case study3 - golden gate bridge
DESCRIPTION
Civil Engineering, National Taiwan University, Case Study.TRANSCRIPT
Golden Gate Bridge
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.
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
G
Photo 1. Golden Gate Bridge adopted suspension design, crossing
the 2,042 meters wide San Francisco Bay.
1、 Introduction
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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
which he installed giant steel
Photo 2
Golden Gate Bridge crosses the San
Francisco Bay, connecting San
Francisco and Marin County.
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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.
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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
Photo 3. Spectacular night view of the Golden Gate Bridge in San
Francisco.
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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
bottom of the ocean. Pier is the
vital structure foundation of the
whole bridge, it determines
whether the Golden Gate Bridge
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
Photo 4. Piers were the most
difficult part in constructing the
Golden Gate Bridge; they must
withstand the impact of
earthquakes and currents.
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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
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
Photo 6. Golden Gate Bridge tower and connecting cables, they are the
vital structure that bear the weight of the bridge and vehicles.
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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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3.1 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
3、 Construction Team
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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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Photo 10. Detail structure of the Golden Gate Bridge.
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.
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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.
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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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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
Photo 12. Irving chose international standard orange that enabled
the Golden Gate Bridge to standout in the fog.
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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.
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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
Photo 14. Golden Gate Bridge painted in international standard
orange can still be seen clearly in the midst of thick fog.
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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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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
Photo 15. The tidal
waves and currents
beneath the Golden
Gate Bridge are
very strong, making
the construction
very dangerous.
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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.
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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
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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.”
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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.
Photo 18. Dense fog makes people feel like being in heaven.
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Photo 19. Golden
Gate Bridge in the
dense fog is also
known as the
“Bridge in Heaven”.
The romantic
atmosphere may
well be the reason
why suicides choose
here to end their
lives.
Photo 20
Golden Gate Bridge
overcame many
challenges and
remained intact for
over 70 years since
completion. It’s
sturdiness and
beauty are deeply
recognized by
people.
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Char
t 1
Ch
alle
ng
es o
f S
an F
ranci
sco G
old
en G
ate
Bri
dge
Duri
ng a
nd A
fter
Const
ruct
ion
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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
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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 動動手
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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.
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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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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.
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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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7. What are the issues to consider when designing a bridge that
connects to two places? Why?
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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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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.
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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.