Bronx–Whitestone Bridge

40.8011125 - 73.8292316Koordinaten: 40 ° 48 '4 " N, 73 ° 49' 45.2 " W

F1

Interstate 678

River East

The Bronx - Whitestone Bridge (often just Whitestone Bridge or colloquially simply Whitestone ) is a suspension bridge over the East River in New York City, which connects the Bronx with the districts of Whitestone and Malba in the borough of Queens on Long Iceland. It is next to the Triborough Bridge / RFK Bridge and the Throgs Neck Bridge one of the three bridge connections between Queens and the Bronx.

Traffic

The six-lane road bridge is part of Interstate 678 at the John F. Kennedy International Airport starts in the south, at Flushing Meadows Park and LaGuardia Airport is not far away passes, as Whitestone Expressway leads to the bridge and on the other side in the Cross Bronx Expressway and the Bruckner Expressway ends and as Hutchinson River Parkway continues to the north. Like most major bridges in New York is also the Bronx - Whitestone Bridge toll.

Description

The planned Othmar Ammann of Bronx - Whitestone Bridge is recognizable even from a distance at her, reduced to the essential elements of a suspension bridge design. The sleek, high steel pillars of the pylons are only connected at its upper end and under the bridge deck by arches of smooth steel plates. The hanging on barely discernible track ropes thin bridge deck oscillates with a slight curve from one bank to another. The bridge deck is measured from anchor block to anchor block 1149 m ( 3770 ft) long and has a clear height of 47 m (157 ft) above MHW.

The Bronx - Whitestone Bridge is a classic example of its time, as suspension bridges under the influence of Deflektionstheorie and cost pressures getting slimmer, have been used less material and therefore cost less, a development that a year later with the construction of the Tacoma Narrows bridge its peak and with their collapse was a temporary end.

The 115 m ( 377 ft) meter high pylons were first assembled from prefabricated elements in a steel box-girder construction.

The two carrying cables having a diameter of 53.3 cm (21 inches) and each consist of 9842 galvanized steel wires, which are summarized in the air spinning process to 37 strands of each 266 wires in a hexagonal profile, is pressed by the hydraulic cable presses to round support cables and then to prevent corrosion were jacketed. They are mounted in large, concrete anchor blocks that get their distinctive appearance in that their top of the curvature of the downwardly bent suspension cable follows.

The six-lane bridge deck has today ( 735 ft ) in the center hole a span of 701 m (2300 ft ) and 224 m above the side openings. The stiffening girder from solid-wall media is only 3.35 meters high and has a width of 24 m (77 ft). However, the ratios of height of the beam to the span of about 1:209 and width of the beam to the span of around 1:30 are far cheaper than at the longer and narrower Tacoma Narrows Bridge.

The bridge still has the eight stay cables, in 1940 stretched from the pylon tips for track support. The stiffening girder vibration absorbers were installed in 1986. The 1946 attached high truss were removed in 2003. On the sides of the stiffening beam 2.44 m high, wedge-shaped panels made ​​of GRP But were aerodynamically calculated, added.

History

Robert Moses, head of the Triborough Bridge Authority, called for a further bridge over the East River after the 1936 was opened Triborough Bridge soon overloaded. In addition, the new airport should (today's La Guardia Airport ) receive a motorway connections to the north and finally had the 1939 New York World's Fair in Flushing Meadows Park obtain a sufficient connection. The final decision to build the bridge by the Triborough Bridge Authority (TBA ) was adopted in April 1937. Othmar Ammann, the chief engineer of both the Port Authority and the TBA, was responsible for the planning and execution of the bridge. That he selected ( with advisory support from Leon S. Moisseiff, the leading representative of the Deflektionstheorie ) flat bridge deck was not only beautiful to look at than the previous truss and to build faster, it has also saved approximately $ 2 million and enabled the drivers ( the then higher still sat in their vehicles than today ) the views of the East River. Ammann there to finish the bridge in a construction time of only 23 months, so that they could be opened on April 29, 1939, one day before the start of the World's Fair, succeeded. She had at that time a total of four lanes and on both sides of a walkway.

Half a year before David B. Steinman's Thousand Islands Bridge was opened two months later followed his Deer Isle Bridge, the vibrations caused by wind were at that time not to explain, but could be limited by Steinman by cable- tension. The collapse of the Tacoma Narrows Bridge in November 1940 was a surprise to the professional world, aroused in the audience but doubts about the safety of the novel suspension bridges. Although Othmar Ammann insisted that his Bronx - Whitestone Bridge, despite occasional slight vibrations was sure Robert Moses said, however, that it is not arriving at the opinion of the competent engineer, but on the fears of motorists who may steer clear of the bridge and thus the would reduce revenue. Therefore, eight stay cables were clamped soon after that should prevent major vibrations. 1946 also installed one large truss to stiffen the bridge deck. Of this amount, the walkways, so that six lanes could be established. Nevertheless, in severe storms occurred more significant oscillations.

In 1998 the bridge by the Alan G. Davenport Wind Engineering Group of the University of Western Ontario was equipped with sensors to determine how the wind affects the bridge. A model of the bridge has been studied in the local wind tunnel. At Lehigh University, a prototype of the proposed new bridge deck was built and tested in long load tests. As a result, this led to the removal of the truss and install the aerodynamic GRP lining of the side surfaces. In addition, the original concrete pavement has been removed and replaced by an orthotropic plate, which is provided with an epoxy resin - sand mixture as a roadbed. These measures have led to the bridge has survived the hurricane Sandy in October 2012 without damage and without special vibrations.