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“The Old Coat hanger”. The Sydney Harbour Bridge - J. J. C. Bradfield & Ralph Freeman -. Harbour Bridge. 1,650’ Steel Arch Main Span Worlds broadest roadway: 8 lanes, 4 rail lines, 2 walkways World’s 2 nd longest arch bridge when completed
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“The Old Coat hanger” The Sydney Harbour Bridge - J. J. C. Bradfield & Ralph Freeman -
Harbour Bridge • 1,650’ Steel Arch Main Span • Worlds broadest roadway: 8 lanes, 4 rail lines, 2 walkways • World’s 2nd longest arch bridge when completed • Bayonne Bridge main arch span: 1,675’ • Connects northern Sydney to the southern urban center • Considered Sydney’s most famous landmark 2nd to Opera House • Average traffic per day: ~ 160,000 Vehicles
Sydney Harbour Hellgate
Upper Chords • Upper Arch Chord provides virtually no load bearing capacity, only stiffness • Originally designed for upper chord to end within towers as at Hellgate • Architectural consultants decided that visually separating the upper chord from the towers conveys sense of structural independence from the masonry towers
Construction • Each Arch half anchored to abutment... …then cantilevered out with use of “creeper cranes” that traveled along the upper arch chord
Bridge Opening • Bridge opened on Saturday March 19, 1932 by J. T. Lang, Prime Minister of New South Wales • Estimated 300,000 to 1 million people in attendance • Public allowed to walk across roadway deck, an event only repeated on the 50th anniversary of opening • Capt. Francis De Groot of the paramilitary group the New Guard on horseback charged and slashed the ribbon before the bridge could be declared open
Bridge Climb! • Thousands of people take guided “bridge climbs” every year. • In order to make the Bridge Climb you must: • pay around $150 • Remove all loose articles (including cameras) • Be in good physical health and not be pregnant • pass a breathalyzer test.
Summary – The 3 S’s • Social: The public interacts with structure through pylon museum & bridge climb. Bridge tolls payback construction and maintenance costs (current bridge toll $2). Arch form cheapest solution. • Scientific: Largest & 3rd longest steel trussed arch (1650’ span). Load tested with 96 steam locomotives in various configurations. Load transferred to abutments entirely through lower arch chord. • Symbolic: Imitative of Hellgate, but on much larger scale. Massive structural form visually separated from purely decorative masonry towers. An Elegant representation of Sydney’s unity and perseverance through financial depression.