Project Overview - Wind Studies and Preliminary Engineering Design
The Golden Gate Bridge’s sidewalks are open to the public and the existing outside railing along the sidewalks is four feet tall. The Golden Gate Bridge Physical Suicide Deterrent Project is being conducted by the Golden Gate Bridge, Highway and Transportation District (District). The Project developed and evaluated alternatives for a potential physical suicide deterrent system for the Bridge. The Project was divided into two phases, described below.
Long span suspension bridges respond dynamically, and potentially dramatically, to wind. Phase 1 focused on performing wind tunnel testing of generic concepts for a potential suicide deterrent for the Golden Gate Bridge (Bridge). The wind tunnel testing determined which generic concepts do not create wind stability problems for the Bridge. Wind tunnel testing focused on three types of generic concepts: 1) adding to the existing railing; 2) replacing the existing railing; and 3) utilizing nets that cantilever out horizontally. Concepts with various heights, component dimensions and wind appendages were tested to determine which combinations of variables are acceptable for the Bridge, from a wind stability standpoint. A Phase 1 Wind Study Report documents the wind testing and summarizes the results. Additionally, it includes descriptions and sketches of each concept that passed the wind test. The report was presented at the Building and Operating Committee of the Board of Directors at their regularly scheduled meeting at 10 a.m. on Thursday, May 24, 2007.
Phase 2 took the Phase 1 generic concepts that passed the wind test and developed potential alternatives for further evaluation. Phase 2 includee both the required federal and state environmental review processes of each potential alternative and included preliminary engineering of the potential alternatives. The proposed alternatives were evaluated against each of the Project Criteria and for anticipated environmental affects. The proposed alternatives included five "build alternatives" and one "No-Build alternative." The Bridge, which is eligible for inclusion in the National Register of Historic Places, is afforded protection under both state and federal historic preservation laws. In accordance with these laws, the District, in addition to developing and releasing for public comment a draft environmental document on July 8, 2008, also consulted with appropriate state and federal agencies. The final environmental document was released on January 22, 2010. Following a 30-day public comment period on the final document, the environmental process was concluded and the District Board of Directors certified the final environmental document on February 12, 2010.