The Golden Gate Bridge makes strange, spooky noises. This event was reported by local residents who passed the legendary bridge in San Francisco, United States of America.
Some residents posted their experiences hearing strange noises while crossing the bridge. The sound that emerged sounded like a squeak and a groan in the wind.
One netizen, via the Twitter account @psychunseen, said that the sound heard was actually much louder and more confusing than what he recorded on the video.
The wind seems to create a kind of subtle howl that travels through the structure of the bridge so people can hear it in cars as they drive across the bridge.
The noise caused great disturbance to local residents. They had to deal with the constant screams every time the wind started to pick up.
Quoted from IFL Science, the noise is thought to originate from a bridge retrofit added in 2020, where the building structure will be secured in the event of high winds. The bridge retrofit in 2020 also added railings that have thinner slats than before, one of which is aimed at preventing suicides.
This addition appears to have had some unintended effect, as strong winds of 35.4 kph or more coming from the west create the lower notes, and winds of 43.5 kmph or more, create the higher frequency notes. As a result, together they make bridges often 'sing'.
Fortunately, such problems are taken seriously. Engineers have devised a plan to repair it. They will transfer samples of the fence down to a wind tunnel, to enable them to analyze how these structures generate noise and find ways to stop it.
The most likely solution was to add a series of U-shaped clips to be placed at each end of each blade to interrupt airflow through it, as well as prevent small eddies that were thought to be creating noise.
The clip reduces noise by up to 75% and only emits a sound that can be heard in very strong winds traveling 101.4 km/h and above.
According to engineers, this is the most cost-effective solution. However, installing clips on both sides of 12,000 slats on a new fence won't be cheap. This new modification is estimated to cost around USD 450 thousand to complete.
"The proposed solution will be invisible to most users of the Golden Gate. Importantly, however, it will not affect the stability of the bridge structure during sustained high winds. The installation is expected to be completed in the first half of 2023," the engineers wrote in their proposal.