John Roebling, the creative genius behind the Brooklyn Bridge project, had first envisioned it in 1852 after having witnessed the horrible delays caused by the East River choked with ice. However, because of suspicions among the public of whether a bridge that would have to be wide enough to allow boats to pass under it and strong enough to sustain the terrible winds and powerful currents of the river was possible, the project seemed unrealistic. The winter of 1866/1867, which was one of the worst ever recorded in New York, forced the people of Brooklyn to demand a bridge.
As a result, on April 16, 1867, the New York legislature passed a bill which would “incorporate the New York Bridge Company, for the purpose of constructing and maintaining a bridge over the East River, between the cities of New York and Brooklyn. ” (1, pg. 16) By June of 1869, John Roebling had completed the design for the bridge and work could finally begin. However, due to an unfortunate on-site accident, Roebling died shortly thereafter. All responsibility for the bridge was assumed by his son, Washington Roebling, who was named the new chief engineer. Time Management – Include time estimates for each stage of wbs.
Construction on the bridge began in fall of 1869 and was completed May 1883, taking the bridge about fourteen years to build. Despite having as talented a chief engineer as Washington Roebling who provided very detailed plans for workers to follow, “the bridge had taken two and one half times as long as the five years John Roebling had predicted”. (1, pg. 104) This is in part due to some of the unforeseen problems with caissons, the underwater foundation Washington Roebling had decided to build the bridge upon, which at the time had been “used for small bridges in Europe, but the ones for the Brooklyn Bridge had to be much bigger. (3, pg. 16) On the other hand, some unexpected caisson problems were dealt with successfully, thereby, avoiding additional delays. Construction on the first of the two caissons to be built, launched, sunk and filled with concrete started with the Brooklyn side of the river in January 1870 and ended in March 1871, taking a little over a year to complete. The caisson had been delivered by the contractor on time and launched into the river without any problems. However, digging down through the river with hand tools, as there was no electrical power, proved to be a formidable task, where “the rate of descent had been less than six nches a week” which “would take nearly two years to sink just the one caisson. ” (2, pg. 196)
With an army background, Roebling knew the answer was blasting which would save time and effort. With such great ideas as blasting being implemented to help speed things along, there were also crises that if they had been handled with as much expertise would not have resulted in the time lost and increased costs experienced. Towards the completion of the Brooklyn caisson, a fire caused by the carelessness of a worker put the project behind “more than two months and cost $15,000. (1, pg. 48) Since compressed air within the caisson made the fire worse, Roebling ordered water to be continuously hosed in areas affected by the fire until he was certain the fire had been put out through drilling holes into the wood. When the fire was found to still be burning couple of hours later, decision was finally made to flood out the caisson to ensure the fire was out. Roebling also decided to fill the bored holes with concrete to reinforce the wood. However, the job had to be undone once it was discovered that the wood beneath the concrete was covered with charcoal.
Any decay in the wood supporting the towers would be unsafe. As a result, he had all concrete taken out and the charcoal scraped away, with much of the wood replaced. Had the decision to flood the caisson been taken earlier, the outcome would have been much different. Intervention Although a lot had been learned through the sinking of the first caisson, the second caisson, which started in May 1871 and completed in June 1872, had challenges of its own. The New York caisson required a lot more digging as the bedrock had still not been reached at 71 feet, when the first man died of the caisson disease.
The Brooklyn caisson had been easier to deal with in this respect as it “had reached its final resting place at 44. 5 feet below the high-water line” (1, pg. 53). As another worker died of the disease, at 78. 5 feet, Roebling made the toughest decision of his career. Since continuing to dig “would have meant enormous expense as well as time lost blasting the bumpy rock ridge into an even surface” and “more lives lost to caisson disease”, he investigated the foundation to determine whether it was stable enough to support the tower.
Once he confirmed that “the strata showed no signs of having been disturbed since the time of deposit several millions of years in the geologic past and so in all likelihood it would remain perfectly stable” (2, pg. 293), he made the decision to stop digging and let the tower stand on sand and gravel instead. Procurement Procuring materials for the bridge construction had its own share of obstacles. Construction of the caissons was of the most vital concern to Roebling. The caissons required were so enormous that they had to be built in a shipyard by a shipbuilder called Webb & Bell.
The extent of risks involved with such an extraordinary order could be understood from the fact that the firm insisted on being paid in advance. However, because the specifications provided to the shipbuilder were very detailed and accurate, the entire process went smoothly. Things did not go as smoothly, however, for the wiring contract which “called for 6. 8 million pounds of wire” (2, pg. 358). In December 1876, bids received from various manufacturers were reviewed for quality and cost efficiency. The specifications called for steel wire of what was known as Number 8, Birmingham Gauge (this was a diameter designation), with a breaking strength of not less than 3,400 pounds. ” Once the tests were completed, the contract was awarded to J. Lloyd Haigh despite Roebling’s warning that he “had no standing, commercially or otherwise” (2, pg. 405). The work of spinning of the cables began on June 11, 1877. In November, one of the wires snapped. Upon inspection of the wires supplied, Roebling found they were as brittle as glass. It was found that “J. Lloyd Haigh, contractor of the cable wire, had been perpetrating a colossal fraud. ” (2, pg. 402) He had been replacing the accepted wire with rejected wire before it was sent off to the bridge. Unfortunately, all the rejected wire had already been worked into the cables and could not be removed. Fortunately, since “the cables had been designed to have a margin of safety of six, that is, they were six times as strong as they had to be”, Roebling concluded that it was perfectly safe, as long as “each of the cables would contain some 150 more wires than originally planned” (2, pg. 06). The contract was taken from Haigh in September 1877 and awarded to Roebling instead. Despite this obstacle, on October 5th, 1878, “the last wire went over, one year and about four months after the cable spinning had begun, or eight months sooner than Roebling had expected” (2, pg. 410). -Limestone Human Resources Key figures: Board of Trustees, Project Manager Considering the obstacles that the chief engineer and his team were able to overcome in building the Brooklyn Bridge, there could not have been a team better suited for the project.
According to David McCullough, since the very beginning of the project, there had been a lot of emphasis placed on verifying the merits of the person the project will be led by. For example, there had been a tour arranged in April 1967 “for everyone to go take a look at some of Roebling’s existing works to see how he had previously handled somewhat analogous situations. ” (2, pg. 35) The attendants consisted of “a representative body, having an even balance of engineering talent, business acumen, and public spirit. Once all were satisfied that John Roebling could indeed build a suspension bridge strong enough to sustain the East River, the legislature would be passed and work of surveying and designing would begin. John Roebling’s past experience (suspension bridges) However, two years later, on June 28, 1869, John Roebling would die as a result of an on-site accident. It would be decided that “Washington Roebling would take up right where his father left off and that no man was better equipped for the job. (2, pg. 97) Bearing the knowledge of sinking of caissons under compressed air and having assisted his father in the preparation of the first designs, there indeed was no one else who was more familiar with John Roebling’s ideas and project. Washington Roebling was better with people, took over his father because of his knowledge, interacted with other engineers. He also worked alongside workers in the caissons, which made him disabled, which is when Emily Roebling assisted.
On one hand, there had been no hardships experienced in appointing for the chief engineer’s position, however, there was one job that was quite a task to keep filled. Earning $2. 00 a day, a workman was subjected to a dark, muddy, and sweaty work environment inside the caisson. “It was no wonder that one man out of three quit every week. In fact, the labor force on the job was so transient, a total of 2500 men worked on the Brooklyn caisson during the ten months it took to sink it. ” (1, pg. 35) As time inside the caisson passed, the workers were subject to the caisson disease. The oundations to support the bridge towers needed to be built on a solid surface instead of the muddy river bottom, which is why the workers “had to dig down through the mud to reach bedrock. ” (3, pg. 16) To do this, enormous wooden boxes called caissons were used. “The caissons sat on the river bottom and protected the workers inside them as they dug. ” The water under the open caisson bottom was kept out using compressed air. As the caisson sank lower due to the digging below and the weight of the tower being built above them, more compressed air was pumped into the caisson to keep the water out.
As a result, workers started experiencing the “symptoms of the caisson disease: stomach cramps, vomiting, dizziness, double vision, leg pains, paralysis. ” (1, pg. 53) Include pictures of workers subject to harsh working conditions This was due to the nitrogen that entered the bloodstream under compressed air atmosphere and formed bubbles in the blood when a worker returned to normal air atmosphere, which blocked the oxygen supply in the bloodstream. At the time, not much was known about this “disease”. Seeing the workers’ discomfort, Roebling appointed a doctor who studied the various cases and “at a depth of 65 feet, Dr.
Smith recommended decompressing in the air lock for only five minutes before returning to the surface. ” However, we know today that at that depth “the men should have decompressed in three stages in the air locks for two hours after each three-and-a-half-hour shift. ”(1, pg. 54) With that advice, the workers continued to suffer from the caisson disease, which resulted in couple of deaths.
References:
- The Brooklyn Bridge by Judith St. George
- The Great Bridge by David McCullough
- The Brooklyn Bridge by Elizabeth Mann
