The Verrazano Narrows Bridge

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The Verrazano Narrows Bridge

• Othmar Ammanns Greatest Work of Structural Art

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THESIS

• In designing the Verrazano Narrows Bridge, Othmar
  Ammann created his greatest work of structural
  art, combining elegance and simplicity over a
  huge span, with important social and symbolic
  roles.

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SCIENTIFIC ASPECTS

• Steel cable suspension bridge
• Length 4260 ft.
• Height 690 ft.
• Deck thickness ratio 1/180
• Simple stiffening deck truss

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• Caisson construction used to build towers
• Each leg of tower stands on 33 foot concrete
  pier, which remains low profile
• Towers designed slightly further apart at the top
  than at the bottom, due to the curvature of the
  earth
• Towers exhibit simple, clean design
• Only one cross-pieces at the top of the towers,
  no ambiguity

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Massive concrete-housed cable anchorages on
either side of bridge -Not only connect the
cables to the ground, but are used to store and
heat salt and cinders for icy conditions.
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Three Ss Social
SOCIAL ASPECTS

• 12-lane, two level bridge (huge traffic volume)
• Large trucking route connecting NJ to Long Island
• Provides more efficient travel route through New
  York City
• Facilitated development of Staten Island
• Increased business growth and in Brooklyn
• Created a vast number of new jobs on either side,
  effectively starting a Verrazano Bridge industry

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SYMBOLIC ASPECTS

• Longest bridge in North America
• Same impact on Staten Island as Brooklyn Bridge
  had on Brooklyn
• Exceptional slenderness for its length while
  still appearing monumental
• Frames entrance to New York Harbor
• Opening of bridge celebrated with parades,
  parties, and an opening ceremony with thousands
  in attendance

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• Framing the entrance to New York, showing its
  sleekness

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Comparison with Golden Gate

• Towers exhibit architectural quantities,
  ambiguous load path due to the four lateral
  elements
• Original deck of Golden Gate not stiff enough,
  lateral bracing had to be added later, and the
  top deck had to be replaced altogether

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Comparison to George Washington Bridge, also by
Ammann

• GW seems bulkier, not sleek
• Originally designed for stone cladding, current
  design seems either incomplete, or too busy
• Original deck also not stiff enough present
  trusswork added later
• Verrazano nearly twice as long, while
  considerably more slender and better at resisting
  forces

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