Three design concepts for a proposed Golden Gate Bridge suicide barrier could endure the harsh winds that blow across the iconic span, but two would dramatically alter its appearance.
A $2 million study conducted over nine months developed three overall design concepts for a highly controversial suicide barrier on the 1.7-mile bridge span.
After testing dozens of designs, engineers found that 8- to 14-foot high wire or glass barriers or a 10-foot steel net could safely withstand the heavy winds that cause the suspension bridge to sway, while also preventing people from climbing the existing 4-foot rail and jumping into the freezing waters of the Bay.
Discussions about a suicide barrier have polarized residents in San Francisco and beyond for decades. Some argue that suicide is a societal issue and solutions should not be played out on the Golden Gate Bridge, a national landmark approaching its 70th birthday that has long defined San Francisco in scores of films, books and photos.
There have, however, been 1,250 suicides off the Golden Gate Bridge since it opened in 1937, according to a Marin County coroner’s report, causing those on the other side of the argument to call the span "the suicide icon of the world."
"That is about the number of lives lost on the Titanic," said John Vidaurri, of the volunteer-based crisis line San Francisco Suicide Prevention.
This is not, however, the first time designs have been presented. In 1999, a design for an 11-foot-high fence was rejected because of concerns that it was unsightly and wouldn’t prevent all suicides.
Despite the rejection,Golden Gate Bridge officials approved a $1.8 million suicide barrier study last September. While funding sources have yet to be identified, plans will continue to move forward with an environmental review this summer.
When it came to designs, engineers focused on historic preservation, cost and maintenance issues. They used designs from other landmarks, and from those, three basic concepts were developed for the proposed barrier: an extension of the current rail, a new rail and a steel net affixed under the sides of the bridge deck.
Each design requires a special device to make the air flow smoothly across the bridge deck. The two devices — a winglet that is similar to an airplane wing, and a fairing that looks like a circular spoiler — would be installed either atop the barrier or below the deck, depending on the design.
The tested barriers were 8 to 14 feet high and designed with horizontal, vertical and grid-like bars. One of the designs consists of 6- to 8-inch vertical glass blades. Some maintained the existing 4-foot rail, while other replaced it.
Although Denis Mulligan, chief engineer for the Golden Gate Bridge Highway and Transportation District, said the steel net design would be the most difficult to install because of maintenance issues, but it would disturb the view from the bridge sidewalk the least.
Using a scaled-to-size model and a computer program, more than 200 wind tests were conducted on the designs. To pass, they had to remain stable in 100 mph winds from the west and 66 mph winds from the east — conditions estimated to occur once every 10,000 years.
"Wind is a pass-fail test," Mulligan said. "We wanted to do the wind [tests] first. We didn’t want the public to fall in love with some concept and then find out later that we can’t have it."
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