Part 2: The Age of Suspension 1900-1915
Last time we discussed the late-19th century construction project that opened the way for a new era of bridge building, not just in New York, but for the world.
This time, we will be looking at a flurry of bridge building that came with first the major expansion of the railway networks and then the introduction of the automobile for commercial and private transportation.
The Williamsburg Bridge
The Williamsburg Bridge was the next major bridge project completed after the Brooklyn Bridge and replaced it to become the longest suspension bridge in the world.
The neo-Gothic style of the Brooklyn Bridge was eschewed when it came to the Williamsburg Bridge, situated further north on the East River, at the south edge of the Williamsburg neighborhood on the Brooklyn side, and the north of what is now the East Village on the Manhattan side.
The thoroughly industrial style, with massive steel towers and trusses, would come to define the modern bridge for the next century.
Whereas the Brooklyn Bridge had used some stone and iron, the Williamsburg was made almost completely out of steel, the building material that would define 20th-century construction.
Designed by chief engineer Leffert L Buck, the bridge took seven years to build and had a pure suspension system, with long cables running between tall towers and connecting downwards to support the bridge at different points.
Like the Brooklyn Bridge, the city set up a separate corporation to manage all aspects of the bridge building.
This practice of setting up separate corporations allowed for private and public interests to work separately to carry out massive projects. This method is still used today, most notably in the reconstruction of Downtown Manhattan after the destruction of 9/11.
At the time of its completion in 1903, the bridge took the title of longest suspension bridge in the world from the Brooklyn Bridge and held it for 23 years.
The project showed that suspension bridges could be built quickly and with price tags that were manageable for the public.
Suspension bridges are incredibly complex, and many at the time thought that their use would only be possible for special cases, like the Brooklyn Bridge, which was made in a suspension style in order to guarantee naval transport in the narrow opening of the East River into New York Habor.
The Williamsburg Bridge was also completed shortly after the decision to combine all of the five boroughs into one city.
This was the beginning of the explosion of skyscraper building and having another bridge connecting the two largest population centers in the city was a necessary element in bringing together the urban fabric that would eventually create New York.
The Manhattan Bridge
It’s fair to say that no one, except for maybe visionary engineers like John A. Roebling, thought the city would expand fast enough to need a second bridge almost right next to the Brooklyn Bridge just a generation later.
Designed by Leon Moisseiff, this was the last of the three iconic suspension bridges, after the Brooklyn and Williamsburg bridges—a trio that has come to define the skyline of the city.
The project shows the harnessing of the new steel technology as well as the frantic rush to connect the two boroughs as the need for more crossings became evident.
It’s difficult to say how planners at the time could have predicted the massive population growth of New York as it became an economic powerhouse at the turn of the century.
The decision to unify all of the boroughs left the planners and engineers scrambling to work with developers looking to capitalize on the need.
All of the major New York bridges required tolls until 1911 when the tolls were abolished by Mayor William Jay Gaynor, but the bridges still presented huge commercial opportunities and helped the movement of goods, residents, and workers.
The Manhattan Bridge looks like the Williamsburg Bridge in many respects, except it has a less skeletal appearance.
This is because the bridge was the first suspension bridge to use the Warren Truss, a series of triangular support beams that run up the bridge’s towers and along the length of the roadway.
It allowed for the bridge to span a longer distance because of a more equal distribution of the weight.
Queensboro Bridge (59th Street Bridge)
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The other important bridge constructed during this time period was the first to connect the growing borough of Queens with Manhattan.
The Queensboro Bridge was completed in 1909, created by engineer Gustav Lindenthaland architect Henry Hornbostel.
The Queenboro Bridge is different than the three suspension bridges further south on the river.
It is a cantilever bridge, which means that the bridge is supported by steel beams radiating from a central point as opposed to being supported from above by hanging steel wires.
Technically, it is a double cantilever bridge, with supports on either side of the river and on Roosevelt Island in the middle of the river.
The Queenboro bridge is double level, allowing for even more traffic to proceed between the boroughs.
At the time, many firms were vying to have their names attached to these projects, but few could boast of the technical competency or bureaucratic know-how to see them through to completion.
Bridges are an example of architects and engineers having to develop systems to be completely in sync to ensure the safety of travelers and to make sure that civic dollars were being put to good use.
In bridge design, this relationship is made all the more important as the lives of millions of people and the economies of cities are based on the success of bridges over a long period of time.
Usually, the architects and engineers were involved in a constant back and forth, as was the case for the Queensboro bridge, using plans and calculations drawn up by the engineer that were augmented by the architect and then turned into scale models.
These iterative processes have only become more advanced since with the standardization of BIM in the late 1970s but little innovation has made iterations a consistent challenge.
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Growing Complications
The bridges described above are both feats of engineering as well as works of complex social navigation.
Not only did the architects and engineers have to contend with rival factions within civil society and finance, but they also had to grow with the growing need for safety and health among workers.
Because of the new technologies, workers also had to become increasingly skilled in steel fabrication, and the massive spans required heavy equipment.
Large steam-based cranes were used for much of the hoisting, but huge amounts of the project such as attaching steel were still done by skilled laborers using basic tools.
These fields of steel development were also used to complete some of the large-scale buildings in the city, such as the Woolworth Building in Manhattan, which was completed in 1913 and was the tallest building in the world.
Steel construction has only become more streamlined since then, though builders still rely on skilled individuals to put the structures together.
The bridges were also essential in connecting the boroughs with the subway system, as most the major East River crossings include subway lines today.