HAKS performed the 2000 Biennial Inspection of the Queensboro Bridge. This double cantilever-truss bridge spans the two East River channels and Roosevelt Island and serves as a vital link between Manhattan and Queens. This double deck bridge is the most heavily traveled East River crossing, carrying 155,000 vehicles per day on nine vehicular lanes. A tenth lane is devoted to pedestrians and cyclists.
Construction of the Queensboro Bridge was completed in March of 1908 and its March 30,1909 opening transformed Queens from a rural outpost into a densely populated borough. The length of this historic landmark structure including approach viaducts totals 7,449 feet. The main bridge itself is 3,726 feet long with cantilever spans of 1,182 feet and 984 feet in length over the west and east channels respectively. Unusual for a double cantilever truss, the bridge was constructed without suspended spans. The width of the bridge is 100 feet and the tower height is 350 feet above mean high water.
The scope of work included a hands-on inspection of all lower and upper main bridge elements. HAKS provided three inspection teams led by licensed professional engineers to perform the inspection. Manlifts of 30,60 and 90 foot heights were used for access as were underbridge travelers and free climbing techniques. Unique inspection elements included steel eyebars and trusspin connections, adjustable rocker links at anchorages and gustavino arches beneath the Manhattan approach. Several cantilever floor beams of the outer roadways were flagged for excessive section loss in their critical top flange angles. Non-destructive testing methods including D-meter steel thickness measurements and dye-penetrant testing forcracks were implemented in addition to standard inspection techniques.