• Design-build project is largest single civil construction contract awarded in New York
  • New cable-stayed bridge will ease congestion at a crucial Hudson River Crossing

As owner’s engineer for the New York State Thruway Authority, HNTB helped to replace at an extraordinarily fast pace the 62-year-old Tappan Zee Bridge over the Hudson River. The design-build project is one of the largest design build contracts in the United States and the largest bridge project in New York’s History.

The new bridge carries 50 million vehicles a year and eases congestion at a crucial river crossing just north of New York City. It features twin three-mile-long structures with eight traffic lanes, four emergency/breakdown lanes, a pedestrian/bike path, space for bus rapid transit, the capacity for future commuter-rail lines and will not require major maintenance for 100 years.

HNTB’s responsibilities include assisting the NYS Thruway Authority in contract management to maximize value for the toll payers. This role included monitoring design and construction to ensure contract compliance, and audits of the quality control/quality assurance program. HNTB also advised the Thruway on the structural health monitoring system which consists of 400+ sensors recording information on weather, tilt, acceleration, strain, joint movement and corrosion.

Location: Hudson River in New York

Client: New York State Thruway Authority