Case Study: Tappan Zee Constructors achieves pinpoint, safer underwater demolition and accelerated debris removal with Trimble Marine Construction Software

Tappan Zee Constructors ‘See’ Below the Hudson River

Tappan Zee Constructors, a joint venture formed to design, build and deconstruct portions of the Governor Mario M. Cuomo Bridge, faced a complex final phase: removing massive submerged bridge elements from the Hudson River under an accelerated schedule. Variable water depths, strong currents, poor visibility and windy conditions made locating and removing debris dangerous, slow and imprecise—traditional “blind” marine demolition risked missed material, safety issues and schedule delays.

The team deployed Trimble Marine Construction software with Trimble GNSS positioning, Teledyne SeaBat T20 multibeam sonar and integrator Measutronics to create high‑resolution 3D subsurface models and provide real‑time machine guidance to on‑water cranes and excavators. The system delivered in‑cab visualization and live updates, eliminated working in the blind, sped demolition and debris removal, reduced diver exposure, improved as‑built documentation and revenue capture, and helped return the riverbed to a cleaner condition.

Tappan Zee Constructors

Blake Yaffee

Area Manager