study of blast effects on building columns using md ... · using md nastran sol 700 by abolhassan...

MSC.Software Confidential

Study of Blast Effects on Building Columns

using MD Nastran SOL 700

By Abolhassan Astaneh-Asl, University of California, Berkeley

Jin Son, MSC Software Corporation

Casey Heydari, MSC Software Corporation


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These studies are dedicated to all

those who are fighting terrorism

throughout the world.


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Important Note:

In this and all presentations and publications on our

projects, involving blast-protection research, we pay

special attention to place information in public domain

in a way that the information can only be used to

enhance the blast and progressive collapse resistance of

structures and not to present information in a way that

can be used for malicious purposes.


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A quote from my professor at the

University of Michigan, Ann Arbor:

“Unlike mechanical engineers, who can

crash test their cars or test fly their

airplanes, in structural engineering, our

buildings and bridges should perform the

first time they are tested!”

Professor Glen V. Berg, University of Michigan


Blast Protection of Major Bridges

and Elevated Freeways

Abolhassan Astaneh- Asl,

Professor and Principal Investigator, UC-Berkeley

Casey Heydari,MSC Software

Marcus Rutner, UC-Berkeley

Jin Son,UC-Berkeley

Vijay Tunga, MSC Software


Collapse of critical

bridges can create

major catastrophes

Bridges need to be

studied and hardened

against terrorist car

bomb attacks.

Sloboda Bridge in Novi Sad, Serbia and Montenegro

Please Note that:


1. To investigate performance of steel bridges

under car bomb blast

2. To develop efficient technologies to prevent

collapse of the span and save lives.

Basic Goals:

Steel Box Piers

Deck

Tower Leg

Cable-Stayed Bridges

Suspension Bridges

DeckTower Leg

Piers


Blast Protection of Decks (Roadway)

Modern Steel Orthotropic DecksTraditional Deck on Steel Girders


Tower and Pier Protection

Steel, Single-Cell Steel, Multi-Cell

Composite, Single-Cell Composite, Multi-Cell

Proposed:


Bridge Deck Protection


Example of Bridge Tower and

Deck Protection

J. Son , MSC VPD Conference, 2009


Bridge Tower and Deck Protection

J. Son , MSC Conference, 2008

Existing

ConditionWith Proposed

Retrofit Added


Study of Blast Effects on Building Columns

using MD Nastran SOL 700

By Abolhassan Astaneh-Asl, University of California, Berkeley

Jin Son, MSC Software Corporation

Casey Heydari, MSC Software Corporation


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General Goals:

• To investigate performance of steel

column in buildings subjected to car

bomb attacks

• To Develop technologies to protect

building columns against car bomb

attacks


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Loads Currently Considered in

Design of Building Structures:

• Gravity Loads (weight of the buildings, occupants and contents)

• Wind Loads

• Earthquakes

• Temperature Effects

• Hydrostatic Pressure

• Soil Pressure


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Background on Column Failure

• The tragic collapse of Murrah Federal Building in Oklahoma City changed that.

• The most vulnerable elements of the buildings are the ground floor columns

• The tragic progressive collapse of the Murrah Federal Building was caused by the removal of

only one column of ground floor.


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Effects of Blast Waves on the Structure

• Blast load is very short

duration but is very large

near the blast.

• This results in very

serious local damage

• Local damage to columns

can lead to partial or full

collapse of building

especially parking

structures.


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Protecting Steel Columns in Buildings

Column without walls

Column within the walls


Walls can be used to protect columns


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Protecting Columns within the Walls

Composite (Steel+Conc.) WallReinforced Concrete Wall


Total Failure of the reinforced concrete walls

and the column base

Yielding of steel plate composite wall and bending of columns

Walls can be used to protect columns

Results of subjecting 3-story building

to the Same Car Bomb


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What happens if a column is Blasted Away?

• The load carried by the damaged column should be

transferred to adjacent columns by Catenary Action

• If the adjacent columns and girders or their connections

cannot resist the force transferred to them, building can

progressively collapse.

Photo: Courtesy: Joseph Hartman, US Army Corps of Engineers


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Protecting Columns without Walls

• The column itself

should be able to

withstand the blast

and not sustain

serious enough

damage that it

collapses under the

gravity load during or

after the blast.



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Protecting Steel Columns Against Blast

• The main parameter

causing the collapse

is the axial gravity

load in the column

which is the weight

of floors above.



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Protecting Steel Columns Against Blast

• Blast tests done on steel columns

• In these tests the columns had no axial load!


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Column Section behavior under Blast Pressure

• During blast, column sections

deform and if axial load exists,

the column can collapse easily.


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Protective Measures for Steel Columns


Results of Previous Work:

E. K. Goodson and A. Astaneh-Asl (MSC VPD Conference, 2004)

Steel Column Subjected to

Blast Charge at Mid-height

Composite (Steel+ Concrete)

Column Subjected to Blast

Charge at Mid-height


Results of Current Work:J. Son, A. Astaneh-Asl and C. Heydari (MSC VPD Conference, 2010)

Steel Column Subjected to Blast Charge at the

Base of Column Causing Base Shear Failure

Base Shear Failure


A. Astaneh-Asl, J. Son and C. Heydari (MSC 2010 Automotive Conference)

Steel Column Subjected to Blast Charge at the Base

of the Column Causing Base Shear Failure

No Axial LoadWith Axial Load Equal to

25% of Axial Yield Capacity


A. Astaneh-Asl, J. Son and C. Heydari (MSC 2010 Automotive Conference)

Steel Column Subjected to Blast Charge at

the Base of Column Causing Base Shear Failure

No Axial LoadWith Axial Load Equal to

25% of Axial Yield Capacity


Failure Modes of Steel Columns Subjected to Blast

Near Its Base


Concluding Remarks

• Axial load in bridges and building columns

is the main parameter for collapse

• Base of the columns need to be designed for

blast shear force.

• Proposed retrofit concepts prevented

catastrophic collapse

• MD Nastran SOL 700 was invaluable in accurate

simulation of blast effects and structural

behavior.


TONY DAVENPORT

MARKETING MANAGER

CLOSING REMARKS

MSC.Software

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