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
"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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