The Brooklyn Bridge Construction: The Cable Suspension Design, the Caisson Disease Epidemic, and the Woman Who Finished It When Her Husband Couldn’t

The Brooklyn Bridge took 14 years to build. It killed its original designer, partially paralyzed his son, disabled over 100 workers with a disease medicine did not yet understand, and was completed by a woman who taught herself engineering while running the project from her bedridden husband’s bedroom. This is one of those stories where every element sounds like it has been added for dramatic effect, and every element is a documented fact.

How It Started, and How That Went

John Augustus Roebling was the German-born engineer who designed the Brooklyn Bridge. By the late 1860s, he had already built several suspension bridges, including the Cincinnati-Covington Bridge, the direct engineering prototype for the Brooklyn project. He had also developed his own method for weaving steel wire cables that made large-scale suspension bridges feasible in ways they had not been before.

In late June 1869, Roebling was surveying the East River site in Lower Manhattan when an approaching ferry crushed his foot against some wooden pilings. Tetanus developed from the injury, and he died three weeks later. He never broke ground on the bridge he designed.

His son, Washington Roebling, took over as chief engineer. Washington had worked alongside his father on the Cincinnati bridge and knew the design well. At 32 years old, he was now in charge. Construction began on January 2, 1870.

What the Caissons Were and What They Did to People

The Brooklyn Bridge required enormous foundations sunk into bedrock beneath the East River. To build them, engineers used pneumatic caissons: giant airtight wooden chambers, open at the bottom, pressed down through the riverbed while workers dug inside. Compressed air kept the water out. Workers entered and exited through airlock chambers.

The compressed air made it possible to work underwater. It also caused a condition nobody understood. Workers who moved from the high-pressure caisson environment to normal air too quickly experienced nitrogen bubbling out of their blood. The results ranged from joint pain to paralysis to death. Workers called it caisson disease. We now call it decompression sickness, or the bends.

At the time, the cause was entirely unknown. Nobody had established a connection between the compressed air and the symptoms. Nobody knew that slowing the ascent from high pressure would prevent the nitrogen from forming bubbles. Workers kept getting sick, and construction continued anyway.

As a result, over the course of the project, more than 100 workers died or suffered permanent disability from caisson disease. Temperatures inside the caissons reached around 80 degrees Fahrenheit. One engineer described the conditions as bringing Dante’s Inferno to life.

Washington Roebling spent more time inside the caissons than many of his men. In early 1872, after working 12 straight hours in one, he rose to the surface too quickly and passed out. The attack left him partially paralyzed, temporarily blind and deaf, and sensitive to light and sound for years. Essentially bedridden, he still had 11 more years of construction ahead of him.

Emily Roebling

Emily Warren Roebling had met Washington during the Civil War, when her brother, a Union general, invited her to visit his camp. Intelligent and well-educated for a woman of her era, she had attended Georgetown Visitation Convent, a prestigious school. Before construction began, she had also traveled with Washington to Germany, where he studied caisson engineering. She understood more about the project than most people realized.

When Washington became incapacitated in 1872, the situation should have ended his tenure as chief engineer. Several board members called for his replacement. Emily refused to let that happen.

She taught herself materials science, cable construction, and strength calculations. Additionally, she mastered the specific engineering problems of the Brooklyn Bridge project. She then became the daily interface between Washington, who directed from his bedroom window with field glasses, and the construction crew below. Instructions, explanations, decisions, contractor management: all of it went through her. For 11 years, Emily Roebling was the effective chief engineer of the Brooklyn Bridge, without the title, without the credit, and without anyone outside the inner circle fully understanding what she was doing.

At the opening ceremony on May 24, 1883, Congressman Abram S. Hewitt praised her publicly, describing her as the link between the chief engineer and the construction crew. This was an understatement. When the bridge opened, Emily crossed it first, traveling by carriage with a live rooster in her lap as a symbol of victory.

Today, the names of John A. Roebling, Washington Roebling, and Emily Warren Roebling appear inscribed on the structure as its builders.

The Engineering That Made It Work

The Brooklyn Bridge was the first major suspension bridge to use steel wire for its cables, replacing the iron wire of previous designs. Steel is stronger and more flexible than iron at the same weight, which allowed the cables to be thinner and the span longer. The main span between the two towers is 1,595 feet, making it the longest suspension bridge in the world when it opened. It held that record for 20 years.

The four main cables each contain 5,434 individual steel wires, wound into strands and then into cables about 15.75 inches in diameter. Workers laid the wires one by one using a spinning wheel that traveled back and forth across the span on a temporary footbridge. The process took years.

One scandal interrupted it. A wire manufacturer sold substandard steel wire that did not meet specifications. Workers had already incorporated some of it into the cables before the fraud came to light. However, engineers calculated that the cables would still bear the required load, and the decision was made to continue. The bridge has stood for 140 years, so the calculation was correct.

What It Cost

Fourteen people died during construction, according to official records. Historians believe the actual number was higher. Furthermore, more than 100 workers suffered permanent injury or death from caisson disease alone.

The financial cost was approximately $15.5 million, equivalent to several hundred million dollars today. New York City and Brooklyn jointly funded it, and cost overruns were significant. The project ran roughly 25 percent over budget.

Washington Roebling spent the rest of his life managing his symptoms. He never fully recovered from caisson disease but outlived the bridge’s completion by decades, dying in 1926 at 89. Emily Roebling died in 1903, at 59, having completed law school after the bridge finished and become an active advocate for women’s rights.