Prof. Boerner's Explorations

by Gerald Boerner

  

Recently we looked at the building of skyscrapers, those monuments to man’s ingenuity and technical expertise. Today, we celebrate the opening of another of these mega-monuments to man’s building capabilities — the Golden Gate Bridge.

I remember the thrill I get every time I cross that strait between the San Francisco Bay and the Pacific Ocean. It is awesome! I look down in amazement at the water far below and get a queasy feeling in my stomach. I am constantly amazed at the feat that those brave workmen accomplished. I have seen a number of documentaries on cable TV that showed the skills required to complete this bridge.

There is no doubt that it is a transportation asset to those living in Marin Country who work in the city (San Francisco) on a daily basis. Prior to the bridge, these same people needed to take the ferry across. Today, we take the ferry from San Francisco to Sausalito as a tourist adventure, not as a daily commute. Isn’t it interesting how a given mode of transportation changes from a routine activity to a tourist oddity.

Anyway, the Golden Gate Bridge represents a monument to its builders and an asset to the people. In this day of planned obsolescence, it is reassuring to see some structures span the years as well as the straits.  GLB

    

“Bridges become frames for looking at the world around us.”
— Bruce Jackson

“Education is all a matter of building bridges.”
— Ralph Ellison

“Bridges are perhaps the most invisible form of public architecture.”
— Bruce Jackson

“Also, if I did join another show, I’d end up burning my bridges to the show I love most.”
— Michael Storm

“For better or worse, MTV sort of bridges the whole country together almost like the BBC does in England. It’s opened up everything so wide that it’s possible for everyone to have different ideas.”
— Joey Ramone

“By failing to keep their end of the bargain, the Bush administration would allow New Jersey projects to deteriorate and make New Jersey highways and bridges less safe.”
— Robert Menendez

“Below us the Thames grew lighter, and all around below were the shadows – the dark shadows of buildings and bridges that formed the base of this dreadful masterpiece.”
— Ernie Pyle

“America’s highways, roads, bridges, are an indispensable part of our lives. They link one end of our nation to the other. We use them each and every day, for every conceivable purpose.”
— Christopher Dodd

  

The Golden Gate Bridge

The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the opening of the San Francisco Bay into the Pacific Ocean. As part of both U.S. Route 101 and California State Route 1, it connects the city of San Francisco on the northern tip of the San Francisco Peninsula to Marin County. The Golden Gate Bridge was the longest suspension bridge span in the world when it was completed during the year 1937, and has become one of the most internationally recognized symbols of San Francisco, California, and of the United States. Since its completion, the span length has been surpassed by eight other bridges. It still has the second longest suspension bridge main span in the United States, after the Verrazano-Narrows Bridge in New York City. In 1999, it was ranked fifth on the List of America’s Favorite Architecture by the American Institute of Architects.

Ferry service

 Golden Gate with Fort Point
in foreground, circa 1891

Before the bridge was built, the only practical short route between San Francisco and what is now Marin County was by boat across a section of San Francisco Bay. Ferry service began as early as 1820, with regularly scheduled service beginning in the 1840s for purposes of transporting water to San Francisco. The Sausalito Land and Ferry Company service, launched in 1867, eventually became the Golden Gate Ferry Company, a Southern Pacific Railroad subsidiary, the largest ferry operation in the world by the late 1920s. Once for railroad passengers and customers only, Southern Pacific’s automobile ferries became very profitable and important to the regional economy. The ferry crossing between the Hyde Street Pier in San Francisco and Sausalito in Marin County took approximately 20 minutes and cost US$1.00 per vehicle, a price later reduced to compete with the new bridge. The trip from the San Francisco Ferry Building took 27 minutes.

Seen from edge of Baker Beach

Many wanted to build a bridge to connect San Francisco to Marin County. San Francisco was the largest American city still served primarily by ferry boats. Because it did not have a permanent link with communities around the bay, the city’s growth rate was below the national average. Many experts said that a bridge couldn’t be built across the 6,700 ft (2,042 m) strait. It had strong, swirling tides and currents, with water 500 ft (150 m) in depth at the center of the channel, and frequent strong winds. Experts said that ferocious winds and blinding fogs would prevent construction and operation.

Conception

Although the idea of a bridge spanning the Golden Gate was not new, the proposal that eventually took place was made in a 1916 San Francisco Bulletin article by former engineering student James Wilkins. San Francisco’s City Engineer estimated the cost at $100 million, impractical for the time, and fielded the question to bridge engineers of whether it could be built for less. One who responded, Joseph Strauss, was an ambitious but dreamy engineer and poet who had, for his graduate thesis, designed a 55-mile (89 km) long railroad bridge across the Bering Strait. At the time, Strauss had completed some 400 drawbridges—most of which were inland—and nothing on the scale of the new project. Strauss’s initial drawings were for a massive cantilever on each side of the strait, connected by a central suspension segment, which Strauss promised could be built for $17 million.

Local authorities agreed to proceed only on the assurance that Strauss alter the design and accept input from several consulting project experts. A suspension-bridge design was considered the most practical, because of recent advances in metallurgy.

South tower seen from walkway

Strauss spent more than a decade drumming up support in Northern California. The bridge faced opposition, including litigation, from many sources. The Department of War was concerned that the bridge would interfere with ship traffic; the navy feared that a ship collision or sabotage to the bridge could block the entrance to one of its main harbors. Unions demanded guarantees that local workers would be favored for construction jobs. Southern Pacific Railroad, one of the most powerful business interests in California, opposed the bridge as competition to its ferry fleet and filed a lawsuit against the project, leading to a mass boycott of the ferry service. In May 1924, Colonel Herbert Deakyne held the second hearing on the Bridge on behalf of the Secretary of War in a request to use Federal land for construction. Deakyne, on behalf of the Secretary of War, approved the transfer of land needed for the bridge structure and leading roads to the "Bridging the Golden Gate Association" and both San Francisco County and Marin County, pending further bridge plans by Strauss. Another ally was the fledgling automobile industry, which supported the development of roads and bridges to increase demand for automobiles.

The bridge’s name was first used when the project was initially discussed in 1917 by M.M. O’Shaughnessy, city engineer of San Francisco, and Strauss. The name became official with the passage of the Golden Gate Bridge and Highway District Act by the state legislature in 1923.

Design

Viewpoint of North end,
showing lanes and traffic.

Strauss was chief engineer in charge of overall design and construction of the bridge project. However, because he had little understanding or experience with cable-suspension designs, responsibility for much of the engineering and architecture fell on other experts.

Irving Morrow, a relatively unknown residential architect, designed the overall shape of the bridge towers, the lighting scheme, and Art Deco elements such as the streetlights, railing, and walkways. The famous International Orange color was originally used as a sealant for the bridge. Many locals persuaded Morrow to paint the bridge in the vibrant orange color instead of the standard silver or gray, and the color has been kept ever since.

Senior engineer Charles Alton Ellis, collaborating remotely with famed bridge designer Leon Moisseiff, was the principal engineer of the project. Moisseiff produced the basic structural design, introducing his "deflection theory" by which a thin, flexible roadway would flex in the wind, greatly reducing stress by transmitting forces via suspension cables to the bridge towers. Although the Golden Gate Bridge design has proved sound, a later Moisseiff design, the original Tacoma Narrows Bridge, collapsed in a strong windstorm soon after it was completed, because of an unexpected aeroelastic flutter.

Ellis was a Greek scholar and mathematician who at one time was a University of Illinois professor of engineering despite having no engineering degree (he eventually earned a degree in civil engineering from University of Illinois prior to designing the Golden Gate Bridge and spent the last twelve years of his career as a professor at Purdue University). He became an expert in structural design, writing the standard textbook of the time. Ellis did much of the technical and theoretical work that built the bridge, but he received none of the credit in his lifetime. In November 1931, Strauss fired Ellis and replaced him with a former subordinate, Clifford Paine, ostensibly for wasting too much money sending telegrams back and forth to Moisseiff. Ellis, obsessed with the project and unable to find work elsewhere during the Depression, continued working 70 hours per week on an unpaid basis, eventually turning in ten volumes of hand calculations.

With an eye toward self-promotion and posterity, Strauss downplayed the contributions of his collaborators who, despite receiving little recognition or compensation, are largely responsible for the final form of the bridge. He succeeded in having himself credited as the person most responsible for the design and vision of the bridge. Only much later were the contributions of the others on the design team properly appreciated. In May 2007, the Golden Gate Bridge District issued a formal report on 70 years of stewardship of the famous bridge and decided to give Ellis major credit for the design of the bridge.

Specifications

Fog at the Golden Gate Bridge,
San Francisco

The center span was the longest among suspension bridges until 1964 when the Verrazano-Narrows Bridge was erected between the boroughs of Staten Island and Brooklyn in New York City, surpassing the Golden Gate Bridge by 60 feet (18 m).The Golden Gate Bridge also had the world’s tallest suspension towers at the time of construction and retained that record until more recently. In 1957, Michigan’s Mackinac Bridge surpassed the Golden Gate Bridge’s total length to become the world’s longest two-tower suspension bridge in total length between anchorages, but the Mackinac Bridge has a shorter suspended span (between towers) compared to the Golden Gate Bridge.

Structure

The weight of the roadway is hung from two cables that pass through the two main towers and are fixed in concrete at each end. Each cable is made of 27,572 strands of wire. There are 80,000 miles (129,000 km) of wire in the main cables. The bridge has approximately 1,200,000 total rivets.

Traffic

Traffic crossing the Bridge
during a foggy morning

As the only road to exit San Francisco to the north, the bridge is part of both U.S. Route 101 and California Route 1. The median markers between the lanes are moved to conform to traffic patterns. On weekday mornings, traffic flows mostly southbound into the city, so four of the six lanes run southbound. Conversely, on weekday afternoons, four lanes run northbound. Although there has been discussion concerning the installation of a movable barrier since the 1980s, the Bridge Board of Directors, in March 2005, committed to finding funding to complete the $2 million study required prior to the installation of a movable median barrier. The eastern walkway is for pedestrians and bicycles during the weekdays and during daylight hours only, and the western walkway is open to bicyclists on weekday afternoons, weekends, and holidays. The speed limit on the Golden Gate Bridge was reduced from 55 mph (89 km/h) to 45 mph (72 km/h) on 1 October 1996.

Aesthetics

The Golden Gate Bridge by night,
with part of downtown San Francisco
visible in the background at far left

Despite its red appearance, the color of the bridge is officially an orange vermillion called international orange. The color was selected by consulting architect Irving Morrow because it compliments the natural surroundings and enhances the bridge’s visibility in fog.

The bridge is said to be one of the most beautiful examples of bridge engineering, both as a structural design challenge and for its aesthetic appeal. It was declared one of the modern Wonders of the World by the American Society of Civil Engineers. According to Frommer’s travel guide, the Golden Gate Bridge is "possibly the most beautiful, certainly the most photographed, bridge in the world" (although Frommers also bestows the most photographed honor on Tower Bridge in London, England).

Aesthetics was the foremost reason why the first design of Joseph Strauss was rejected. Upon re-submission of his bridge construction plan, he added details, such as lighting, to outline the bridge’s cables and towers.

Suicides

As a suicide prevention initiative,
this sign promotes a special
telephone available on the bridge
that connects to a crisis hotline.

The Golden Gate Bridge is not only the most popular place to commit suicide in the United States but the most popular in the entire world. The deck is approximately 245 feet (75 m) above the water. After a fall of approximately four seconds, jumpers hit the water at some 76 miles per hour (122 km/h). At such a speed, water has proven to take on properties similar to concrete. Because of this, most jumpers die on their immediate contact with the water. The few who survive the initial impact generally drown or die of hypothermia in the cold water.

An official suicide count was kept, sorted according to which of the bridge’s 128 lamp posts the jumper was nearest when he or she jumped. By 2005, this count exceeded 1,200 and new suicides were averaging one every two weeks. For comparison, the reported second-most-popular place to commit suicide in the world, Aokigahara Forest in Japan, has a record of 78 bodies, found within the forest in 2002, with an average of 30 a year. There were 34 bridge-jump suicides in 2006 whose bodies were recovered, in addition to four jumps that were witnessed but whose bodies were never recovered, and several bodies recovered suspected to be from bridge jumps. The California Highway Patrol removed 70 apparently suicidal people from the bridge that year.

There is no accurate figure on the number of suicides or successful jumps since 1937, because many were not witnessed. People have been known to travel to San Francisco specifically to jump off the bridge, and may take a bus or cab to the site; police sometimes find abandoned rental cars in the parking lot. Currents beneath the bridge are very strong, and some jumpers have undoubtedly been washed out to sea without ever being seen. The water may be as cold as 47 °F (8 °C).

The fatality rate of jumping is roughly 98%. As of 2006, only 26 people are known to have survived the jump. Those who do survive strike the water feet-first and at a slight angle, although individuals may still sustain broken bones or internal injuries. One young man survived a jump in 1979, swam to shore, and drove himself to a hospital. The impact cracked several of his vertebrae.

Engineering professor Natalie Jeremijenko, as part of her Bureau of Inverse Technology art collective, created a "Despondency Index" by correlating the Dow Jones Industrial Average with the number of jumpers detected by "Suicide Boxes" containing motion-detecting cameras, which she claimed to have set up under the bridge. The boxes purportedly recorded 17 jumps in three months, far greater than the official count. The Whitney Museum, although questioning whether Jeremijenko’s suicide-detection technology actually existed, nevertheless included her project in its prestigious Whitney Biennial.

Various methods have been proposed and implemented to reduce the number of suicides. The bridge is fitted with suicide hotline telephones, and staff patrol the bridge in carts, looking for people who appear to be planning to jump. Iron workers on the bridge also volunteer their time to prevent suicides by talking or wrestling down suicidal people. The bridge is now closed to pedestrians at night. Cyclists are still permitted across at night, but must be buzzed in and out through the remotely controlled security gates. Attempts to introduce a suicide barrier had been thwarted by engineering difficulties, high costs, and public opposition. One recurring proposal had been to build a barrier to replace or augment the low railing, a component of the bridge’s original architectural design. New barriers have eliminated suicides at other landmarks around the world, but were opposed for the Golden Gate Bridge for reasons of cost, aesthetics, and safety (the load from a poorly designed barrier could significantly affect the bridge’s structural integrity during a strong windstorm).

Strong appeals for a suicide barrier, fence, or other preventive measures were raised once again by a well-organized vocal minority of psychiatry professionals, suicide barrier consultants, and families of jumpers after the release of the controversial 2006 documentary film The Bridge, in which filmmaker Eric Steel and his production crew spent one year (2004) filming the bridge from several vantage points, in order to film actual suicide jumps. The film caught 23 jumps, most notably that of Gene Sprague as well as a handful of thwarted attempts. The film also contained interviews with surviving family members of those who jumped; interviews with witnesses; and, in one segment, an interview with Kevin Hines who, as a 19-year-old in 2000, survived a suicide plunge from the span and is now a vocal advocate for some type of bridge barrier or net to prevent such incidents from occurring.

On October 10, 2008, the Golden Gate Bridge Board of Directors voted 14 to 1 to install a plastic-covered stainless-steel net below the bridge as a suicide deterrent. The net will extend 20 feet (6 m) on either side of the bridge and is expected to cost $40–50 million to complete. However, lack of funding could delay the net’s construction. See also Suicide bridge.

Wind

Since its completion, the Golden Gate Bridge has been closed due to weather conditions only three times: on 1 December 1951, because of gusts of 69 mph (111 km/h); on 23 December 1982, because of winds of 70 mph (113 km/h); and on 3 December 1983, because of wind gusts of 75 mph (121 km/h).

Seismic retrofit

Vertical section of
Golden Gate Bridge span

Modern knowledge of the effect of earthquakes on structures led to a program to retrofit the Golden Gate to better resist seismic events. The proximity of the bridge to the San Andreas Fault places it at risk for a significant earthquake. Once thought to have been able to withstand any magnitude of foreseeable earthquake, the bridge was actually vulnerable to complete structural failure (i.e., collapse) triggered by the failure of supports on the 320-foot (98 m) arch over Fort Point. A $392 million program was initiated to improve the structure’s ability to withstand such an event with only minimal (repairable) damage. The retrofit’s planned completion date is 2012.

     

References

Other Events on this Day:

• In 1813…
  In the War of 1812, Col. Winfield Scott, assisted by American naval forces, captures Fort George, New York.

• In 1890…
  Louis Glass and William Arnold receive patents for the first judebox, known as the “Nickel-in-the-Slot”.

• In 1919…
  A Navy seaplane commanded by Albert Read reaches Lisbon, Portugal, on the first transatlantic flight (with a few stops along the way).

• In 1937…  
  San Francisco’s Golden Gate Bridge opens.

Dates and events based on:

William J. Bennett and John Cribb, (2008) The American Patriot’s Almanac Daily Readings on America. (Kindle Edition)

Background information is from Wikipedia articles on:

Wikipedia: Golden Gate Bridge… 
http://en.wikipedia.org/wiki/Golden_Gate_Bridge

Brainy Quote: Bridges Quotes… 
http://www.brainyquote.com/quotes/keywords/bridges.html