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Throggs Neck Bridge

Unlike many bridges proposed by Robert Moses, the Throgs Neck Bridge was not part of the circumferential highway network proposed in 1929 by the Regional Plan Association (RPA). With the postwar era dawning, Moses proposed a series of new bridges and connecting expressways to meet anticipated growth in vehicular traffic. One proposal in his 1945 plan had a "Throgs Neck" span situated two miles east of the Bronx-Whitestone Bridge.
Although Moses received a windfall from his Triborough Bridge and Tunnel Authority (TBTA), he needed additional Federal and state funds to fulfill his ambitious plans. Unlike his earlier arterial proposals, he received neither immediate funding nor unanimous support. The turning point came in the mid-1950's, when the Federal Bureau of Public Roads (BPR) expressed interest in building the Interstate highway system. Believing that he could obtain Federal and state funds for his arterial proposals, some of which had been shelved for years, Moses pitched a joint plan developed by the TBTA and the Port of New York Authority before the BPR.

In 1955, the Joint Study of Arterial Facilities, which was chaired by Moses, recommended a new crossing at the mouth of the East River between Bayside, Queens and Fort Schuyler in the Bronx. The specifications were as follows:

The recommended crossing would be a six-lane suspension bridge. The center of the structure would be 3,100 feet long and the side spans each 900 feet long. Including anchorages, the bridge would extend 5,200 feet. The low ground on both the Bronx and Queens sides of the East River calls for long approach viaducts - 3,900 feet long in the Bronx and 2,800 feet long in Queens. It is estimated that the Throgs Neck Bridge could be completed within three and one-half years after it is financed.

According to the Joint Study, the Throgs Neck Bridge project would include construction of the Clearview and Throgs Neck expressways, and extensions of the Cross Bronx Expressway.

By the time the Joint Study was released, nearby East River crossings were already operating at or above capacity. Annual traffic volume on the Triborough Bridge had exceeded 38 million vehicles, while that on the Bronx-Whitestone Bridge neared 30 million vehicles. After vigorous opposition from community groups on both sides of the East River, construction on the new bridge began in 1957.


DESIGN AND CONSTRUCTION:

Once again, Moses commissioned Othmar Ammann for bridge design work. In approaching the design of his first long-span suspension bridge since the Tacoma Narrows Bridge disaster, Ammann was fully aware of public fears about deck movement. For the Throgs Neck Bridge, he employed a more conservative design. In many respects, the design of the Throgs Neck Bridge is similar to that of the retrofitted Bronx-Whitestone Bridge two miles to the west.
The Throgs Neck Bridge was designed with a 28-foot-deep stiffening truss. The raising of the deck began at each tower and proceeded simultaneously toward mid-span and the approach roads. The single-deck structure carries six lanes of vehicular traffic that rest on a series of laterally arranged transverse floor trusses. These transverse trusses are framed into two longitudinal stiffening trusses located in the vertical planes of the suspension cable. A lateral system of stiffening trusses between the top and bottom chords of the truss provides additional bracing. Together, the system of lateral, longitudinal and transverse trusses forms a rigid frame that offers sample resistance to load and wind forces. The concrete pavement rests atop this extensive truss system, providing motorists with unobstructed views of New York City and Long Island Sound.
The two 3,205-foot-long suspension cables support the 1,800-foot main span and two 555-foot side spans (a truncation from the originally planned 3,100-foot main span and 900-foot side spans) some 142 feet over the East River. Each cable, which measures 23 inches in diameter, contains 37 strands of 296 galvanized steel wires. More than 13,000 miles of wire were used in the assembly of the cables.

The anchorages of the Throgs Neck Bridge, like those of the nearby Bronx-Whitestone Bridge, are austere in design. Each of the concrete anchorages, which measure 140 feet wide by 200 feet long by 150 feet high, weighs approximately 170,000 tons.
The approach viaducts to the Throgs Neck Bridge consist of continuous plate-girder spans carried on reinforced concrete piers. Sections of the approaches were constructed off-site in South Plainfield, New Jersey and shipped by rail to Jersey City before they were floated to the site by barge. The approaches consist of 12,357 tons of structural steel. Together, the bridge and approach roads form the shape of a "reverse S." On the Queens side, the TBTA moved 421 homes from the right-of-way of the Clearview Expressway to the site of the Bayside and Oakland golf courses. On the Bronx side, the TBTA obtained a right-of-way easement from SUNY-Maritime at Fort Schuyler in exchange for an adjacent landfill project on their property. Material dredged from the East River for the bridge footings was used for the new landfill.

 

Created By: Joseph Tartaglia 76
Created On: 01/26/2014
Last Update On: 02/14/2014