On February 20, 2013, the New York State Society of Professional Engineers (NYSSPE) Rockland County Chapter held an Engineers Week Luncheon on the Tappan Zee Hudson River Crossing Project (Tappan Zee Bridge) – Pile Installation Demonstration Program. The event was held at the Palisades Mall in West Nyack, New York.
The presentation covered the existing bridge and its foundations, the EIS, geographic setting and subsurface conditions, pile installation, vertical and lateral pile testing, and noise attenuation & environmental monitoring. The speaker for the luncheon was Tony Canale, P.E., Senior Associate, Mueser Rutledge Consulting Engineers, Tappan Zee Bridge Team Member.
The presentation covered the Pile Installation Demonstration Program for the Tappan Zee Bridge redesign. The speaker discussed specifically the Environmental Impact Study (EIS), which focuses on how the pile installation would affect the fish in the Hudson River. The total number of piles to be installed in the river for the new Tappan Zee Bridge will be approximately 1,000 (+/- 200). This number is subject to change based on the actual design process.
The speaker discussed the measures that will be taken to minimize the disturbance to the fish, especially the sound associated with the pile driving.
The speaker’s summary and conclusions, regarding the pile installation demonstration program were as follows:
- Subsurface investigation, pile installation demonstration program and environmental monitoring cost about $35 million.
- Substantially reduced the uncertainty in foundation design thus reducing the risk on the foundations.
- Environmental impacts of pile driving were directly observed and measured.
- Vibrations on existing bridge due to the pile driving were minimal.
- Observed capacity of friction piles in clay were lower than capacities determined by dynamic measurements.