<< Back to Geotechnical 

Governor Mario M. Cuomo Bridge (Tappan Zee Bridge Replacement)

The $3.9+ billion New York State Thruway Authority (Thruway) Tappan Zee Bridge Replacement Project includes construction of a new bridge to replace the existing over-congested Tappan Zee Bridge. The total length of the new bridge is about 4 miles and it spans over the Hudson River between Tarrytown in Westchester County, New York and South Nyack in Rockland County, New York.

YU & Associates, Inc. (YU) is providing geotechnical services to support the Thruway Tappan Zee Bridge Replacement Project in coordination with the Design-Build Team.

YU provided subsurface investigation services at the site including conventional test borings with Standard Penetration Tests (SPTs) and Cone Penetration Test (CPT) soundings. YU was also involved in performing pre construction conditions documentation (pre-con) for structures surrounding the site. YU photographically documented the existing defects for the buildings/structures including cracks, concrete spalling, rust, paint peeling, water damage, missing bricks and tiles, etc., at all accessible locations of the structures. YU also video-taping the pre-construction conditions of the subject structure. YU prepared a pre con report including description of observed defective conditions of the documented area, along with photographic and video documentation of areas that can be accessed.
YU qualified field personnel assisted in the geotechnical instrumentation installation in the field, data reduction and interpretation, and generation of monitoring reports. Other services will be provided by YU to the Design-Build Team include, oversight to the pile installation and testing (O-cell, CSL, etc.) during development of deep foundation system for supporting the new bridge. The deep foundation system consists of driven friction piles and large-diameter drilled shafts.

YU also provides office support including report preparation and computer drafting task using Bentley’s Micro Station.


Rockland and Westchester Counties,
New York


  • Geotechnical Subsurface Investigations (Marine and Land Borings and CPT Soundings)
  • Pre-Construction Conditions Documentation
  • Deep Foundation Installation Inspection
  • Geotechnical Instrumentation
  • MicroStation Drafting Support for the Design-Build Team
Design-Build Team HDR, Inc. / Tappan Zee Constructor, LLC
New York State Thruway Authority