' The essence of design is having the imagination and the desire to create something '
The Humber Bridge
The Humber Bridge is a suspension bridge with the north tower sited on the high water line and
the south tower founded in shallow water 500m from the shore.
The Humber Bridge |
On the north bank, the Hessle side span is 280m long with
the anchorage on higher ground north of the Hull-Doncaster
railway line.
The southern side span is 530m long with the anchorage about
30m inshore and some 300m west of Barton Haven.
On the north bank, a hard well-jointed bed of chalk comes
close to the surface and is covered by a tough layer of glacially
deposited chalky boulder clay.
The chalk has provided good foundations for both the anchorage
and tower on this bank and the boulder clay has provided a
good basis for the approach road embankment and the toll plaza
area.
On the south side, in the areas where both the tower and
the anchorage are located, soft alluvium is underlain by beds
of boulder clay, sand and gravel.
Below these beds, at a depth of 30m, there is a deep bed
of stiff, heavily fissured Kimmeridge Clay, on which the tower
and anchorage have been founded.
 Click to view Media Library images of the Humber Bridge.
Design Conditions
The bridge provides dual two-lane carriageways for highway
traffic and there is a combined footpath and cycle track along
each side of the bridge.
The bridge has been designed to cater for traffic loading
as set out in British Standard 153 except that, for long loaded
lengths, the minimum lane load has been increased from 5.84kN/m
(400lb/ft) to 8.76kN/m (600lb/ft).
The special vehicle for which the bridge has been designed
has a total weight of equivalent to 1794kN (180 tons).
The design has also taken account of loading due to wind
varying in maximum velocity from 43.8m/sec (99 mph) at a height
of 5m above Ordnance Datum to 66.6m/sec (149 mph) at tower
top level (162.5mOD).
Anchorages
The anchorages are massive concrete structures each containing
tow chambers within which the main cables splay out into separate
strands.
At the splay position, the cables are supported by steel
saddles mounted on top of reinforced concrete pillars.
The ends of the main cable strands are attached to steel
crosshead slabs at the face of anchor blocks by strand shoes
and anchor bolts.
The crosshead slabs are pre-stressed against the face of
the anchor block by high tensile bars anchored at the rear.
The anchorages also support the ends of the side spans.
Hessle Anchorage is situated on the line of the bridge about
280m north of the high water mark.
It is 65.5m long x 39m wide and founded in hard chalk at
a depth of about 21m below ground level.
Barton Anchorage is sited 30m behind the river flood bund.
Above ground, it is similar to Hessle Anchorage but the foundation
is cellular, 72m long by an average 40m wide, filled with
sand and water and constructed within a framework of diaphragm
walls which reach 35m below ground level into Kimmeridge Clay.
This anchorage has been designed to give an approximately
uniform bearing pressure under all conditions of cable pull.
Certain parts above ground level – the mass concrete
infill, the architectural ribs on the anchorage and the deck
slab – were not therefore cast until cable spinning
was complete.
Subsequently the mass concrete infill was added while the
box sections for the deck were being erected.
To view a gallery of images of the Humber Bridge please click
here
Tower Foundations (Piers)
The piers are reinforced concrete structures which support
the towers.
Hessle Pier is situated on the high water mark.
It is a reinforced concrete structure 44m wide x 16m long
x 11.5m high and founded in hard chalk at a depth of about
8m below the ground level.
Barton Pier is located in the river about 500m from the
south bank.
It comprises a reinforced concrete structure some 16m thick
supported on twin hollow circular caissons each about 24m
in diameter sunk by underwater excavation and founded in Kimmeridge
Clay about 36m below the river bed.
Although heavily ballasted during construction, the caissons
have been left empty in the final condition.
Towers
Each tower consists of two tapered vertical reinforced concrete
legs braced together with four reinforced concrete horizontal
beams.
The legs, built by slip-forming, are hollow columns 155m
high and vary from 6m x 6m at the base to 4.5m x 4.75m at
the top.
The inside faces of the legs are vertical and 18.4m apart.
There is an electric lift in one leg of each tower for maintenance
use.
At deck level a reinforced concrete plat form is cantilevered
out on three sides of each leg to form the link between the
main and side span footways.
To view a gallery of images of the Humber Bridge please click
here
Main Cables
Each cable comprises 14,948 parallel galvanised drawn wires
which, for the purpose of erection and anchorage, were divided
into 37 strands.
In addition, on the Hessle side span, there are a further
800 wires in each cable divided into four strands held by
strand shoes both at the anchorage and at the tower saddles.
With spinning and adjustment of the strands completed, the
cables were compacted into a circular shape.
After the completed suspended structure had been erected,
the cables were coated with red lead paste, wrapped with soft
steel galvanised wire and painted.
Hanger Ropes
The deck structure is suspended from the main cables by inclined
high tensile steel wire strands of approximately 62mm diameter.
They are inclined so as to be capable of transmitting horizontal
forces between the deck and main cables and, by absorbing
energy, assist in dampening oscillations that might otherwise
be induced under certain wind-loading conditions.
To view a gallery of images of the Humber Bridge please click
here
Suspended Structure
The suspended structure consists of stiffened steel plate
panels welded together to form a hollow box section 22m wide
and 4.5m deep, with 3m wide panels cantilevering from each
side.
To maintain the shape of the section, and to form cross-girder
webs, transverse diaphragms are fitted at 4.525m centres.
The upper flange of the box forms the carriageways and the
cantilever panels the footways and cycle tracks.
The connections for the hangers are provided by brackets
welded to the edge of the box at intervals of generally 18.1m.
At each tower and anchorage the deck is supported by two
A-frame rockers.
The rockers transmit both vertical and lateral loads while
permitting longitudinal movement, vertical rotation and a
small amount of lateral rotation of the deck.
upper end of each rocker is pinned to a bracket on the end
diaphragm of the box and the two lower ends to either the
lower tower portal or to the front of the anchorage.
Expansion joints in the carriageway at each tower are of
the rolling leaf type and between the side span and the abutment,
of the compressible rubber type.
Along both sides of each carriageway there are crash barriers
consisting of four tensioned wire strands carried on posts
at 4.525m centres and anchored at each abutment and at the
towers.
A tube-type parapet, 1.16m high, runs along the outside edge
of each footway.
The carriageways are surfaced with a 38mm thickness of mastic
asphalt and the footways with a double dressing of rubber
bitumen and 3mm chippings. Four maintenance gantries give
access beneath the bridge deck.
The streamlined shape makes the deck aerodynamically stable
and greatly reduces wind loads on the bridge.
To view a gallery of images of the Humber Bridge please click
here
Road Approaches
The bridge and its associated bridges and highway form an
extension of the A15 (T) road with links to the A63/M62 on
the north bank and A180/M180 to the south.
Links are also provided to Beverley at the northern end
of the bridge and Scunthorpe to the south-west.
Ancillary Items
Extensive car, coach and lorry parking areas and the toll
plaza (complete with computerised toll registration equipment)
are sited at the northern end of the bridge.
Aircraft warning lights are fitted on the towers and navigation
lights for river traffic are fitted to the underside of the
bridge deck.
Emergency telephones and matrix signs are located along the
bridge and early warning signs are provided at the approaches
to the bridge.
Extensive landscaped areas surround the bridge and within
the northern area a Tourist Information Centre, Cafeteria
and Public Toilets (including disabled) are provided.
Engineer and Contractors
The bridge was designed by Freeman Fox and Partners (now
Hyder) and construction was undertaken by a variety of contractors,
the principal ones being John Howard & Co (sub structure)
and British Bridge Builders, a consortium formed by Sir William
Arrol & Co Ltd, Cleveland Bridge and Engineering Co Ltd
and Redpath Dorman Long (super structure).
To view a gallery of images of the Humber Bridge please click
here
For more information about The Humber Bridge please click
here
Sue Griffiths, Secondary Improvement Adviser (Intervention)
Tel: (01482) 392418
Email: sue.griffiths@eastriding.gov.uk
The Learning Partnership
Tel: (01482) 391338
Email: learning.partnership@eastriding.gov.uk
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