As It Happens

Engineers are figuring out how to make the Golden Gate Bridge stop humming

Last year, the Golden Gate Bridge started to emit a mysterious hum. Now a team of engineers, including Ontario-based firm RWDI, are trying to silence it.

Ontario-based engineer firm RWDI enlisted to help find a solution

Engineers believe the retrofitted railing is causing the Golden Gate Bridge to hum loudly. (Jeff Chiu/The Associated Press)

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A year after San Franciscans first noticed a loud, mysterious hum coming from the Golden Gate Bridge, a team of engineers are hard at work trying to figure out how to silence it. 

Residents and bridge workers first noticed the hum last year, after the west sidewalk of the bridge was retrofitted with new, more aerodynamic railing in order to make the 84-year-old bridge safer in high winds.

"After studying the effect extensively, we now know that when high winds pass through those new railing slats with a specific angle, [it] creates that humming sound or effect that people have heard for miles away from the bridge," Paolo Cosulich-Schwartz, public affairs manager for the Golden Gate Bridge, told As It Happens host Carol Off. 

According to the San Francisco Chronicle, the hum can be heard as far as Daly City, approximately 16 kilometres away.

"It's really loud," San Francisco resident Aneela Brister told the Chronicle. "Huge and all-encompassing. It makes you worry if the bridge is coming apart."

The hum has inspired all kinds of reactions. It's been compared to a "giant orange wheezing kazoo," and the soundtrack for a David Lynch film

Cosulich-Schwartz says he's heard "mixed feedback" about the hum, which he pointed out shares frequencies that are used to calibrate musical instruments, giving it an "intrinsic musical quality." 

"Understandably, those that live close to the bridge and can hear the sound from their homes have tended to find it distressing," he said.

"But some people have also told us they enjoy the sound. They'd like it to stay."

Despite the handful of fans, Cosulich-Schwartz says his team has been hard at work over the last year, testing designs that they hope will eliminate or dampen the sound.

Golden Gate engineers have even enlisted Ontario-based engineer firm RWDI to help.

Last fall, a scale model of the new bridge railing was brought to a wind tunnel in the province to try to recreate wind conditions experienced at the Golden Gate Bridge. The railing is designed to withstand winds up to 160 kilometres per hour.

"We've been able to recreate the humming effect and we've also been able to test various modifications to the railing that can dampen or potentially eliminate the noise," said Cosulich-Schwartz.

The team aims to announce a solution this summer.

"Our hope is that once we come out of the final testing that we have a solution that is cost-effective and will be easy to implement and soothe our neighbours' ears very shortly."


Written by Althea Manasan and Lito Howse. Interview with Paolo Cosulich-Schwartz produced by Jeanne Armstrong.

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