October 9, 2013

An Important note from the Principal Investigator Abolhassan ASTANEH-ASL on the document that follows:

The following PowerPoint was presented at 2002 University of California, Berkeley “Open House” Cal Day.

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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Tall Buildings Proud Achievements or Hubris-

Including World Trade Center By

Abolhassan Astaneh-Asl

Professor

University of California, Berkeley 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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Dedicated to the memories of all victims

of 9/11 attacks and to the firefighters and

rescuers who so heroically sacrificed

their lives to save others.

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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

Graphics: Tall Building Structures, Analysis and Design, by Bryan Stafford Smith and Alex Coull, John Wiley & Sons

Major Developments:

1. Steel

2. Electric Elevator

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This photo may be subject to copyright by others.

The Modern Skyscrapers, 1960’s and Beyond

Started with development of light skins and a

skeleton to carry all the loads.

1880’s

1930’s

1960’s 6 of 38

First Skyscraper The Home Insurance Building, Chicago

Photo: Library of Congress. Courtesy of the Frances Loeb Library, Graduate School of Design, Harvard University

Completion: 1885 (Demolished 1931)

Height: 138 feet

Stories: 10

Load Bearing Material: Steel

Facing Material: Brick

Structural Engineer:

William LeBaron Jenney

(1832-1907)

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Why People Build

Skyscrapers? 1. Humankind’s Fascination with reaching the sky

2. Demand by Business Activities to be Close to

Each Other and to the City Center

3. They are Prestige Symbols for Corporations

4. Limitations of Space in Dense Urban Areas

8 of 38 These photos may be subject to

copyright by others.

Who Designs and Builds a

Skyscraper? 1. Architects design Architectural Aspects

2. Structure Engineers design the Structure

3. Mechanical Engineers design mechanical systems

4. Electrical Engineers design electrical systems

5. Fire Engineers design fireproofing

6. Construction Engineers build them

1. Architects design Architectural Aspects

2. Structure Engineers design the Structure

3. Mechanical Engineers design mechanical systems

4. Electrical Engineers design electrical systems

5. Fire Engineers design fireproofing

6. Construction Engineers build them

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World’s 10 Tallest Buildings Before 9/11

WTC

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World Trade Center Design,

Construction,

Collapse and;

Lessons Learned

Credit:Photographer Unknown

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The Architect

Minoru Yamasaki

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Yamasaki’s Initial Designs, 1960’s

Credit:PANYNJ

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The problem of elevators

and the innovative solution

23 Express Elevators, 1600 foot per minute

72 local elevators

4 freight elevator

16 escalators

44

78

110

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The Structural Engineer

Leslie E. Robertson

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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 17 of 38

Floors

Credit: PANYNJ

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Wind Induced Vibrations

were controlled by 3M viscous dampers

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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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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 Fire

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External and Internal Columns as well as

floors were damaged in 3 floors

Ensuing Fires

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External and Internal Columns as well as

floors were damaged in 3 floors

Ensuing Fire and Collapse of Floor Joists

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External and Internal Columns as well as

floors were damaged in 3 floors

Buckling of Columns due to Long

Unbraced Length

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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

Steel Structure

by A. Astaneh-Asl

Research Funded by National

Science Foundation

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Congressional Hearing

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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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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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Lessons Learned and Future Work

1. Need better fire protection for the structure and better egress routes for the occupants

2. Need new systems that can prevent progressive collapse of structures in an economically and in architecturally pleasing manner.

3. Review fire codes and structural engineering codes to ensure protection for “important” structures against terrorist attacks.

4. Work towards living in a more peaceful world.

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Wish you were here

Photo by: Andre Souroujon

….and more than 3000 of our loved ones who so

violently perished. 37 of 38

Wish you were here Concluding Remarks:

We need to undertake a scientific study of this

threat and find out how vulnerable our buildings

are. Then through sustained research and

development programs respond to this threat and

save the lives of people who can become the

victims of this type of attack. We owe it to the

memory of those who lost their lives during the

9/11 barbaric attacks.

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