Brooklyn Bridge

2018. Photo by Lewis Firman

2018. Photo by Lewis Firman

in New York

Brooklyn Bridge is a hybrid cable-stayed/suspension bridge, crossing the East River to connect Manhattan and Brooklyn.

Main span 1,595.5 feet (486.3 m).

It was originally called the New York and Brooklyn Bridge, and the East River Bridge. Formally named 'Brooklyn Bridge' in 1915.

The bridge was conceived by German immigrant John Augustus Roebling. He had previously designed and constructed shorter suspension bridges, including the Delaware Aqueduct and the John A. Roebling Suspension Bridge between Cincinnati, Ohio, and Covington, Kentucky. However he died in 1869 following an accident, and his 32-year-old son Washington A. Roebling took charge of the project.

During construction, many workers suffered from the bends, then known as "caisson disease", and Washington Roebling himself succumbed in January 1870, leaving him unable to physically supervise the site work. He then had to supervise the project from his apartment, supported by his wife Emily Warren Roebling. She embarked on intensive civil engineering studies, and for 11 years paid a key role in supervising the bridge's construction.

The above information is condensed from the Wikipedia entry.

Described in 'The Engineer' in 1883, from which: Deck is 85 or 88 ft wide, 135 ft clear above water at 90degF. Four main cables, each 15.75" outside dia, comprised of 5282 galvanised steel wires. The wires were formed into 19 'ropes' of 278 wires. Each main cable anchorage weighs 60,000 tons. 110 reported cases of 'caisson disease'.

J. A. Roebling's Previous Bridges

To put Brooklyn Bridge in historical and size context, Roebling's bridges are listed in chronological order (based on the excellent Wikipedia entry for John. A. Roebling, accessed 1 March 2018). Additional detail from 'A Span of Bridges'.

Note that five of the suspension bridges in the list were aqueducts.

'The Shaky Bridge' near the Trenton Water Filtration Plant. Span c.20 feet [6 m]. Demonstration project.

'Demonstration Bridge' spanning two buildings of the former Roebling Plant, Trenton, NJ.

1844 Allegheny Aqueduct Bridge – Pittsburgh; 162 feet (49 m) spans; demolished 1861 when canal abandoned. Timber flume. Utilised existing piers. Two suspension cables, eah with 1900 iron wires 1/8" diameter.

1846 Smithfield Street Bridge – Pittsburgh; Eight spans each of 188 feet (57 m). Cost constraints require re-use of old, narrow piers. Cast iron towers. Two cables for each span, 4½" dia. 750 wires of 1/6" diameter in each. Well-sized stiffening girders. Also had inclined stays radiating from top of towers. Replaced 1881–1883

1848 Lackawaxen Aqueduct – spanning the Lackawaxen River at Lackawaxen, Pennsylvania; two spans of 115 feet (35m) each, two 7-inch (18 cm) cables; no longer extant.

1849 Roebling's Delaware Aqueduct – spanning the Delaware River from Lackawaxen, Pennsylvania to Minisink Ford, New York, four spans of 134 feet (41 m) each, two 8-inch (20 cm) cables; converted to vehicular and pedestrian use, restored in 1965 and 1995

1850 High Falls Aqueduct – one span of 145 feet (44 m), two 8½-inch (22 cm) cables.

1850 Neversink Aqueduct – spanning the Neversink River; one span of 170 feet (52m), two 9½-inch (24 cm) cables

1854 Niagara Falls Suspension Bridge – spanning the Niagara River from Niagara Falls, New York to Niagara Falls, Canada. At 821 feet (250 m) its span was much greater than Roebling's previous bridges. Four main cables, 10 1/4" dia, each having 3640 iron wires from Richard Johnson. Note: Charles Ellet, a rival to Roebling, had built the first bridge to span over 1000 ft (Wheeling bridge, 1010 ft). This soon collapsed.

1859 Allegheny Bridge – Pittsburgh; 344-foot (105 m) spans

1866 John A. Roebling Suspension Bridge – spanning the Ohio River from Cincinnati, Ohio to Covington, Kentucky; 1,057 feet (322 m) long with a deck clearance of 100 feet (30 m).

Note that Roebling was succeeding at a time when failures of suspension bridges were by no means rare.

See Also

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