How the Bridge was Built

How the Bridge was Built. . Considered one of the greatest triumphs of nineteenth-century engineering when it opened in May, 1883, the Brooklyn Bridge was built to provide a suitable all-weather link between the then independent and rapidly growing cities of New York and Brooklyn. The brilliant engineer John Roebling proposed a great suspension bridge, a pioneering structure in its use of steel which would leave the busy East River free of obstruction. When he died in an accident as the bridge was being surveyed, his son Washington was chosen to complete the structure. , Washington was totally disabled in 1872 by caisson disease (the bends) and could never visit the site again. His remarkable wife Emily became his chief administrative aide and enabled Washington to finish the project successfully., 1870 The Bridge Foundation , The majestic towers of the bridge rest on wooden foundations called pneumatic caissons. Each caisson is a giant bottomless chamber which was built on land and slowly sunk to the river bed exactly where the tower was to rise. Inside the chamber, workers excavated debris until firm ground to support the weight of the tower was reached. The caisson was then filled with concrete., 1870 The Tower’s Begun , The stone blocks for the towers were lifted into place by boom derricks and a system of steam pulleys. The weight of the first stone course for the tower caused the caisson to settle to the river bed; the excavation began., 1871 Work in the Caisson , Within each caisson was an elaborate system of air locks and supply shafts. Compressed air was pumped in to keep the river water out. Workers entered the caisson through air locks. Debris was removed through shafts filled with water and carried from the site on scows. Many men fell ill to the bends caused by rapid changes in pressure when leaving the caisson., 1872 The Towers Rise , The towers support the cables and thereby the entire weight of the bridge roadway and traffic. They are constructed of New Jersey limestone and Maine granite, and each rises 272 feet and 6 inches above high water. In 1872 the towers reached the height of the roadway., 1876 The Towers are Joined , Massive stone anchorages on either shore secure the cables and resist their tremendous pull. Each anchorage weighs 60,000 tons and is 89 feet high. Before cable making could begin, the towers were joined by wire rope loops, called “travelers:” these would carry men and material between the anchorages. The first traveler was completed August 14, 1876., August 1876 Frank Farrington , Master-Mechanic Franck Farrington is first to cross East River by a traveler wire., 1877 Preparation for Cable Spinning , All the work on the bridge was done without disturbing traffic in the busy port. When the towers were completed, cable spinning began. Work platforms were supported on wires high above the river and were reached by walkways that ran from anchorage to anchorage over the tops of the towers., 1877 The Carrier Wheels , For the cable spinning wire was looped around a carrier wheel hung from the traveler and pulled across the river from Brooklyn to New York. The system, driven by steam engines, worked like a conveyor belt. Over 14,000 miles of wire were used in the cables., 1877 Cable Spinning , As the wires for the cables were spun in place, workers adjusted them to exact position and make sure all were parallel. When 278 wires were spun, they were bound to form a strand. Nineteen strands formed one cable. The cable stands were bolted to eyebar chains encased in the masonry of the anchorage. An iron anchor plate holds the end of each chain in place. , Each anchor plate weights 23 tons. Eighteen eyebars radiate up from it’s base , Section of cable 15 ¾ inches thick. 19 strands per cable., 1878 Cable Wrapping , John Roebling designed the unique machine used to wrap the cables of the bridge. An iron clamp compressed the strands, forming a cable into a perfect cylindrical arrangement. A wrapping device bound the cable with a tight spiral of soft wire and the cable was then coated with white lead. This process stiffened the cables and protected them from weather., 1881 Suspending the Roadway , The bridge floor is made of steel trusses suspended from the cables by wire rope. At midspan the roadway is 135 feet above the water and allows easy passage of river traffic., May 24, 1883 A Union of Hears and a Union of Hands Finis Coronat Opus. “The finish crowns the work” commemorates the opening of the bridge linking the cities of New York and Brooklyn in 1883. After thirteen years of innovative and courageous effort the exultation was appropriate. In the years following the Civil War this image of success must have been especially poignant and expressive of both spiritual recovery and technological growth. The two cities clasping hands suggests the final consolidation of New York and Brooklyn with other boroughs in 1898., Edward I. Koch, Mayor of the City of New York , Howard Golden, Borough President of Brooklyn , Andrew J. Stein, Borough President of Manhattan , The 1983 Brooklyn Bridge Centennial Commission , The New York City Department of Transportation