New York City's Bridges: George Washington Bridge (2)

One last look at New York City (well, New Jersey actually) and the George Washington Bridge. This photo (taken in 2002) shows preparations for painting the bridge's west tower. The tarp around the scaffolding may be required to prevent lead-based paint from entering the river. The steel towers are composed of arches above and below the bridge deck. The green cliffs behind each tower makes the bridge more attractive.

Note that two suspension cables hang from the top of each tower leg. The 107,000 miles of steel wire used for the suspension cables were manufactured by John Roebling & Sons, whose founder had designed the Brooklyn Bridge. Contractors were allowed to bid the job with either suspension cables or with suspension chains, which seems unthinkable now.

When the bridge was first built, the deck was supported by very thin (twelve-foot deep) plate girders under the roadway. The theory was that the enormous mass of the long deck would act as a stiffener to prevent large movements during windstorms. It may have been fortunate therefore, that they later put a lower deck on the bridge with a deep truss.

We've looked at every river crossing connected to Manhattan, but there are many other interesting bridges in the area. The Bayonne Bridge (1931), the Bronx-Whitestone Bridge (1939), the Throgs Neck Bridge (1961), and the Verrazano-Narrows Bridge (1964) were all designed by Othmar Ammann during the golden age of bridge engineering for New York City.

New York City's Bridges: George Washington Bridge (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: George Washington Bridge

In contrast to the East and Harlem Rivers, there is only one bridge that crosses the Hudson River to Manhattan. The George Washington Bridge forms an important link in I-95/US-1 that speeds vehicles across the Hudson and through the most congested part of Manhattan. The bridge connects Fort Lee in New Jersey to the Washington Heights area of Manhattan. It was named after George Washington who unsuccessfully tried to prevent the British from entering Manhattan. After he failed, he quickly crossed from Fort Washington to Fort Lee where the bridge now stands.

The George Washington Bridge is an iconic landmark because of its huge skeletal towers. The design originally called for the towers to have a granite facade, but this was eventually abandoned, perhaps because the bridge was built during the Great Depression. When it was completed in 1931, it doubled the record for the longest suspension bridge with a main span of 3500 ft and with towers that were 650 ft tall. The Brooklyn Bridge was built in 1883 with a main span of 1600 ft and 280 ft towers. The Akashi Kaikyo Bridge was built in 1998 with a main span of 6500 ft and 930 ft towers.

The George Washington Bridge is owned by the Port Authority of New York, designed by Othmar H. Ammann, and with architectural support from Cass Gilbert. The bridge originally had six vehicle lanes and sidewalks. In 1946 two additional lanes were added in the middle of the deck. A lower deck was added in 1962, which gave the bridge a total of fourteen lanes (the most on any bridge) and allowing it to carry about 300,000 vehicles a day.

New York City's Bridges: George Washington Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: Spuyten Duyvil Bridge

The Harlem River is a tidal strait that allows water to flow from the broad Hudson into the East River (the Hudson and East Rivers meet at the southern tip of Manhattan Island). The Spuyten Duyvil Swing Bridge is along the east bank of the Hudson River and blocks entry into the Harlem River when it is closed.

The term Spuyten Duyvil refers to the swift running creek that was at this location before it was dredged by the US Army Corps of Engineers to create the current north end of the Harlem River. The name means 'devils spout' and refers to the wild currents that flowed through the creek.

The current bridge at the north entrance to the Harlem River was built in 1899 to replace an earlier bridge built by the New York and Hudson River Railroad. The current bridge has a 290 ft long swing span, 610 ft of total length, and only 5 ft of vertical clearance when it is closed.

Trains stopped using the bridge in 1982, it was struck by a ship the following year, but it was repaired for use by Amtrak a few years later to carry passenger trains to and from Pennsylvania Station.

New York City's Bridges: Spuyten Duyvil Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: Henry Hudson Bridge

In contrast to most big city rivers, the Harlem hasn't had any new bridges built across it in 40 years. In fact, New York City (NYC) seems barely to have funds for maintaining its existing bridges.

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.

New York City's Bridges: Broadway Bridge

The Broadway Bridge crosses over the Harlem River Ship Canal, which connects the Harlem River to the east with the Hudson River to the west. The bridge has a double deck with four traffic lanes and two sidewalks on the bottom and three sets of subway tracks on the top. The bridge provides 304 ft of horizontal clearance through the canal, 136 ft of vertical clearance when the bridge is open, and 24 ft of vertical clearance when the bridge is closed.

The current lift bridge was opened to subways in 1960, to vehicular traffic in 1962, but it couldn't be raised until 1964. Apparently, the need for tall vessels to navigate the Harlem River isn't very acute. I read that they only allow one bridge to open at a time, and during the summer several of the bridges have difficulty opening due to thermal expansion of the decks. One would need a very compelling reason (and a great deal of patience) to take a ship taller than 24 ft any distance along the river.

New York City's Bridges: Broadway Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: University Heights Bridge

Another swing bridge. This structure started it's life upstream in 1895 as the Broadway Bridge and was moved to University Heights (West 207th Street) in 1906. The swing span was eventually replaced in 1992. This bridge connects the University Heights section of the Bronx with the Inwood section of Manhattan. It is another highly ornamented bridge designed by Alfred P. Boller.

Gustav Linderhal, the newly elected chief bridge commissioner, wanted a lift bridge at this location, but the other commissioners were leery of the expense. A lift bridge was a new concept at the beginning of the last century. It really is a better idea since ships were routinely smashing into the pivot pier of the Harlem River swing bridges. A lift bridge would give these ships much greater horizontal clearance. However, the city jumped at the chance of using the discarded swing span of the Broadway Bridge instead.

New York City's Bridges: University Heights Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: Washington Bridge

The Washington Bridge consists of two 510 ft long steel arch spans supported on stone masonry piers and with stone masonry arch approaches. This was the first long span arch bridge to use plate girders for the arch ribs.

The bridge is situated between high bluffs in Manhattan and the Bronx with the deck 152 ft above the Harlem River, making it one of the tallest bridges in New York. One of the arches spans over the river and the other spans over railroad tracks and the Major Deegan Expressway.

The bridge was built in 1888 from a proposed design by C. C. Schneider that was pared down to bring the cost to $3 million. It was considered a rival in beauty to the Brooklyn Bridge when it was completed. Although the bridge was built quickly (in two years), at cost, and with considerably less financial scandal than other New York City bridge projects, a controversy concerning bridge commissioners' salaries delayed the opening by several months. Today, the Alexander Hamilton Bridge carries most of the traffic formerly carried by the Washington Bridge.

New York City's Bridges: Washington Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: Alexander Hamilton Bridge

The Alexander Hamilton Bridge carries the Trans-Manhattan Expressway over the Harlem River from Washington Heights to the Bronx. The bridge is 2,375 ft long while the steel arch span over the Harlem River is 555 ft long. The bridge includes on and off ramps to the Major Deegan Expressway and to Harlem River Drive. Robert Moses (in the 1950s) planned this bridge project as part of I-95 in order to get 90% of the $21 million cost to be paid by the federal government.

I-95 crosses the Hudson River on the George Washington Bridge, crosses under parking lots and high-rise buildings as it goes across Manhattan, crosses the Harlem River on the Alexander Hamilton Bridge, and then crosses the Bronx as the Cross-Bronx Expressway. The Hudson River on the west side of Manhattan is 3600 ft wide and requires a suspension bridge to cross it. The Harlem River on the east side of Manhattan is about 400 ft wide and only requires a steel deck arch to cross it. Because I-95 is eight lanes wide, the Alexander Hamilton Bridge is actually two parallel arch structures with four steel ribs to support the wide deck. More information on this bridge is provided by NYC Roads.

New York City's Bridges: Alexander Hamilton Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: High Bridge

The High Bridge was originally a stone masonry aqueduct that was completed in 1848. It consisted of fifteen arches that carried two cast iron pipes across the Harlem River Valley at 174th Street. It was designed by John B. Jervis and closely resembled the Puente Trajan in Spain that was built around 110 A.D. A third pipe and a walkway was added in 1864.

By 1920, a channel had been built around Manhattan and the aqueduct was to be removed as an obstacle to navigation. After considerable protests it was decided to replace the five arch spans in the river with a steel arch. However, the resulting structure was not nearly as attractive.

The New York City Water Department transferred the bridge to the park system in 1955. The bridge was closed to pedestrians in 1960 after several incidents of vandalism on the bridge.

A 2006 study found no major structural problems on the bridge but said it would cost $30 million to reopen the walkway. So far, $5 million in funds has been raised.
As usual, much more information is available from NYC Roads.

New York City's Bridges: High Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: High, Alexander Hamilton, and Washington Bridges

After crossing under eight movable bridges, we reach the northern part of Manhattan where three arch bridges span high above the Harlem River. This is in the Washington Heights area, a ridge that rises to 265 ft above sea level (where Fort Washington stood during the American Revolutionary War).

The first (southernmost) structure is the High Bridge, which has been closed for many years. However, Mayor Bloomberg promised during an Earth Day celebration that he would allocate resources to reopen this pedestrian bridge (and former aqueduct).

The next structure is the Alexander Hamilton Bridge, which is part of the Trans-Manhattan Expressway. This 12-lane expressway carries traffic from the George Washington Bridge over the Hudson River across Manhattan to the Alexander Hamilton Bridge across the Harlem River.

The third (northernmost) structure is the Washington (Heights) Bridge a very old (1888) historic structure that currently carries 181st Street traffic across the Harlem River.

We will look at each of these bridges in more detail over the next few days.

New York City's Bridges: High, Alexander Hamilton, and Washington Bridges by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: Macombs Dam Bridge

This bridge's name derives from an earlier bridge and dam that Alexander Macomb (a farmer and landowner) built on this site in 1814. The current bridge was designed by Alfred P Boller and it was completed in 1895. The main span is 412 ft long over two 150 ft wide channels. Thus, it is the biggest of Boller's Harlem River swing bridges and it's considered the most attractive of his Gothic Revival designs. Like his other bridges, the Macombs Dam Bridge consists of an oddly-shaped through truss due to the tower above the center pier. It was recently rehabilitated (as shown in photo) with new trusses, a new deck, and a new motor. In fact plans have also begun to retrofit this bridge to resist an earthquake that is likely to occur in the area.

As usual, much more information on this bridge is available from New York City Roads.

New York City's Bridges: Macombs Dam Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: 145th Street Bridge

Another Alfred P. Boller swing bridge very much like his Madison Avenue and Macombs Dam Bridges over the Harlem River. The 145th Street Bridge was built between 1901 and 1905 with a 300 ft long swing span. A great deal of information about this bridge is provided online by the City of New York Roads.

On a modern swing bridge, the center span is supported on a piston that is lifted up by hydraulics and then swung around with an arm (there are also locking devices at the ends of the swing span). The machinery that drives these early 20th century swing bridges are similar. As a bridge engineer, I rely on a mechanical engineer to design this machinery, although I suppose there may be some engineers who can design a movable bridge on their own. The operation of these bridges also relies on the Coast Guard who maintain the safety of waterways as well as with municipal authorities who periodically inspect the bridge (and the bridge operator). Thus, a movable bridge is a kind of hybrid which requires close cooperation between many different disciplines.

New York City's Bridges: 145th Street Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: Madison Avenue Bridge

I think we're going to get tired of Harlem River swing bridges before we ever reach the Hudson. It's funny that people in Paris can get all their needs met living next to a river crossed by low arch bridges while New Yorkers require a dozen movable bridges across the Harlem River.

The Madison Avenue Bridge was designed by Alfred P. Boller and built in 1910 to replace an earlier swing bridge. It has a Y-shaped ramp on the Manhattan side that carries Madison Avenue and 138th Street traffic to and from the Bronx. The main span is 300 ft long with about 25 ft of clearance over the river. It has four vehicle lanes, two sidewalks, and carries about 50,000 vehicles a day.

Like the other Harlem River swing bridges it has a wide hexagonal fender protecting the center pier. It has gazebos at each corner, one of which has perhaps been enlarged to measure the water level. There is also a building for the operator above the pivot pier. The center span is a truss very similar to the center span of most the swing bridges across the Harlem River.

New York City's Bridges: Madison Avenue Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: Park Avenue (Metro North) Railroad Bridge

A shipping channel was dug in the 19th century by the US Army Corps of Engineers in the Harlem River and crossed by a succession of fixed and movable bridges. Today, the Harlem River is eight miles long (between the East and Hudson Rivers), it's about 18 ft deep at low tide, and it's about 350 ft wide. Most of the movable bridges cross at a skew, making the main span even longer, and so the piers were built in the river.

The current Park Avenue Bridge is the fourth movable bridge at this site and the first lift bridge. It was built between 1954 and 1956 alongside the older bridge. It carries four railroad tracks and has 25 ft of vertical clearance closed and 135 ft when it's open. The main span is 340 ft long. It was originally owned by the New York, New Haven, and Hartford Railroad and it's currently owned by Metro North.

New York City's Bridges: Park Avenue (Metro-North) Railroad Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: Third Avenue Bridge

Actually, this photo is of the 1898 swing bridge that was replaced in 2004. A new swing bridge was floated into place by a barge to replace the center two spans of the existing bridge.

This part of the Harlem River (between Manhattan and the South Bronx) is crossed by a variety of movable bridges, which make an interesting subset of river crossings. Among the various movable bridges are bascule bridges, like giant teeter-totters. There are swing bridges (like the Third Avenue Bridge) that move the channel spans parallel to the waterway. There are lift bridges (like the Triborough Lift Bridge) that are like elevators that raise the channel spans up to the top of towers. There are several less common movable bridge types, including innovative recent designs for footbridges. Most movable bridges require an operator to safely open and close the bridge, a mechanical engineer to maintain the bridge, and some patience on the part of the public every time a ship wants to pass. Therefore, if a bridge carries many vehicles, engineers will try to build it high enough so it doesn't interfere with river traffic. However, this requires long ramps to raise the deck above the tallest vessel. Since the latest Maersk container ships can be 80 meters above the water, that makes keeping bridges out of their way quite a challenge.

New York City's Bridges: Third Avenue Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution 3.0 United States License.

New York City's Bridges: Willis Avenue Bridge

I'm afraid the next few bridges upstream on the Harlem River are being replaced.

The Willis Avenue Bridge is an interestingly-shaped swing bridge that was built in 1901. It carries traffic from First Avenue in Manhattan to Willis Avenue in the Bronx. Apparently it's getting old and it's also a source of accidents and so the City of New York wanted to replace it. They offered to sell the existing bridge for $1 and even promised to move it for the buyer, but there were no takers. The estimate for the replacement bridge was $417 million but when the bids were opened, the low bid was $617 million, which will make it the most expensive bridge across the Harlem River.

New York City's Bridges: Willis Avenue Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: Triborough Lift Bridge

This is the Manhattan arm of the Triborough Bridge. Robert Moses wanted it to cross the Harlem River at 103rd Street (a straight shot across Ward's Island into Queens) but a variety of pressures resulted in it being constructed at 125th Street instead. It was built to resemble the George Washington Suspension Bridge across the Hudson River (on the other side of Manhattan) with its tall, steel-laced towers.

Its a three-span bridge with a 310 ft lift span supported on 210 ft high towers and a 770 ft total length. In the closed position the deck has a 55 ft vertical clearance over the Harlem River and in the open position it is 135 ft above the river. The bridge carries six lanes of traffic and two sidewalks. It was originally going to be the world's heaviest lift bridge, but the designer, Othmar Ammann was able to reduce its weight by such means as replacing the concrete deck with asphalt on a steel deck. The Triborough Bridges were opened to traffic in 1936.

New York City's Bridges: Triborough Lift Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution 3.0 United States License.

New York City's Bridges: Ward's Island Bridge

The Harlem River flows along the east side of Manhattan, north of Ward's Island. At the river's mouth is Ward's Island Bridge (sometimes referred to as the Harlem River Pedestrian Bridge), the only footbridge across the Harlem River. This rather spindly-looking structure was designed by Othmar Ammann in 1939, but because steel wasn't available until after the war, construction didn't begin until 1949.

It's a lift bridge with counterweights to raise the 330 ft long center span to the top of the towers. In fact, the bridge is only used from April to October and the center span is left in the raised position for the rest of the year.

The bridge consists of four ramps carrying pedestrians across FDR Drive on the Manhattan side, three spans across the Harlem River, and a gradual descent onto Ward's Island.

It has a modern, streamlined appearance, but because it is 937 ft long with tall towers and only 12 ft wide, it lacks a dramatic presence and appears flimsy.

New York City's Bridges: Ward's Island Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: Triborough and Hell Gate Bridges (2)

Both the Triborough and the Hell Gate Bridges have architectural details without structural purpose.

The Triborough Suspension Bridge has vertical members between the tower struts and finials at the top of the tower legs that make the bridge resemble a piece of Arts-and-Crafts furniture.

The arch on the Hell Gate Bridge has a reverse curve at the ends to give it a more interesting shape without improving its strength. Moreover, the stone towers at the ends of the arch serve no purpose.

Engineers often feel obliged to dress up their bridges in architectural details that do little or may even detract from their structural form. This is discussed in detail in 'The Tower and the Bridge," by David P. Billington.

New York City's Bridges: Triborough and Hell Gate Bridges (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

New York City's Bridges: Triborough and Hell Gate Bridges

North of Roosevelt Island, two handsome bridges connect Ward's Island to the Queens across the East River.

The Triborough Suspension Bridge has a 1380 ft long main span. It was designed by Othmar Ammann and completed in 1936. It is part of the 'Y' shaped Triborough Bridge Project which includes a lift bridge over the Harlem River and a truss bridge over the Bronx Kill, a narrow strait separating Randall's Island from the Bronx. This project was originally owned by the City of New York, but it was transfered to the Triborough Bridge and Tunnel Authority in 1933.

North of the Triborough Suspension Bridge is the Hell Gate Arch Bridge, a railroad bridge with a 1017 ft main span. It was designed by Gustav Linderthal and completed in 1917.

New York City's Bridges: Triborough and Hell Gate Bridges by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.