Archives and Special Collections, College of Staten Island, CUNY
Title: Arches of Steel, picture of Verrazano Narrows Bridge

| home | the narrows | from transportation asset to barrier | winning support for the bridge |
| construction | dedication | assessment | image gallery | bibliography | credits |

CONSTRUCTION

Designer of the Bridge

The designer of the Verrazano-Narrows Bridge, Othmar Hermann Ammann (1879-1965) was a graduate of the Federal Polytechnic Institute in Zurich (1902), who immigrated to the United States in 1904 and became a naturalized citizen in 1924. An authority on bridges, he also designed the George Washington, Bayonne, Triborough, Throgs Neck, and Bronx-Whitestone bridges.

Image of Othmar Ammann and Robert Moses

Othmar H. Ammann, left, with Triborough Bridge and Tunnel Authority Chairman Robert Moses on October 10, 1961, the day the first steel was erected for the Staten Island tower.
MTA Bridges and Tunnels Special Archive

Components of a Suspension Bridge

The deck - carries traffic
The cables - support the deck
The tower foundation - support the towers
The anchorages - hold the ends of the cables in place

The Deck

To form the deck, sixty seperate chunks of steel, each the size of a ten-room ranch house and weighing four hundred tons, had to be lifted 220 feet in the air to link the 6,690 foot span. Each steel piece, in addition to several smaller ones, would be linked to the suspender ropes dangling from the cables and would finally be linked together horizontally across the water. Seasonal contractions and expansions of the steel cables cause the double-decked roadway to be 12 feet lower in the summer than in the winter.

Image of the bridge deck with construction workers
MTA Bridges and Tunnels Special Collection, 1990.

 

image of the bridge deck from below
Library of Congress, HAER, NY 24-Brok, 57-23

The Cables

The central element in any suspension bridge are the cables. The four cables of the Verrazano-Narrows Bridge weigh 39,192 tons. To create the cables, 26,108 wires were carried across the Narrows. Each wire had a specific location side by side and one on top of the other and a specific tension. The cable work took from March 4, until August 22, 1963 and involved 600 men working 71/2 hour days, five days per week. After the cables were compacted and banded they measured 35 7/8 inches in diameter and could sustain a minimum of 220,000 pounds per square inch.

image of the cables being spun
MTA Bridges and Tunnels Special Collection, 1990.

 

The Towers

The 4,260-foot distance between the Verrazano-Narrows Bridges towers is so far that compensation for the curvature of the earth was necessary. The monumental 693-foot high towers are 1 and 5/8 inches farther apart at their tops than at their bases. Each tower weighs 27,000 tons and is held together with three million rivets and one million bolts.

image of one bridge tower being constructed
MTA Bridges and Tunnels Special Collection, 1990.

 

 

 
image of the bridge tower, completed, with cables and deck
Library of Congress, HAER, NY, 24-Brok, 57-11

The Tower Foundations

On the Staten Island side, the tower foundations lie 105 feet below mean high water. Before construction could begin, sand islands were built to serve as working areas. On the islands, steel-and-concrete open-dredge caissons with 66 circular wells, each 17 feet in diameter, were constructed. The massive caisons, each measuring 129 by 229 feet, were sunk to rest at depths beneath the bay bottom at which the soils had been predetermined to be weaight-bearing. Atop tha caissons, the tower pedestrals were built.

image of construction of the tower foundations.
MTA Bridges and Tunnels Special Collection, 1990.

| home | the narrows | from transportation asset to barrier | winning support for the bridge |
| construction | dedication | assessment | image gallery | bibliography | credits |

Archives & Special Collections
College of Staten Island, CUNY
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Copyright 2005 College of Staten Island, Archives & Special Collections