Brooklyn Bridge

The bridge was conceived by German immigrant John Augustus Roebling in 1852,[17] who spent part of the next 15 years working to sell the idea.[18] He had previously designed and constructed shorter suspension bridges, such as Roebling's Delaware Aqueduct in Lackawaxen, Pennsylvania, and the John A. Roebling Suspension Bridge between Cincinnati, Ohio, and Covington, Kentucky.

In February 1867, the New York State Senate passed a bill that allowed the construction of a suspension bridge from Brooklyn to Manhattan.[19] Two months later, the New York and Brooklyn Bridge Company was incorporated. The company was tasked with constructing what was then known as the New York and Brooklyn Bridge.[20][21] While conducting surveys for the bridge project, Roebling sustained a crush injury to his foot when a ferry pinned it against a piling. After amputation of his crushed toes, he developed a tetanus infection that left him incapacitated and soon resulted in his death in 1869. His 32-year-old son, Washington Roebling, was later designated to replace his father.[22] "After a week I had become sufficiently composed to take a sober look at my own situation," Washington later wrote. "Here I was at the age of 32 suddenly put in charge of the most stupendous engineering structure of the age! The prop on which I had hitherto leaned had fallen -- henceforth I must rely on myself -- How much better when this happens early in life, before we realize what it all implies."[23] Construction of the Brooklyn Bridge began in 1869.[12] The bridge's two towers were built by floating two caissons, giant upside-down boxes made of southern yellow pine, in the span of the East River, and then beginning to build the stone towers on top of them until they sank to the bottom of the river. Compressed air was pumped into the caissons, and workers entered the space to dig the sediment, until the caissons sank to the bedrock. Once the caissons had reached the desired depth, the caissons were filled in with brick piers and concrete. The whole weight of the bridge still rests upon these constructions.[24] Many workers became sick with the bends during this work.[25] This condition was unknown at the time and was first called "caisson disease" by the project physician, Andrew Smith.[26][27] Washington Roebling suffered a paralyzing injury as a result of "caisson disease" shortly after ground was broken for the Brooklyn tower foundation on January 3, 1870.[28] Roebling's debilitating condition left him unable to physically supervise the construction firsthand. As chief engineer, Roebling supervised the entire project from his apartment with a view of the work, designing and redesigning caissons and other equipment. He was aided by his wife, Emily Warren Roebling, who provided the critical written link between her husband and the engineers on site.[29] Emily Warren Roebling understood higher mathematics, calculations of catenary curves, strengths of materials, bridge specifications, and intricacies of cable construction.[30][29][31] She spent the next 11 years helping to supervise the bridge's construction. When iron probes underneath the caisson for the Manhattan tower found the bedrock to be even deeper than expected, Roebling halted construction due to the increased risk of decompression sickness. He later deemed the sandy subsoil overlying the bedrock 30 feet (9.1 m) below it to be firm enough to support the tower base, and construction continued.[32] The construction of the Brooklyn Bridge is detailed in The Great Bridge (1972), the book by David McCullough,[29] and in Brooklyn Bridge (1981), the first PBS documentary film by Ken Burns.[33] Burns drew heavily on McCullough's book for the film and used him as narrator.[34] It is also described in Seven Wonders of the Industrial World, a BBC docudrama series with an accompanying book, as well as the book Chief Engineer: Washington Roebling, The Man Who Built the Brooklyn Bridge (2017).[35]