First permanent piles for New Tappan Zee Bridge

After months of pre-construction works, the 'formal construction' of the new Tappan Zee Bridge in the Hudson River, started last Wednesday. The beginning of the construction, with the first driven permanent piling, was announced by the Governor Andrew Cuomo.

The foundation consists of steel piles driven into the silty soil beneath the river. A barge is used to move the piles to the construction site and many steps are included for their installation. Two parts of the piles are welded constructing the final pile to support the bridge. The first part is driven by a vibratory hammer and the second part by an impact hammer, especially equipped with a covering for noise reduction. The weld between them is often inspected. After the installation, steel reinforcement and concrete fill the pile and the final pile cap is added. Then an upward construction of the piers starts from the water level. According to Cuomo the project is scheduled to be finished by 2018.

Source: newyork.cbslocal.com, governor.ny.gov