A ghostly, ear-rattling thrum emanating over the Golden Gate Bridge and throughout San Francisco’s Presidio neighborhood appears to be the result of high winds gusting through new slats on the bridge handrails.
Officials at San Francisco’s 311 call center acknowledged the issue on Twitter after it snowballed Friday night, with multiple users posting recordings of the deafening noise.
We can heat this in our house more than three miles away from the bridge. It's crazy making.https://t.co/IM0UbEcZ1c
— Ray Ryan (@rjrjr) June 6, 2020
Some of these audio records were taken in cars tooling across the bridge. In one posted Friday afternoon, a wall of sound seemed to envelope the vehicle, drowning out the engine and the low crackle of a car radio.
While many people flinched at the noise and began spewing complaints on social media, others said it was beautiful. Paolo Cosulich-Schwartz, a spokesman for the Golden Gate Bridge Highway and Transportation District, said the throbbing musical tones “were a known and inevitable part of a wind retrofit project” that the bridge had planned for years.
As part of that larger project, engineers replaced the thick, chunky slats on the western handrail with thinner slats, designed the help make the orange span more aerodynamic. Those slats allow more air to flow on the bridge, enabling the structure to withstand gusts of up to 100 miles per hour, as opposed to 68 miles per hour with the old rails.
We can heat this in our house more than three miles away from the bridge. It's crazy making.https://t.co/IM0UbEcZ1c
— Ray Ryan (@rjrjr) June 6, 2020
Work on that element of the project began last year, and it’s now three-quarters of the way done.
“The humming or singing is indeed part of the wind retrofit,” Cosulich-Schwartz said, noting that officials had heard these tones before, when they built scale models of the bridge and conducted wind tunnel testing, creating typical weather conditions for the San Francisco Bay.
So, wall-to-wall humming may be a feature of the Golden Gate Bridge going forward. But only at very specific times, when strong winds blow from the west — as they did Friday afternoon.
Rachel Swan is a San Francisco Chronicle staff writer. Email: rswan@sfchronicle.com Twitter: @rachelswan
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Hear that ghostly hum on the Golden Gate Bridge? It's here to stay - San Francisco Chronicle
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