Report: Golden Gate Bridge suicide barrier concepts comply with wind stability criteria

By James Lanaras

May 25, 2007

All three concepts for a suicide deterrent system on the Golden Gate Bridge comply with wind stability criteria for the famous span, according to a report issued yesterday.

All three also would change the appearance of the bridge that has long been a destination for those intent on suicide.

There is an average of two suicides a month at the bridge, according to Dr. Mel Blaustein, president and board of directors of the Psychiatric Foundation of Northern California and Medical Director of St. Francis Hospital in San Francisco.

The Building and Operating Committee of the Board of Directors of the Golden Gate Bridge, Highway and Transportation District released the 121-page report on the wind tests of the three options at its meeting yesterday.

The firms DMJM Harris of Oakland and West Wind Laboratory in Marina conducted the tests, part of a $2 million study on the feasibility of a suicide deterrent system.

The report contains the conclusions of wind tunnel testing of adding 10 to 14 feet to the existing four-foot railing on the bridge, replacing the existing railing with an 8- to 14-foot railing, and adding a net system that extends horizontally from the bridge.

"Wind tunnel testing and analysis has determined the combinations of height, solid ratio and wind devices for all three generic concepts that will comply with the established wind stability for the Golden Gate Bridge," the report concludes.

According to the report, the existing 4-foot railing with pickets between a top and bottom rail appears open and allows wind to pass through, and is 60 percent solid.

"This presents a challenge to concepts that add on to the existing railing," the report notes, and the installation of a transparent, curved winglet, or edge, is necessary to satisfy wind criteria.

"The testing indicated that an addition to the existing railing must be very open so that wind can pass easily through. The testing determined that the addition must also have no more than 12 percent solids.

Replacing the existing railing with a new 8- to 14-foot railing provides more latitude and acceptable options for wind devices compared to adding on to the existing railing, the report states. A new railing could be up to 23 percent solid and a vertical replacement railing could be tilted 20 degrees inward or outward with no appreciable change in wind response to the bridge.

Adding a netting system that extends horizontally out from the bridge disturbs airflow as it approaches the top of the stiffening truss and railing, the report states.

"It was surprisingly difficult to arrive at acceptable net options," the report notes.

A netting system would require replacing the existing railing between the main towers with a less solid and more aerodynamically efficient railing and winglets would need to be added, according to the report.

The district has been exploring some form of suicide prevention barrier since the issue was raised again about two years ago.

Blaustein said the Psychiatric Foundation of Northern California is encouraged by the results of the tests.

"Whatever they want to put up is fine as long as its stops the suicides," Blaustein said.

"The aesthetics are not a major problem. The Empire State Building and the Eiffel Tower both have barriers," Blaustein said. He estimates there have been at least 1300 suicides on the bridge since it opened in 1937. So far there have been 18 this year, Blaustein said.

The wind studies on the three concepts are Phase 1 of the environmental studies and preliminary design work for a suicide deterrent system on the bridge.

Phase 2 will take the generic concepts that passed the wind tests and develop potential alternatives for further evaluation. Phase 2 also will include federal and state environmental review and preliminary engineering of each alternative, including a "no build" option. The first environmental document for Phase 2 will be released in the fall and a final environmental document is expected in spring of 2008.

The public and state and federal agencies have until June 14 to comment on the Phase 1 wind studies.

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