Today in History: Tappan Zee Bridge Opens for Crossing the Hudson

by M.C. Millman

Sixty-eight years ago today, the three-mile Tappan Zee Bridge span opened to drivers, enabling them to cross the Hudson River. 

The bridge was named after the Native American Tappan people who lived in the area, along with the  Dutch word for "sea". It linked the two portions of the Thruway mainline, from the Bronx to Buffalo, and transformed the region in a significant way as previously, the nearest Hudson River crossing to the George Washington Bridge was 44 miles.

Discussion of creating the span began in the 1800s, but countless obstacles stood in the way of the bridge's development, including fierce local opposition and engineering challenges. It took until the 1950s for the idea to earn political consensus and for engineering advances to make it possible to build one of the most innovative bridges of its time in the United States.

Eighty-one million dollars (more than a billion dollars today), and nearly four years after construction began, the Tappan Zee bridge became a reality. 

Construction of the bridge was approved in 1942. The Thruway began construction on March 12, 1952, and the Tappan Zee opened to commuters on December 17, 1955. Ten thousand people worked on the bridge over those forty-five months, with up to 1,000 employees working on the bridge at a time. Construction required the displacement of more than 100 homes in South Nyack as well as the village's commercial center. When it opened, the Tappan Zee Bridge linked two portions of the roadway for a total Thruway length of 423 miles, which became the longest operating toll expressway in the nation.

One of the biggest engineering challenges of building the bridge was how to stabilize a span that would cross the river at one of its widest points. It would need huge foundations for the 1,212-ft wide navigation channel. The bedrock needed to anchor such a span would require a depth of approximately 250 feet. The usual practice at the time was to use long steel piles, but the cost of the amount needed was astronomical, so a different solution was necessary.

The Tappan Zee Bridge was the first permanent bridge in the U.S. that was supported in part by airtight floating concrete boxes, a novel solution of Emil H. Praeger the engineer who eliminated the need to anchor everything to bedrock and instead used the water's natural buoyancy to support some of the weight. Eight giant buoyant caissons provided enough upward force to bear 70-80 percent of the weight of the span plus traffic. The novel approach made engineering history, and the bridge earned a place on the National Register of Historic Places. The Tappan Zee Bridge was also the ninth longest span in the world.

The question that remains today is why the widest point of the river was chosen to build the bridge when seemingly it would make the most sense to choose the narrowest point. The narrowest point would only have been one mile across instead of the three miles the Tappan Zee Bridge became. Additionally, the river floor at that location was muddy, with the bedrock much harder to reach than the river bed at the narrower point of the Hudson. While a proposal for the narrower area of the river was presented by top engineers, it never turned into a reality.  

According to Jim Doig, a professor emeritus at Princeton University who spoke to Melissa Block on NPR.org,  after interviewing some of the key government officials involved in the building of the Tappan Zee Bridge,  he discovered why it was built where it was. 

The answer, of course, revolves around money. Given that the bridge became a centerpiece of a gigantic highway system and that bridge tolls were expected to raise a lot of money, Governor Dewey wanted those tolls to help pay for the construction of the rest of the Thruway. 

Had he allowed the bridge to be built further south, where the river is narrower, the bridge and its tolls would have fallen under the Port Authority, who would have gotten the revenue instead of New York State.

In the first five years after the bridge opened, the reliable new river crossing led to Rockland County's population increasing by 50 percent. By 1965, Rockland County continued to expand by more than 3,000 new residential units per year, along with new post offices and other public services. 

Photo Credit: Gov. Mario M. Cuomo Bridge