Abstract
The Golden Gate Bridge was fabricated and erected between 1932 and 1937 (Figure 1) . At that time the art and science of corrosion protection for structural steel bridges was little understood or appreciated. The corrosion protection originally specified for all structural steel elements on the Golden Gate Bridge, with the exception of the wires in the main cables and suspender ropes, was about the same as that Henry Ford was specifying for the fenders of a Model A. The structural steel plate used for fabrication was given a coat of red lead primer of unspecified thickness over steel that had been given no treatment whatsoever prior to receiving the primer. Consequently, the structural steel for the Golden Gate Bridge's two massive towers was coated in the fabrication plants and yards of the Bethlehem Steel Corporation in Pottstown, Pennsylvania with a light coat of red lead primer and shipped to San Francisco. It soon became apparent, as the structural sections were shipped from Pottstown, Pennsylvania to San Francisco, California via the Panama Canal, that a simple coat of red lead primer offered absolutely no corrosion protection. After the towers for the Bridge had been fabricated and while the structural steel elements for the stiffening truss of the Bridge were being fabricated, the engineers, recognizing that the original specified coating system was not providing any corrosion protection, modified the system to the best of their ability with the materials available but still did not understand the significance of a well researched surface preparation procedure prior to applying the primer coats. Corrosion was well advanced on most structural steel components of the Golden Gate Bridge prior to and during the erection of the structure in San Francisco. When the Golden Gate Bridge was opened to traffic in May 1937, the Chief Engineer recognized that a comprehensive corrosion protection system must be started immediately to assure a long corrosion controlled life for the structure. With the intervention of World War II, and a change in management attitudes immediately following WWII, the program was not carried forth in the manner originally contemplated. It was not until early in the 1960's that the management of the Golden Gate Bridge realized that corrosion was destroying the Bridge prematurely. About 1965 a very comprehensive corrosion control program and structural restoration program that utilized the highest technical coatings available at the time to arrest the spread of corrosion, was instituted along with a structural repair, replacement, and restoration program that would assure a long and useful life of the structure. This program continues today.
The Golden Gate Bridge
