Second Severn CrossingEdit profile
The Second Severn Crossing (Welsh: Ail Groesfan Hafren) is a bridge which carries the M4 motorway over the River Severn between England and Wales, inaugurated on 5 June 1996 by HRH The Prince of Wales to augment the traffic capacity of the original Severn Bridge built in 1966. The bridge marks the lower limit of the River Severn and the start of the Severn Estuary.
Its location is further to the south than the old bridge and being more in line with the landward sides of the M4 motorway, is a shorter journey when travelling between England and South Wales. The junctions at each end are designed for most traffic to use this crossing – to use the old Severn Bridge crossing one has to leave the M4 and join the M48 motorway either at Aust or near Magor. The new crossing carries more traffic than the Severn Bridge, which is still in use. It is wider than the Severn Bridge, having three lanes and hard shoulder each way, compared to the two lanes, cycle path and footpath of the original crossing. The path taken by the bridge is close to that of the Severn Tunnel which has carried the railway line beneath the river since 1886.
On 6 February 2009, the bridge was closed by weather for the first time since its opening after three vehicles were struck by falling ice, damaging windscreens. Bad weather, and again falling ice, repeated this in December 2009.Tolls
In contrast to the original Severn Bridge crossing, the tolls are collected on the Welsh side near Rogiet (but in the same westbound direction as on the first crossing). Tolls can only be paid for by cash or cheque, or by use of the Severn TAG system, which is a wireless electronic toll collection system that does not require vehicles to stop. Cash can be paid at the manned booths or coins can be used at the automated coin gates.
Credit/debit cards are not accepted on either bridge, which causes confusion to some motorists as the signs announcing the "No Cards" rule is after the last opportunity to stop and get cash. However, drivers who do not have the means to pay are able to get a bill from the toll operator and pay by post later. In June 2010, Norman Baker, the Parliamentary Under-Secretary of State for Transport, stated that cards would be accepted in time for the 2010 Ryder Cup in October. In September 2010, the Highways Agency announced that a temporary system for accepting card payments would be in place for the Ryder Cup from 27 September to 3 October 2010. However, users would be required to enter their PIN and cash was still the recommended payment method to avoid delays. A permanent card payment system which will not require a PIN should be ready early in 2011. In May 2011, UK Transport Minister Mike Penning said that motorists would be able to use credit and debit cards that did not use a PIN number from July 2011.
Tolls charges are based on a three tier pricing system:
Motorbikes and UK disabled badge holders travelling in a vehicle are exempted from paying a toll, although these vehicles must stop at the toll booth to confirm their eligibility.
The toll prices are updated every year on 1 January in accordance with the Severn Bridges Act of 1992. In late 2008, UK VAT was reduced from 17.5% to 15%, but the bridge toll remained unchanged. For reasons of convenience the tolls are kept at round multiples of 10p (the bridge toll is largely paid in cash, not with cards), but the 13p VAT reduction was not passed on immediately. In 2009, the planned toll for cars would have been £5.50, as the announcements listed, but the actual toll charged was £5.40.Historical toll charges
The crossing is 3.2 miles (5.1 km) long, consisting of a single central navigation span over the "Shoots" channel and approach viaducts on either side. The Shoots channel is the deepest section along the width of the Severn Estuary, and a longer span was required to ease the passage of shipping under this section. The central bridge section, called the Shoots Bridge, is of cable-stayed design and the central span (between the bridge pylons) is 499 yards (456.3 m) in length. The approach viaducts are of a segmental bridge design. Its Welsh end is near Sudbrook, Monmouthshire and its English end at Severn Beach in South Gloucestershire. The crossing forms a gentle S shape and near the English side crosses over the top of the Severn Tunnel.
The sides of the bridge are fitted with special railings to reduce lateral wind loads coming from the Severn Estuary onto the traffic and this has reduced the number of times that speed restrictions have been needed. The overall design of the new crossing makes it more resistant to high winds than the old Severn Bridge.Construction
The crossing was built by a business consortium under a public-private partnership. A company called Severn River Crossing plc, led by John Laing plc and GTM-Entrepose, was formed to build the new crossing. The company also took over the responsibility of managing and maintaining the old Severn Bridge crossing, as well as managing and maintaining the new crossing. The cost of constructing the new crossing was expected to be paid for by tolls collected from motorists using the two crossings. Work on the new crossing began in 1992 with completion in 1996.
Sub-assemblies for the bridge were constructed onshore and then shifted by a large tracked vehicle (similar to that used to move the Apollo and Space Shuttle at Cape Kennedy) onto a barge, prior to being floated out on the high tide to the appropriate site. The 37 bridge pier foundations on the approach viaducts are 107.3 yards (98.1 m) apart, and consist of concrete pneumatic caissons weighing 37 tonnes, which were sunk into the mud of the estuary. The decking consists of 3.8 yards (3.5 m) post stressed match cast sections, weighing 200 tonnes each.
The cable stayed section of the crossing is over 984 yards (899.8 m) long, consisting of a 38 yards (35 m) wide deck made from steel plate girders with a composite reinforced concrete slab. These were prefabricated on shore and put in place using balanced cantilever methods. There are two 489 feet (149 m) high twin leg, reinforced and pre-stressed concrete pylons carrying 240 cables which support the bridge deck. Cable vibrations were experienced during construction and secondary cables were added to eliminate this. To avoid detracting from the aesthetics of the primary cables, the secondary cables are very slender and are not very noticeable.Environmental criticism
Prior to the bridge's construction environmentalists raised numerous concerns and criticisms, chiefly about the immediate damage from construction work and the effects of long-term pollution from a projected increase in car traffic. The approach viaducts from the east sit on English Stones, a rocky outcrop uncovered at low tide. And the crossing is built near extensive mudflats in the Severn Estuary used by various migrating birds, although the Newport Wetlands Reserve was established nearby on the Welsh side in 2000.