The Sydney Harbour Bridge - J. J. C. Bradfield

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The Old Coat hanger
The Sydney Harbour Bridge - J.
J. C. Bradfield Ralph Freeman -
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Harbour Bridge

• 1,650 Steel Arch Main Span
• Worlds broadest roadway 8 lanes, 4 rail lines,
  2 walkways
• Worlds 2nd longest arch bridge when completed
• Bayonne Bridge main arch span 1,675

• Connects northern Sydney to the southern urban
  center
• Considered Sydneys most famous landmark 2nd to
  Opera House
• Average traffic per day 160,000 Vehicles

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Sydney Harbour
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Other Proposals for the Crossing
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Design bids by Ralph Freeman with Dorman Long
Co.
Design Main Span Cost
Cantilever 1,600 22,200,000
Cantilevered Arch 1,650 18,200,000
Arch 1,650 17,100,000
Pounds Sterling converted to American dollars by 1 4.8665 Table and illustration from April 1932 Civil Engineering Pounds Sterling converted to American dollars by 1 4.8665 Table and illustration from April 1932 Civil Engineering Pounds Sterling converted to American dollars by 1 4.8665 Table and illustration from April 1932 Civil Engineering
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Sydney Harbour
Hellgate
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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

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Upper Chord Differences
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Construction

• Each Arch half anchored to abutment...

then cantilevered out with use of creeper
cranes that traveled along the upper arch chord
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Deck Construction
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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

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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.

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Summary The 3 Ss

• 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 Sydneys unity and
  perseverance through financial depression.

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