A 672-foot, 6,500-ton long section of the old Tappan Zee Bridge (far left) will be taken down via a controlled explosive demolition on Saturday morning. In the foreground is the new $3.9-billion new Gov. Mario M. Cuomo Bridge spanning the Hudson River connecting Westchester and Rockland counties. Photo Credit: New York State Thruway Authority

TARRYTOWN—Tappan Zee Constructors, the contractor building then new $3.9-billion Tappan Zee Bridge here, is planning a controlled demolition on Saturday morning using explosives to bring down a 672-foot section of the east anchor span of the old Tappan Zee Bridge.

The old Tappan Zee Bridge first opened for traffic in December 1955 and closed when traffic was diverted to the new span (the Gov. Mario M. Cuomo Bridge) in October 2017.

The New York State Thruway Authority has issued a traffic advisory warning motorists of heavy traffic delays in connection with the demolition that is scheduled to begin at 9: 30 a.m. on Jan. 12. During the controlled demolition period, New York State Police will stop New York State Thruway traffic (I-87/I-287) approaching the Gov. Mario M. Cuomo Bridge in both directions between exits 11 (Nyack South Nyack – US Route 9W) in Rockland County and 9 (Tarrytown, Sleepy Hollow Route 9) in Westchester County for at least 45 minutes. Significant delays are expected and motorists should avoid the area and take alternate routes on the day of the activity, the New York State Thruway Authority advises. The traffic stop will be lifted after TZC determines the area is safe to reopen to traffic.

The demolition of the section of the eastern span became necessary when last September during demolition work, Tappan Zee Constructors and project engineers learned that the eastern anchor span of the old bridge, while stable, was damaged with certain key components highly stressed. The east anchor span to come down weighs 6,500 tons and is 140-feet above the Hudson River.

“Tappan Zee Constructors (TZC) is planning for the limited use of explosives to lower the old Tappan Zee Bridge's east anchor span on Saturday, January 12, weather permitting. Through extensive engineering analysis, it has been determined that this is the safest method to proceed with lowering the span given its current state, the contractor said in a prepared statement. “TZC has worked with local, state, and federal agencies to review the controlled demolition plans and subsequent operations to remove the steel from the Hudson River. Throughout the planning and execution of this operation, the safety of our workers and the travelling public is our top priority.”

The contractor explains that the explosive charges will be used to deliberately fail vertical members supporting the span, allowing the project's demolition team to safely lower the span eastward, away from the main navigation channel, using specialty marine salvage equipment. Marine salvage experts will then remove the material from the river during the following weeks. The steel will be recovered with the assistance of chains, previously laid on the riverbed. The chains will support the salvaged structure in the river, enabling TZC to place the material on barges for removal from the project site.

The U.S. Coast Guard is planning to establish a 2,500-foot safety radius around the controlled demolition site during the operation. The Hudson River's main navigation channel will temporarily be closed at 7:30 a.m. for approximately three hours. No residential areas are within the safety zone and local residents are not expected to be affected. However, monitors placed in key locations in Westchester and Rockland counties will monitor any vibrations or air-blasts generated by the demolition.

TZC is also coordinating with Metro-North Railroad regarding trains on the Hudson Line, which it says will may be only minimally affected. In the event of inclement weather, the rain date for the controlled demolition is Sunday, January 13.

Once the demolition is completed, the only remaining visible remnant of the old bridge will be a portion of the west span, near Rockland County, which will be dismantled.

Instant Insights /

Explosives to Bring Down Portion of Old Tappan Zee Bridge This Saturday

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