Best Supporting Actors Temporary Trestles Take A Bow

July 19, 2018
Best Supporting Actors Temporary Trestles Take A Bow

The sky trestle in Tarrytown allowed TZC to install the bridge’s final concrete deck panels.

The recent progress on the eastbound span approaches was supported by temporary platforms, called trestles, which enabled the project team to maneuver heavy duty machinery over difficult terrain.

The most unique of these structures was the project’s sky trestle, which was built on the piers of the Tappan Zee Bridge. Located high above the steep edge of the Westchester shoreline, the sky trestle allowed Tappan Zee Constructors (TZC) to place the project’s final deck panels on the eastbound span.

Its work complete, the sky trestle is being dismantled, freeing up space to complete the eastbound roadway and remove the last of the land-based piers of the Tappan Zee Bridge.

At the Rockland shoreline, another temporary trestle south of the eastbound span is also being dismantled, following the installation of the project’s final steel girder.

The project’s trestles were crucial to the construction of the twin-span bridge right from the beginning. As early as 2013, when TZC began installing the bridge’s foundations, the trestles provided access over near the Rockland and Westchester shorelines. This also reduced the amount of dredging required for the project, as large cranes could access the shallow water without the use of floating barges.

The longest of these trestles, extending 1,000 feet from the Rockland shoreline, ran parallel to the old bridge. This trestle also provided TZC with direct access to the New York State Thruway, reducing the amount of construction traffic on local roads.

TZC later reduced the size of this trestle and converted it into a permanent maintenance dock in South Nyack, equipping it with floating landings, handrails, gangways and dark-sky compliant light poles. The dock is designed to assist Thruway crews and emergency responders near the new bridge.

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