It’s New NY Bridge time, again. The people behind the biggest US public infrastructure project under construction will hold their annual Tappan Zee Bridge public meeting this week at 6:30p on Wed June 15 at Nyack High School.
In 2016, while work progresses on the new bridge, motorists have embarked on a cashless tolling future, with the implementation of toll-by-plate technology and the removal of the Tarrytown toll plaza. Construction crews have made substantial progress on the New NY Bridge, benefiting from the mild 2016 winter: project managers say 100,000 tons of steel will be installed this year.
Over the last few months, crews have been able to install piers in the space where the old bridge and the new bridge overlap. Originally, this work had been planned for late 2017 after the legacy bridge had been demolished. However, some innovative engineering allowed this work to proceed this Spring ahead of schedule. “In April, the first such installation was successfully executed near the Rockland shoreline in a bold overnight operation unlike any other on the project,” writes the New NY Bridge team in their June 2016 monthly update.
To date, all of the bridge’s massive piles have been installed in the riverbed with large cranes and pile hammers, which require a great amount of overhead space. Overcoming the low clearance under the existing bridge at the shoreline — just under 30 feet — was achieved by temporarily removing two panels of the existing Tappan Zee’s road deck to establish a ceiling-less work area for crews to install the replacement bridge’s 75-foot-tall piles.
The first step was designing a floating frame that would act as a template for the pier’s foundations and provide a water-free workspace in which the construction team would operate. The 12-foot-tall steel structure, called a cofferdam, was moved snugly between two of the existing bridge’s piers and secured using mooring lines in shallow water near the Rockland shoreline. The cofferdam’s hollow, tub-like form was then drained of all water. This dry work area was then prepared for installation of the foundation piles.
Work began at 9p, Friday, April 29, when maintenance teams deployed protective barriers, including a specialized barrier truck, on the deck of the bridge to separate traffic from the work area. Crews then swiftly removed two 50-foot-long portions of the Tappan Zee Bridge’s deck to allow cranes to place the foundation piles in the correct locations. The piles were then driven deep into the riverbed. All of the pier’s foundation piles were successfully installed and trimmed to the appropriate length by just after 8a on Saturday, April 30. The deck segments were then reinstalled, the lanes were reopened and traffic flow returned to normal.
The annual meeting will include a presentation on this progress as well as an update on what is planned for the remainder of 2016.
There will be an additional session on Tues June 14 at Washington Irving School, 103 S. Broadway in Tarrytown, also starting at 6:30p. Nyack High School, where the Rockland County meeting will take place on June 15, is located at 360 Christian Herald Road in Upper Nyack.
