A project surveyor inspects measurements atop the new bridge’s structural steel.
As millions of pounds of steel and concrete are installed above the Hudson River, the New NY Bridge project’s surveyors are using lasers and other state-of-the-art technology to ensure that these materials are placed with pinpoint precision.
Experts use sophisticated tools and Global Positioning System (GPS) technology to track the installation of each bridge element on the 3.1-mile project site. Their work is essential at each stage of construction, as even a millimeter of deviation can alter the overall structure of the bridge. Surveyors have worked on the New NY Bridge project from the very beginning, helping establish the exact locations and boundaries of the new bridge’s landings in South Nyack and Tarrytown. By analyzing the shape and contour of the Earth’s surface, surveyors were also able to help project engineers establish the necessary dimensions of the bridge and its materials.
Although the work of surveyors is heavily based in mathematics, it can be a physically demanding job. Surveys are required at many different locations on the project site, including high atop the bridge’s structural steel. These locations are only accessible by climbing, requiring surveyors to carefully carry all of their equipment along the way. These specialized instruments include tools that measure angles and altitude, such as theodolites and altimeters. The team also uses GPS technology to create reference points on the river with a high degree of precision. The technology is combined with advanced machinery mounted on tripods, called robotic total stations, to allow surveyors to calculate distances using lasers.
Once the data is collected, surveyors can interpret and analyze the results with the rest of the project team on land. These analysis sessions regularly include many different groups on the project team, including civil engineers, survey staff, and construction managers.
Surveyors continue to track the placement of structural steel and road deck panels along the new twin-span crossing as construction progresses above the Hudson River. You can view the latest project progress via the project’s webcams and photo gallery as well as by visiting the New NY Bridge construction viewing platforms at Scenic Hudson RiverWalk Park in Tarrytown and Memorial Park in Nyack.
