The document outlines the research question, thesis statement, and structure for analyzing the design and collapse of the Tacoma Narrows Bridge. It explores how the bridge's flexible design made it susceptible to oscillations in high winds, despite advanced engineering for the time. Lessons learned include the need for dynamic testing, aerodynamic modeling, and more rigid designs to withstand vibrational frequencies. The collapse highlighted the importance of considering factors like wind forces that engineers were not fully aware of previously.

1. Detailed outline
Research question:
What happened to the Tacoma Narrows Bridge and what steps
can engineer take to avoid this situation from happening again?
Thesis statement:
There are important lessons that engineers can learn from
studying the design and the collapse of the Tacoma Narrows
Bridge so they can avoid this from happening again in the
future.
I. Introduction
II. Design
A. As the Tacoma Narrows Bridge was being designed,
engineers were not expecting wind that hits at 42 miles per
hour.
B. The Tacoma Narrows Bridge was too weak to hold because
the bridge was too light, too shallow and too long.
III. Cause of collapse
How could a modern bridge with advanced design suffer failure
from wind?
A. the main reason of the failure of Tacoma Narrows bridge was
it’s great flexibility, while the bridge was moving it acted like
aerofoil, creating drag and lift.
B. aerodynamic were a bit understood, engineers were supposed
to test bring modals and suspension.
IV. For avoiding future problems
A. Engineers must utilise computer simulations that makes them

2. better understand design and pressure of wind flow.
B.
Detailed outline
Research question:
What happened to the Tacoma Narrows Bridge and what steps
can engineer take to avoid this situation from happening again?
Thesis statement:
There are important lessons that engineers can learn from
studying the design and the collapse of the Tacoma Narrows
Bridge so they can avoid this from happening again in the
future.
I. Introduction
II. Design
A. As the Tacoma Narrows Bridge was being designed,
engineers were not expecting wind that hits at 42 miles per
hour.
B. The Tacoma Narrows Bridge was too weak to hold because
the bridge was too light, too shallow and too long.
III. Cause of collapse
How could a modern bridge with advanced design suffer failure
from wind?
A. the main reason of the failure of Tacoma Narrows bridge was
it’s great flexibility, while the bridge was moving it acted like
aerofoil, creating drag and lift.
B. aerodynamic were a bit understood, engineers were supposed
to test bring modals and suspension.

3. IV. For avoiding future problems
A. Engineers must utilise computer simulations that makes them
better understand design and pressure of wind flow.
B.
The Tacoma Narrows Collapse
March, 2017
Imagine yourself driving through the third longest bridge with
your beloved Golden Retriever on a hot sunny day. However,
you suddenly feel the bridge kneeling towards the right and left.
Seeing everyone in front of you vacating their cars and running
away from the bridge before it collapses. Most likely, you
would do the same even maybe 3 times faster before it’s too

4. late. But sadly, when it’s too late and the bridge has collapsed
you will eventually realize that you have left your beloved dog
behind. The First Tacoma Narrows Bridge was being completed
and designed in the state of Washington, Tacoma. The Tacoma
Narrows bridge was constructed by Leon Moisseiff to be the
third longest bridge and the most flexible bridge ever
constructed. The construction of this bridge took 10 years.
Construction began from the 1930’s to July 1, 1940.
Unfortunately, The Tacoma Narrows Bridge collapsed within
the same year it was accessible for the public. The cause of the
collapse was from a high random windstorm. The collapse of
the bridge was recorded on film by Barney Elliott, the footage
of the film is still used today for students majoring in
engineering all over the globe. Minutes before the collapse
people witnessed an unusual reaction in the bridge. The bridge
was waving in a really strange way. Because, the bridge was
built to be the most flexible bridge ever built. The Tacoma
Narrows bridge might be today one of the greatest engineer
failure disasters due to the collapse within the same year it was
built in. There are important lessons that engineers can
determine from studying the design and the collapse of the
bridge to be able to avoid a terrible disaster like this from
happening again in the future.
On November 7, 1940 high winds at the speed of 42 mph (64
km/h) buffeted the place and the bridge was moving
considerably. At about 11 Am the first failure approached, when
a part of concrete fell of the bridge. Minutes after, a 600 foot
part of the bride went loose. At this time, the bridge kept
moving back and forth in a weirdly way. According to (Tacoma
Narrows Bridge collapses, 2009), “At one time, the elevation of
the sidewalk on one side of the bridge was 28 feet above that of
the sidewalk on the other side.”. In other words, all of a sudden
the altitude of one side of the bridge was 28 feet higher than the
sidewalk on the other side. Regardless of the strong carpent
steel used in the making of the bridge, it showed no match in

5. force while defending against the windstorm which finally led
to the collapse.
After the Tacoma Narrows bridge collapsed, many people were
unsure of what they have witnessed. The wildy toss left many
questions behind, only engineers can answer them. Many
engineers have studied the bridge collapse from the video
footage (Elliott,2009) and have came to an instinct. Before they
came to an instinct a huge and long argument about the causes
of the collapse between those who worked on the bridge and
others who might have an insight on why the bridge collapsed.
There were many different sayings on why a random windstorm
caused such a disaster to a national bridge in front of the eyes
of the public. But after years of hard work and delicate studies
on the footage of the collapse engineers and architecture came
into a settlement about the mysterious reason that led to the
collapse of the bridge.
The Tacoma Narrows Bridge, the third longest suspension
bridge in the world. The main cause of the collapse lies on a
part of the bridge and the type stiffening floor and girders. The
bridge suspensions were too weak to hold itself from a random
high windstorm. The blame of the collapse is mostly placed on
the twisting made by the aerodynamic forces. Aerodynamic
forces haven’t been seriously taken in the design of any bridge.
because, The Tacoma Narrows bridge fundamental weakness
was from its great flexibility. According to (first investigations-
partial answers to why) “The deck was too shallow at 8 feet (a
1/350 ratio with the center span). The spans were too long
compared with the length of the centre span. The cables were
anchored at too great a distance from the side spans. The width
of the deck was extremely narrow compared with its centre span
length, an unprecedented ratio of 1 to 72.” While the bridge was
moving vertically and in torsion it acted like aerofoil, creating
drag and lift. Another cause
The failure of the Tacoma Narrows Bridge has ended

6. Moisseiff's career. According to (Lessons From the Failure of a
Great Machine)” it abruptly ended an entire generation of
bridge engineering theory and practice, and the trend in
designing increasingly flexible, light, and slender suspension
spans.”. In other words, they have failed to do their jobs in
constructing a bridge that meets its requirements to be safe for
the public to use. The Tacoma Narrows Bridge was narrow
compared with other suspension bridges previously built and
very long. According to (Franklin Miller, Jr. (1963)) :The
original design called for stiffening the suspended structure
with trusses. However, funds were not available, and a cheaper
stiffening was adopted using 8-foot tall girders running the
length of the bridge on each side.”. In other words, the bridge
original design was perfect but, there was no enough money and
they had to choose the only 8-foot tall griders which are not
stiff enough to resist such a windstorm.
Aerodynamic forces haven’t been taken seriously in the design
of The Tacoma Narrows Bridge. By that time most bridges have
been only designed to stand normal conditions. However, a
lesson was learnt and engineers designing any bridge must
consider aerodynamic effects and dynamic actions. dynamic
models, elastic models and studies of resonance, aerodynamic,
wind tunnels and damping must be in the design of any bridge.
In the case of harmonic oscillations, the bridge was not
structured to be very rigid. However, Civil engineers and
architects can now increase the natural frequencies of the bridge
to be able to stand greater windstorm wave frequency of very
high winds. In addition (the physics teacher) states that most
new bridges are much more rigid than the Tacoma Narrows
Bridge.

7. Conclution
References
Tacoma Narrows Bridge collapses. (2009). Retrieved March 15,
2017, from http://www.history.com/this-day-in-history/tacoma-
narrows-bridge-collapses
Fuller, R. G. (2000). Twin Views of the Tacoma Narrows
Bridge Collapse. College Park, MD: AAPT, One Physics
Ellipse.