The Severn Bridge is a motorway suspension bridge spanning the River
Severn and River Wye between Aust, South Gloucestershire in England, and
Chepstow, Monmouthshire in South Wales, via Beachley, Gloucestershire, a
peninsula between the two rivers. It is the original Severn road crossing
between England and Wales and took three and half years to construct at a cost of
£8 million. It replaced the Aust ferry. The bridge was opened on 8 September
1966, by Queen Elizabeth II, who hailed it as the dawn of a new economic era for
South Wales. The bridge was granted Grade I listed status on 26 November
1999. History
The first proposal for a bridge across the Severn, approximately in the same
location as that eventually constructed, was in 1824 by Thomas Telford, who had
been asked to advise on how to improve mail coach services between London and
Wales. No action was taken, and over the next few decades the railways became the
dominant mode of long-distance travel, with the Severn Railway Bridge at
Sharpness being opened in 1879 and the main line Severn Tunnel in 1886.
However, the growth of road traffic in the early 20th century led to further
calls for improvements, and in the early 1920s Chepstow Urban District Council
convened a meeting of neighbouring local authorities to consider a Severn
crossing to ease congestion and delays on the A48 passing through the town. In
1935 Gloucestershire and Monmouthshire County Councils jointly promoted a
Parliamentary Bill to obtain powers to build the bridge over the estuary, with
75% of costs to be met by the Ministry of Transport from the Road Fund.
However, the Bill was rejected by Parliament after opposition from the
Great Western Railway Company. After World War II, plans began to be
made for a nationally funded network of trunk roads, including a Severn Bridge,
for which the contract was awarded to Mott, Hay and Anderson, with Freeman Fox
and Partners. The public inquiry into the scheme was held on 24 September 1946
at Bristol University. However, because Government funding was prioritised for
the similar Forth Road Bridge, construction of the Severn Bridge was
not started until 1961: the UK government announced in 1962 that
construction costs would be 'recovered' by means of a toll of 2s 6d on all
vehicle crossings, though walking or cycling across the bridge would be
charge-free. The substructure was completed by contractors John Howard and
Co in 1963. The superstructure contract was awarded to Associated Bridge
Builders Ltd in 1963, and completed in 1966.
Component structures The Severn Bridge crossing consists of
four structures, which, listed in order from England to Wales, are: the Aust
Viaduct, Severn Bridge, Beachley Viaduct and Wye Bridge. The Severn Bridge and
Aust Viaduct was granted Grade I listed status on 26 November 1999, while the
Wye Bridge and Beachley Viaduct was granted Grade II listed status on 29 May
1998. = Aust Viaduct =
The 514 ft Aust Viaduct is a twin box girder structure with a concrete deck,
which carries the roadway from the top of Aust Cliff to the first gravity
anchorage of the old Severn Bridge. The roadway is then carried over the top of
the concrete anchorage to the Severn Bridge.
= Severn Bridge = The Severn Bridge is located close to
the former Aust Ferry. The bridge is a suspension bridge of conventional
design, with the deck supported by two main cables slung between two steel
towers. In 1966 the cables supporting the bridge deck were spun from 18,000
miles of wire. The main cables, are each made up of 8,322 individual 5mm wires.
An unusual feature of the suspension cables carrying the deck is that they
are not vertical, as for most suspension bridges, but rather arranged in a
zig-zag fashion, with adjacent mounts closely spaced. The triangulation this
offers is an attempt to reduce vibration, as is the prominent use of
Stockbridge dampers on the cables. The bridge is 5,240 ft long, consisting of a
3,240 ft central span between the towers and the two 1,000 ft side spans. The
towers rise to 445 ft above mean high water and are of hollow box
construction. The deck is an orthotropic steel box girder of aerofoil shape with
cantilevered cycle tracks and footway supported from the box. The shape of the
bridge was determined by the designers Freeman, Fox and Partners following wind
tunnel tests for the Forth Road Bridge, after the original wind tunnel model was
accidentally destroyed. The sections of the deck were built at Fairfield-Mabey
in Chepstow, and each 132 tonne section was then floated down the river before
being hoisted into position. = Beachley Viaduct =
The 2,444 ft Beachley Viaduct is also of similar box girder construction as the
Severn Bridge but is supported on steel trestles as it crosses the Beachley
peninsula. The peninsula contains an army camp, which the bridge crosses.
= Wye Bridge = The Wye Bridge is a 1,340 ft long
cable-stayed bridge, which crosses the border marked by the River Wye between
England and Wales, 2 miles south of Chepstow. It consists of a single large
cable stayed section with two single-leg pylons supporting the bridge deck from
the centre of the roadway. The deck is an orthotropic box girder similar to the
Severn Bridge but has a different appearance as it has two sets of cable
stays on each of two towers. Originally there was only one set of cable stays
but these were replaced during the strengthening works. The Wye Bridge was
built by Cleveland Bridge & Engineering Company.
Post-construction changes In January 1977, it was announced that
bridge traffic would be restricted to a single lane in each direction following
the discovery of several weaknesses in the ten-year-old structure. The lane
closures would last for several months. The Severn Bridge crossing was
strengthened and resurfaced in the late 1980s as the weight of traffic grew. The
work included the strengthening of the Severn Bridge towers and deck, an
extension to the existing Wye Bridge towers and the replacement of the
original single stays with two stays. The open structure of the new stays is
designed to facilitate maintenance. Most of the strengthening work was inside the
deck box and towers and so is not visible. The surfacing is a 35 mm thick
layer of mastic asphalt over an acrylic waterproofing membrane.
Tolls Shortly after the opening of the Severn
Bridge, Anglo-Welsh poet Harri Webb wrote an Ode on the Severn Bridge:
Two lands at last connected Across the waters wide,
And all the tolls collected On the English side.
The toll is indeed collected on the English side, and only on vehicles
travelling westwards from England to Wales, leading some people to describe
it as a "tax on entering Wales", both in jest and also as a more serious
anti-toll campaign. Originally, tolls were charged in both directions, but the
arrangements were changed in the early 1990s to eliminate the need for a set of
toll booths for each direction of travel and the potential for traffic waiting to
pay the toll backing up onto the bridge itself.
In 1966, the toll for using the new motorway crossing was set at 2s 6d for
all vehicles apart from solo motorcycles which enjoyed a reduced toll of 1s. For
a small car the bridge toll represented a saving of 7s on the price, at that
time 9s 6d, of using the ferry crossing. By 1989, the toll had reached £2 each
way for goods vehicle having an unladen weight exceeding 1.525 tonnes and
passenger vehicles adapted to carry more than 16 passengers and £1 each way for
other vehicles. Currency depreciation has been a feature of UK monetary policy
in the intervening decades, and the RPI is a widely applied surrogate for the
resulting impact of general price inflation: if the Severn toll had
increased in line with general inflation since September 1966, when Queen
Elizabeth II opened the bridge, the original value of £0.125 would have
reached £2.02 each way in January 2010. As of January 2015, the toll is £6.50
for a car, increasing to £19.60 for a heavy goods vehicle. Motorcycles and
disabled badge holders are exempt from the tolls, although both must stop at
the toll booths to have their eligibility confirmed, and also to allow
the barrier to be raised. The tolls for the Second Severn Crossing are the same,
although in that case, the tolls are collected on the Welsh side,
sufficiently far from the bridge that even severe queueing doesn't reach it. A
system known as the Severn TAG made by Amtech is also in operation, which
allows drivers to pay electronically without having to stop at the toll
booths. TAGs are available either on a per-trip or a seasonal basis, although
only the latter attracts a discount. Credit/debit cards were not originally
accepted on either bridge, but drivers who did not have the means to pay were
able to get a bill from the toll operator and pay by post later. Card
payment was made available in time for the 2010 Ryder Cup, however, users would
be required to enter their PIN and cash was still the recommended payment method
to avoid delays. The cycle path and footpath, which run
along either side of the roadway, may be used free of charge. Only the original
bridge has such a public access. = Historic overview of the charges =
Ownership Ownership and operation of the bridge
passed to Severn River Crossing plc on 26 April 1992 as part of the deal to
build the Second Severn Crossing. As of November 2010, Severn River
Crossing Plc was owned 35% John Laing, British developer
infrastructure operator 35% Vinci, French concessions and
construction company 15% Bank of America, American
multinational banking and financial services corporation
15% Barclays Capital, British multinational investment bank
The company's 2011 annual report showed the same companies still owned, through
subsidiary companies, all the issued ordinary share capital of the Plc.
Ownership of the bridge and the Second Severn Crossing will return to the UK
government when the revenue required to build and maintain them, as defined in a
Concession Agreement with the Secretary of State for Transport, has been
collected. In 2010, the concession was expected to end in 2017. In 2012,
changes were made to the agreement to reflect the effect of changes in VAT and
Corporation Tax and the costs of installing credit card handling systems.
The net effect was to increase the required revenue from £995.83 million to
£1,028.91 million in 1989 prices. 40 year inspections
During its 40th year of operation, the bridge was inspected to check for
corrosion of the suspension cables. According to the Highways Agency, the
inspection concluded that the bridge needed restrictions on heavy goods
vehicles. Such vehicles are now restricted to one lane on the bridge,
with weight restriction signs in place. A system of installing a rubber casing
on the cables with dry air circulation is to be used on the Forth Road Bridge
and a similar system may be implemented on the Severn Bridge, in a move to halt
the progress of the corrosion. Simultaneous closures in 2009
On 6 February 2009, during a week of snowfall throughout Britain, both Severn
bridges were closed simultaneously due to ice falling from the bridge structure
and damaging vehicles. On 22 December 2009 both bridges were closed again for
the same reason. This was only the third time that both
bridges have been closed together, the first being due to a chemical fire in
Avonmouth some years earlier. See also
List of crossings of the River Severn List of crossings of the River Wye
Aust Severn Powerline Crossing References
External links Severn River Crossing PLC
Severn Bridge at Structurae ST58NE Aust M4 motorway - Images of
England Bridge celebrates 40th birthday, BBC
News, 8 September 2006 Archive pictures of the bridge being
built Video of the Queen opening the bridge in
1966 Motorway Database: M48
Severn Bridge traffic webcam