But in September, workers dismantling the east span heard a loud popping sound and soon discovered that the structure was unstable. Taking that part of the bridge apart piece by piece could lead to collapse, Tappan Zee Constructors, the company responsible for the demolition, determined. After the demolition, only a portion of the west span, nearer Rockland County, will remain; it will continue to be dismantled piece by piece, according to Tappan Zee Constructors. The instability of the east span was discovered a day after Gov. That bridge was built to replace the Tappan Zee, which opened in 1955.

Source: New York Times January 05, 2019 23:48 UTC