BC_Crisan+Bogdan+-++Harbour+Bridge

The **Sydney Harbour Bridge** is a steel arch bridge across Sydney Harbour that carries rail, vehicular, and pedestrian traffic between the Sydney central business district (CBD) and the North Shore. The dramatic view of the bridge, the harbour, and the nearby Sydney Opera House is an iconic image of both Sydney and Australia. The bridge is locally nicknamed **The Coathanger**[1] because of its arch-based design, although this usage is less prevalent than it once was. The bridge was designed and built by Dorman Long and Co Ltd, Middlesbrough, Teesside and was the city's tallest structure until 1967. [//citation needed//] According to Guinness World Records, it is the world's widest long-span bridge[2] and its tallest steel arch bridge, measuring 134 metres (429.6 ft) from top to water level. [//citation needed//] It is also the fourth-longest spanning-arch bridge in the world.

The bridge's ends are located at Millers Point (in Sydney's Rocks area) and Milsons Point (in Sydney's lower North Shore area). It carries six lanes of road traffic on its main roadway, two lanes of road traffic (formerly two tram tracks) and a footpath on its eastern side, and two railway tracks and a bicycle path along its western side, being 305 mm (1 ft) larger than the east side. The road across the bridge is known as the Bradfield Highway, Sydney, and is about 2.4 km (1.5 miles) long, making it one of the shortest highways in Australia. (The shortest, also called the Bradfield Highway, is found on the Story Bridge in Brisbane). The Sydney Harbour Bridge is not completely stationary. It can rise or fall up to 18cm depending on whether it is hot or cold.[3] 

Deck
At 48.8 m (151.3 ft) wide, it is the widest long-span bridge in the world (Guinness World Records, 2004). The bridge deck portion of the highway is 1.15 km (0.71 miles) long. It is concrete and lies on trimmers (beams that run along the length of the bridge). The trimmers themselves rest on steel beams that run along the width of the bridge. The trimmers and beams are visible to boats and people that pass underneath the bridge. 

Arch
The arch is composed of two 28-panel arch trusses. Their heights vary from 18 m (55.8 ft) at the center of the arch to 57 m (176.7 ft) (beside the pylons). The arch span is 503 m and the weight of the steel arch is 39,000 tons. The arch's summit is 134 m (440 ft) above mean sea level, though it can increase by as much as 180 mm (7 in) on hot days as the result of steel expanding in heat. Two large metal hinges at the base of the bridge accommodate these expansions and contractions and thereby prevent the arch from being damaged. About 79% of the steel came from Middlesbrough, in the North East of England. The rest was Australian-made. The granite used was quarried in Moruya, New South Wales, the concrete used was also Australian made. The total weight of the bridge is 52,800 tonnes, and six million hand-driven rivets hold the bridge together. The rivets were made at the Park Bridge Ironworks in Lancashire England. The Dawes Point pylon

Pylons
The two pairs of pylons at each end are about 89 m (276 ft) high and are made of concrete and granite. The granite was quarried at Moruya, New South Wales, 250 km south of Sydney. Abutments, which support the ends of the bridge, are contained at the base of the pylons. They prevent the bridge from stretching or compressing due to temperature variations. Otherwise, the pylons serve no structural purpose and are primarily to visually balance the bridge itself. They were never an essential part of the design but were added to allay concerns about structural integrity.[4] Although inserted into the design for their aesthetic value, all four pylons have now been put to use: a museum and tourist centre with a lookout of the harbour is contained in the south eastern pylon. The south western pylon is used by the New South Wales Roads and Traffic Authority (RTA) as a base for their CCTV cameras overlooking the bridge and the roads around that area. The two pylons on the north shore are now venting chimneys for fumes from the Sydney Harbour Tunnel. The RTA maintenance shed for the bridge is contained within the bottom of the southern pylon and the traffic management shed (tow trucks and safety vehicles used on the bridge) is contained in the bottom of the northern pylon. 

History
//"There the proud arch Colossus like bestride// //Yon glittering streams and bound the strafing tide"// — Prophetic observation of Sydney Cove by Erasmus Darwin .[5]



Early proposals
There had been plans to build a bridge as early as 1815, when Francis Greenway proposed that a bridge be built across the harbour. Nothing came of this. The building of the current bridge can be said to have started in 1890, when a royal commission determined that there was a heavy level of ferry traffic in the Sydney Harbour area, best relieved with the construction of a bridge. Vehicular access to the north shore was undertaken with a series of smaller bridges located further westwards in the harbour, but this was insufficient for the traffic in the Sydney/North Sydney area. 

Planning
Designs and proposals were requested in 1900, but a formal proposal was not accepted until 1911. In 1912, John Bradfield was appointed chief engineer of the bridge project, which also had to include a railway. After travelling extensively to look at a number of bridges worldwide, he based his idea upon New York City's Hell Gate Bridge. Bradfield completed a formal design for a single arch bridge in 1916, but plans to implement the design were postponed until 1922, primarily because of World War I.  Sydney Harbour from the air, showing the Opera House, the CBD, Darling Harbour, the Bridge, the Parramatta River, North Sydney and Kirribilli in the foreground In November 1922 the New South Wales parliament passed laws that allowed the bridge's construction. Construction tenders for the bridge were requested the same year, and the British firm Dorman Long and Co Ltd, Middlesbrough won. To offset concerns about a foreign firm participating in the project, assurances were given by Bradfield that the workforce building the bridge would all be Australians. The building of the bridge coincided with the construction of a system of underground railways in Sydney's CBD, known today as the City Circle, and the bridge was designed with this in mind. The bridge was designed to carry six lanes of road traffic, flanked by two railway tracks and a footpath on each side. Both sets of rail tracks were linked into the underground Wynyard railway station, on the south side of the bridge, by symmetrical ramps and tunnels. The eastern-side railway tracks were intended for use by a planned rail link to the Northern Beaches; in the interim they were to be used to carry trams from the North Shore into a terminal within Wynyard station. Serious initiatives started after the end of World War I. Tenders were called for in 1923 either an arch or a cantilever bridge would meet the requirements. Dr J.J.C. Bradfield was responsible for setting the parameters of the tendering process. He and his staff were to ultimately oversee the entire bridge design and building process. The Bradfield Highway, which is the paved section of the bridge and its approaches, still bears his name to this day. The tender of Dorman Long and Co. Ltd., of Middlesbrough, England for an arch bridge was accepted. The Dorman Long and Co's Consulting Engineer, Sir Ralph Freeman, carried out the detailed design of the bridge. The design was similar to New York's Hell Gate Bridge built in 1916. The Hell Gate Bridge was a little shorter in span but was much lighter in construction as it only carried four railway tracks. The design was also similar to that of the later Tyne Bridge in Newcastle Upon Tyne in England. 

Construction
The arch being constructed. Painting by Grace Cossington Smith (1926). The construction project itself began in 1923, with the demolition of 800 homes and a high school campus. The owners of these homes received compensation, but their occupants did not. The building of the bridge was under the management of Bradfield. Three other people were involved in the bridge's design and construction: Laurence Ennis, the engineer-in-charge at Dorman Long and Co was the main supervisor (Bradfield visited occasionally throughout the project, and in particular at the many key stages of the project, to inspect progress and make managerial decisions); Edward Judge was Chief Technical Engineer of Dorman Long and later became President of the British Iron and Steel Federation; Sir Ralph Freeman was hired by the company to design the accepted model in further detail. Later a bitter disagreement broke out between Bradfield and Freeman as to who actually designed the bridge. Another name connected with the bridge's design is that of Arthur Plunkett. The official ceremony to mark the "Turning of the First Sod" occurred on the 28th July 1923. This was followed by the building of two worksheds at Milsons Point to assist in building the bridge — the light and heavy workshops. Their purpose was to build the bridge's many parts. In January 1925, the excavations to build the abutments and approach spans began. In October 1925, the building of the abutments and approach spans themselves began, and these were completed in September 1928. Construction of the bridge itself began in December 1928, with the construction of the bridge parts in the workshops. Construction of the arch of the bridge began in 1929, with two separate teams building the arch on each side using creeper cranes. The first panel was erected on the southern side in March 1929. The southern end of the bridge was worked on a month ahead of the northern end, in order to detect any errors and to ensure that they did not happen on the northern side. HMAS Canberra (1927) sailing under the completed arch in 1930 from which the deck is being suspended. During construction the two halves of the arch were held up by numerous support cables. Once the arch halves were completed the cables were slowly released to bring the two halves of the arch together. This was finalised on the afternoon of 19 August 1930. Ennis and four associates personally witnessed this whilst standing on top of the bridge. Following a parting that occurred due to the contracting of metal in the evening, the ends were rejoined at 10 pm, and have remained joined since then. The support cables were then surplus to the design and removed. They were subsequently used to provide the support cables for the Walter Taylor Bridge, over the Brisbane River in the western suburbs of Brisbane, Queensland. The road and the two sets of tram and railway tracks were completed in 1931. Power and telephone lines, and water, gas and drainage pipes were also all added to the bridge in that year. On 19 January 1932, the first test train, a steam locomotive, safely crossed the bridge. About 90 others also crossed the bridge in the months that followed as part of a series of tests to ensure the bridge's safety. The construction worksheds were demolished after the bridge was completed, and the land that they were on is now occupied byLuna Park and the North Sydney Swimming Pool. The standards of industrial safety during construction were poor by today's standards. Sixteen workers died during construction,[6] but surprisingly only two from falling off the bridge. Several more were injured from unsafe working practices undertaken whilst heating and constructing its rivets, and deafness experienced by many of the workers in later years was blamed on the project. The total financial cost of the bridge was $10 million (double the original quote). This was not paid off in full until 1988. 

Opening
De Groot declares the Bridge open. The bridge was formally opened on 19 March 1932. Amongst those who attended and gave speeches were the State Governor, Sir Philip Game, the Minister for Public Works, and Ennis. The Premier of NSW, Labor politician Jack Lang, was to open the bridge by cutting a ribbon at its southern end. However, just as he was about to do so, a man in military uniform moved forward on horseback and slashed the ribbon with a sword, declaring the bridge open //"in the name of His Majesty the King and all the decent citizens of NSW."// [//citation needed//] He was promptly arrested. The ribbon was hurriedly retied and Lang performed the official opening ceremony. After he did so, there was a 21-gun salute and a RAAF flypast. The intruder was identified as Francis de Groot. He was convicted of offensive behaviour (he was fined £5) after a psychiatric test proved he was sane. He was a member of a right-wing paramilitary group called the New Guard, opposed to Lang's leftist policies and resentful the fact that King George V hadn't been asked to open the bridge. De Groot was not a member of the regular Army but his uniform allowed him to blend in with the real cavalry. This incident was one of several that Lang had with the New Guard in that year. A similar ribbon-cutting ceremony on the bridge's northern side by North Sydney's mayor, Alderman Primrose, was carried out without incident. It was later discovered that Primrose was also a New Guard member, but his role in and knowledge of the de Groot incident, if any, are unclear. A message from a primary school in Tottenham, 340 miles (550 km) away in rural NSW, arrived at the bridge on the day and was presented at the opening ceremony. It had been carried all the way from Tottenham to the bridge by relays of school children, with the final relay being run by two children from the nearby Fort Street Boys' and Girls' schools. A picture from a Commemorative brochure Other features of the opening ceremony included a vast display of floats and marching bands — one quite remarkable by Depression standards. The public was allowed to walk on the highway. There had been numerous preparatory arrangements. On 14 March 1932, three postage stamps were issued to commemorate the imminent opening of the bridge. One of these stamps, with a face value of five shillings, is worth several hundred dollars today. Several songs were also composed in advance for the occasion. These have now been largely lost or forgotten. The bridge itself was regarded as a triumph over Depression times, earning the nickname "the Iron Lung ", as it kept many Depression-era workers employed. The bridge has been the site of 40 suicides, many of which took place within months of the bridge's opening, during the Great Depression. [//citation needed//] 

Road
From the Sydney CBD side, motor vehicle access to the bridge is normally via Grosvenor Street, Clarence Street, Kent Street, the Cahill Expressway, or the Western Distributor. Drivers on the northern side will find themselves on the Warringah Freeway, though it is easy to turn off the freeway to drive westwards into North Sydney or eastwards to Neutral Bay and beyond upon arrival on the northern side. The Bridge originally only had four wider traffic lanes occupying the central space which now has six, as photos taken soon after the opening clearly show. The width of the lanes now is so small that buses passing each other in adjacent lanes do so a few inches apart. In 1958, tram services across the bridge were withdrawn and the tracks replaced by two extra road lanes; these lanes are now the leftmost southbound lanes on the bridge and are still clearly distinguishable from the other six road lanes. Lanes 7 and 8 now connect the bridge to the elevated Cahill Expressway that carries traffic to the Eastern Distributor. In 1988, work began to build a tunnel to complement the bridge. It was determined that the bridge could no longer support the increased traffic flow of the 1980s. The Sydney Harbour Tunnel was completed in August 1992. It is intended only for use by motor vehicles. Before it was officially opened for use, the tunnel was made open for pedestrian access, with people on that day able to walk down the tunnel's roadway. The Bradfield Highway is designated as a Travelling Stock Route which means that it is permissible to herd livestock across the bridge, but between midnight and dawn, and after giving notice of intention to do so. In practice, because of efficient methods of rail and road transport, and the relocation of the abattoirs and markets, such an event has not taken place for about fifty years. 

Tidal flow
Southern approach to the Sydney Harbour Bridge, showing the overhead lane marker gantries The bridge is equipped for tidal flow operation, permitting the direction of traffic flow on the bridge to be altered to better suit the morning and evening rush hours traffic patterns. The bridge has eight lanes in total, numbered one through eight from west to east. Lanes three, four and five are reversible. One and two always flow north. Six, seven and eight always flow south. The default is four each way. For the morning rush hour, the lane changes on the bridge also require changes to the Warringah Freeway, with its inner western reversible carriageway directing traffic to the bridge lane numbers three and four southbound. The bridge has a series of overhead gantries which indicate the direction of flow for each traffic lane. A green arrow pointing down to a traffic lane means the lane is open. A flashing red 'X' indicates the lane is closing, but is not yet in use for traffic travelling in the other direction. A red 'X' means the lane is in use for oncoming traffic. This arrangement was introduced in the 1990s, replacing a slow operation where lane markers were manually moved to mark the centre median. It is possible to see odd arrangements of flow during night periods when maintenance occurs, which may involve completely closing some lanes. Normally this is done between midnight and dawn, due to the enormous traffic demands placed on the bridge outside these hours. 

Tolls
Misty evening in the early 1980s There is currently a toll of $2.00 now ,for all vehicles headed into the CBD (southbound). There is no toll for northbound traffic (though taxis traveling north may charge passengers the toll in anticipation of the toll the taxi must pay on the return journey). There are toll plazas at the northern and southern ends. The two eastern lanes (which continue over the Cahill Expressway at the southern end of the bridge) have their tollbooths at the northern end, while the other southbound lanes (for CBD traffic) are serviced by tollbooths at the southern end of the bridge. There is a bridge-long median strip between lanes 6 and 7 to separate traffic which has already paid the toll (at the northern end) from other southbound traffic (which must pay the toll at the southern end). The toll was originally placed on travel across the bridge, in both directions, to recoup the cost of its construction. This cost was recovered in the 1980s, but the toll has been kept (indeed increased) by the State Government's main roads infrastructure department (the RTA) to recoup the costs of the Sydney Harbour Tunnel. After the decision to build the Sydney Harbour Tunnel was made in the early 1980s, the toll was increased (from 20 cents to $1, then to $1.50, and finally to $2 by the time the Tunnel opened) to pay for its construction. The Tunnel also had an initial toll of $2 southbound. After the increase to $1, the concrete barrier on the Bridge separating the Bradfield Highway from the Cahill Expressway was increased in height, because of the large numbers of drivers crossing it illegally from lane 6 to 7, in order to avoid the toll. The Toll for all southbound vehicles was increased to $3 in March 2004. Originally it cost a car or motorcycle six pence to cross, a horse and rider being three pence. Use of the bridge by bicycle riders (provided that they use the cycleway) and pedestrians is free. Later governments capped the fee for motorcycles was capped at one-quarter of the passenger vehicle cost, but is once again the same as the cost for a passenger vehicle. 

Pedestrians
Sydney Harbour Bridge from the Northwest Pedestrian access from the northern side involves climbing an easily-spotted flight of stairs at Milsons Point. Pedestrian access on the southern side is more complicated, but signposts in the Rocks area now direct pedestrians to the long and sheltered flight of stairs that leads to the bridge's southern end. These stairs are located near Gloucester Street and Cumberland Street in the Sydney Rocks area. The bridge can also be accessed from the south by getting on Cahill Walk, which runs along the Cahill Expressway. Pedestrians can access this walkway from Circular Quay by a flight of stairs, or a lift, alternately it can be accessed from the Botanical Gardens. 

Rail
The bridge lies between Milsons Point and Wynyard railway stations, located on the north and south shores respectively, with two train lines running along the western side of the bridge. Milson's Point station is part of the North Shore line. In 1958, tram services across the bridge were withdrawn and the tracks they had used were removed and replaced by two extra road lanes; these lanes are now the leftmost southbound lanes on the bridge and are still clearly distinguishable from the other six road lanes. The original ramp that took the trams into their terminus in the underground Wynyard railway station is still visible at the southern end of the main walkway under lanes 7 and 8 although the tunnels have been sealed off. Maintenance crew painting the bridge

Maintenance
In 2006, the first complete repainting for many years commenced. A reason for the decision was the concern that weight of the many layers of paint acquired over the years might be having a destructive effect on the bridge's structure. Because of the previous regime of continuous maintenance painting with lead-based paint, precautions had to be taken to prevent falling paint from contaminating the harbour. This required that each section being painted be sealed off and blasted to remove old paint, then extracted by vacuum. 

Tourism
The New South Wales and Australian flags respectively on top of the Harbour Bridge The South-east pylon for many years operated as lookout and tourist attraction for Sydney, containing a number of telescopes and antiquated arcade games which operated on pennie s, long after that currency had gone out of operation. The couple that ran this tourist venue also kept a number of white cats which gave the interior of the pylon a memorable odour. The pylon has recently been renovated and returned to its tourist function.[7] Since 1998, BridgeClimb[8] has made it possible for tourists to climb the southern half of the bridge. Tours run throughout the day, from dawn to dusk and are only cancelled for electrical storms or high wind. Night climbs are also available. Groups of climbers are provided with protective clothing appropriate to the prevailing weather conditions and are given an orientation before climbing. During the climb, attendees are secured to the bridge by a wire lifeline. Each climb begins on the eastern side of the bridge and ascends to the top. At the summit, the group crosses to the western side of the arch for the descent. Each climb is a three-and-a-half-hour experience. In December 2006, BridgeClimb[9] launched an alternative to climbing the upper arches of the bridge. The Discovery Climb allows climbers to ascend the lower chord of the bridge and view its internal structure. From the apex of the lower chord, climbers ascend a massive staircase to a platform at the summit. The cost for the climbing excursion is $179-295 AUS and there are some restrictions in place. Visitors are not allowed to bring their own cameras or any other personal gear with each person even being required to go through a metal detector and take an alcohol-breath test, however the authority in charge takes photos which are available to those who climb it. 

[edit] Celebrations Of The Harbour Bridge
Since the opening, the bridge has been the focal point of much tourism and national pride. In 1982, the bridge celebrated the 50th anniversary of its opening. Once again, the bridge was closed to vehicles and pedestrians allowed full access for the day. The celebrations were attended by Edward Judge, who represented Dorman Long. Australia's bicentennial celebrations on 26 January 1988 attracted large crowds in the bridge's vicinity as merrymakers flocked to the foreshores in order to view the events on the Harbour. The highlight was the biggest parade of sail ever held in Sydney, with square-riggers from all over the world, surrounded by hundreds of smaller craft of every description, passing majestically under the Sydney Harbour Bridge. The day's festivities culminated in a fireworks display in which the bridge was the focal point of the finale, with fireworks streaming from the arch and roadway. This was to become the pattern for later firework displays. During the millennium celebrations in 2000, the Sydney Harbour Bridge was lit up with the word "Eternity", as a tribute to the legacy of Arthur Stace a Sydney artist who for many years inscribed that word on pavements in chalk in beautiful Copperplate writing. The Olympic fireworks in 2000 In May 2000 the bridge was closed to vehicular access for a day to allow a special reconciliation march — the "Walk for Reconciliation" — to take place. This was part of a response to an Aboriginal Stolen Generation inquiry, which found widespread suffering had taken place amongst Australian Aboriginal children forcibly placed into the care of white parents in a little-publicised state government scheme. A large number of Australians walked the bridge in a symbolic gesture of crossing a divide. During the Sydney 2000 Olympics in September and October 2000, the bridge was adorned with the Olympic Rings. It was included in the Olympic torch's route to the Olympic stadium. The men's and women's Olympic marathon events likewise included the bridge as part of their route to the Olympic stadium. A massive fireworks display at the end of the closing ceremony ended at the bridge. The East-facing side of the bridge has been used several times since as a framework from which to hang static fireworks, especially during the elaborate New Year's Eve displays. In 2005 Mark Webber drove a Williams-BMW Formula One Car across the bridge. Walkers on the Sydney Harbour Bridge's 75th Anniversary with LED caps.

[edit] 75th anniversary
In 2007, the 75th anniversary of its opening was commemorated with an exhibition at the Museum of Sydney, called "Bridging Sydney" [4]. An initiative of the Historic Houses Trust, the exhibition features dramatic photographs and paintings with rare and previously unseen alternative bridge and tunnel proposals, plans and sketches. On 18 March 2007, the Sydney Harbour Bridge celebrated its 75th anniversary. The occasion was marked with a ribbon-cutting ceremony by the Governor of New South Wales, Marie Bashir and the Premier of NSW, Morris Iemma. The bridge was subsequently open to the public to walk southbound from Milsons Point or North Sydney. Several major roads, mainly in the CBD were closed for the day. An Aboriginal smoking ceremony was held at 7pm. Approximately 250,000 people (50,000 more than were registered) took part in the event. Bright yellow souvenir caps were distributed to walkers. A series of speakers placed at intervals along the bridge formed a sound installation. Each group of speakers broadcast sound and music from a particular era (eg. King Edward VIII 's abdication speech; Gough Whitlam speech at Parliament House in 1975 ), the overall effect being that the soundscape would "flow" through history as walkers proceeded along the bridge. A light show began after sunset and continued late into the night, where the bridge was bathed in constantly-changing, multi-coloured lighting, designed to highlight structural features of the bridge. In the evening the bright green caps were replaced by orange caps with a small, bright LED attached. The bridge was closed to walkers at about 8:30 PM. 

[edit] New Year's "Bridge Effect"
//Main article: Sydney Harbour New Years Eve Fireworks // As part of the fireworks display on New Year's Eve each year since 1998, the Sydney Harbour Bridge has what is referred to coloquially as the "Bridge Effect", in which a light display on a framework is used to complement the fireworks. As the scaffolding and framework are clearly visible for some weeks before the event, revealing the outline of the design, there is much speculating as to how the effect is to be realised. The effects have been as follows: 
 * 1998-99 - Smiley face with hair.
 * 1999-2000 - "Eternity" in Copperplate writing, in honour of Arthur Stace
 * 2000-01 - Rainbow Serpent and Federation Star.
 * 2001-02 - Uluru
 * 2002-03 - Dove of Peace
 * 2003-04 - Light show
 * 2004-05 - Disco ball
 * 2005-06 - Love Heart (3 concentric love hearts with lights behind the middle)
 * 2006-07 - Coathanger and a diamond to celebrate the bridge's 75th anniversary or Diamond Jubilee in 2007.
 * 2007-08 - An Hourglass.

[edit] Gallery
Walkers on the Sydney Harbour Bridge || The Bradfield Highway from a car driving north across the bridge. || Seen from the Rocks. A climbing party is visible near the top. || Sydney Harbour Bridge as viewed from east Circular Quay. || Sydney Harbour Bridge as viewed from Kirribilli on the North Shore. || Sydney Harbour Bridge as viewed from the Sydney Opera House. ||
 * [[image:http://upload.wikimedia.org/wikipedia/en/thumb/7/7b/P3180120.JPG/120px-P3180120.JPG width="120" height="90"]]
 * [[image:http://upload.wikimedia.org/wikipedia/commons/thumb/e/ea/Sydney_Harbour_Bridge_night.jpg/120px-Sydney_Harbour_Bridge_night.jpg width="120" height="27"]]