Photo Vinny DuPre The Queensboro Bridge looking toward Roosevelt Island and Queens. As the longest bridge spanning the East River, the Queensboro Bridge is also unique for its history and design. On Monday, March 30, Sam Schwartz, president of the New York City Bridge Centennial Commission, announced a week of events, beginning on May 31, to celebrate the 100th birthday of the Queensboro Bridge.

Conceived in 1838 by politicians, business leaders and engineers, the Queensboro Bridge faced numerous obstacles and delays before plans for its construction were finalized in 1901. By that date, the Brooklyn Bridge had been completed (1883) and both the Williamsburg and Manhattan Bridges were well underway. The New York City Department of Bridges initiated construction in 1902 and the Queensboro Bridge unofficially opened to traffic on March 30, 1909. A formal ceremony marking the opening followed on June 12 of that year.

With its steel, cantilevered design, the Queensboro Bridge presents a contrast to the three Brooklyn-based suspension bridges. In order to connect Midtown and the Upper East Side of Manhattan with Long Island City in Queens, engineers determined that the cantilever design had three principal attractions:

• It was stronger than the suspension model.

• It permitted a longer span and wider clearance below the roadway.

• It was more economical.

Moreover, unlike the Brooklyn, Manhattan and Williamsburg Bridges, the Queensboro Bridge could take advantage of the midstream island (known as Blackwell's, Welfare and now Roosevelt Island) for two anchorages.

The cantilevered structure consists of several components, each of two layers. It is best compared to a diving board, in which the cantilever span is similar to the board that extends over the surface of the water. The Queensboro Bridge has two cantilevered spans that extend outward from the mid-channel anchorages. The spans are of unequal lengths; at 1,182 feet, the span to Manhattan is 98 feet longer than the span to Queens, which measures 984 feet. The anchorages themselves are joined by a truss span of 630 feet.

Key figures in the history of the Queensboro Bridge are Commissioner of Bridges Gustav Lindenthal and the designers of the Williamsburg Bridge, Leffert L. Buck and Henry Hornbostel. The final product represents a collaboration of these three brilliant engineers. Lindenthal and Hornbostel shared the view that the design for any structure should be a fusion of art and engineering. Thus, spans were designed to curve gracefully over the deck and small architectural details were attached throughout the structure. Four 350-foot towers topped with decorative spires, two on Roosevelt and one each in Manhattan and Queens, supported the deck of the bridge. The chords of the cantilevers are connected by a series of steel eye-bars. At the Manhattan approach, two elegant 18- foot bronze torchieres flanked the entrance.

When originally constructed, the Queensboro Bridge carried pedestrians, vehicles and trains. The top level had two pedestrian walks and two elevated railway tracks. The lower deck had three vehicular lanes and both of the two outer roadways had two trolley lanes. An elevator located at the western anchorage gave pedestrians and carts access to Welfare Island (today known as Roosevelt Island) until the late 1950s.

The bridge, which resembles a horizontal Eiffel Tower because of the trusses that make up the cantilever, has long been an iconic part of the city's skyline, appearing in such movies as Woody Allen's "Manhattan" and on television in "Taxi". Paul Simon cited the bridge's other name in the title of his song, "The 59th Street Bridge Song (Feelin' Groovy)". The Queensboro Bridge also

marks a key point in the New York City Marathon; at the 16th mile, runners wend their way up the ramps and head to Manhattan on the bridge, which is specially carpeted for the occasion. The Queensboro Bridge was designated a national monument in 1974.

A series of events will mark the centennial beginning Sunday, May 31, including parades from the Queens and Manhattan sides meeting at a mid-span ceremony, walking tours, lectures, and exhibitions. For a full listing of activities and/or to make a contribution, visit http://www.nycbridges100.org.

Key Statistics:

Number of lanes: 10 (four upper, five lower) for autos; one outer roadway for pedestrians and bicyclists.
Western cantilever span: 1,182 feet
Center truss span: 630 feet
Eastern cantilever span: 984 feet
Total span: 3,724 feet
Total length: 7,449 feet
Width: 100 feet
Towers: Four, 350 feet
Daily traffic: 200,000 vehicles
Upper level vertical clearance: 12 feet
Lower level vertical clearance: 130 feet

In spring 2007, a group of civic-minded individuals realized that several of New York City's bridges were approaching their 100th anniversaries. In order to commemorate the significance of these magnificent spans and their role in making New York City the greatest metropolis in the world, the group formed the NYC Bridge Centennial Commission, a 501 (c) 3 corporation. The aim of the commission is to promote the 100th-year anniversary of six historic New York City bridges; to educate the public about the bridges' role in the life of the city; to encourage respect for the history of New York City; to heighten the public's awareness of the city's infrastructure and the need to maintain it, and to stimulate the interest of the public in celebrating the centennial of these six bridges.