1. PROGRESSIVE COLLAPSE SUSCEPTIBILITY OF A LONG SPAN
SUSPENSION BRIDGE
Progressive Collapse and Structural Robustness: An International Perspective
Clay J. Naito, Ph.D., P.E., Associate Professor and Associate Chair
Konstantinos Gkoumas, Ph.D., P.E., Associate Researcher
Pierluigi Olmati 1
P.E., Ph.D. Student
Email: pierluigi.olmati@uniroma1.it
Luisa Giuliani 2
Ph.D., Assistant Professor
Email: lugi@byg.dtu.dk
1 Sapienza University of Rome
2 Technical University of Denmark (DTU)
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org

2. 2 Presentation outline
Introduction on the progressive collapse
The Messina Strait Bridge
Damage based approach and numerical simulations
1
2
3
4 Conclusions
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org

3. 3
Progressive Collapse case history
Ronan Point – May 16, 1968
Progressive Collapse triggered by
precast concrete bearing wall failure
(gas deflagration).
Ali Khobar – June 25, 1996
Progressive Collapse was stopped
(ANFO detonation, 9 ton TNTeq).
Oklahoma City – May 19, 1995
Progressive Collapse triggered by
concrete column failure
(ANFO detonation, 1.8 ton TNTeq).
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
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Introduction

4. 4
Progressive Collapse case history
Deutsche Bank – September 11, 2001
Progressive Collapse was stopped
(Debris impact).
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
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4
Introduction

5. 5
Ronan Point – May 16, 1968
General view of Ronan Point prior to
demolition/photo 1987/photographer
M Glendinning
Features:
- apartments building;
- built between 1966 and 1968;
- 64 m tall with 22 story;
- walls, floors, and staircases were made of precast
concrete;
- each floor was supported directly by the walls in
the lower stories, (bearing walls system).
References:
NISTIR 7396: Best practices for reducing the potential for
progressive collapse in buildings. Washington DC: National
Institute of Standards and Technology (NIST), 2007.
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
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4
Introduction

6. 6
Cause Damage Pr. Collapse
Features:
- apartments building, built between ‘66 and ’68;
- 64 m tall with 22 story;
- walls, floors, and staircases were made of precast
concrete;
- each floor was supported directly by the walls in
the lower stories, (bearing walls system).
The event:
- May 16, 1968 a gas explosion blew out an outer
panel of the 18th floor;
- the loss of the bearing wall causes the
progressive collapse of the upper floors;
- the impact of the upper floors’ debris caused the
progressive collapse of the lower floors.
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
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4
Introduction
Ronan Point – May 16, 1968

7. 7
Ali Khobar – June 25, 1996
References:
NISTIR 7396: Best practices for reducing the potential for
progressive collapse in buildings. Washington DC: National
Institute of Standards and Technology (NIST), 2007.
Features:
- apartments building;
- precast concrete wall and floor components
were the structural bearing system;
- ductile detailing and effective ties between
the precast components.
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Introduction

8. 8
Features:
- apartments building;
- precast concrete wall and floor components
were the structural bearing system;
- ductile detailing and effective ties between
the precast components.
Cause Damage Pr. Collapse
The event:
- June 25, 1996 9 ton of
TNTeq detonated in front
of the building;
- the exterior wall was
entirely destroyed;
- collapse did not progress
beyond areas of first
damage.
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Introduction
Ali Khobar – June 25, 1996

9. 9
Progressive Collapse
Definitions:
1- "Progressive collapse is defined as the spread of an initial local failure
from element to element resulting, eventually, in the collapse of an entire
structure or a disproportionate large part of it." (ASCE 7-05 2005)
2- "A progressive collapse is a situation where local failure of a primary
structural component leads to the collapse of adjoining members which, in
turn, leads to additional collapse. Hence, the total collapse is
disproportionate to the original cause." (GSA 2003)
3- "Progressive collapse. A chain reaction failure of building members to an
extent disproportionate to the original localized damage." (UFC 4-010-01
2003)
References:
(ASCE 7-05 2005): "Minimum design loads for buildings and other structures." American Society of Civil
Engineers (ASCE).
(GSA 2003): "Progressive collapse analysis and design guidelines for new federal office buildings and major
modernization projects." General Services Administration (GSA).
(UFC 4-010-01 2003): "DoD minimum antiterrorism standards for buildings." Department of Defense (DoD).
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Introduction

10. 10
Cause Damage Pr. Collapse
Disproportionate Collapse ???
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Introduction

11. 11
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Introduction

12. 13
Cause Damage Pr. Collapse
Disproportionate Collapse ???
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Introduction

13. 14 Presentation outline
Introduction on the progressive collapse
The Messina Strait Bridge
Damage based approach and numerical simulations
Conclusions
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4

14. 15
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Messina Bridge

15. 16
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Messina Bridge

16. 17
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
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Messina Bridge
Proposed Messina Strait Bridge
Length of main span: 10827 feet
Height of tower: 1255 feet
Golden Gate Bridge
Length of main span: 4200 feet
Height of tower: 746 feet

17. 18
DECK
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
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4
Messina Bridge

18. 19 Presentation outline
Introduction on the progressive collapse
The Messina Strait Bridge
Damage based approach and numerical simulations
Conclusions
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4

19. 20
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
Damage based approach, numerical simulations

20. 21
εy ε 1 ε 2 ε 3
σy
χy χ 1 χ 2 χ 3
My
(a) (b)
M1 σ1
M2 σ2
Flexural
My
[MN m]
M1
[MN m]
M2
[MN m]
χy [1/m] χ1 [1/m] χ2 [1/m] χ3 [1/m]
Railways
girders
60 63 6.3 0.0015 0.0085 0.01 0.015
Highway
girders
130 136.5 13.65 0.001 0.0045 0.005 0.01
Transverse 80 84 8.4 0.00155 0.0095 0.011 0.0155
Axial σy [MPa] σ1 [MPa] σ2 [MPa] εy [-] ε1 [-] ε2 [-] ε3 [-]
Hangers 1620 1782 162 0.0077 0.01925 0.024 0.03
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Damage based approach, numerical simulations

21. 22
East side
330 m
DS1
DS2
DS3
DS4
DS5
DS6
1650 m960 m
210 m
80 m
not to scale
Airbus A380-800
West side
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Damage based approach, numerical simulations

22. 23
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Damage based approach, numerical simulations
st side
330 m
DS1
DS2
DS3
DS4
DS5
DS6
210 m
8
Airbus

23. 24
1650 m960 m
not to scale
East hanger West hanger
Mid-point
West extremity point
East extremity point
Damage zone
East side
West side
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Damage based approach, numerical simulations

24. 25
Moments on the high way deck – DS 1
Mid-point
West extremity point
Yield moment
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Damage based approach, numerical simulations

25. 26
Moments on the high way deck – DS 3
Mid-point
West extremity point
Yield moment
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Damage based approach, numerical simulations

26. 27
Moments on the high way deck – DS 4
Mid-point
West extremity point
Yield moment
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Damage based approach, numerical simulations

27. 28
Moments on the high way deck – DS 5
Mid-point
West extremity point
Yield moment
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Damage based approach, numerical simulations

28. 29
Moments on the high way deck – DS 6
Mid-point
West extremity point
Yield moment
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Damage based approach, numerical simulations

29. 30
Average axial force on the East and West hangers
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Damage based approach, numerical simulations

30. 31
Relative displacement at the Mid-point
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Damage based approach, numerical simulations

31. 32
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Damage based approach, numerical simulations

32. 33 Presentation outline
Introduction on the progressive collapse
The Messina Strait Bridge
Damage based approach and numerical simulations
Conclusions
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4

33. 34
On the numerical simulations:
1- The progression of the damage from the hangers to
the bridge deck occurs for at least 8 destroyed
hangers.
2 - The complete failure of the deck occurs for at least
10-12 destroyed hangers.
3 - The progression of the damage to an adjoin hanger
occurs for 12 destroyed hangers.
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Conclusions

34. 35
On the performance evaluation of this long span
suspension bridge:
1- When the damage could be considered
disproportionate?
- When the deck fails?
- When the damage progresses to an adjoin
hanger?
(And when the initial damage could be considered
to be local?)
2- Research on the progressive collapse should lead on
a quantitative evaluation of the progressive collapse
susceptibility.
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org
1
2
3
4
Conclusions

35. Progressive Collapse and Structural Robustness: An International Perspective
Clay J. Naito, Ph.D., P.E., Associate Professor and Associate Chair
Konstantinos Gkoumas, Ph.D., P.E., Associate Researcher
Olmati P, Giuliani L
Sapienza University of Rome & DTU
pierluigi.olmati@uniroma1.it
www.francobontempi.org