Bridge paper

The builders could not have imagined that it would be still in use over 100 years after its opening (ENDEX Engineering 2007). So who were these people who built the bridge? What gave them the energy to construct one of the world’s greatest marvels? It can be safely said that there were only three people who believed in the project from start to finish. These were the Roeblings’; father, son, and son’s wife. The story of their achievement is the same so while the remainder of this paper will dwell on son Washington Roebling’s achievements it could just as easily be the story of the other two.

Education and Practical Training Washington Roebling was the son of an impressive man, born May 26th 1837 in Saxonburg, Pennsylvania. Few remember his father; which says something about Washington’s accomplishments. His father owned a very successful wire rope business and was a pioneer in the field of iron and steel cable. As Washington grew older, he began to help his father in engineering endeavors. Since wire rope is a superb match for suspension bridge construction with flexibility and a high tensile strength, the Roeblings’ did much work in this field (Invention Factory 2007).

Before entering the army, Washington went to Rensselaer Polytechnic Institute in Troy, New York. Much like civil engineering majors today, it took him four years to receive his degree, but it was much more hands on than is allowed today. The education back in the 1800’s was mostly on-the-job training, whereas today computer technologies and weeding out nonconformists through mindless homework play a huge role in education. Today modern engineering students, co-ops and internships help provide realistic situations.

During the civil war, in which Washington Roebling served superbly as an engineer officer in the 6th New York Calvary, Washington began to make a name for himself. He built a 1200 foot suspension bridge across the Rappahannock River and spent much of his time in a hot air balloon, the civil war version of air reconnaissance. Before the construction of the Brooklyn Bridge, John sent Washington to Europe to study new methods for the sinking of the foundations. Later in his life, Washington would bestow almost all the credit and knowledge obtained for the Brooklyn Bridge to his father.

Knowledge from the army and from his dad were used in his finishing of the two giant granite masonry towers that climbed 276 feet above high water over which to suspend wire cables to support a road 135 feet at its highest point above the water. This height was needed for ships to pass under. The bridge would be wide, at 85 feet, and the cables that would support the span would be bound to huge anchorages of 60,000 tons each (ENDEX Engineering 2007). The Brooklyn Bridge was an innovative project. Table 2 shows all the accomplishments and innovations that are related to the Brooklyn Bridge.

Socioeconomic and Political Environments After the Civil War, Washington returned to the family business, assisting in completing two more suspension bridges across the Ohio River (Invention Factory 2007). During this time Washington’s father, John, became interested in building a bridge across the East River. New York legislators finally realized the need for a route over the East River and passed a bill for some sort of construction. The largest restriction that the plans for the structure had to abide by was its height over the river, which was set to avoid contact with masts of ships that passes under it.

This idea of a bridge was

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nothing new. For 60 years, different ways of linking Brooklyn and New York had been considered (Trachtenberg 1965). Soon, the city of New York set up the first ferries from Manhattan to Brooklyn in 1812 but more versatile transit was needed. The Brooklyn Bridge was erected out of economic necessity and urban sprawl (Brooke and Davidson 2006). New York City was a huge immigration hub. In the mid-1800’s, men and women began to emigrate from Europe and many settled in Brooklyn. As a result, many lived in boarding houses.

Brooklyn at this time consisted mainly of Irish immigrants. Immigrants were paid very poorly considered the work they performed as it was always the most demanding and risky. From 1860 to 1870, Brooklyn’s population growth was 50 percent; the fastest growing city at the time (Trachtenberg 1965). Manhattan was the opposite of Brooklyn, in that it was primarily a business district in the mid 1800’s. Approximately 40 percent of wager earners in Brooklyn had jobs in Manhattan. The northeastern coast was a major hub for imports and manufacturing goods after the Erie Canal was built.

At the time the only way to get from Manhattan to Brooklyn was by fairy which was often slow and hampered by storms. Taking the ferries tended to be very dangerous. Plans for a either a bridge or a tunnel over the East River were interrupted by the Civil War. Bridges were thought to be impossible as no materials where known to be strong enough to support the needed span. Part of the problem was that the bridge needed to be high above the channel to allow masted ships to pass beneath it, even at high tide. These details had proved insurmountable until then.

A fleet of ferries shuttled people and goods across the river every day. John Roebling, with his wire rope business and history of successful suspension bridges, had a viable solution (Invention Factory 2007). The Brooklyn Bridge would use steel in its cables. Good wrought iron breaks at 30 tons where good steel of the same size breaks at 75 tons (2. 5 times stronger) (Hart 1967). While it was not trusted at the time because of its newness, the Roeblings’ had faith in its strength. At the time, suspension bridges were viewed with suspicion.

Many had failed in storms or under live loads; however, none of the bridges John had built had ever failed. One of the reasons he had succeeded was that he made them very stiff, preventing flexing from wind that would plague other suspension bridge builders into the next century and most famously in the Tacoma Narrows Bridge in 1940, more than 70 years after John. After due debate, the Brooklyn Bridge Company was formed with John Roebling as chief engineer (Invention Factory 2007). One thing that the times lent to the project was a good source of cheap labor.

Poor immigrants, mainly Irish, were the ones who worked the most on the bridge. They also took the brunt of the casualties. Approximately 20-30 people died during construction and administration viewed it as necessary and unavoidable. Labor was very manual and at the time workers had very little power in politics. The Irish workers did not enjoy the choice of date, as it coincided with the Queen’s birthday. Technological Context & Construction Details In December 1849, an accident mangled Roebling’s father’s left hand while undergoing testing on the innovative wire rope machinery.

This new technology would set this bridge far ahead of its time, utilizing a braded configuration allowing flexibility and easier handling (Trachtenberg 1965). The Brooklyn Bridge would use steel in its cables. Good wrought iron breaks at 30 tons where good steel of the same size breaks at 75 tons (2. 5 times stronger) (Hart 1967). While steel was not trusted at the time because of its newness, the Roeblings’ had faith in its strength. At the time, steel or no steel, suspension bridges were viewed with suspicion. Many had failed in storms or under live loads; however, none of the bridges John had built had ever failed.

One of the reasons he had succeeded was that he made them very stiff, preventing flexing from wind that would plague other suspension bridge builders into the next century and most famously in the Tacoma Narrows Bridge in 1940, more than 70 years after John’s lifetime. Construction was very hazardous at that time, even for chief engineers. At the start of the project, the Brooklyn Bridge Company lost a crucial member. A ferryboat crushed John Roebling’s foot when he was on site. After having his toes amputated, during which he declined anesthetic, an infection set in and killed him (ENDEX Engineering 2007).

Surprisingly there was little debate over who should succeed him. Washington Roebling was already deeply involved with the project so he was appointed successor (Invention Factory 2007). In 1872 disaster struck again. Washington himself was down in the caissons more than any one else. He was suddenly struck with what was called caisson sickness, and is what is modernly called the bends (Invention Factory 2007). This disease was not understood at the time and results from prolonged exposure to high pressures and then sudden decompression, allowing nitrogen bubbles to form in blood and possibly clog them.

Washington was not the first to fall ill from the bends, in fact, people had already died of it but work proceeded on. After coming back even though clearly sick, Washington was bedridden, crippled for the remainder of the project. He was only able to stand for 10 minutes at a time when the bridge opened in 1883 (Smithsonian Associates 2004). Washington remained head engineer giving orders from his bed but the person most visible to visitors at the project was his wife, Emily. She knew just as much about the project as Washington.

When a board of enquiry was put together to try to oust the bedridden head engineer she removed sufficient doubt from its members for Roebling to stay (Smithsonian Associates 2004). To say she was the head engineer would only be a very slight exaggeration. The towers that supported the span were made out of limestone, granite and concrete. Newly found techniques for making steel made it a cheap, strong metal for the suspension cables (Hart 1967). The first order of business was to sink the two giant caissons into the riverbed to support the towers (Figure 1).

These were made of 12 x 12 yellow pine beams and weighed by themselves 3000 tons, having 15 foot thick roofs to keep the excavators from getting crushed by the eventually 80,000 tons of rock piled on top to make up the Towers. John found a new way to devise a foundation. The caissons were floated into place and then sunk into position, driven downward by the towers on top and crews underneath removing the actual riverbed (ENDEX Engineering 2007). Once they reached solid ground the caissons would be pumped full of grout and serve as a perfect foundation. They were undoubtedly the most tedious and difficult part of the bridge construction.

Excavation methods consisted of shovel, pick, wheelbarrow, steel bar stone breakers, winches, and ten ton hydraulic jacks, eventually blasting after Washington Roebling conducted a series of experiments in the caisson. Initial rate of caisson excavation and lowering produced 6 inches per week, with a workforce of 360 people constructing the bridge (Trachtenberg 1965). Compressed air was used in the caissons to keep the water out, and the deeper they got (78 feet on the New York side, 45 feet on the Brooklyn side) the higher the pressure needed (ENDEX Engineering 2007). This was dangerous in more way than one.

Fires could be catastrophic, and occasionally there would be a blowout that subsequently would allow water back in. The largest of these air releases blew rocks and mud 500 feet into the air in 1870. Fires, from using dynamite, were the worst however. One was found smoldering in the 15 feet of wood under the Brooklyn Caisson, fed by compressed air (ENDEX Engineering 2007). Eventually some timbers were replaced and the rest of the holes were pumped full of grout. The New York caisson was stopped after 78 feet not because it had reached rock but because conditions had become intolerable.

As a result, to this day it rests on sand; surprisingly stable (ENDEX Engineering 2007). The Brooklyn and New York Towers were completed in 1875 and 1876 respectively (ENDEX Engineering 2007). The cables were strung after the completion of the towers. Perhaps the greatest calamity struck in the middle of this. A cable snapped, killing two men, and it was found to be very substandard (ENDEX Engineering 2007). Incidentally, the contractor who supplied the steel cable was not John Roebling’s Sons Co, which at the time was owned exclusively by Washington’s brothers. The cables were flawed.

Eventually, the wire in all the cables, including 1520 suspenders and 400 diagonal stays, was approximately 3600 miles long (ENDEX Engineering 2007). Personal Characteristics Washington fought in the civil war both on the ground as a military observer from hot air balloons. Washington served at Gettysburg with distinction on Little Round Top and was at the siege of Richmond (Invention Factory 2007). He became very noble and selfless, though cocky at times, during the Civil War. Perhaps the most important part of his war career, however, was that he met his wife to be, Emily Warren, because he served under her brother, General G.

K. Warren (ENDEX Engineering 2007). He ended the war at the rank of a Colonel. After the war he helped his father build the Cincinnati-Covington Bridge (now called John A. Roebling Suspension Bridge) before the Brooklyn Bridge. Despite many the huge hurdles of the Brooklyn Bridge project, among which was the fact that Washington became horribly sick and bedridden for most of the actual building from decompression sickness when the huge caissons for the twin towers were sunk in the Hudson riverbed (hence the traditional term ‘caisson sickness’), he managed to oversee all stages of its construction.

He did this only with the help of his wife Emily Warren Roebling, who almost every day visited the site and reported to him and who some felt built the bridge herself (The Great Engineers, 1967). The Brooklyn Bridge was opened May 24th 1883 by the president of the United States U. S. Grant, to fireworks and one cent ticket passes to cross. Apparently it was a great relief to Washington Roebling as his health began to slowly improve.

After the completing this engineering marvel in 1883, Washington lived a relatively quiet life, mostly as a result of being still partially crippled from his illness, and when his wife died in 1903 he remarried in 1908. He spent much of his time collecting minerals, which was his one great hobby, eventually having 16,000 specimens and ending up in the Museum of Natural History’s mineral and gem collection (Smithsonian Associates 2004). This hobby added balance to his life and probably kept him from accomplishing very much else as it took so much of his time.

He outlived his wife Emily and remarried. He became president of his fathers company, John Roebling’s Sons, in 1921 at the age of 79. He brought incredible energy to the position, modernizing the factory with electricity and adding a galvanized wire section. The business prospered under his leadership until 1926, when Washington Roebling died. When one has hobbies such as athletics help keeps a healthy time management of school work and fun down time. College is one of the few times were one can have fun.

There is a time and place to enjoy your hobbies but to enjoy these hobbies one must put in an honest day’s work. Conclusion When the Brooklyn Bridge opened to traffic on May 24th 1883, it was one of the grandest engineering marvels of that century in North America. The construction was composed of many firsts. Despite innumerable setbacks, including the untimely death of the original designer of the plan, John A. Roebling, and the crippling of his son, Washington Roebling, who succeeded him in the chief engineer duties it, was finished in 14 years, having been commenced January 2, 1870.

At the time of completion it was 50% longer than any other suspension bridge, it was the first to use steel cables, much stronger than hemp or cast iron previously used. The towers that supported the four main cables (each of which supports a total dead & live load of about 6 million pounds) for the span were the largest stone and masonry objects of their kind rising approximately 276 feet above the high water mark (Smithsonian Associates 2004). The challenges of this are hard to fathom in today’s world of reinforced concrete.

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