Tappan Zee-Hudson River Crossing

PROJECT OVERVIEW

The Tappan Zee-Hudson River Crossing Bridge, completed in 2017, became an instant icon for its sleek design. The cable-stayed structure features twin deck’s supported by cables. The attached chamfered towers mimic the mouth of the Hudson River. This modern engineering marvel is one of the widest cable-stayed structures in the world.

Hinman was the blast and fire consultant for the Tappan Zee-Hudson River Crossing. This project was led by the Tappan Zee Constructors, which includes American Bridge, Fluor, HDR, Buckland & Taylor, URS and GZA.

The original estimate by the New York State Thruway Authority of this replacement bridge project was $5.2 billion. Because of a highly innovative design, this project was won with a reduced bid of $3.4 billion, $800 million less than the next lowest bid. Hinman helped contribute to these savings during the proposal phase. We did this by limiting the hardening to only those key structural elements that prevent catastrophe collapse.

Hinman’s contribution included analytical verification of structural damage for over two dozen explosive threats.

HINMAN SOLUTION

Hinman is part of the pre-construction team led by HDR for this project. The team has just completed the Accident Threat Vulnerability Risk Assessment (ATVRA) portion of the work with the assistance of experts from government and the project peer reviewers HNTB and Arup. Hinman’s contribution included analytical verification of structural damage for over two dozen explosive threats.

In addition, we evaluated the structural response of the bridge for fire threats using our in-house stochastic cost-benefit model. Our analysis had unexpected results supported by the project peer reviewers. As a result, these findings have the potential to change the standard of protection for bridges in the New York Area and across the nation.

Hinman continued to work with the pre-construction team during the following phase of work. During this phase, we developed mitigation design strategies for the Tappan Zee-Hudson River Crossing Bridge.