Golden Gate Bridge 1〠Introduction
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olden Gate Bridge is on the San Francisco Bay and connects the Golden Gate Bay on the Pacific Ocean. The bridge was finished in 1937 and was the longest suspension bridge in the world when finished. It is now the landmark symbol of San Francisco in the state of California. Golden Gate Bridge connects the north of San Francisco Peninsula to the south of Marin County, both California State Route 1 and U.S. Route 101 pass through this bridge. It is an important traffic route to the cities on either sides of the San Francisco Bay.
Photo 1. Golden Gate Bridge adopted suspension design, crossing the 2,042 meters wide San Francisco Bay.
Before Golden Gate Bridge was built, San Francisco and Marin County mainly depended on ferries to cross the San Francisco Bay. Many people wanted to build a bridge that crossed the ocean to connect to San Francisco and Marin County; however, experts at that time indicated that a bridge could not cross the 6,700 feet (2,042
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meters) wide strait. The weather condition of the San Francisco Bay also hindered the building of a bridge that awaited to be conquered: dense fogs that constantly blanketed San Francisco Bay; gusty winds with speed reached over 60 miles per hour; forceful swirl in the bay and the ocean passage with water depth over 150 feet (around 500 meters) which made it difficult to cross. If were to build a bridge, namely the Golden Gate Bridge; to cross the ocean, it would inevitably have to overcome these natural obstacles. To the engineering experts at that time, this was a bridge that could never be built. According to the initial assessment by the engineers at the San Francisco area, to build a bridge across ocean with so many natural obstacles, it would take at least 1,000 million US dollars. As for the estimated completion date, it would be a dream that was impossible to come true. Joseph Strauss was the Chief Engineer of the Golden Gate Bridge. When he was a student, he designed a 55 miles long (89 kilometers) railroad bridge across the Bering Strait as his graduate thesis. He also designed over 400 bridges inland. Strauss has rich experience in bridge design but he himself never designed a “suspension bridge”. He drew a simple conceptual bridge design sketch in Photo 2 Golden Gate Bridge crosses the San Francisco
Bay,
connecting
San
Francisco and Marin County.
which 2
he
installed
giant
steel
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suspended arms on each side of the strait, and used a suspended bridge in the middle to connect to the suspended arms. Strauss promised the local authority that he could finish such a bridge with 1.7 million US dollars. Through the advancement in metallurgy, such a cantilever bridge was gradually accepted as a feasible concept. Strauss spent more than 10 years to persuade the residents of the northern California into accepting this bridge construction project. He also recruited Charles Alton Ellis, Leon Moisseiff, and Irving Morrow to join the Golden Gate Bridge design. Ellis and Moisseiff together elaborated their professional engineering technique, giving Golden Gate Bridge the precise mathematical calculation and stable structure design. They put wind resisting technology into the structure design, making it a suspension bridge across the strait by ways of the modern engineering technology, successfully counteracted the natural factors that was unfavorable to bridge building. Irving Morrow’s design, on the other hand, made the appearance of the Golden Gate Bridge beautiful. H coordinated the Golden Gate Bridge with its surroundings to reflect a harmonious beauty, whether the street lamps in the dense fog, the shape of the bridge towers, and even the color of the Golden Gate Bridge – the international standard orange.; these all came out of Irving Morrow’s inspiration. The international standard orange is able to bring out the bridge in the dense fog; this design attends to both traffic safety and the bridge beautification. Strauss himself was not an expert to suspension bridge, but the team he led was able to combine the mature engineering technology and the innovative designing perspective to create the legend of the Golden Gate Bridge. After over 70 years of testing by the harsh weather condition, Golden Gate Bridge is still the landmark building of San Francisco, standing firm on the San Francisco Bay, shouldering the task of connecting the traffic on either ends. │舊金山金門大橋│GOLDEN GATE BRIDGE│
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Photo 3. Spectacular night view of the Golden Gate Bridge in San Francisco.
2、 Structure Many inevitable natural obstacles shall need to be overcome in order to build such a challenging suspension bridge. How to make this bridge firmly suspended between two distant cities across the strait? The bridge span was itself a huge challenge to the engineering technology of the time. Engineering team must go through conscientious mathematical calculations to ensure the bridge structure would not disintegrate in the strong winds, they must try different measures to overcome the natural obstacles that lay in the bridge construction. Golden Gate Bridge mainly depends on two stable piers to support the bridge towers, steel cables of the bridge towers hoist the bridge so that the bridge would not swing too much with the constant strong winds, and can firmly take on the traffic communication for both two islands on either side of the Golden Gate Bridge. In the following, we will describe in detail the two most important structures of the Golden Gate Bridge: the piers and the 4
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bridge towers. 2.1 Piers Golden Gate Bridge began construction in 1933 from the pier on the Marin County end. Originally the engineering team planned to seek hard rock above the water level to set up the piers; however, geologists thought such piers would not withstand earthquakes. Finally Chief Engineer Strauss agreed to deepen the north side bridge foundation to 100 feet below the surface, and penetrating 35 feet into the rock layer under the Photo 4. Piers were the most bottom of the ocean. Pier is the difficult part in constructing the vital structure foundation of the Golden Gate Bridge; they must whole bridge, it determines withstand the impact of whether the Golden Gate Bridge earthquakes and currents. is capable of resisting the strong current in the bay. Rooting the pier into the rock layer in the bottom of the ocean is a necessary procedure as well as a crucial engineering technology. The pier on the south side of the Golden Gate Bridge was the most difficult construction of the whole process. It has to be installed at the point which was 1,200 feet away from the shore and in the depth of 100 feet below the water. Engineering study report indicated that under such depth, the visibility underwater was close to zero. Tidal waves, swirls and ledges et al natural factors made the construction work exceptionally difficult. From │舊金山金門大橋│GOLDEN GATE BRIDGE│
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the overall assessment, we could understand that this would be a tough mission. How to build the pier on the south side became a huge test of the construction. Engineers finally made a concrete frame with the total height at 750 feet, of which 15 feet was above the water level, and extracted the sea water within. Construction engineers then installed the steel bars of the pier inside the concrete frame. Once the steel bars structure of the pier was finished, engineers then installed pipes to inject the sea water into the frame, allowing the sea water to run inside of the pier to offset the impact of the waves on the pier. This would achieve a better earthquake-proof effect.
Photo 5. Steel bars of the pier structure were built within the concrete frame to offset the impact of waves.
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2.2 Bridge Towers Golden Gate Bridge has two bridge towers, each at 342 meters high, of which 227.4 meters is above the water. The height equals to a 70 stories building and is the fourth tallest bridge tower in the world. Two steel wires, 92.7 mm in diameter weigh 24.5 thousand tones, are connected on top of the tower. Thousands of steel bars connect the steel wires with the bridge. Each of these wires is 750 feet long. The main cable of the Golden Gate Bridge is 7.650 feet long and 3 feet in diameter. Each cable is intertwined by steel wires
Photo 6. Golden Gate Bridge tower and connecting cables, they are the vital structure that bear the weight of the bridge and vehicles.
that is 27.252 feet long and is as thick as a pencil. Stretching all the way from Marin County to San Francisco, this main cable holds the bridge firmly and is also the reason why the Golden Gate Bridge stands firm for over 7 decades. Golden Gate Bridge is able to withstand swings at 21 feet in horizontal and 10 feet in vertical range. This resisting range enables the bridge to stand firm in the strong winds; it also prevents the bridge from disintegrate due to over swinging in earthquakes. Since opening for traffic on May 27th 1937, the Golden Gate Bridge has been constantly taking the full 6 │舊金山金門大橋│GOLDEN GATE BRIDGE│
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lanes load of vehicles of all sizes and pedestrians crowding the side walks on the bridge. It went through several strong earthquakes and remained standing in the strong winds and high tides, serving as the major communication route for over 70 years. It proves to be a bridge across that ocean that stands the test of time.
金
Photo 7. Golden Gate Bridge has two bridge towers, each at the height of a 70 stories building.
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3、 Construction Team 3.1 Joseph Strauss Strauss was the Chief Engineer of the Golden Gate Bridge. He was born in Cincinnati, Ohio. His father was a painter and writer, mother a pianist. Strauss was a productive engineer who designed over 400 small bridges; however, he never had any experience in building suspension bridges. He was not very precise about the Golden Gate Bridge conceptual drawing and he lacked the engineering theory concept to suspension bridge constructions. His design sketch was not a possible concept and he needed a strong engineering team to help him accomplish the task. He hired two engineering mathematical experts, one was Charles Ellis and other one was Leon Moisseiff. Ellis and Moisseiff together tailored a precise bridge construction ratio and wind resisting structure design. They made Golden Gate Bridge an idea that no longer existed on papers but a practical construction plan. Strauss later recruited Irving Morrow to help design additional function to the bridge as well as increase the artistic level of the bridge façade. Though Strauss was not green to suspension bridge, as a Chief Engineer, he still needed to face problems big and small in the construction process. Due to limited funding, he was forced to raise money from citizens and the US troops. In addition, Strauss respected construction safety greatly. According to the statistics, one out of 100 workers would die during the construction. Strauss │舊金山金門大橋│GOLDEN GATE BRIDGE│
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considered the human lives were highly valuable and thus he installed several safety nets in the construction sites to protect the safety of the workers. Unfortunately, there were still 11 people frozen to death by the sea water due to the collapsing of the steel scaffold that went into the ocean during construction. They were unable to be rescued by the safety nets installed by Strauss. Strauss’s value to the construction safety also extended to the bridge safety. “Safety” is a very important designing concept that is easily neglected. Strauss’s team valued the bridge safety as much as he did. From structural design to the street lamps on the bridge, the safety of the pedestrians and the traffic were put into concern. Till this day, the initial idea that Strauss had and his persistence on the overall construction are still the main reasons why the Golden Gate Bridge is recognized by the world.
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Photo 8. Golden Gate Bridge under construction: the bridge towers.
Photo 9. Bridge towers of the Golden Gate Bridge; steel cables connected between bridge towers.
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3.2
Charles Alton Ellis
Ellis was a professor, structural engineer, and mathematician; he was in charge of the Golden Gate Bridge structure. His career background included professor at University of Michigan, Illinois, and Purdue. He was hired as a team member to Strauss’s team mainly in charge of the sophisticated calculation to the bridge structure. During the process, he and Moisseiff elaborated their individual expertise to come up with the sturdy ratio and structure for the Golden Gate Bridge. The bridge remains standing after several earthquakes all because of Ellis’ work. He contributed greatly to the primary public technology and survey that he was in charge of. Strauss was afraid of the aura was taken away by Ellis for his becoming popular, after a technical and regulation delay, he ordered for Ellis to take a leave of absence and handed Ellis’ work to a subordinate staff. Ellis was in concern with the construction process and hoped to participate the building of the bridge towers; however, before the end of his vacation, Ellis received a telegram from Strauss, hoping him to never to return for work. Ellis was shocked, after all, he had spent three years of his life focusing on the building of the Golden Gate Bridge. Now he was asked to step aside before the bridge was accomplished. This great contributor behind the curtain was missing from the list when the bridge was completed. However, in recent years, people gradually noticed Ellis’ contribution to the Golden Gate Bridge, and restored him the honor he deserved.
Photo 10. Detail structure of the Golden Gate Bridge.
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3.3 Leon Moisseiff Moisseiff graduated from University of Columbia and received his master degree in Civil Engineering in 1895. He promoted all steel bridge to replace the concrete and rock buildings of the 20th century. Moisseiff proposed “deflection theory” that would enable the Golden Gate Bridge to resist the shaking of the strong winds. The first bridge construction he ever conducted was the Tacoma Narrow Bridge. Soon after the Tacoma Bridge was finished, it was found to twist and distort from in the wind; four months later, this bridge collapsed from the wind blow. Moisseiff’s reputation was questioned and people began to doubt if the Golden Gate Bridge would suffer the same fate as that of the Tacoma Narrow Bridge. However, when Ellis and Moisseiff were working together, they did consider the strong winds environment of the Golden Gate Bridge, and putting great regards to the ratio of bridge span and width. Ellis thought the ratio and structure design of the Golden Gate Bridge would exempt it from the threat of collapsing like the Tacoma Narrow Bridge. When people stand on the bridge during normal days, they would feel the slight shaking of the bridge. This shaking is under the safe range, unlike Tacoma Bridge that twisted severely in the wind due to resonance. Time proves that Golden Gate Bridge indeed is capable of withstanding the test of strong winds at the Golden Gate Bay. Though Moisseiff contributed greatly to the Golden Gate Bridge, the failure of the Tacoma Bridge overshadowed his contribution to other constructions. However, it was also because of the example of a failure bridge that people realized the importance of the bridge structure stability and safety. │舊金山金門大橋│GOLDEN GATE BRIDGE│
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Photo 11. Upward view of the Golden Gate Bridge Tower, the orange color goes well with the blue sky.
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3.4 Irving Morrow Morrow was recruited into the Golden Gate Bridge design team by Strauss in 1930.. Unlike Ellis and Moisseiff that were in charge of the bridge structure design, Morrow was in charge of the smaller functions of the bridge such as street lamps, rails and pedestrians overpass, etc. What remains the most important part of his design work is the color of the Golden Gate Bridge, the international standard orange. The bridge authority at the time did not think there was any type of red paint that could resist the high saline weather; some people even suggested to paint the bridge with dark grey color or the highly visible yellow or black stripes. Morrow did not take in those suggestions. To be persistent with his idea, he found a type of paint which made the bridge authority give in and decided to paint the Golden Gate Bridge in the international standard orange color. After painted international standard orange, the Golden Gate Bridge stood out of the fog. The color served the traffic safety purpose on one hand, and on the other hand, it made the bridge coordinated harmoniously with its surroundings. This is Morrow’s main contribution to the Golden Gate Bridge, his design engraved the image of the bridge deeply in people’s mind.
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Photo 12. Irving chose international standard orange that enabled the Golden Gate Bridge to standout in the fog.
4、 Construction Obstacles The most difficult part in building the Golden Gate Bridge, besides the exceptional long span, was the ever changing weather in San Francisco Bay. Overcame the natural weather factors that were disadvantageous to bridge building was the major break through in the Golden Gate Bridge construction history. In the following, we will describe the obstacles during the construction of the Golden Gate Bridge and some of the challenges that the bridge would face in the future. 4.1 Persistently Foggy Weather Fog often rises in San Francisco Bay, and it often comes unexpectedly with the density that the one cannot see what is in front. Even after the completion of the Golden Gate Bridge, because of the 16
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fog, the full view of the bridge was hard to be seen. The weather in San Francisco Bay changes to rapidly that sometimes it is covered in dense fog and the next minute, it is sunny and clear. The fog brought along obstacles to the building of the Golden Gate Bridge, for example the corrosion of the steel. Fog normally carries high saline and moisture so materials used in building the Golden Gate Bridge had to be corrosion resisting materials; but what type of materials were corrosion resisting at that time? Since there were no materials that were corrosion resisting and fit for bridge building, the strategy was to paint the bridge with corrosion resisting paints. Morrow decided to paint the Golden Gate Bridge with international standard orange for he wanted to use the paint to resist the steel corrosion, and at the same time to increase the visibility of the bridge in the fog for safety protection effects.
Photo 13. Dense fog often covers the entire Golden Gate Bridge and brings difficulty to constructions. │舊金山金門大橋│GOLDEN GATE BRIDGE│
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Photo 14. Golden Gate Bridge painted in international standard orange can still be seen clearly in the midst of thick fog.
4.2 Strong Winds The wind speed in San Francisco Bay is extremely strong that sometimes it can reach 60 miles per hour. Even after the completion of the bridge, one can feel the bridge slightly shaken by the wind when standing on the bridge. How would the wind speed affect the bridge? What are the challenges to overcome when building bridge where the strong winds blow? In addition to making people and vehicles on the bridge feel safe and sturdy, there also need to prevent the bridge from disintegrate in the strong winds. The ration of the bridge therefore has to be correctly generated before the construction. Thanks to Ellis and Moisseiff, the mathematical and bridge structure experts, who used sophisticated calculations to help the bridge resist the strong winds, making the Golden Gate Bridge to deflect slightly during the strong winds instead of shaking violently and collapse. From completion till this 18
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day, the Golden Gate Bridge only shut down for three times due to wind speed. For a ocean crossing bridge that is going to celebrate its 70 years anniversary, the Golden Gate Bridge proves that it stands the test of winds. 4.3. Strong Ocean Currents The ocean current under the Golden Gate Bridge is strong and the water is freezing cold. During the construction period, there were 11 workers fell into the safety net that were supposed to help them survive the fall; however, as the water was icy cold, the workers were unfortunately frozen to death from the water. With the current being so strong, it was also not very easy for the divers at that time to see the conditions under the ocean. The process of the construction thus became very dangerous, and the difficulty of the construction also was highly elevated. In recent years, the Managing Council of the San Francisco City has been drafting research project to utilize the currents under the Golden Gate Bridge current as power source for electricity, hoping to use the natural currents to provide powers for the San Francisco residents. However, such concept requires considering the ecological aspects of the environment. As indicated by the energy expert of the San Francisco Environment Department Peter O’Donnel “when fish runs into those turning turbine blades, it would be as if inflicting hanging on themselves; just like slices of sushi on the plate.” Therefore, such a concept currently requires further considerations in order to be put into practice in the future.
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Photo 15. The tidal waves and currents beneath the Golden Gate
Bridge
are
very strong, making the
construction
very dangerous.
5、 Challenges after Completion 5.1 Earthquakes “Safety” has always been the primary concern when building bridges. A strong bridge must able to withstand the test of different natural catastrophes. “Earthquake” is a type of natural catastrophes that directly endangers the safety of the bridges, and earthquakes happen quite frequently in San Francisco area. Golden Gate Bridge spans over thousand meters and the vibration during the earthquake could easily collapse the bridge. Ellis and Moisseiff did target the bridge width and span and perform sophisticated ration calculation; the piers were also grounded into the rock bed at the bottom of the ocean. In terms of earthquake proof design, since there were comprehensive considerations during the construction, Golden Gate Bridge’s design was far more careful than that of the nearby Bay Bridge. In 1989, a 20
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Richter scale magnitude 7.1 Loma Prieta earthquake struck San Francisco. Many houses and roads collapsed in the earthquake, even the other bridge on San Francisco Bay – the Bay Bridge – was not exempt from the earthquake and suffered from the breakage on the bridge surface. Miraculously, the Golden Gay Bridge was unharmed in this catastrophe. To prevent the Golden Gate Bridge from collapsing from the strong quakes, the basic main structure of the bridge must be maintained constantly. Several supporting structures that could help resist the strong quakes were also added to the bottom of the bridge. The structure ratio of the Golden Gate Bridge itself is also a key element for resisting earthquakes. Although Golden Gate Bridge survived several earthquakes, there is no guarantee that the bridge will survive other even stronger quakes. In the future, more advanced technologies should be developed for collapse-free constructions. A good construction still requires even more technologies after completion to extend its life span.
Photo 16. Golden Gate Bridge stood through many strong earthquakes owing to the constant maintenance. │舊金山金門大橋│GOLDEN GATE BRIDGE│
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5.2 Steel Corrosion Golden Gate Bridge suspends on the San Francisco Bay; mist, moist and strong winds are corrosive to the steel structure, causing the paint to come off and the steel to rust that weaken the structural support. Paint is a type of protection for the Golden Gate Bridge to resist corrosion. The international standard orange paint is mainly for resisting corrosion and ensuring the traffic safety in the mist; as well as to create a harmonious beauty with the surrounding environment. “International standard orange” is composed of red, yellow and black colors. This color has already been the signature color of Golden Gate Bridge and it makes the bridge remain exceptionally beautiful in the dense fog. After the completion, the maintenance work of the Golden Gate Bridge is also a painstaking task. Workers must examine and replace the corroded steel or rivets periodically, and then coating the steel with corrosion resisting paints to extend the life of Golden Gate Bridge. Since completion, some steel components have already been replaced with new ones but the basic structure and the main cables of the Golden Gate Bridge have not yet been replaced. Here we learned that the advancement of engineering does not stop at the development of new technologies and innovative functions; sometimes it is also for preventing from deterioration. Only with the unceasing advancement of the engineering technology can the construction masterpieces from many years ago to be preserved to this day, and move on to the future generations.
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5.3 Suicide The purpose for building the Golden Gate Bridge was for communicating the traffic on both sides; however; since the completion of the bridge until this day, a problem has been bothering the local authority - “suicides”. Each year, many people chose to end their lives at the Golden Gate Bridge. Golden Gate Bridge has become a popular site for suicide. According to the official statistics, by 1993, over 1000 people committed suicide at the Golden Gate Bridge. The Golden Gate Bridge Board of Directors decided to invest 2 million US dollars to study the feasibility of installing protective rails in preventing suicide attempts. Though the number of suicides decreased, there still cannot prevent people from leaping out of the Golden Gate Bridge to end their lives. When Strauss was building this bridge, he highly valued the safety of the workers during construction. In order to prevent the workers from falling into the ocean, he even installed safety nets. This showed that he respected human lives very much. Little did he know that within 72 years of completion of this epic bridge, there were over 1,300 lives that decided to end here.
Photo 17 Since completion, Golden Gate Bridge has been the popular suicide spot.
Up till this day,
over 1300 people chose to end their lives here.
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The latest statistic published by the Marin County Coroner’s Office in California indicated that, there were 31 people ended their lives by jumping off the Golden Gate Bridge, which was 3 lives less than the previous year. Coroner Holmes said that there were 34 people committed suicide by jumping off the bridge in 2008. In the past 72 years, there were over 1,300 people committed suicide there. The Golden Gate Bridge District is seeking 50 million US dollar funding to install stainless steel protective net underneath the pedestrians walk on either side of the bridge to intercept the jumpers. Relevant departments are still making environmental assessment study for installing the protective nets. Out of the 31 suicides, 20 bodies were found by the US Coast Guard. 9 bodies were either found in other counties or missing. Their suicides were witnessed or caught on surveillance cameras. Two suicides cases were found with suicide notes. Holmes said that the statistic figure actually was quite reserved, as many suicides did not leave any trace behind which made it hard to calculate. There is no knowing exactly how many committed suicide at the bridge. Golden Gate Bridge is one of the most famous suicide spots in the world. In the past 5 years, there was average one person every two weeks that jumped from the bridge. Four seconds after leaping off the 67 meters high bridge, the suicide will hit the ocean surface at 120 miles per hour. Until 2003, there were 26 attempted suicides. - Epochtimes, USA. http://www.dajiyuan.com 24
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Why would someone choose such a bridge to end his/her life? The distance from the bridge to the ocean surface is about 60 meters, there is great impact on the ocean surface after leaping off the bridge. It is almost impossible to survive the strong current. Besides Golden Gate Bridge, there are other famous suicide spots: Empire State Building of New York City, Saint Peter’s Basilica (The Papal Basilica of Saint Peter) in Vatican, Milan Cathedral (Duomo di Milano), Mihara Volcanic Peak in Japan, and Eiffel Tower of Paris, etc. Statistically speaking, however, Golden Gate Bridge remains on the top of the suicides’ list. This fact makes one wonder, what is the special meaning of committing suicide from the Golden Gate Bridge? Why Golden Gate Bridge and not other places? There is a Bay Bridge that is not far from the Golden Gate Bridge but the number of jumpers were nowhere near the number as that of the Golden Gate Bridge, why? Many experts who study suicides have proposed their hypothesis. A column in the News of the World wrote “Richard Seiden, the honorary professor to the School of Public Health in UC Berkeley, has been studying suicides of the Golden Gate Bridge for years. His research showed that many suicides preferred to romanticize their death, thinking that leaping off the Golden Gate Bridge to be something beautiful; whereas jumping off the Bay Bridge was ‘lame’. Golden Gate Bridge is the world first bridge across the ocean, crossing north and side sides of the San Francisco Bay. The bridge is majestic and the view is spectacular. When the dense fog blankets the bridge, only the top of the bridge towers appear to be floating in mid air, and this makes people sigh with owe, claiming it the ‘bridge in heaven’. 10 million tourists visit here each year. Some claim that after a few minutes standing on the bridge, they feel the urge to commit suicide. There is also an urban legend saying that the Golden Gate Bridge ‘talks’, and it whispers to urge you make the leap.” │舊金山金門大橋│GOLDEN GATE BRIDGE│
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Photo 18. Dense fog makes people feel like being in heaven.
Whatever reasons people have in choosing the Golden Gate Bridge as the terminal of their lives, the fundamental issue still lies in the social care. Local newspaper once did a pole and found that 54% of the local San Francisco people were against installing safety rails on the Golden Gate Bridge. They thought that even if the suicides did not jump from the Golden Gate Bridge, they would still find other places to do commit suicide. Installing the safety rails perhaps would reduce the suicide rate, the rails would not help the suicidal people get through the difficulties in life. Though no safety rails were installed on the Golden Gate Bridge, there were surveillance cameras and telephones for seeking assistance. This could help those with suicide attempts or passer-bys to contact with the Bridge control tower, notifying the management about the possible suicide attempts and location. Here we learned that obstacles reside not only in the process of construction. There are other management, maintenance and safety issues after the completion. 26
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Photo 19. Golden Gate Bridge in the dense fog is also known
as
the
“Bridge in Heaven”. The atmosphere
romantic may
well be the reason why suicides choose here to end their lives.
Photo 20 Golden Gate Bridge overcame challenges
many and
remained intact for over 70 years since completion.
It’s
sturdiness
and
beauty are deeply recognized
by
people.
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Chart 1
Challenges of San Francisco Golden Gate Bridge During and After Construction
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6、 General Discussion Building a ocean crossing large scale bridge may not be a difficult task for the modern technology of today; however, before the ages when the computers were not invented, to resist the disadvantageous natural environment and at the same time fulfilling the need of human being were huge construction challenges. Golden Gate Bay is a place that is foggy, windy with strong currents and constant earthquakes. Building a suspension bridge with exceptionally long span to connect two places in order to promote economy and transportation was not an easy job. Chief Engineer Strauss himself was not an expert of suspension bridges; however, through the unyielding effort of his persistence to the idea, and assembling an elite team of different expertise, the Golden Gate Bridge was finally completed in 1937. The case of Golden Gate Bridge made us understand the importance of team work. Some ideas may not be achieved by our own capability, it may well be achieved by the support of teammates with abilities that we lack. As new generation engineers, we should not be bound by our insufficient professional ability and be afraid of taking the first step towards our ideas. Many successful cases were realized gradually with the courage in pursuing ideas and the attitude in humble learning. In addition to being human’s challenge against the nature, Golden Gate Bridge also brings about the construction safety issues. Under normal circumstances, construction work tends to focus on user safety and reinforce the structural safety during the construction; however, it tends to neglect the “builders’” safety. How to achieve 0 casualty during construction was one of the goals to which Strauss │舊金山金門大橋│GOLDEN GATE BRIDGE│
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paid great respect; it should also be highly regarded by the future construction process.
Photo 21. Teamwork and construction safety are what we should learn from the Golden Gate Bridge.
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Practice Part I : Use Your Brain
1. Do you think building an ocean crossing bridge on San Francisco Bay was a good decision? Why? Would you be able to come up with other transportation tools to promote the communication and economic development of San Francisco County and Marin County?
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2. If you were Strauss, what methods would you have adopted in reducing the construction personnel casualty during the bridge building process? (Use the natural environment of San Francisco Bay for the overall consideration.)
第二部份
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動動手
│舊金山金門大橋│GOLDEN GATE BRIDGE│
土木工程概念設計 Conceptual Design Studio
3. Try think of some facilities that can be added to the San Francisco Golden Gate Bridge to elevate the driving safety of vehicles in the dense fog.
│舊金山金門大橋│GOLDEN GATE BRIDGE│
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土木工程概念設計 Conceptual Design Studio
4. If you were the designer of the Golden Gate Bridge, what color would you have painted the bridge? Why? Elaborate your ideas.
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│舊金山金門大橋│GOLDEN GATE BRIDGE│
土木工程概念設計 Conceptual Design Studio
5. San Francisco Golden Gate Bridge is a famous suicide spot. Some people think that even if these people do not commit suicide at the Golden Gate Bridge, they would still choose other spots to end their lives. Do you agree with this? Think of other ways to reduce the suicide rate of the Golden Gate Bridge.
│舊金山金門大橋│GOLDEN GATE BRIDGE│
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土木工程概念設計 Conceptual Design Studio
6. San Francisco Golden Gate Bridge must charge for the bridge crossing to support the bridge maintenance expenses; however, the income remains negative after all these years. Draft a proposal to increase the Golden Gate Bridge operation income, think of the negative effects that might come with the proposal, and how to solve these negative effects.
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│舊金山金門大橋│GOLDEN GATE BRIDGE│
土木工程概念設計 Conceptual Design Studio
7. What are the issues to consider when designing a bridge that connects to two places? Why?
│舊金山金門大橋│GOLDEN GATE BRIDGE│
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土木工程概念設計 Conceptual Design Studio
8. If you are the managing authority of the San Francisco Golden Gate Bridge, and you receive a huge amount of subsidizing fund for repairing the Golden Gate Bridge, what are the facilities you want to add the most? Explain why.
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│舊金山金門大橋│GOLDEN GATE BRIDGE│
土木工程概念設計 Conceptual Design Studio
Part II : Use Your Hands 1. Elaborate your imagination and design a bridge to connect Taiwan and Pen-Hu. What type of bridge you would design and what are the facilities and function on the bridge? Draw conceptual sketches.
│舊金山金門大橋│GOLDEN GATE BRIDGE│
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土木工程概念設計 Conceptual Design Studio
2. Find a bridge in life, take photos and paste the photos in the box below. Try and analyze the advantages and disadvantages of the bridge, and propose the improvement suggestion in the future.
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│舊金山金門大橋│GOLDEN GATE BRIDGE│