 |
Contracts
Awards
WTC 7 STRUCTURAL ANALYSIS AND COLLAPSE HYPOTHESES, CONTRACT
MODIFICATIONS FOR STRUCTURAL AND BLAST ANALYSES
Under GSA Contract number GS23F0278M, NIST Order No.
SB1341-06-8-0539, as a firm fixed price effort, has been awarded to
APPLIED RESEARCH ASSOCIATES, INC. (ARA) of Albuquerque, New Mexico, to
append the following tasks to the original contract awarded on March 31,
2006. Under the appended tasks, the ARA (1) shall conduct analyses of
impact damage and fire effects to provide candidate initiating events
which may lead to structural failures and global collapse, and (2) shall
determine if there is any scenario of a hypothetical blast event or
events that could have occurred in WTC 7 on September 11, 2001.
As part of determining likely modes of failure in WTC 7, impact by
falling debris from WTC 1, fire events, and hypothetical blast events
are being considered for their contribution to the collapse of WTC 7.
NIST has documented debris damage and fire growth and spread in WTC 7,
based on available evidence. NIST is analyzing scenarios for the event
that initiated the collapse of the building. As a part of this work,
NIST is considering whether hypothetical blast events could have played
a role in initiating the collapse. While NIST has found no evidence of a
blast or controlled demolition event, NIST would like to determine the
magnitude of hypothetical blast scenarios that could have led to the
structural failure of one or more critical elements as a result of
blast.
ARA is an engineering firm founded in 1979 that performs research and
design studies for complex defense, security, environmental,
transportation, and readiness problems. This study will be managed from
the Silicon Valley Office of ARA that specializes in finite element
analysis and nonlinear structural dynamics under blast and impact
loading, impact and penetration mechanics, failure analysis, and blast
effects and the analysis of progressive collapse in buildings. ARA is
partnering with Simpson Gumpertz & Heger Inc. (SGH) of Waltham,
Massachusetts, to conduct the appended tasks, and with Loizeaux Group
International (LGI), the consulting services branch of Controlled
Demolition Incorporated (CDI) of Phoenix, Maryland.
SGH is an engineering firm that specializes in design, investigation
and retrofit of buildings and structures of all types. SGH has expertise
in building structures, materials, and investigations and conducted the
thermal-structural response analyses of each WTC tower, as part of their
contract for the WTC towers investigation.
Loizeaux Group International (LGI) has expertise in a wide range of
demolition, explosion and explosives-associated technology. This
includes explosive processes and their direct and collateral effects of
blast and resulting vibration, projectiles, and overpressure. They have
conducted investigations involving commercial explosives, terrorist
devices, commercial gas, and industrial accidents involving dusts, hot
metals, and combustion processes.
The specific tasks that ARA will perform with SGH (task 1) and LGI
(task 2) include:
- Identify and analyze hypothetical blast scenarios in three
phases, with the results from each phase being used to decide if the
analyses in the next phase is required:
- Identify hypothetical blast scenarios, using analysis
and/or experience, to determine conditions that would fail
specified column sections by direct attachment of explosive
materials.
- Analyze the overpressure produced by the blast load and
determine if the overpressure would have failed windows in
WTC 7.
- Determine if the overpressure would result in sound
levels transmitted through intact WTC 7 windows that could
be heard outside the building.
- Conduct the following analyses using a three-dimensional ANSYS
model (provided by NIST) of the lower 16 floors of WTC 7:
- Review the ANSYS model provided by NIST for conducting
structural analysis of damage to components and the effect
of time-varying temperatures. Identify possible
revisions/improvements to the ANSYS model that may improve
efficiency, accuracy and/or capture of critical failure
modes.
- Work with NIST staff to incorporate agreed upon changes
to the ANSYS model.
- Determine the structural response of WTC 7 for up to six
scenarios of structural damage from debris impact and
temperature histories provided by NIST. NIST will conduct
analyses of other scenarios in parallel. Work with NIST to
identify the structural response and failure modes for each
analysis.
The ARA team has expertise and experience in failure analysis,
nonlinear structural analysis, damage of steel and concrete structures,
progressive collapse analyses, nonlinear constitutive and damage
modeling, analysis of structures subjected to thermal loads, and blast
effects on structures. The team will be led by Dr. Steven W.
Kirkpatrick. Select experience of key project personnel is summarized
below:
- Dr. Steven W. Kirkpatrick is the program manager for this
project. Dr. Kirkpatrick is a Principal Engineer with 21 years of
experience in structural dynamics, failure analysis, finite element
analysis, impact and blast/penetration mechanics, and vehicle
crashworthiness. He has more than 40 publications in these areas.
His research experience includes a wide range of government and
commercial projects for rail, highway, civil, military, and
aerospace applications. He has been a program leader for many
studies requiring close collaboration between experimental and
computational efforts with emphasis on model validation. Dr.
Kirkpatrick was previously the PI for the ARA participation in the
NIST WTC investigation in performing the aircraft impact analyses.
Dr. Kirkpatrick has a doctorate in mechanical engineering from
Stanford University.
- Mr. Charles Needham is a Principal Engineer for the Southwest
Division of ARA. He has experience with numerical hydrodynamics,
shock, fireball and thermal effects modeling, conventional
explosives and munitions effects and structure interaction,
explosive safety and storage. He has 14 years specific experience
with SHAMRC, a state-of-the-art hydrodynamic code for two- and
three-dimensional fluid dynamics problems with applications for
conventional munitions. Mr. Needham has a master’s degree in
astrophysics from the University of New Mexico.
- Mr. Joseph Crepeau is a Principal Computer Scientist for the
Southwest Division of ARA. His responsibilities include the
maintenance and development of features for SHAMRC, as well as
training for its applications. Mr. Crepeau has a master’s degree in
computer science from the University of New Mexico.
- Ms. Lee Ann Young is a Principal Engineer I for the Southwest
Division of ARA. She has spent the last 14 years at ARA working in
the areas of human vulnerability to explosions, penetration
mechanics, and conventional weapon effects. Ms. Young has a master’s
degree in applied statistics from the University of New Mexico.
- Dr. Mehdi Zharghamee is a Principal and Head of the Engineering
Mechanics and Infrastructure Division at SGH and has 30 years of
engineering experience in analysis and design of precision
structures. He has been responsible for analysis, design, and
failure investigation of complex structural and mechanical systems.
Dr. Zarghamee has a doctorate in structural engineering from the
University of Illinois and his S.M. in Mathematics from the
Massachusetts Institute of Technology.
- Dr. Omer Erbay is a Senior Engineer with SGH and has experience
with the analysis of the structural response of the WTC towers to
impact damage and fire conditions and structural analysis of
buildings and bridge piers. Dr. Erbay has a doctorate in structural
engineering from the University of Illinois.
- Frank Kan, a Senior Project Manager, has been with SGH for 16
years. He has been involved in structural and seismic analysis,
design, and investigation of buildings, bridges and special
structures. Mr. Kan received his M.S. in Civil Engineering from the
Massachusetts Institute of Technology.
- Mr. Mark Loizeaux is CEO of LGI and President of CDI, and has
been responsible for the design and performance of CDI’s projects
since 1976, including the felling of major steel industrial,
commercial and office buildings across the United States and
internationally. Several of these buildings were major structures up
to 439 ft tall, with column flanges ranging from 6 in. thick
(laminated steel flanges) to 4 in. thick (hot-rolled flanges). His
experience with steel structures includes the demolition of major
steel bridges and construction and communication towers as tall as
1,200 ft. He is responsible for all aspects of CDI explosives
demolition design and control of related consequences, including
control of fly of debris, air overpressure, vibration and debris
impact on surrounding structures. He has been recognized as an
expert in demolition and explosives operations in U.S. Federal Court
and the Courts of Australia.
Back
to WTC Contracts
|
