An Important note from the Principal Investigator ... Special...An Important note from the Principal...
Transcript of An Important note from the Principal Investigator ... Special...An Important note from the Principal...
October 9, 2013
An Important note from the Principal Investigator Abolhassan ASTANEH-ASL on the document that follows:
The following PowerPoint was presented to combined students enrolled in CE92 and CE92 in the Department of Civil and Env.
Engineering at University of California, Berkeley in 2002.
Abolhassan ASTANEH-ASL, Ph.D., P.E.
Professor and Principal Investigator for the NSF Funded UC Berkeley WTC Project (Duration: 10-2001 to 9-2002)
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Special Joint Lecture of CE92/CE24
World Trade Center and Engineering
Aspects of 9/11
Abolhassan Astaneh-Asl, Professor (www.ce.berkeley.edu/~astaneh)
University of California, Berkeley
WTC
9/11
Investigation
Future?
Credit:Wtcphotos.com
This document is part of the “World Trade Center Post-Disaster Reconnaissance and Perishable Structural
Engineering Data Collection”, a research project funded by the U.S. National Science Foundation at the Univ. of
California Berkeley with Prof. Abolhassan ASTANEH-ASL as Principal Investigator
(http://www.ce.berkeley.edu/~astaneh) as the Principal Investigator. Duration of the project was from 10/2001 to
9/2002. Further Information and project archives are at http://lib.berkeley.edu/ENGI/WTC. © 2001 Abolhassan
ASTANEH-ASL.
"This work is licensed under a Creative Commons Attribution-NonCommercial -No Derivatives License."
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The lecture is dedicated to the memories
of all victims of 9/11 attacks and to the
firefighters, police officers and other first
responders who so heroically sacrificed
their lives to save others. A. Astaneh-Asl
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Outline
1. Tall Buildings
2. Protection against terrorist attacks
3. World Trade Center
4. Lessons learned and future work
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Q. How and Where did Skyscrapers Start?
A. In Chicago, 1880’s
Source of Graphics: Tall Building Structures, Analysis and Design, by Bryan Stafford Smith and Alex Coull, John Wiley & Sons
Major Developments:
1. Steel
2. Electric Elevator
Nu
mb
er
of
Sto
ries
10
0
80
60
40
20
0 1850 1890 1870 1930 1910
Otis’s
Elevator
Steel
Rolled
New York
Era
Chicago
School
Wrought
Iron
and Cast
Iron Era
Elec.
Elev.
Year
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World’s 10 Tallest Buildings
WTC 1 2 3 4 5 Petronas Sears Jin Mao Citic Plaza Shun Ming Malaysia Chicago China New York China China
88 stories 110 stories 88 stories 110 stories 80 stories 69 stories
1,483 ft 1,450 ft 1,381 ft 1,360 ft 1,283 ft 1,260 ft
6 7 8 9 10 Empire State Central Plaza Bank of China Emirates Tower 1 The Center New York Hong Kong Hong Kong U.A. E. Hong Kong
102 stories 78 stories 70 stories 55 stories 79 stories
1,250 ft 1,227 ft 1,209 ft 1,165 ft 1,148 ftt 6 of 40
Who Designs and Builds a
Skyscraper?
1. Architects design aesthetic and allocate spaces
2. Structure Engineers design the structure to carry the loads
3. Fire Engineers design fireproofing
4. Geotechnical Engineers design foundations
5. Environmental Engineers design hydraulic and other env. systems
6. Construction Engineers build them
7. Mechanical Engineers design mechanical systems
8. Electrical Engineers design electrical systems
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Height of Skyscrapers
1368ft 1381 1450 1483 1509 1883ft
Planned, not
completed yet 8 of 40
Forces that buildings are
designed for:
Some Buildings
in Recent Years
Wind Blast Seismic Gravity Planes
Only
WTC Designed
for Boeing 707
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World Trade Center Design,
Construction,
and September 11 Events
Credit:Photographer Unknown
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The Architect
Minoru Yamasaki
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The Structural Engineer
Leslie E. Robertson
Credit:Photo by Alan McWeeney/New Yorker
LERA Photo
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Typical Framing System Water Tower Place, Chicago
Credit: 100 World’s Tall Buildings Credit: “Building Structures” by W. Schuller
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The Steel Structure
Credit:PANYNJ
Towers had large column-free areas
209 ft
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Tube System
Credit: PANYNJ
Column Section 15 of 40
Floors
Credit: PANYNJ
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World Trade Center
Construction
Credit:PANYNJPhotographer Unknown
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Construction of WTC Tower
Credit:PANYNJ
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Car bomb caused collapse of 3
parking floors but structure
survived.
The 1993 Attacks
Credit: Engineering News Record 19 of 40
World Trade Center
The 9/11 Attacks
Credit:Photographer Unknown
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3-D Plane Hit Areas and Casualties
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External and Internal Columns as well as
floors were damaged in 3 floors
Plane Impacting the Structure
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Plane Impacting the Structure
External and Internal Columns as well as
floors were damaged in 3 floors
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External and Internal Columns as well as
floors were damaged in 3 floors
Ensuing Fires
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The
damaged
floor
collapsed
dropping
top portion
on the lower
part
collapsing
the entire
structure
Final Collapse Due to Gravity
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Post Collapse Investigation of WTC Steel Structure
(Sept. ’01-Present)
By A. Astaneh-Asl
Research Funded by the
National Science Foundation
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http://lib.berkeley.edu/ENGI/WTC
Copyright © 2001 Abolhassan ASTANEH-ASL
Studies of World Trade Center, Principal Investigator: A. Astaneh-Asl , University of California, Berkeley
Sponsor: National Science Foundation
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Here are some examples of our field findings.
Photo: A. Astaneh-Asl Photo: HNSE
Photo by W. Farrington for A. Astaneh’s NSF Report Photo by A. Astaneh-Asl
Copyright © 2001 Abolhassan ASTANEH-ASL
Copyright © 2001 Abolhassan ASTANEH-ASL
Copyright © 2001 Abolhassan ASTANEH-ASL
Photo by William Farrington for A. Astaneh’s WTC NSF Project. Copyright © 2001 UC Board of Regents
FEMA/ASCE BPAT Work (Oct. ‘01-March ’02)
Hindrances to investigations:
The recycling of steel structure, loss of perishable
data, FEMA/ASCE non-disclosures agreement, ….
and outrage of the victim’s families and firefighters
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Hearings of
the Committee on Science,
U.S. House of Representatives
Chairman Boehlert,
Committee on Science
A. Astaneh-Asl
University of California
A bill was introduced in Congress to establish “National
Construction Safety Team” within Dept. of Commerce (NIST) to
investigate future building collapses as well as the WTC
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Here at UC-Berkeley, we have continued analytical studies
of the WTC with collaboration of researchers and
engineers from LLNL, IIT, and MSC Software Corp.
UC-Berkeley and MSC Software Corporation
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Close ups
Fully loaded plane entering the structure and damaging it..
Studies of World Trade Center, Principal Investigator: A. Astaneh-Asl , University of California, Berkeley
Sponsor: Civil and Mechanical Systems Program, National Science Foundation
University of California Berkeley and MSC Software Corporation
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University of California, Berkeley and MSC Software Corporation
Studies of the World Trade Center
Principal Investigator: A. Astaneh-Asl , Sponsor: National Science Foundation
Fire Heating-
up Damaged
Structure,
Weakening it
and the
Structure
Collapses
under the
Gravity Load.
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Current Status of our Studies
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Future of WTC?
One of the first attempts
Ref: The New York Times
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Developing Protective Systems
At University of California, Berkeley
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The car bomb exploded too close to the building,
knocking out columns and transfer girders. Then due
to progressive collapse, ½ of the building collapse
under gravity load.
The Case of Progressive Collapse of
Murrah Building, Oklahoma City, 1995
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Analysis at LLNL and Actual Full Size
Test at Univ. of California at Berkeley
Vertical Displacement of
20.8 inches
Cables
A.Astaneh-Asl, D. McCallen, E.
Madsen, B. Jones, R. Jong, W. Li,
Y.Zhao,
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http://lib.berkeley.edu/ENGI/WTC
Copyright © 2000 Abolhassan ASTANEH-ASL
Composite Shear Walls Can Be Used
Around Stairwells to Protect Egress
Routes
Research Data on Fire Resistance Can be Useful
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http://lib.berkeley.edu/ENGI/WTC
Copyright © 2000 Abolhassan ASTANEH-ASL
Lessons Learned and Concluding
Remarks
1. Need better fire protection for structures
2. Need better egress routes for the occupants
3. Need new systems to prevent progressive collapse
4. Developers, architects, structural engineers and fire engineering should work together from the start of the project and consider safety of the occupants the highest priority regardless of the cost.
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Wish you still were here, …
Photo by: Andre Souroujon
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….and more than 3000 of our loved ones who so
violently perished on 9/11.