How the Brooklyn Bridge Was Built: The Story of One of the Greatest Engineering Feats in History

When Emi­ly Roe­bling walked across the Brook­lyn Bridge on May 24th, 1883, the first per­son to cross its entire span, she capped a fam­i­ly saga equal parts tri­umph and tragedy, a sto­ry that began six­teen years ear­li­er when her father-in-law, Ger­man-Amer­i­can engi­neer John Augus­tus Roe­bling, began design work on the bridge. Roe­bling had already built sus­pen­sion bridges over the Monon­ga­hela Riv­er in Pitts­burgh, the Nia­gara Riv­er between New York and Cana­da, and over the Ohio Riv­er between Cincin­nati and Cov­ing­ton, Ken­tucky. But the bridge over the East Riv­er was to be some­thing else entire­ly. As Roe­bling him­self said, it “will not only be the great­est bridge in exis­tence, but it will be the great­est engi­neer­ing work of the con­ti­nent, and of the age.”

New York City offi­cials may have had lit­tle rea­son to think so in the mid-1860s. “Sus­pen­sion bridges were col­laps­ing all across Europe,” notes the TED-Ed video above by Alex Gendler. “Their indus­tri­al cables frayed dur­ing tur­bu­lent weath­er and snapped under the weight of their decks.” But the over­crowd­ing city need­ed relief. An “East Riv­er Bridge Project” had been in the works since 1829 and was seen as more nec­es­sary with each pass­ing decade. Despite their mis­giv­ings, the author­i­ties were will­ing to trust Roe­bling with a hybrid design that com­bined meth­ods used by both sus­pen­sion and cable-stayed bridges. Two years lat­er, he was dead, the result of a tetanus infec­tion con­tract­ed after he lost sev­er­al toes in a dock acci­dent.

Roebling’s son Wash­ing­ton, a civ­il engi­neer who had fought for the Union Army at the Bat­tle of Get­tys­burg, took over the project, only to suf­fer from paral­y­sis after he got the bends while trapped inside a cais­son in 1870. For the remain­der of the bridge’s con­struc­tion, he would advise from his bed­room, relay­ing instruc­tions through his wife Emily—who became after a time the bridge’s de fac­to chief engi­neer. She “stud­ied math­e­mat­ics, the cal­cu­la­tions of cate­nary curves, strengths of mate­ri­als and the intri­ca­cies of cable con­struc­tion,” writes Emi­ly Nonko at 6sqft.  She knew the bridge so well that “many were under the impres­sion she was the real design­er.”

“1.5 times longer than any pre­vi­ous­ly built sus­pen­sion bridge,” the video les­son notes, Roebling’s design worked because it used steel cables instead of hemp, with tow­ers ris­ing over 90 meters (295 feet) above sea lev­el. This is almost three times high­er than edi­tors at the New York Mir­ror pro­ject­ed in 1829, when they called the brand new “East Riv­er Bridge Project” an “absurd and ruinous” propo­si­tion. “Who would mount over such a struc­ture, when a pas­sage could be effect­ed in a much short­er time, and that, too, with­out exer­tion or trou­ble, in a safe and well-shel­tered steam­boat?”

Just six days after Emi­ly Roe­bling crossed the new­ly opened Brook­lyn Bridge, a stam­pede killed twelve peo­ple, and months lat­er, P.T. Bar­num led 21 ele­phants over the bridge to prove its safe­ty. Who would cross such a struc­ture? It turned out, for bet­ter or worse, any­one and every­one would dri­ve, walk, run, sub­way, bike, scoot, climb up, leap from, and oth­er­wise “mount over” the East Riv­er by way of the neo-goth­ic won­der (and lat­er its much ugli­er sib­ling, the Man­hat­tan Bridge). Learn much more in the short les­son above how John A. Roebling’s bom­bas­tic claims about his design were not far off the mark, and why the Brook­lyn Bridge is one of the great­est engi­neer­ing feats in mod­ern his­to­ry.

Relat­ed Con­tent:

A Mes­mer­iz­ing Trip Across the Brook­lyn Bridge: Watch Footage from 1899

An Online Gallery of Over 900,000 Breath­tak­ing Pho­tos of His­toric New York City

Immac­u­late­ly Restored Film Lets You Revis­it Life in New York City in 1911

Josh Jones is a writer and musi­cian based in Durham, NC. Fol­low him at @jdmagness