(picture via berkeleyhomes-dot-com on Flikr)
Today marks the 75th anniversary of one of the most famous and sentimental bridges in the world. The Golden Gate Bridge. In typical San Francisco fashion the celebrations have begun in a shroud of fog, but the party is just beginning and will continue through the night when a firework display will be lit off at 9:30. (If you are brave enough to challenge the crowds and the parking then you may want to download the GoGGBridge app to plan your sight-seeing adventure!) The bridge is the second longest main span suspension bridge in the world.
The Golden Gate bridge is a marvel of engineering for the 1930′s, answering a demanding need for relief from automobile congestion and expensive ferry systems connecting Marin to San Francisco. In 1928 alone over 2 million cars were ferried across the Golden Gate. The origin of the idea of the bridge actually began back in 1916 when a newspaperman, James Wilkins, launched an editorial campaign for a Golden Gate Bridge. This caught the attention of M.M. O’Shaughnessy, a San Francisco engineer, who then contacted several engineers including Joseph Strauss to counsel him on the design and cost of the bridge. Fast forward to January 5, 1933 after years of political debate, design revisions, and funding the first shovel of dirt was turned in Marin County to mark the commencement of construction of the bridge.
The Chief engineer, Joseph Strauss, was remarkably not technically an engineer but talented enough to bring the concept of the suspension bridge to the public and smart enough to surround himself with brilliant engineers who’s innovative structural designs brought the bridge to reality. Although Strauss is noted as Chief Engineer the final suspension design was conceived by Leon Moisseiff, and the towers by architect Irving Morrow who also gave the bridge its beautiful Art Deco details. The Principal Engineer on the project was Charles Alton Ellis who completed most of the technical and theoretical aspects of the bridge and collaborated closely with Moisseiff who completed the structural design, introducing his “deflection theory”.
As you can see in the picture above one of the most interesting challenges of the bridge was the design of the two large cables that span between the two towers. The cables were designed by John a. Roebling and had to be spun on site due to the enormous weight. Several innovations in cable manufacturing and erection were marked by the design for the bridge.
The bridge was completed on May 27th, 1937 and was amazingly enough $1.3 million under its original $35 million budget. As of April of 2011 almost 2 million cars have driven across the Golden Gate Bridge.
(photo via Pascell on Flickr)
The American Society of Civil Engineers named the Golden Gate Bridge a National Historic Civil Engineering Landmark in 1984. Please join CSW|ST2 in celebrating this icon of American engineering and take a walk across the Golden Gate Bridge. 75 years and still going strong!