1 - BRBF Introduction_Star Seismic Academy

Part 1: BRBF IntroductionBucharest, June 14, 2010

Innovative anti-seismic tool

Cost-savings

Faster construction

Outstanding performance

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Buckling Restrained Braced Frame

• Star Seismic

• Buckling Restrained Braced Frames (BRBF) History

• BRB element

• Verification tests

• BRBF system

• Application

• Cost advantages

• Projects

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Part 1: BRBF Introduction

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Managing Director: Argan Johnson

Star Seismic LLC, USA

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Managing Director: Cesar Mendez Franco

Star Seismic Latin America

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Managing Director: Zoltan Bago

Star Seismic Europe

• Star Seismic


• BRB element


• BRBF system

• Application

• Cost advantages

• Projects

www.starseismic.eu


Development in Japan and USA

Introduction in the USA 1st paper: Convention of Structural Engineers Association of California (SEAOC),

2000

1st building: University of California, 2000

Several design presentations: Convention of Structural Engineers Association of California (SEAOC)

North American Steel Construction Conference (NASCC)

American Institute of Steel Construction (AISC)

American Society of Civil Engineers (ASCE)

Steel TIPS

Governing provisions 2005 ASCE-7

2005 AISC Seismic provisions

FEMA 450

2006 IBC

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History of BRBF

Eurocode

EN 15129

EC 8 …?To be edited

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History of BRBF

• Star Seismic


• BRB element


• BRBF system

• Application

• Cost advantages

• Projects

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Ductility

Material

• Mild steel

Member

• BRB

Structure

• BRBF

Ductility:

The ability to sustain large inelastic deformations

without significant loss in strength

Permits structures to survive severe earthquakes

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Pcr

Limited Hysteretic Energy Dissipation

Strength and stiffness Hysteretic Degradation

Unbalanced behavior

Tension

Compression

Conventional bracing

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PT = 100kN

PC = 40kN

PC = 60kN

PC = 90kN

PC = 100kN

Small amplitude buckling

P C P C

P CP C

P C P C

P C P C

P T P T

How Does a Buckling-Restrained Brace Work?

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Continuous support

(Mechanics Definition)

Balanced Hysteresis

(Performance Definition)

Tension

Compression

How Does a Buckling-Restrained Brace Work?

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• Star Seismic


• BRB element


• BRBF system

• Application

• Cost advantages

• Projects

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PERFORMANCE

Full scale tests

University of California, San Diego

University of Utah, Salt Lake City

Lehigh university, Pennsylvania

Verification tests

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Northridge (1994, M6.7) Earthquake simulation

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Backbone curve

• Star Seismic


• BRB element


• BRBF system

• Application

• Cost advantages

• Projects

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Response of BRBF in seismic event

Tension Brace: Yields Compression Brace: Yields

Elastic Columns and Beams


Compression Brace: Yields Tension Brace: Yields


Elastic Columns and Beams

• Star Seismic


• BRB element


• BRBF system

• Application

• Cost advantages

• Projects

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Single Diagonal Inverted V V Bracing

X- Bracing

Two Story X- Bracing

Application – BRB Configuration

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Application – Inverted V, X and single brace

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Application – New structures

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Application – Seismic retrofit

Arpechim – Pitesti?

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PROHITECH

Earthquake PROtection of HIstorical Buildings

by Reversible Mixed TECHnologies

develop sustainable methodologies in the seismic protection of existing constructions

save human lives

reduce economic and cultural losses

innovative materials and special devices, allowing ease of removal if necessary


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PROHITECH

Earthquake PROtection of HIstorical Buildings

by Reversible Mixed TECHnologies

PROHITECH WP5: Innovative materials and techniques

”BRBF systems do not usually require structural members andfoundation strengthening as do conventional braced frame systemsusing traditional braces, thereby achieving more cost savings.”

”the installation of BRBs allows for a decrease in the cross-sectional area of the steel-frame beams and columns, thus theweight of steel framing members used in the entire building caneasily be reduced.”


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Connection – to steel

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Connection – to concrete

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Connection – collar

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Manufacturing

• Star Seismic


• BRB element


• BRBF system

• Application

• Cost advantages

• Projects

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Energy dissipation

High behavior factor

Low seismic design forces

Lower structural costs

Savings on beams, columns and foundation

Less material and labor

Savings on connactions

Faster construction, savings on crane

Larger area to be used

Cheaper post-earthqake repair

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Cost savings with BRBs

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Special Concentrically

Braced Frame

Independent cost analysis

q=6 q=8Buckling Restrained

Braced Frame

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• 3 story:

• over 50 000EUR savings, 9 EUR/m2

• 3% of entire structural cost

• 6 story:

• over 230 000EUR savings, 19EUR/m2

• 6% of entire structural cost


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• 34% (!) savings on

lateral load resisting

system


• Star Seismic


• BRB element


• BRBF system

• Application

• Cost advantages

• Projects

www.starseismic.eu


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One Rincon Hill

195m height

Projects – San Francisco

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LA Live

199m height

10 000kN in compression

Projects - Los Angeles

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Projects - Los Angeles

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University of California

UCSF Hospital

Projects – San Francisco

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Thank you for yourattention

[email protected]

1 - BRBF Introduction_Star Seismic Academy

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