Strauss was chief engineer over the project but had little understanding of suspension bridges so had to hire experts in that field. Strauss original plans was to build a symmetrical cantilever hybrid bridge but after talks with Leon Moisseiff and Charles Ellis the experts he hired they changed it to an original suspension bridge. Irving Morrow was an architect who design the shape of the bridge and the lighting setup and arch deco theme. Leon Moisseiff produced the basic structure designs introducing his deflection theory that a thin road way would flex in the wind and the stress would be submitted through the cables. Ellis was a Greek scholar and mathematician so did most of the technical and theoretical work like calculating the computation of stresses, the preparation of stress sheets, as well as the development of the specifications, contracts and proposal forms. However he was given no credit in his lifetime through to an argument with Strauss and getting sacked before the construction of the bridge. The construction of the bridge began on the 5 December 1933 with the final cost to be 35 million dollars. Strauss remained head of the project, overseeing day by day activities and putting safety precaution into place. The most conspicuous precaution was the safety net suspending under the floor of the bridge from end to end saving 19 lives however there was eleven fatalities. The bridge was painted a vermillion orange so it blends in with the natural setting, and is used to protect the bridge from the salt content in the air, to stop in corroding the steel components. The bridge painting is still an on going task and is the primary maintenance job. Due to the length of the bridge 1.7 miles long it was split into six main structures, San Francisco (south) approach viaduct, San Francisco (south) anchorage housing and pylons S1 and S2,Fort Point arch, Suspension bridge, Marin (north) approach viaduct and Marin (north) anchorage housing and pylons N1 and N2.The bridge lighting was a complicated and important part of the structure which had many aspects. Irving morrow designed the whole network of lighting, producing intensity of light at different levels for different parts of the bridge. This was to further the uniqueness of the bridge for example the towers to be darker so they seem to disappear into the evening darkness. The lamps glowed amber to provide warmth for the passing motorist plus producing no glare to blind the driver. With the light post on a slant to form an angle to achieve the arc deco theme. The lighting was finally the last piece in the jigsaw to produce a magnificent structure. The arch deco theme was achieved by simplified the pedestrian railings to small, even posts allowing motorists to have an unobstructed view by positioning the post far apart. Wide, vertical ribbing was added on the horizontal tower bracing to accent the sun's light on the structure and rectangular tower portals themselves when thinner the higher it approach the top. (reference 1)
The opening of the bridge was on may 27, 1937 with many celebrative events throughout the week: Including fireworks displays overhead aircrafts competition and many more. The bridge became a big spectacle and brought many people far and wide to see it .On the first day many reports believed that 200,000 pedestrians walked across the bridge with thousands of automobiles to cross in the following day.
Construction statistics (reference 1)
Length
Total length of Bridge including approaches from abutment to abutment is 1.7 miles.
Length of suspension span including main span and side spans: 1.2 miles.
Length of one side span: 1,125 ft = 343 m
Width of Bridge: 90 ft = 27 m
Width of roadway between curbs: 62 ft = 19 m
Width of sidewalk: 10 ft = 3 m
Clearance above mean higher high water: 220 ft
Weight
total weight of each anchorage: 54,400,000 kg
Original combined weight of Bridge, anchorages, and approaches: = 811,500,000 kg
Total weight of Bridge, anchorages, and approaches (1937): 894,500 tons = 811,500,000 kg
Total weight of Bridge, anchorages, and approaches in (1986): 887,000 tons = 804,700,00 kg
Deflection and load capacity
Maximum transverse deflection, at center span: 27.7 ft
Maximum downward deflection, at center span: 10.8 ft
Maximum upward deflection, at center span: 5.8 ft =
Live load capacity per lineal foot: 4,000 lbs. = 1,814.4 kg
Structural properties
Height of tower above water: 746 ft
Height of tower above roadway: 500 ft
Diameter of one main cable including the exterior wrapping: .92 m
Length of one main cable: 2,332 m
The structure was mainly main out of concrete and 75,293,000 kg of steel. The only way a suspension bridge can withheld its enormous weight and be stable it through the vertical cables that are attach to the deckThese cables support the deck of the bridge, transferring the weight to the towers at the end. The main cables continue past the tower, and are anchored past the far ends of the bridge. They are carefully balanced so that the force pulling inward on the towers is equal to the force pulling outward. As a result, the weight pulls directly down into the base of the tower. The towers can be fairly thin, since they aren't being pulled to either side. The deck can also be thin, since it is being supported by the cables. So therefore the bridge is perfectly balance and continues to rebalance its forces when loads is applied to the bridge by transferring the weight through the cables. The advantages of suspension bridges are longer span’s can be achieved that other types and less material is required due to the cables holding the bridge up.
My opinion of the bridge is that it is a magnificent practical structure which spans an enormous length to connect San Francisco to Marin county. It has made transport much easier and has been a good investment because it has paid the initial bonds off through toll charges and continuously makes money. It is now the main California route 101 and would be very impractical if the bridge wasn’t build. I remember driving over the bridge and thinking how long it would take if the ferry service was still in place. I really approve of the arc deco design and how the towers are full of detail and sculpture with sharp defining corners. Also I think the vermillion orange really makes the bridge stand out which can look very impressive from many miles away. The bridge has a great history of how it got constructed and still has many project running at the moment(e.g. putting suicide barriers into place) .The bridge is definitely a focal point and feature of San Francisco which must be seen if visited.
References
1. ‘Research library/construction information‘.Golden Gate Bridge, Highway and Transportation District. http://goldengatebridge.org/research/construction.php. 2006-2010
2.Two Bay Area Bridges". US Department of Transportation, Federal Highway Administration. http://www.fhwa.dot.gov/infrastructure/2bridges.cfm. Retrieved 2009-03-09.
Pictures
Construction pictures:
Modern day
