This enabled a whole line of
supporting trestles to be removed from the
scheme saving time for the client.
All of this work had to be completed to
a very tight deadline around live A1 traffic
management. Switching the traffic from
one carriageway to another was precisely
scheduled, so bridge construction had to be
completed on time to allow diverted traffic to
run safely beneath the new structure.
The bridge over the A1 was completed
on schedule within the tight programme
timetable, ensuring traffic could continue
to flow throughout the works. The entire
construction of this complex bridge was
completed in just nine weeks.
A different set of challenges was
negotiated for the 40m-long bridge spanning
the East Coast Mainline.
“The biggest challenge for this bridge
was the short possession periods during
which the bridge could be constructed,” says
Cleveland Bridge Project Manager Michael
Whinn.
“As one of the UK’s busiest rail arteries,
A steelwork contractor’s expertise has enabled challenging
crossings to be erected safely, accurately and on time for the
A14 improvement scheme.
FACT FILE
A14 Cambridge to
Huntingdon
improvement scheme
Main Client:
Highways England
Delivery organisation:
A14 Integrated Delivery
Team
Main contractor:
Costain Skanska, Balfour
Beatty joint venture
Designer: Atkins and
CH2M joint venture
Steelwork contractor:
Cleveland Bridge
Steel tonnage: 9,245t
/Design_for_steel_bridge_construction#Fabricating_the_steelwork
/Bridges
/Plan_curvature_in_bridges
/Design_for_steel_bridge_construction#Modelling_the_structure
/Design_for_steel_bridge_construction#Transportation
/Design_for_steel_bridge_construction
/Design_for_steel_bridge_construction#Erection_during_possessions