When and safety of the structure. An

            When
designing a structure, the engineer must take numerous factors into
consideration in order to create a stable design. The design for an outdoor
structure must account for the possible effects of wind to ensure the integrity
and safety of the structure. An example of the failure to incorporate the wind
effects into the structure is the Tacoma Narrows bridge collapse of 1940 and
the engineering crisis of the Citigroup Center in 1978. Both structures were designed
in such a way that the wind acting upon the structure caused collapse in one
case and serious possibility of catastrophe in the other. With the Tacoma
Narrows collapse, miraculously a dog was the only casualty. The Citigroup
Center vulnerability was discovered and resolved before any catastrophe occurred.
This resulted in the former collapsing with a dog as the only casualty, and the
latter needing immediate repairs to resolve the vulnerability.  

 

Key points: Tacoma Narrows

           

During the planning phase of
the bridge, there were two competing designs being considered. One design for
the bridge was a commonly used suspension type with 25 foot high trusses under
the road to strengthen and stabilize the bridge. This design had an estimated cost
11 million dollars. The other design used eight foot girders with an estimated
cost of eight million dollars, and thus was chosen due to its reduced cost. The
eight foot girders did not make the deck sufficiently rigid, and therefore it
was susceptible to movement caused by winds. Some vertical movement was noticed
during construction. There was a failed attempt to stabilize the bridge, yet it
was opened to traffic when the engineers declared the structure was safe. Two
additional attempts to stop the oscillations were made without success and the
collapse followed. On the day the bridge collapsed, the movement of the deck
developed a yet unobserved movement with an oscillating in a torsional, or
twisting, pattern. As the amplitude of the oscillations increased, the
suspension cables started to snap, and the weight of the deck could not be held
by the remaining cables, resulting in collapse of the deck.

Key Points: Citigroup Building

 

            The
design called for the building to be set on four columns positioned at the center
of each side of the building. This was because of an agreement with a church
located in the northwest corner of the building. The design included multiple V-shaped
braces on each side of the building, centered on each of the four columns.
These braces were designed to collect forces placed on the building to their
point, where it would be then be absorbed into the ground through the columns. During
construction, the builder requested and was granted permission by the
engineer’s firm to substitute the welded joints of the braces with bolted
joints. A student was working on her thesis when she discovered that the bolted
joints of the braces were significantly susceptible to failure when subjected
to quartering winds OEC citation here. Quartering wind is when wind hits a
building’s corner, hitting both sides at once, and causes significantly more
force to be put upon the building. Upon her discovery, she notified the
engineer of the design flaw. He found that while the welded joints would have
been strong enough to withstand the additional forces, the bolted joints would
be susceptible to failure under the same forces. With his confirmation, the
engineer notified the architect and Citicorp that repairs needed to be made
immediately.

 

 

Comparison: Tacoma Narrows and Citigroup Building Key
Points

 

            In
both cases, the original design of the structure would have been able to
withstand the forces that compromised the final product. However, changes were
made to the design in order to cut costs. These changes compromised the
integrity of the Tacoma Narrows Bridge to the point of collapse, and the
Citigroup center had the possibility of collapsing if repairs were not made.
Interestingly, both structures used the same construction and steel supply
company, Bethlehem Steel. There is a significant difference between the two
cases that is peculiar.
With the Tacoma Narrows Bridge, they actually observed a problem manifesting as
oscillations but chose not to close and investigate but to remain open and
attempt to repair the bridge, and as a result no successful solutions were
implemented to fix the problem before the bridge collapsed. The difference with
the Citigroup building is that the flaw was discovered by chance and in time to
make repairs. This difference is interesting, as the structure with an obvious
problem wasn’t fixed in time, while the one with no visible problem was able to
be fixed before it had the chance to collapse.

 

Ethical Issues: Tacoma
Narrows

           

Rather than using the industry
standard suspension bridge design, a new and relatively untested design was
chosen due to its lower cost. The less expensive choice had inherent risks as
an unproven design, but they were accepted, resulting in a collapse and need
for constructing a new bridge. Another poor choice was made when the engineers
declared that the oscillations were safe and opened the bridge, despite having
no factual basis in their claim of safety. These choices run counter to the
concept of Mill’s Utilitarianism, in which the best choice to make is the one
that produces the maximum benefit for the greatest number of people. Instead of
using a more expensive design that was standard, an untested design was used
and ultimately failed, negatively affecting numerous people who relied on the
bridge for quick and easy transportation.

Ethical Issues: Citigroup
Building

 

            During
the design process of the Citigroup Building, the engineer failed in his duty
to ensure that his design would be structurally sound under all conditions.
While the design of the building did meet the New York Building Code of the
time, which did not explicitly state the need to consider quartering winds, the
Code is intended to be a minimum requirement, and all possible factors should
be properly accounted for (Kremer, 2002). Furthermore, the engineer should have
ensured that if any changes or substitutions were made in construction, that he
would be consulted before any decisions were made. Moreover, the engineer
actively misled the public and remained silent about the matter until almost 20
years after the affair, preventing other engineers from learning from his
mistake and possibly finding similar problems in projects of their own (Kremer,
2002). The engineer’s actions are in direct opposition to Immanuel Kant’s
concept of Duty Ethics, which describes that every person has a duty to prevent
harm and to consider the well being of society as supreme. By failing to
prevent the crisis initially and choosing not to inform the public of the
danger, the engineer risked not only the Citigroup Building, but tens of
thousands of lives and potentially billions of dollars lost if the building
were to collapse.

 

 

Legal Issues: Tacoma
Narrows

           

            The engineering and
construction firms could have been held liable under tort law for the
construction of an unsafe bridge that eventually collapsed. By accepting the
task of designing and building the bridge, the firms accepted the duty of care
in providing the public a safe and functional bridge. They failed in their
duty, as evidenced by the oscillations and eventual collapse of the bridge
which would not have occurred had the more expensive but reliable design been
used. Through the collapse, the people who relied on the bridge for faster
transportation and better business strategies lost their ability to do so for
the next 11 years, causing them various degrees of financial injury.

Legal Issues: Citigroup
Building

 

            Through the rapid
response of the engineer and repair team, the Citigroup Building evaded
catastrophe. However, had the student not chosen to research the building, the
resulting disaster would have rivaled the Bhopal Union Carbide disaster.
Because the engineer was careless in his calculations and design of the
building, thousands of lives could have been lost and caused potentially
billions of dollars in property damage alone. As such, the engineer, his firm,
the builder, and Citicorp could all have been charged with criminal negligence
and corporate manslaughter due to the numerous losses by result of the
collapse.

 

 

Code of Ethics Review

 

            In
both of the cases, the engineers involved violated the first and third
principles as outlined by the American society of civil engineers (ASCE, 2017).
The Tacoma Narrows engineers violated the first through their desire for a
cheap bridge to construct over a proven safe and reliable design, and violated
the third by their public statement that the oscillations were safe despite
them not knowing whether or not they truly were safe. The engineer in charge of
designing the Citigroup building violated the first principle by allowing the
danger to arise as a result of his oversight in the design, and violated the
third through his actions to ensure the public did not learn of the affair in
order to save his reputation. In addition to the first and third, the engineer
also violated the seventh principle (ASCE, 2017). Through his efforts to hide
his mistake, the engineer prevented any of his peers to learn from his mistake
and stop any similar design flaws from moving on from the design stage.

 

Solutions: Tacoma Narrows.

 

            Shortly
after the collapse, the Bronx Whitestone Bridge was reinforced with steel
trusses. This was because the design of the Bronx Whitestone Bridge was very
similar to the design of the Tacoma Narrows Bridge. In the long term, the
collapse greatly increased the research into bridge aerodynamics and
aeroelastics. This research has greatly influenced the design of all subsequent
long-span bridges.

 

 

Solutions: Citigroup
Building

 

            Immediately
upon the discovery and reporting of the flaws, steps were quickly taken to repair
the building before any damage could be done. These repairs were successful, as
the Citigroup building has not collapsed in the time between when the repairs
were made and present day. The lasting results of this incident, while delayed
due to the secrecy, manifested themselves as lessons for engineers to learn
from. The affair provided an example of ethical behaviour for engineering
textbooks to use in teaching engineers in training, and demonstrated the possible
risks of aiming to meet building code alone.

 

Conclusion:

 

            In
the cases of the Tacoma Narrows Bridge collapse and the engineering crisis
involving the Citigroup Building, the decisions and statement made, or lack
thereof, were both professional and ethical blunders. Designs were improperly
tested before construction, and changes were made that compromised the
structure’s stability in order to reduce costs. Fortunately, no loss of life
beyond a dog occurred as a result of these two cases, and the engineering
profession benefited from the knowledge gained in the aftermath. Both cases
demonstrated the necessity that the design of an outdoor structure must account
for all the possible effects that wind may have upon it. Failure to account for
these factors compromises the integrity and safety of the structure, which
risks considerable damage and loss of life should the structure fail.