An old engraving of a pneumatic caisson that were needed for building the foundations for the piers for the Brooklyn Bridge, New York, USA in the early 1870s. It is from a Victorian book of the 1880s. Opened in 1883, the bridge was the first fixed crossing across the East River. Pneumatic caissons (pressurised caissons), which penetrate soft mud, are bottomless timber boxes, filled with compressed air to keep water and mud out. Workers move debris (muck) from to a pit, connected by a muck tube to the surface. A crane removes this by bucket, to be taken away by barge (right).
An old engraving of a pneumatic caisson that were needed for building the foundations for the piers for the Brooklyn Bridge, New York, USA in the early 1870s. It is from a Victorian mechanical engineering book of the 1880s. Opened in 1883, the Brooklyn Bridge was the first fixed crossing across the East River between Manhattan and Brooklyn. It was also the longest suspension bridge in the world at the time of its opening, with a main span of 1,595 feet (486 m) and a deck 127 ft (38 m) above the water. It was originally called the New York and Brooklyn Bridge or the East River Bridge but was officially renamed the Brooklyn Bridge in 1915. It was designed by John A Roebling. Shallow caissons may be open to the air, whereas pneumatic caissons (pressurised caissons), which penetrate soft mud, are bottomless boxes, usually a massive timber construction as here, sealed at the top and filled with compressed air to keep water and mud out at depth. An airlock allows access to the chamber. Workers, called sandhogs, move mud and rock debris (called muck) from the edge of the workspace to a water-filled pit, connected by a tube (called the muck tube) to the surface. A crane at the surface removes the soil with a clamshell bucket. Here it is being loaded on to a barge (right) for disposal. The Brooklyn side's caisson, built first, originally had a height of feet ( m) and a ceiling composed of five layers of timber, each layer 1 foot ( m) tall. Ten more layers of timber were later added atop the ceiling. The thickness of the caisson's sides was 8 feet ( m) at both the bottom and the top. The caisson on the Manhattan side was slightly different because it had to be installed at a greater depth. To protect against the increased air pressure at that depth, the Manhattan caisson had 22 layers of timber on its roof.
Size: 4252px × 1831px
Location: New York, USA
Photo credit: © M&N / Alamy / Afripics
License: Licensed
Model Released: No
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