Avonmouth Bridge
Encyclopedia
The Avonmouth Bridge is a road bridge
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...

 that carries the M5 motorway
M5 motorway
The M5 is a motorway in England. It runs from a junction with the M6 at West Bromwich near Birmingham to Exeter in Devon. Heading south-west, the M5 runs east of West Bromwich and west of Birmingham through Sandwell Valley...

 over the River Avon
River Avon, Bristol
The River Avon is an English river in the south west of the country. To distinguish it from a number of other River Avons in Britain, this river is often also known as the Lower Avon or Bristol Avon...

 into Somerset
Somerset
The ceremonial and non-metropolitan county of Somerset in South West England borders Bristol and Gloucestershire to the north, Wiltshire to the east, Dorset to the south-east, and Devon to the south-west. It is partly bounded to the north and west by the Bristol Channel and the estuary of the...

 near Bristol
Bristol
Bristol is a city, unitary authority area and ceremonial county in South West England, with an estimated population of 433,100 for the unitary authority in 2009, and a surrounding Larger Urban Zone with an estimated 1,070,000 residents in 2007...

, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. The main span is 538 ft (164 m) long, and the bridge is 4554 ft (1,388 m) long, with an air draught above mean high water level of 98.4 ft (30 m). It also contains a separate footpath and cycleway.

The bridge was built with three lanes each way, with full hard shoulders
Shoulder (road)
A hard shoulder, or simply shoulder, is a reserved area by the verge of a road or motorway. Generally it is kept clear of motor vehicle traffic...

. From 2002 to 2004, it was widened to four lanes each way, resulting in the hard shoulders no longer being of full width.

The bridge was built to allow tall ships underneath. This gave the bridge steep gradient
Gradient
In vector calculus, the gradient of a scalar field is a vector field that points in the direction of the greatest rate of increase of the scalar field, and whose magnitude is the greatest rate of change....

s that cause heavy vehicles to slow down, resulting in congestion during rush hour and the summer tourist season: traffic can stack up both on the bridge and on the approaches.

Surface

The approach and initial climb up the bridge have a smooth asphalt surface, however on the top of the bridge the surface is uneven and bumpy. In September 2006, it was announced that the entire bridge would be resurfaced, only five years after that had last been completed. This was completed in November 2009 by the construction firm Stirling Lloyd. However the surfacing was carried out by Swiss firm Aeschlimann using their own workforce and also importing all the plant used. A revolutionary new asphalt
Asphalt
Asphalt or , also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits, it is a substance classed as a pitch...

called Gussasphalt was used on the bridge deck. Gussasphalt is Aeschlimanns flagship product, in addition to a smooth skid resistant finish, it requires no compaction and can be applied in very thin layers, thus reducing the weight added to the bridge. It is also very flexible and as a result should last longer than the previous resurfacing effort.

External links

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