B. Thayer Associates provided professional engineering and survey services in connection with damage sustained by the Harlem River Lift Bridge South Fender System due to a fire of September 20, 2010. The walkway planking and the timber fender system were both heavily fire-damaged. Several navigational lights and signs were missing or destroyed, and the south concrete pier had some scaling damage.
Our scope of services included a field survey, the upgrade and design of the navigational lighting and associated electrical utility, and the upgrade and replacement of the navigational signage.
Topographic mapping of the fender system, bridge piers, and Manhattan side bulk-heading was performed by a combination of conventional and GPS techniques. The mapping was tied into the New York State Plane Coordinate system horizontally. The New York City Railroad Datum was tied into the mapping as well as tidal data from the Spuyten Duyvil tide gauge.
The navigation light design updated the traditional high pressure sodium lamps to long life energy efficient LED lamps. The signage design upgraded the navigational signage to high visibility and reflective information and warning signs. All work was done to Metro North Railroad, U.S. Coast Guard, and American Railway Engineering and Maintenance-of-Way Association standards.
Reconstruction of the Harlem River Lift Bridge South Fender System
Location: Manhattan and Bronx, NY
Client: MTA Metro-North Railroad