MATERIALS ISSUES RELATED TO THE COLLAPSE OF THE WORLD TRADE CENTER
Wednesday, February 20, 2002 2:00 pm
Room 611, Washington State Convention & Trade Center
Toni Grobstein Maréchaux, National Materials Advisory Board,
An exciting and timely presentation of invited presentations beginning
with the question - Why?
But, focusing on the structural materials answers and innovations that
can minimize the chances of a reoccurrence of the September 11th disaster
and generally improve the performance of existing and new structural building
materials. The construction industry uses larger volumes of material than
any other, and is a $40 trillion per year business worldwide. New technologies
for better, more fire resistant, and more cost effective structures are
a tremendous opportunity for materials science.
Featuring the following presentations:
||Why Did the World Trade Center Collapse? Science, Engineering,
Presenter: Christopher Musso, Massachusetts Institute of Technology,
There have been numerous reports detailing the cause of the World
Trade Center collapse on September 11, 2001. Most have provided qualitative
explanations. However, simple quantitative analyses show that some
common conclusions are incorrect. For example, steel could not have
melted in the Tower fires and there was more structural damage than
simple softening of the steel at elevated temperatures. Some guidelines
for improvements in future structures will be presented.
New Materials for Building Structures?
Presenter: John Hooper, Skilling Ward Magnusson Barkshire, Seattle,
Although new materials are being introduced into building structures,
their introduction is slowed by many factors including cost and
the code approval process. Our "new materials", generally,
relate to finding new ways to use familiar materials. Advances in
analysis tools and methodologies has allowed this opportunity to
extend the envelope and geometric application of traditional materials
such as steel, timber and concrete as well as developing new concepts
for nonstructural items such as curtain walls and stairs. Applications
of these advances will be presented with additional discussion regarding
the next generation. Research is underway that, over time, will
allow for carbon, kevlar, mylar and other composites to enter building
structure mainstream. Some examples of these opportunities will
be presented along with an estimated timetable for use.
A Structural Engineer's Dream for Ideal Post 9/11 Construction
Presenter: Loring A. Wyllie, Jr., Degenkolb Engineers, San Francisco,
A Structural Engineer uses existing construction materials to design
many large, complex structures that will provide safety to occupants.
Connections must be adequate and designs should consider extraordinary
conditions such as strong winds and earthquakes. With the recent
wave of terrorist attacks there is a desire to toughen our structures
to improve their performance under extreme and unexpected loadings.
While some improved structural details will help, better materials
would significantly improve performance for these unexpected conditions.
This presentation will focus on some of the material properties
that Structural Engineers would consider ideal for survival under
extreme conditions. Normally, material changes are relatively minor
and focus on higher strength, improved chemistry to facilitate connections,
or improved ductility. Rather than trying to make minor changes
to existing materials, the speaker will step back and dream of new
materials that would significantly improve our built environment
for the unexpected loadings and conditions, which may occur.
Virtual Materials and Service Life Design
Presenter: Geoffrey Frohnsdorff, National Institute of Standards
and Technology, Gaithersburg, Maryland
The designer of a building, or other constructed asset, must exercise
many judgments in ensuring that the intended life will be achieved
without large unforeseen expenses. The generally satisfactory performance
of buildings attests to the generally good judgment of designers.
However, enough durability problems occur to suggest that more needs
to be done to help ensure achievement of the intended service life
at a reasonable life-cycle cost. Possibilities for increasing the
likelihood of satisfactory long-term performance are: 1) establishing
service life design standards, 2) providing reliable and realistic
accelerated tests and models for predicting long-term behavior of
materials and components, and 3) providing convenient access to
reliable, easily-usable knowledge about the long-term performance
of materials and components.
If you are at all interested in the facts surrounding the materials failures
contributing to the World Trade Center collapse, or your professional
focus is on the design, testing, and application of structural materials,
don't miss this important presentation by some of the top materials and
structural engineers in the field.