Most NYC bridges were part of big expressway projects that had a negative impact on neighborhoods and sustainable development to the area. While the Thames and Seine River bridges are of a comfortable scale for walking across, most NYC river crossings seem to require an automobile.
Henry Hudson was a 17th century sailor who spent a couple of years exploring the area around present day NYC while trying to find the Northwest Passage for the Dutch East India Company. For some reason, much of the northeastern US and Canada was named after him, including this bridge.
The original idea for this crossing was planned by NYC in 1904 to relieve congestion on the nearby Broadway Bridge. It was hoped that the bridge could be completed on the 300th anniversary of Hudson's voyage to New York (in 1609) but the only thing that got built was a pedestal for a statue of Henry in Riverdale where the north end of the bridge would be built. It took Robert Moses, the Triborough Bridge Authority, and the bridge designer David Steinman to get the crossing built 30 years later.
The Henry Hudson Bridge is a fixed, steel plate girder, deck arch bridge with a main span of 840 ft across the Harlem River. The fact that it's fixed means there are no pinned connections along the arch to release moments (and make the analysis easier). The bridge provides 143 ft of vertical clearance and was the longest such bridge when it was built in 1936. Steinman wanted to build a six lane bridge but the bankers didn't think it was warranted and insisted on a four lane bridge instead. David complied, but he designed the bridge so it could carry a second deck, which was built two years later. The initial bridge cost $5 million and the top deck cost another $2 million. It carries four traffic lanes on the lower deck and three lanes on the upper deck.
This design may be efficient, but I find driving on the lower deck of a long span bridge an unpleasant experience. In earthquake country, it can also be a deadly experience. The top deck of the Cypress Viaduct collapsed during the October 17, 1989 Loma Prieta Earthquake killing 41 people. The replacement for the nearby, seismically deficient East Bay Bridge doesn't have a second deck.
More information on the Henry Hudson Bridge is provided (as usual) by New York City Roads. Like many other NYC crossings, this bridge is currently being rehabilitated (at a cost of $50 million). Although it's not listed among the repairs, the bridge badly needs painting (look closely at photo). Without meaning to sound too chauvinistic, I'll just mention that on major California toll crossings, a paint crew can spend their entire career painting one bridge. When they get done priming and painting the entire bridge, they go back to the other end and start over again.
In the background of the photo, we can see the Spuyten Duyvil Bridge in its open position. It carries Amtrak trains and so it only needs to be closed when a train is coming. Because the bridge has only five feet of vertical clearance, ship traffic is stopped whenever the Spuyten Duyvil Bridge is closed.
All of the photos of Harlem River bridges shown during the last two weeks were taken from the deck of a 'Circle Line Cruise' boat that goes around Manhattan Island. As you can tell from the photos, the only bridge that had to be opened for the boat was the Spuyten Duyvil Bridge.
New York City's Bridges: Henry Hudson and Spuyten Duyvil Bridges by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.