The Brooklyn Bridge

In the 19th century, the booming New York communities of Brooklyn and Manhattan were divided by the East River. A bridge was the answer, but it would require an engineering feat such as the world had never before seen. In the end, a bridge was erected, but at the cost of the death of its chief designer and a life of suffering for its chief engineer..

In the middle of the winter of 1852, engineer John Roebling found himself trapped on a ferry going between the city of Brooklyn and Manhattan Island. The waters had frozen solid around the boat and Roebling and his 15-year-old son, Washington, spent hours on the vessel waiting for it to work its way through the ice. As he sat there, the elder Roebling, a renowned civil engineer, pondered the possibility of building a bridge between these two bustling cities to alleviate this problem. However erecting such a structure would be no easy feat. The East River, which was more an arm of the sea rather than a river, was a third of a mile wide and subject to rushing tides and swirling hazardous waters.

John Roebling's Dream

When Roebling returned to his home in Trenton, NJ, that winter, he began to seriously study the problem of the East River bridge and draw up plans. Roebling, a German immigrant, was already well known for the bridges he had built at Pittsburgh, Cincinnati and Niagara Falls. Given his experience, Roebling decided that the bridge at Brooklyn should be a suspension bridge. Such a bridge could span long distances but needed only two supports. However, the longest suspension bridge built so far was completed in Wheeling, West Virginia in 1849. It had a span between its towers of only around 1,000 feet. A bridge across the East River would need a span of about 1,600 feet between towers, more than 50% longer.

Because of this, Roebling's design called for a bridge of spectacular dimensions. The supporting towers, built of stone in the gothic style, would stand nearly 300 feet tall. The roadbed of the bridge itself would be a huge 85 feet wide. To support the Manhattan tower it would be necessary to excavate an incredible 78 feet underwater through the muck of river bed to the bedrock below. The whole bridge, including the approaches, would be enormous at over a mile in length. All in all, such a construction in the mid-19 the century would require amazing effort.

Despite Roebling's sterling reputation, critics were skeptical about his bridge plan. Suspension bridges were a new design and many of them, such as one at Angers, in France, had suffered spectacular collapses. In 1866, however, another freeze of the river shutting down ferry service made it obvious that something had to be done. The next year the New York Bridge Company was formed by an act of legislature. The company appointed Roebling as the chief engineer of the project.

Unfortunately, during the planning stage for the bridge John Roebling was badly injured in an accident on June 28th 1869. He was standing on a dock surveying the location for the bridge's Brooklyn tower when a speeding ferry hit the wharf. Roebling's foot was crushed. Despite the amputation of his toes, lockjaw set in and he died about a month later on July 22nd.

Fortunately, his son, Washington, was a fully trained engineer by then and had already assisted his father with a bridge project, giving him an understanding of the older man's methods. His knowledge of the East River bridge plans was exhaustive, so the company board appointed Washington as the new chief engineer as of August, 1869.

The Dangerous Caissons

The first challenge in erecting the bridge was to build the foundation for the bridge towers. Since the towers were to be located in the river, a device called a caisson would be used to excavate the riverbed down to the bedrock. A caisson is a large wooden box (bigger than the tower foundation) with an open bottom. It is lowered to the river bottom and pressurized air is pumped into it to keep the water out.

Men can then enter the caisson through an "airlock," which is a closed room with doors both to the outside and inside of the device. Workers enter the room at normal pressure, then the outside door is closed and air is pumped in until the pressure is equal to that inside the caisson, so the inner door can be opened. Workers can then climb down to the bottom of the casing and dig at the river bed under relatively dry conditions.

At the time that the Brooklyn Bridge was built, not much was known about the effect of high pressure air on human bodies, especially at the depths involved at the bottom of the East River on the Manhattan side. Under pressure, nitrogen in the air can be dissolved into liquids in the body. When the pressure is lessened, the gas can come out of those solutions and form bubbles in dangerous places. Often a sufferer would be bent in two by the pain, which gives the disease its nickname: "The Bends."

The solution to the problem is to decompress anyone leaving the caisson very slowly so that the dissolved nitrogen can be carried away and released into the lungs. Unfortunately, this was unknown to scientists during the era that the bridge was being built.

This condition, often called "Caisson Disease," made working in the caissons very dangerous. Workers would seemingly be struck with the disease randomly after they emerged from the airlock. The symptoms varied widely from person to person but included swollen joints, vomiting, double vision, dizziness, paralysis and sometimes even death.

In addition to the threat of the bends, there was also the more routine horror of working in the dark, dank conditions of the caisson. Edmond Farrington, a master mechanic on the project wrote:

Inside the caisson, everything wore an unreal weird appearance. There was a confused sensation in the head… The voice sounded faint and unnatural and it became a great effort to speak. What with the flaming lights, deep shadows, the confusing noise of hammers, drills and chains, the half-naked forms flittering about … one might get a sense of Dante's inferno.

Eventually the muck of the river bed was cleared away and concrete was poured inside the caissons to create the foundations for the bridge's gigantic towers. While directing this operation inside the caisson on the Manhattan side in 1872, however, Washington Roebling himself came down with a severe case of the bends that nearly took his life. He was taken to his home in Brooklyn where observers did not think he would last the night.

Even with Washington Roebling sick, construction on the bridge, which was only about half finished, continued. The Brooklyn tower rose first, followed by the one on the Manhattan side. Washington, seemingly by an act of shear will, began to recover, though he would suffer the pain of this disease for the rest of his life.

The Towers Rise

Through the rest of the year, the towers remained under construction. The granite blocks, quarried in Maine, were lifted into position by great derricks. Ninety thousand tons of them were used in each tower. By the end of the year the Brooklyn tower was about 140 feet high, half of its eventual height. The Manhattan tower, likewise, was not far behind.

The next year, 1873, work began on the anchorages. These were to tie the bridge's main cables to the ground. At each anchorage, four 23-ton anchor plates would be buried under tons of masonry. Each would hold one of the bridge's four cables from moving.

The Brooklyn Bridge is a hybrid, cable-stayed/suspension bridge. John Roebling had designed it to be six times stronger than necessary using two different, independent support systems. The suspension part of the bridge worked by running four large cables across the length of the bridge. These were anchored on each end and held aloft by the towers. From these cables, secondary vertical cables would be attached which ran down to the bridge's roadbed and held its weight.

In addition to the suspension design, the Brooklyn Bridge also used a cable-stayed system. In this design the cables that support the roadway run up on an angle to the top of the tower, then down the other side to another portion of the roadway. The weight of the two sections of the roadway balance on the tower, keeping them stable.

Making the Steel Cables

By 1876 both the anchorages and the towers were ready. Next, the bridge would need the cables to be put in place. The decision was made to use the newly-invented steel wire in the cable, something that had never been done before. A company run by J. Lloyd Haigh was given the contract to make the cable. Washington, whose family was also in the steel cable business, did not trust Haigh to make a quality product and had it inspected before it was shipped to the bridge. However, Colonel William Paine, in charge of the inspections, began to believe that Haigh was somehow still substituting inferior wire. Paine arranged for his men to actually follow a wagon full of inspected wire to the bridge and found out that it was stopping at a secret warehouse along the way where the "good" wire was unloaded and an inferior wire was substituted.

From then on all shipments were escorted to make sure there were no unscheduled stops. Haigh was forced to add 150 extra wires to the cables, at his own expense, to make up for the poor quality cable he had been using.

In the fall of 1877 they started to install the main cables on the bridge. Each piece of steel wire was attached to the Brooklyn anchorage, then run over the top of the two towers and down to the Manhattan anchorage. Two hundred and eighty of these wires were woven into a "strand" and 19 of these strands became a cable. The cable was then bound and wrapped with more wire. The whole process to create the four main cables took about a year.

The final portion of the project was to create the roadbed for the bridge. Steel beams to support the roadbed were hung from the suspender wires, which were in turn hung from the main cables. By the end of 1878, a temporary wooden plank path was built on top of the beams so it was possible to actually cross the bridge on foot. This milestone was recognized by a small celebration. Unfortunately, Washington Roebling was still too sick to participate, but the trustees and engineers honored Emily Roebling, his wife, by allowing her to make the first official crossing.

Opening of the Bridge

Unfortunately, by the time the bridge was finally opened on May 24, 1883, Washington was still confined to his bed. He could only watch the dignitaries at the bridge making their speeches by telescope. Among the attendees at the ceremony was the President of the United States, Chester A. Arthur, and the governor of New York, Grover Cleveland. Because he could not attend the celebration at the bridge, Washington's wife, Emily, who had become his de facto chief assistant in the project, arranged for a reception at their house where Washington was congratulated by a select group of friends and dignitaries.

Within 24 hours of the bridge's opening it is estimated that 250,000 walked across the structure. That evening the night was filled with magnificent fireworks display and newspapers were hailing the bridge as "the Eighth Wonder of the World." The construction of John Roebling's vision changed the character of New York City forever, connecting Brooklyn and Manhattan into one urban area.

The cost of this wonder was high, however. In addition to John Roebling's life, 27 workers perished during the 14 years of construction. Also for the rest of his life Washington Roebling would have to deal daily with the pain that came from finishing his father's magnificent conception.

Copyright Lee Krystek 2015. All Rights Reserved.