A plan to hush Golden Gate’s hums
The maddening hum of safety slats on the pedestrian handrails of the Golden Gate Bridge will finally be silenced under a recently released proposal by the Golden Gate Bridge, Highway and Transportation District.
The fix — devised and tested by bridge engineers in consultation with aerodynamic and
acoustic experts — calls for attaching U-shaped aluminum clips containing a thin rubber sleeve to all 12,000 vertical slats on the railings.
The rubber will absorb vibrations where the vertical slats meet the horizontal rails, and reduce 75% of the vibrations that cause the bridge to whistle under high-wind conditions. The clips will be painted the signature bridge color of International Orange in order to blend in with bridge’s architecture.
The cost of fabricating the clips is estimated to be $450,000 to be covered by the operating budget of the Bridge District. Installation will be done by bridge crews as part of
their regular maintenance schedule, at no extra cost. The plan will be taken up at the Friday meeting of the district’s Board of Directors.
If approved, the project is expected to be completed by the end of 2022.
Since July 2020, the Bridge District has been trying to solve the whistling, which San Francisco residents started complaining about almost as soon as the safety slats were installed in the handrails in April 2020.
Many fixes were tested, including adding
horizontal bars to the slats and adding coarse tape to the edge of the slats. The U-shaped clips have been by far the most effective of the remedies tested, bridge district officials said.
Sound studies conducted in nearby residential neighborhoods indicate that with the rubber cushion the sound of the vibrating slats would be indistinguishable from the normal sound of the bridge during all conditions.
The slimmer slats replaced the original
wider ones to give the bridge a slimmer profile and make it safer in high winds. Bridge officials also said the narrower slats were needed to ensure the bridge’s aerodynamic stability after the installation of suicide deterrents on the bridge’s edges.