The Manhattan Bridge: Steel Cables and a Phased Opening

The Manhattan Bridge is a steel-cable suspension bridge across New York’s East River, connecting Manhattan and Brooklyn and accommodating rail, road, and pedestrian traffic. It formally opened to road traffic on December 31, 1909, while the entrance plaza and rail services developed in subsequent stages.

A 1908 construction report gave the main span as 1,470 feet and the two side spans as 725 feet each, approximately 448 and 221 meters respectively. These dimensions refer to the suspended portion, excluding the approaches extending into the neighborhoods. The design provided for eight tracks, a central roadway, and sidewalks on both sides.

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The New York City Department of Bridges’ 1905 bidding documents included earlier resolutions. In 1898, the Board of Public Improvements asked the bridge commissioner to organize plans, surveys, and depth soundings. A 1899 statement of the scheme also linked the new bridge to streets on both banks. On the Manhattan side, the entrance would be near Canal Street; on the Brooklyn side, the aim was a more direct route toward the junction of Atlantic and Flatbush avenues.

Contemporary arguments specifically identified congestion at the old bridge’s exits and around Fulton Street. The intention was to separate passengers traveling in different directions and shorten journeys to southern and southeastern Brooklyn.

The city ordinance published with the bidding documents provided for the bridge, piers, approaches, and necessary materials and labor to be organized through contracts, awarded by the bridge commissioner to the lowest qualified bidder. The city’s financial officer was to raise construction funds under the relevant resolutions. Public authorities determined the route and review standards, while contractors undertook the fabrication and erection specified in their contracts.

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Several structural schemes were considered during the project. Gustav Lindenthal had advocated suspending the deck from eyebar chains. Wire cables were ultimately adopted, retaining the general combination of steel towers, a suspension system, and stiffening trusses. The 1908 report also explained that the pins originally proposed at the tower bases were omitted, requiring the towers to resist longitudinal bending caused by changes in traffic loading.

Yanev and Gill’s engineering chapter states that Leon Moisseiff performed the redesign calculations under Buck and Nichols, using deflection theory to account for changes in cable geometry under load and reduce unnecessary truss weight. The Department of Bridges later asked Ralph Modjeski to check foundations, cables, trusses, and other issues. The design was thus not put into service on one person’s judgment alone.

The 1908 report described four main cables and four stiffening trusses. Supported by the steel towers, the main cables ran into massive anchorages at both ends, where anchor bars and girders transferred their tension to the masonry. The anchorages consisted of rubble masonry, concrete, and granite facing, while nickel steel was used in parts of the trusses.

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Construction had to proceed amid a busy waterway and established neighborhoods. A report from early 1908 stated that the Brooklyn anchorage was complete, the Manhattan anchorage nearly complete, and the main towers roughly half built. Sections of the steel towers were riveted in the factory, delivered by barge near the tower bases, and lifted with equipment mounted on the towers. As the towers grew, the lifting equipment was raised in stages.

The department’s technical specifications made drawing approval and quality inspection formal requirements. Contractors had to submit detailed construction drawings and plans for equipment and material handling, obtaining the engineer’s approval before proceeding with the relevant work. On completion, they also had to supply record drawings matching the finished structure. The engineer could reject defective materials, with the contractor bearing the cost of correction; failure to identify a defect earlier did not release the contractor from responsibility.

These clauses also reveal the difficulties of site management. Working space could not unduly obstruct adjacent property, street traffic, or other municipal works, and tower and anchorage construction had to be coordinated. Suspenders required both allowances for elongation from temperature and permanent loads and full-size testing.

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The opening at the end of 1909 marked an important stage for road traffic. The engineering history separately dates streetcar service to 1912 and early rapid-transit service to 1915, showing that the different transport modes did not begin operating together. Tracks on the bridge could become actual transport capacity only when connecting lines and operating arrangements beyond the bridge were in place.

Carrère and Hastings designed the monumental entrance on the Manhattan side. The 1975 landmark designation report records preliminary plans in 1910, approval of a fuller plaza scheme in 1912, and construction of the arch and colonnade between 1912 and 1915. The elliptical plaza both directed traffic and made the new bridge a prominent gateway within the city’s public space.

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The New York City Department of Transportation’s official 2001 report records that rehabilitation on the south side included removing old lead-based coatings and replacing some bearings and members beneath the tracks. Paint removal took place within negative-pressure containment, while bearing replacement used temporary jacking and support systems and kept traffic moving. Maintenance, too, was constrained by operating conditions.

The same report distinguishes the ribbon-cutting for the new pedestrian and bicycle path from its actual opening. The ceremony took place in May, while the path opened on June 25 after construction was completed. It reconnected Manhattan’s Chinatown with Downtown Brooklyn.

References: [5]