 |
Contracts
Awards
WTC 7 STRUCTURAL ANALYSIS AND COLLAPSE HYPOTHESES
Under solicitation number SB1341-06-Q-0186, a fixed price purchase
order has been awarded to APPLIED RESEARCH ASSOCIATES, INC. (ARA) of
Albuquerque, New Mexico:
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. Specific
examples of the team’s past work include:
- Analysis of the aircraft impact on the WTC towers using explicit
finite element analysis to model the dynamic impact loads and
resulting progression of damage and component failures in the
towers.
- Vulnerability and progressive collapse analyses of buildings for
General Services Administration (GSA), including courthouses,
embassies, and typical office buildings. ARA engineering services
for GSA included development of the “Progressive Collapse Analysis &
Design Guidelines for New Federal Office Buildings and Major
Modernization Projects.”
- Studies of progressive collapse and the effects of blast on
buildings for the United States Department of Defense (DoD). ARA
services included development of the “Unified Facilities Criteria (UFC)
– Design of Buildings to Resist Progressive Collapse” for the DoD.
- Studies on both static and dynamic buckling and collapse of
structures. Scope included development of explicit nonlinear finite
element methodologies for prediction of buckling loads.
- Studies on the degradation and failure of structures subjected
to localized thermal loading. Evaluation of combined effects of
material degradation and geometric changes resulting from dynamic
temperature profiles.
ARA will conduct analyses, in collaboration with NIST, to determine
the location and cause of the initiating event (i.e., the first
component or group of components that failed) that led to global
collapse of WTC 7. The analyses will determine the series of component
and subsystem failures subsequent to the initiating event that led to
global collapse that are consistent with observations from video and
photographic records and other evidence. NIST will conduct all fire
analysis of the building and analysis of the structural response to
fires in-house and supply ARA initiating event data based on the
in-house analyses.
ARA will conduct nonlinear dynamic collapse analyses using LS-DYNA
that include analyses of detailed full floor models and global models.
The detailed floor analyses will determine likely modes of failure for
Floors 8 to 46 due to failure of one or more supporting columns (at one
or more locations), and aid the development of a more coarse model for
use in the global analyses that captures essential behaviors and failure
mechanisms. Two types of global analyses will be conducted. Sensitivity
studies will be conducted to determine the response of WTC 7 to various
scenarios of initiating events. Final analyses will support the
determination of the location and cause of the initiating event, by
incorporating data from NIST for simulating the initiating event, as
well as the location and cause of subsequent failures that led to global
collapse. The specific tasks that ARA will perform include:
- Conduct detailed analyses of floor components and subsystems
with appropriate steel and concrete constitutive models.
- Determine the floor response to gravity loads for up to twenty
initiating event scenarios
- Develop an equivalent representation of the tenant floors for
the global model.
- Conduct global analysis under service gravity loads to determine
the structural response of WTC 7 to different initiating events,
including characterization of the load redistribution within the
structural system for two states of damage from debris impact.
- Conduct a sensitivity study to determine the global structural
response to gravity loads for up to twenty initiating event
scenarios
- Conduct final global analyses that simulate up to five
initiating events and the subsequent failure sequences up to the
point of global instability.
The team from ARA 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 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 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.
- Dr. Robert Bocchieri, Principal Engineer, will provide expertise
in nonlinear dynamic finite element analysis, solid mechanics,
materials constitutive modeling, rate-dependent material behavior,
fracture mechanics and failure analysis, mechanics of composite
materials, and structural dynamics. Dr. Bocchieri has a doctorate in
aerospace engineering from the University of Texas at Austin.
- Mr. James Brokaw, Senior Security Engineer and Director of the
Security Engineering Group, will provide expertise in the analysis
of progressive collapse in buildings. He has served as the lead
consultant for numerous projects of national significance subject to
terrorist threats and assisted in the development of GSA’s
progressive collapse analysis and design guidelines. Mr. Brokaw has
a Master’s Degree in civil engineering from West Virginia
University.
- Mr. Robert MacNeill, Senior Engineer, will provide expertise in
finite element analysis (FEA) and thermal analysis. Mr. MacNeill is
an experienced user of LS-DYNA, having implemented many advanced
features of the code and is skilled at constructing complex
parametric finite element models designed to easily interface with
simulation based design (SBD) systems and design databases. Mr.
MacNeill has a Master’s Degree in mechanical engineering from the
Rochester Institute of Technology.
- Mr. Brian Peterson, Senior Engineer, will provide expertise in
nonlinear dynamic finite element analysis, impact and penetration
mechanics, solid mechanics, materials constitutive modeling,
fracture mechanics, and failure analysis. Mr. Peterson has
experience in testing of materials and structures and has extensive
experience with advanced features of LS-DYNA. Mr. Peterson has a
Master’s Degree in mechanical engineering from Stanford University.
Back
to WTC Contracts
|
