Tappan Zee Bridge.

The article discusses the construction and engineering of the Tappan Zee Bridge on Interstate 87 across the Hudson River in New York, with information on plans for a replacement bridge. Topics include the bridge's anticipated structural capacity and projected life span of 50 years when it was erected in 1955, its status as a fracture-critical bridge which lacks structural redundancy in the event of a failure due to fatigue crack growth, and the estimated costs of designing, contracting, and constructing a replacement bridge according to plans as of April 2013.