A Way of
Thinking
Dr. Mete A. Sozen, Purdue University |
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Dr. Mete A. Sozen is
shown with UB-EERI-SLC students (from left) Darren Vian, Prof.
Sozen, Gordon Warn, and Benedikt Halldorsson following his seminar. |
On April 5, 2002, Dr. Mete A. Sozen of Purdue University gave the 2002 EERI
Distinguished Lecture entitled "A Way of Thinking," which was included
as the ninth in the ongoing seminar series on earthquake engineering topics.
However, at the request of Dr. Sozen, the seminar was not webcast. Mr.
Darren Vian, Ph.D. candidate in the Department of Civil, Structural and
Environmental Engineering (CSEE), president of the UB-EERI Student
Chapter, and member of the MCEER Student Leadership Council (SLC), opened
the seminar by welcoming the standing-room-only audience of approximately
sixty people, and introducing the speaker. Prof.
Sozen began his presentation by explaining how it would differ from most
technical presentation on engineering topics. In his abstract for the
presentation, he wrote: "Structural engineering is a profession. A
profession is characterized by the need to exercise judgment within a
domain defined by a set of canons. The structural engineering canons have
developed sometimes as a result of and sometimes despite the interaction
between science and experience. That structures were built successfully
without science and, worse yet, even with the wrong science for hundreds
of years and that science has, so far, been insufficient to guarantee
predictability, emphasize the challenge in discriminating between the
poles: "Science is all!" and "Experience is all!" The
territory in between is vast and slippery. It is difficult to navigate a
true course without giving in to the lure of one pole or the other. Today,
ready access to versatile and powerful software enables the engineer to do
more and think less. It is not often questioned whether the exact analysis
of the approximate model qualifies as an approximate analysis of the
structure itself. To contemplate once again the role of analysis in design
is not a waste of time. A way of thinking about
structural design was developed in a series of iterations in the mid 20th
century by three engineers. Their goals were not global. The whole was
made up of specific solutions for specific problems. But when their
contributions are viewed together, a complete way of thinking about
structural design becomes discernible. The goal of this talk is to
encourage engineers to review the works of Harald M. Westergaard, Hardy
Cross, and Nathan M. Newmark as a whole not for the specific processes but
for the general principles of their art of thinking about structural
design. Of the three, Harald M. Westergaard was
the immaculate and painstaking scholar with a penchant for simple and
direct expression. His vision of the relationship between theory and
design is captured by his statement ".. a simple device can yield
perhaps 80 percent of the truth whereas the next 10 percent would be
difficult to obtain and the last 10 percent impossible...." Hardy Cross
was the creative genius more interested in the engineering artifact than its
analysis. Though intensely interested and eminently successful in the
development of analytical methods for structures, he kept his students' eyes on
the prize by repeating that a building is to build and not to analyze. Perhaps
he said it all about the role of analysis in design when he wrote "All
analyses are based on some assumptions which are not quite in accordance with
the facts. From this, however, it does not follow that the conclusions of the
analysis are not very close to the facts." As a
graduate student in 1930's at Urbana, Illinois, Nathan M. Newmark worked
with Professors Cross, the artist, and Westergaard, the analyst. In
retrospect, he appears to have excelled them both in scholarship and
creativity. It is difficult to capture Newmark's state of mind with a
single quote. Things came easily to him and, in general, he did not take
the time to write to be understood. But his flashes of genius in applied
mechanics demonstrate his thinking was a perfect fusion of his gifted
teachers. His quick grasp of the important and his ability to cut through
seemingly complex problems using sophomore-level mechanics is at once
astounding and delightful. He was a master of the synecdoche. A dam would
be modeled as a rigid object with a single degree of freedom. A
multidimensional ground motion became a pulse. His understated apology
after having represented one component of an entire ground motion by one
half of a square wave, "It would be possible to consider a sinusoidal
pulse but this complicates the expressions unnecessarily," is enough
to make one stop in one's tracks. Because of the pinnacles of his
achievements in simplifying geotechnical and structural design, it is easy
to miss that his strongest contribution was to expand and deepen the way
of thinking set into motion by Cross and Westergaard. The
thinking of Cross, Westergaard and Newmark did not always intersect
completely. But when it came to the relationship of structural mechanics
to design (all three had design experience and remained active and
interested in structural design throughout their careers), they were
completely together. To them, structural mechanics was perfect as long as
it was not applied. When it was applied, it had to be applied with
judicious care to maximize return in relation to investment. As long as
one was going to be wrong anyway, one might as well be wrong the easy way. After
Dr. Sozen's interesting and personal presentation, Mr. Vian moderated the
discussions and finally, after thanking our guest with a generous
applause, the seminar was closed. --Submitted
by Benedikt Halldorsson, UB-EERI secretary
World
Trade Center Disaster
Emmanuel Velivasakis, LZA Technology, A Division of The
Thornton-Tomasetti Group
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Emmanuel Velivasakis
described the role of structural engineers at ground zero in the
aftermath of the World Trade Center attack. |
On Friday, March 15, 2002, Emmanuel
Velivasakis of LZA Technology gave a presentation entitled "World Trade
Center Disaster." It was the eighth presentation in the ongoing seminar
series on earthquake engineering topics held at the University at Buffalo.
Mr. Darren Vian, Ph.D. candidate at
the Department of Civil, Structural and Environmental Engineering (CSEE),
president of the UB-EERI Student Chapter, and member of the MCEER Student
Leadership Council (SLC), opened the seminar by welcoming the audience and
introducing the speaker.
Mr. Velivasakis described how in New
York City, emergency response teams, including hundreds of police officers and
firefighters, were immediately dispatched to the World Trade Center site by the
Mayor's Office of Emergency Management. Simultaneously, the New York City
Department of Design and Construction retained four major construction
management firms to assist in the search and rescue operation, as well as LZA
Technology, which was charged with responsibility for all structural engineering
operations at the site.
He discussed and showed numerous
examples of how the structural engineer played a crucial role in enabling the
intense search and rescue effort to proceed without hindrance on a 24-hour
basis, while maintaining safety in an environment fraught with the risk and
danger posed by partially collapsed and severely damaged structures. With
many photographs to illustrate the situation facing the engineers, Mr.
Velivasakis expanded on the services provided by LZA Technology at and
around ground zero. These services included immediate damage assessment of
buildings in the collapse area, assistance with demolition and temporary
stabilization procedures, design of grillages and analysis of existing
structures to support construction equipment, coordination of the survey
monitoring of existing damaged structures, and inspection of hundreds of
buildings in the area surrounding the collapse site. Mr.
Velivasakis' presentation was received by generous applause, after which
Mr. Vian moderated the discussions. After Mr. Velivasakis answered
numerous questions from the audience, the seminar was closed. --Submitted
by Benedikt Halldorsson, UB-EERI secretary
Using
Synthetic Aperture Radar and Other Remote Sensing Technologies to Detect
Earthquake Damage in the 1999 Marmara, Turkey Earthquake
Ronald T. Equchi, ImageCat, Inc.
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Ronald
T. Eguchi discussed the application of remote sensing technologies to
post-earthquake damage detection. |
Ronald T. Eguchi of ImageCat, Inc.gave a seminar entitled
"Using Synthetic Aperture Radar and Other Remote Sensing Technologies to
Detect Earthquake Damage in the 1999 Marmara, Turkey Earthquake" at the
University at Buffalo on March 6, 2002. Mr. Eguchi's presentation was the
seventh in the ongoing seminar series.
As with the other seminars held this semester, Darren Vian
opened the event by welcoming the audience and introducing the speaker.
Mr. Eguchi described the activities of an MCEER research
team, who for the past several years have been investigating the use of remote
sensing technologies in post-earthquake damage detection. This research has
focused on various aspects of damage detection including: 1) detection of damage
or no damage, 2) quantification of various damage states, on a regional basis,
and 3) quantification of damage to specific buildings. The research team has
found that currently available remote sensing data (namely, SPOT, Landsat, and
certain radar data, such ERS) can indeed detect major changes to cities caused
by extensive damage from an earthquake. In certain situations, remotely sensed
data can also verify particular damage states (such as collapsed buildings).
To test and validate the methodology, the research team
applied specially developed change detection algorithms to two areas of Turkey.
Both areas, Golcuk and Adapazari, were devastated in the 1999 Marmara, Turkey
earthquake. In Golcuk, severe damage was observed to multi-story residential
structures, in addition to some ground subsidence problems. To estimate change,
a broad set of change detection algorithms was applied to the analysis. For the
two areas above, Landsat and ERS data were used to assess major structural
changes caused by the earthquake. These data were provided by the European Space
Agency. For the Golcuk area, they also obtained SPOT data from researchers in
Turkey who are also investigating the use of remotely sensed for damage
detection.
The significance of these findings is far-reaching. As
demonstrated in many prior disasters, delayed or impeded response can lead to
further damage (as in the case of unchecked fires) and prolonged recovery.
Ultimately, these impacts burden the local and regional infrastructures with
higher recovery costs and additional social burdens. They concluded that by
developing and implementing technologies that allow for more rapid evaluation of
regional damage, a community's level of resilience can be increased. This
research is sponsored by MCEER and by the National Science Foundation through a
special grant on the Marmara, Turkey earthquake.
Mr. Eguchi's presentation was received by generous applause,
after which Mr. Vian moderated the discussions. A number of interesting
questions were posed from the active audience, and after the discussions, the
seminar was closed.--Submitted
by Benedikt Halldorsson, UB-EERI secretary |
