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A Tale of Two Bridges | Tappan Zee Hudson River Crossing

March 17, 2022 @ 12:00 pm - 1:30 pm

A Tale of Two Bridges | Tappan Zee Hudson River Crossing

The Old Tappan Zee Bridge (Governor Malcolm Wilson–Tappan Zee Bridge) crossed the Hudson River at one of its widest points. It connected South Nyack in Rockland County with Tarrytown in Westchester County in the Lower Hudson Valley. The $4 billion New Tappan Zee Bridge (Gov. Mario M. Cuomo Bridge) is a 3.1-mile multi-span dual-bridge replacement for the Governor Malcolm Wilson–Tappan Zee Bridge.

The geology at the site is characterized by Fordham Gneiss on the east bank Triassic Brunswick Formation on the west bank and generally consists of a thick deposit of soft, organic soils overlying glacial lake varved clays up to 500 feet in thickness in between.  The bridge’s main span towers and anchor piers are open-ended steel pipe piles bearing on either glacial till or bedrock. The remaining portions of the bridge are supported by H-piles, drilled shafts, and steel pipe piles.

Description | This course provides a limited project overview of the two Tappan Zee Bridges, which crossed the Hudson River, summarizing some construction challenges. These bridges, completed in 1955 and 2017, crossed the Hudson at one of its widest points. The geology, engineering, design, and construction of these projects will be discussed.

Objective | Upon completion of the course, participants will have an understanding of the challenges associated with two different specific construction projects, completed decades apart with the same final objective – to span the Hudson River.

Presenter | Craig Calabria, PhD, PE

Date | Thursday, March 17, 2022


  • 12:00 PM – 1:00 PM| Webinar
  • 1:00 PM – 1:30 PM | Q & A


  • Member | $15
  • Non-Member | $30

PDH | 1

Register today!


March 17, 2022
12:00 pm - 1:30 pm

Sustaining Associates

PSPE would like to thank our Sustaining Associates for their support: