Monday, March 19, 2012

Happy Birthday to the "Coathanger"

Happy 80th Birthday to the Sydney Harbour Bridge

Official name              Sydney Harbour Bridge
Carries                        Trains, Motor vehicles, pedestrians and bicycles
Crosses                      Port Jackson
Locale                        SydneyAustralia
Design                        Through arch bridge
Total length                1,149 m (3,770 ft)
Width                        49 m (161 ft)
Height                       134 m (440 ft)
Longest span             503 m (1,650 ft)
Clearance below       49 m (161 ft) at mid-span
Construction begin    28 July 1923
Construction end      19 January 1932
Opened                   19 March 1932
Coordinates             33°51′08″S151°12′38″E

The Sydney Harbour Bridge is a steel through arch bridge across Sydney Harbour that carries rail, vehicular, bicycle 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 nicknamed "The Coat hanger" because of its arch-based design.

Under the directions of Dr J.J.C. Bradfield of the NSW Department of Public Works, the bridge was designed and built by British firm Dorman Long and Co Ltd of Middlesbrough (who based the design on their 1928 Tyne Bridge in Newcastle upon Tyne) and opened in 1932.

Sydney Harbour from the air, showing the Opera House, the CBD, Circular Quay, the Bridge, the Parramatta River, North Sydney and Kirribilli in the foreground

According to the Guinness World Records, it is the world's widest long-span bridge. It is also the fifth longest spanning-arch bridge in the world, and it is the tallest steel arch bridge, measuring 134 metres (440 ft) from top to water level.

Until 1967 the Harbour Bridge was Sydney's tallest structure.

An estimated 469 buildings on the north shore, both private homes and commercial operations, were demolished in order to allow construction to proceed, with little or no compensation being paid. Work on the bridge itself commenced with the construction of approaches and approach spans, and by September 1926 concrete piers to support the approach spans were in place on each side of the harbour.

The south-eastern pylon containing the tourist lookout,. Both pylons were made of granite quarried at Moruya, NSW

As construction of the approaches took place, work was also started on preparing the foundations required to support the enormous weight of the arch and loadings. Concrete and granite faced abutment towers were constructed, with the angled foundations built into their sides

Sydney Harbour Bridge under construction

Once work had progressed sufficiently on the support structures, a giant' creeper crane' was erected on each side of the harbour.

The arch being constructed. Courtesy, State Library of New South Wales

Once the arch was completed, the creeper cranes were then worked back down the arches, allowing the roadway and other parts of the bridge to be constructed from the centre out. The vertical hangers were attached to the arch, and these were then joined with horizontal crossbeams. The deck for the roadway and railway were built on top of the crossbeams, with the deck itself being completed by June 1931, and the creeper cranes were dismantled. Rails for trains and trams were laid, and road was surfaced using concrete topped with asphalt. Power and telephone lines, and water, gas, and drainage pipes were also all added to the bridge in 1931.

HMAS Canberra sailing under the completed arch from which the deck is being suspended in 1930

(Note: HMAS Canberra was sunk during the battle of Savo Island, in the Pacific theatre of war on August 8–9, 1942. As HMAS Canberra’s guns took aim at the Japanese, Chōkai and Furutaka opened fire on her, scoring numerous hits within a few seconds. Aoba and Kako joined in with gunfire, and within the next three minutes Canberra took up to 24 large caliber hits. Early hits killed her gunnery officer, mortally wounded her captain (Getting), and destroyed both boiler rooms, knocking out power to the entire ship before Canberra could fire any of her guns or communicate a warning to other Allied ships.)

The roadway of the bridge, (below) from the southern or city approach. From left: walkway, eight traffic lanes (the two leftmost once carried the Sydney trams), two railway tracks, and cycleway. The gantries with lights controlling traffic tidal flow are clearly visible, while the tollbooths can be seen near the bases of the high-rise buildings.

A popular tourist attraction, you can climb the bridge on organised tours. All climbers are required to wear a special ‘jump suit’ and are provided with protective clothing appropriate to the prevailing weather conditions and are given an orientation briefing 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.
Bridge Climb participants, wearing the mandatory special jumpsuits 
In December 2006, Bridge Climb 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 staircase to a platform at the summit.

Bridge Climbers admire the view mid-climb, while a second group reach the top of the arch.


momto8 said...

thanks! my daughter is studying engineering in college and learning to build bridges....she LOVES this stuff!!

Cro Magnon said...

Lady Magnon will be there in a week; she loves the bridge, but mostly she loves the ferries.

JohnD said...

It's a beautiful structure and the Blue Granite for the pylons is amongst the hardest granite in the world and was quarried at Moruya (on the coast and not far from here) and ferried up the coast on barges. I did my 'Industrial Archeology' study at the old quarry and wharves on the Moruya River.