The Golden Gate Bridge finished construction on April 19, 1937 — and fifty years later, the suspension would sag when hundreds of thousands walked on it at once.
During the working week, over 112,000 vehicles drive over San Francisco’s Golden Gate Bridge. But in 2020, this number fell by over 40% during the pandemic’s shelter-in-place orders. Given the GGB’s dimensions, about 1,200 passenger cars can fit on the bridge at once. Crunching some numbers: This means that almost three million tons of weight could be pushed down on the bridge’s suspension during rush hour.
That’s a fuck-ton of weight… literally. And, if you add an additional million-and-a-half ton to that figure we wrote above, you’ll have about the poundage that was weighing down the bridge when bipeds crowded the Golden Gate Bridge in 1987 to celebrate its 50th anniversary.
When the dip was noticed along the 1.7-mile bridge, bridge officials closed it to foot traffic as well, so that a half-million other people waiting to cross wouldn’t further strain the bridge’s already strained suspension.
On-site engineers repeatedly said that the bridge was in no danger of collapsing that day, though concerns quickly arose of the “no-escape, no exit” nature of the place where the crowd had gathered. (If someone panicked, they were stuck. If someone had a medical emergency, they were stuck. If someone decided the vibe wasn’t resonating, they were stuck.)
However, because the day’s weather was mild, concerns about heat stroke and exhaustion were quelled.
Originally, the bridge was engineered to hold just about 4,000 pounds for every foot of the structure. During the mid-1980s, aging concrete was replaced with a more modern (and much lighter) steel framework. This single building material swap allowed for the weight-bearing capacity to grow to 5,700 pounds per foot of bridge — a fact engineers present-day made abundantly clear during the 50th-anniversary festivities, which concluded with a pyrotechnic “waterfall” that showered from the Bridge to the Bay below.
Even if the bridge would’ve, in fact, surpassed its load-carrying limit on that May day in 1987, the Golden Gate Bridge wouldn’t have outright collapsed like in a thriller blockbuster featuring the Rock. Suspension bridges, like the Golden Gate Bridge, bend like a paperclip when weighted down with an unsupportable amount of weight.
They deform, rather than snap. And even if a part of the bridge did collapse, the entirety of the roadway would’ve fallen with it. Sections of the roadway are supported by cables and not by each other. Alas: If one piece of the “deck,” as it’s called, plunges, it doesn’t cause a domino-like effect that would see other pieces of road dive into the Pacific.
Amid a looming recession and spiraling anxieties re: the climate crisis and growing evergreen woes around Covid-19 (and now monkeypox), it’s nice to know that a hyperlocal marvel of human engineering can at least bear the weight of our heavy shoulders.