There are few bridges in the world which attract the same attention as the Golden Gate Bridge in San Francisco. This is a vital element of the transport network in the region and is both part of US Route 101 and State Route 1. The Golden Gate Bridge connects San Francisco to Marin County and has a history which is both interesting and bizarre in equal measures. So what do we know about the Golden Gate Bridge?
The need for the Golden Gate Bridge
Prior to the initial idea for the Golden Gate Bridge the only way to get between San Francisco and Marin County was via ferry. However the short journey over the river was treacherous due to the very strong currents underneath the surface and a distinct lack of suitable landing places. It is said that tides in the region can push through 528 billion gallons of water every six hours and the water flows at around 5.6 mph at peak times. The only other alternative to get from San Francisco to Marin County is a boat trip of several hundred miles crossing a number of major US rivers.
The idea for the Golden Gate Bridge
The initial idea for the bridge came about in 1916 when the idea was floated in the San Francisco Bulletin by an engineer called James Wilkins. The article caused a flurry of interest in the region although when San Francisco’s City Engineer came forward to suggest the bridge would cost in excess of $100 million the idea looked very much to be dead in the water. However, a number of engineers were encouraged to come forward with alternative ideas for a cheaper design which is where the idea for the suspension bridge came about.
Rather bizarrely it was a poet and engineer by the name of Joseph Strauss who came forward with an idea for a suspension bridge with massive cantilevers at either side of the strait. These would be connected by a central suspension section and more importantly for the local authorities he suggested it would cost no more than $17 million to build. While initially his idea received widespread criticism in the local press and was described as “ugly” this was in fact the beginning of the infamous Golden Gate Bridge.
The building process
While Strauss had been involved in over 400 drawbridges and had designed a number of theoretical suspension bridges during his graduate thesis he was deemed to be too inexperienced to oversee the project although he was installed as part of the main team.
Even though the initial idea was floated in 1916 it took many years to gain the required support from neighbouring authorities with a number of government agencies coming forward with specific problems and issues. These issues vary from a guarantee that local workers would be employed on the project to the potential impact upon the local ferry service. It took a number of reviews and federal hearings to finally push the project further forward and in 1924 approval was given for the transfer of the land required for the bridge and the road network either side of the structure.
It was also around this time that the bridge got its name in connection with the Golden Gate strait over which the bridge would span.
The final design
After finally receiving official confirmation that the project would go ahead, Strauss was put in charge of the engineering team, although this was on the basis that he took outside advice on suspension bridges which were not believed to be his forte. Interestingly he brought in a number of well-known engineers including Irving Morrow and Charles Alton Ellis who had significant experience in both the design of the structure and the design of the various elements of the bridge which included the lighting system.
While Charles Alton Ellis was heavily involved in the project he was also a key feature in the Tacoma Narrows Bridge which actually collapsed in a wind storm very soon after completion. The official diagnosis was an unexpected aeroelastic flutter although there were many flutters in the hearts of the San Francisco local authorities when this issue arose!
Finance
When finally construction of the Golden Gate Bridge began on 5 January 1933 it had been the issue of finance which held back the project, coming straight after the Wall Street crash. By the time the project commenced the estimated value was up to around $35 and it was decided that a bond issue would be used to fund the bridge. However, coming so soon after the Wall Street crash there was little interest in commercial paper and it was only when the founder of Bank of America came forward with a plan to buy the entire bond issue that the project was able to get off the ground.
The building of the bridge
Construction of the bridge began on 5 January 1933 and Strauss was still heavily involved in the project at the time even though this was nearly 20 years after his initial design was accepted. Interestingly the project finished in April 1937 and was actually $1.3 million under the projected budget, something which went down very well with the local authorities!
The bridge was opened on 27 May 1937 although for some strange reason the celebrations lasted one week and saw 200,000 people cross by foot or rollerskate. The commemoration of the opening of the bridge reached bizarre levels with beauty queens, local dignitaries and Pres Roosevelt all heavily involved in opening up the bridge to the public. Indeed there was even an official bridge song entitled “There’s a silver moon on the Golden Gate”.
Facts about the Golden Gate Bridge
The bridge was so far ahead of its time that it was not until 1964 that it was overtaken as the longest suspension bridge in the world.
The bridge has approximately 1.2 million rivets holding the various metal elements together.
The road crossing the bridge is six lanes wide and depending on the time of day it has either four lanes southbound and two lanes northbound or four lanes northbound and two lanes southbound – a very modern transport system.
The longest unaided span of the bridge is around 4200 feet (i.e. the gap between the supports) although the total length of the bridge is nearly 9000 feet. It is 90 feet wide and nearly 750 feet high.
The bonds issued to fund the project were finally paid off in 1971 with a $35 million principal payment and nearly $39 million in interest, all of which was raised from tolls from the bridge.
The Golden Gate Bridge is “the most popular” suicide venue in United States with well over 1000 people known to have jumped to their deaths from the bridge. People are known to travel from far and wide to attempt suicide from the bridge.
The bridge has its own suicide patrol and suicide hotline telephones situated at regular intervals along the structure.
The bridge is closed to the public at night time and cyclists are only allowed to cross the bridge after being cleared by the toll booth workers.
While traditional vehicles such as cars and lorries incur a toll to cross the bridge there is no such cost afforded to cyclists and pedestrians.
Recently local authorities voted through plans to install a suicide net underneath the bridge which will extend 6 m either side and cost between $40 million and $50 million to install.
The distinctive “red” colour of the bridge is actually a dark orange paint which was added as a top coat to the lead based primer. However, while the paintwork is regularly “touched up” it has been replaced in recent times for a more environmentally friendly paint solution.
During the history of the Golden Gate Bridge it has only been closed three times, all due to excessive wind conditions.
Unfortunately the structure is located very close to the San Andreas Fault and as such is at serious risk of potential earthquake damage. Initially it had been forecast that the structure would be able to withstand significant earthquake activity but there are now concerns about the supports of the bridge. As a consequence a $392 million structural strengthening programme has been approved by the local authorities and work on the bridge is expected to be completed in 2012.