Detail of UBBTM

Material Specifications

UBBTM

(Unbonded Brace)

UBBTM Performance

Layout Image

Chevron type V-shaped type Single type

China

Taiwan

Japan

The USA

Yielding partElastic partPanel zone Elastic part Panel zone

Core Plate

Steel Tube

Yielding part absorbs energy from a severe earthquakes.

Non-buckling and equivalent strength in tension and compression enables a variety of layout patterns.

Feature of UBBTM UBBTMs are adopted more than 800 projects in the world.

Hysteresis loops in tension and compression have equal strength and stiffness, in the pre- and post-yield ranges.

1) Same stiffness in tension and compression2) Same strength in tension and compression3) Stable and symmetric behavior in tension and compression

BCJ Approval**License Number BCJ-ST0125-03 (effective to Oct.2015) & BCJ-ST0126-02 (effective to Oct.2015)

UBB received a "BA" classification approval from Building Center of Japan (BCJ) as both a seismic control member and a structural element, and as a result can be used to achieve designs that are more economical than regular structural systems.

Satisfaction of seismic manual issued by AISC

UBBTM has been conducted a number of loading tests which satisfy design requirement of seismic design manual issued by American Institute of Steel Construction (AISC ).

Ratio of Axial Force/Yield StrengthP/Py 2

1.5

1

0.5

0

-0.5

-1

-1.5

-2-2 -1.5 -1 -0.5 0 0.5 1 1.5 2

Steel Material : JIS SS400(similar to ASTM A36)

Axial Strain

Absorption of seismic energy

Core Plate JIS SN400 [similar to ASTM A1043(Gr.36)]JIS SN490 [similar to ASTM A1043(Gr.50)]NSSMC Standard BT-LYP225(Certified material by Ministry of Land, Infrastructure, Transport and Tourism)ASTM A36ASTM A1043 (Gr. 36)ASTM A1043 (Gr. 50)

Minimum core plate thickness is 12mm (1/2in.) [19mm (3/4in.) or thicker is recommended].

Steel Tube ASTM A500, JIS STKR400 or JIS STK400, Thickness : 3.2 mm to 16 mmWidth or Diameter : 100 to 500 mm (larger sizes are possible upon request)

Mortar As per Technical specification

Design of Steel Tube As per Technical specification

2006Retrofit project in Tokyo Institute of Technology

2011 1000t UBB performance test at National Center for Research on Earthquake Engineering

2008UBB application for bridge.

OSAKI CENTER BUILDING, 5-1, Osaki 1-Chome, Shinagawa-ku, Tokyo 141-8604, JapanTel. +81-3-6665-4330

Unit 1508, Cityland Herrera Tower 98 V.A Rufino St. corner Valero St.Salcedo Village, Makati City 1200, PhilippinesTel. +63-2-511-7959, +63-2-845-0749

http://www.eng.nssmc.com/english/

NSENGI_steel_structures@eng.nssmc.com

Contacts

Head office

Manila Branch

URL

e-mail

Most Widely Used BRB(Buckling Restrained Brace) in the World!!

What's Response Controlled Structure? Performance Data

Unbonding Material

UBBTMs

Fatigue Test

Engineering R&D Institute #1,Futtsu, Japan

Building Research Institute Laboratory, Tsukuba, Japan

Earthquake energy input

Response Controlled Structure with UBBTM

Response control devices UBBTM s absorb seismic force to minimize the damage and the horizontal deformation of structure

Conventional Structure

Primary frame itself has to resist seismic force

UBBTM Configurations and Core Material Types

UBBTM’s Main Components

UBBTM Concept

After a severe earthquake

Horizontal vibration during earthquake

Features

Conventional Structure Response Controlled Structure with UBBTM

Less damage of primary frame because UBBTMs absorb seismic energy.

Severe damages on primary structure that may occur make the building be unable to use continuously.

Smaller horizontal vibration as UBBTMs absorb seismic energy.

Severe horizontal vibration.

Structure with UBBTMs as response control devicesabsorbs seismic energy.

Primary frame itself (columns and girders) resists an earthquake.

Typical Result, Full-Scale Shaking Table Test

*Building Research Institute Laboratory, Tsukuba, Japan

Early 1980sOriginal research and development of BRBs by Nippon Steel Corporation 1987

1987UBB applications have started in Japan.

1998Very Large UBB (22m, 72.5ft long)Osaka International Convention Center

1999First BRB/UBB project in the USAThe new Plant & EnvironmentalSciences Building at U, C Davis

2000Exposed Braces with Cast End ConnectionsToyota Stadium, Aichi

1997Exposed and Circular Tube UBB comprising Buttress StructureNihon TV Tower, Tokyo

UBBTM is a structural brace element consisting of a steel core plate which is restrained by mortar and steel tube.A membrane called the unbonding material, between the mortar and the core plate, ensures that axial forces in the core plate do not transfer to the mortar and the steel tube.This ingenious combination of components produces stable and symmetric tension-compression hysteretic behavior.

▼ UBBTM’s components

Core Plate

Steel Core Plate (Core Plate & Unbonding Material)

Restraining Member(Mortar & Steel tube) Completed UBBTM

Steel Tube

Core Plate

Steel Tube

Mortar

Seismic force Seismic force

UBBTM

non-bucklingBuckling/

Deformation

Conventional Brace

Tension load:Resist by Steel Core Plate

Compression load:Steel Core Plate restrained by mortal and steel tube absorbs seismic energy

Tension load:Resist by brace

Compression load:Brace may buckle

Force

Tension

Deformation

Compression

Force

Tension

Deformation

Compression

Type of Core Plate

Cruciform (+)

Material Specification

●ASTM A36●ASTM A1043 (Gr. 36)●ASTM A1043 (Gr. 50)

●JIS SN400 [similar to ASTM A1043(Gr. 36)]●JIS SN490 [similar to ASTM A1043(Gr. 50)]●NSSMC Standard BT-LYP225

or

or

Flat Plate (--)

Full-Scale Dynamic Shaking Table Tests*

Fatigue Resistance

The JMA Kobe Observatory ground motion (Kobe, 1995) was applied at maximum velocities from 10 to 70 cm/s (4 to 27.6 in/s), and the UBBTM showed stable hysteretic behavior for axial strains as high as 7.5%.The El Centro ground motion (California, 1940) was applied at maximum velocities from 5 to 90 cm/s (2 to 35.4 in/s) and the UBBTM showed stable hysteretic behavior for axial strains as high as 7.2%.

-1,5

00

1,5

00

0

-40

04

00

0

-40 -20 20 400

-3.0 -1.0-2.0 1.0 2.0 3.00

Axial deformation（mm）

Axial strain（％）

Axi

al f

orc

e （kN）

Axi

al s

tre

ss (

N/m

m2)

Pinned EndIsolator

200 metric ton mass Column

UBBTM

Load Application Beam

Shaking Table

Under low-cycle fatigue testing, UBBTMs show stable hysteretic behavior for over 100 cycles at an axial strain of ± 1%.

Subassembly Tests Subassembly tests for UBBTMs have been performed in the USA and Japan within the range between 450kN (100kips) and 6000kN (1350kips).

Tests for Pin-End Type Tests of UBBTMs with pinned connections have been performed in the USA and Japan for braces up to 14.0m (45.9ft) in length.

Number of cycles to fracture (Cycles)1

0.01

0.1

1

10

2.0％

0.75％

100

10 102 103 104 105

LYP100LYP225SN400B

Stra

in o

f yi

eld

ing

par

t ε

bp

(%)

Ap

pro

x.

30

cycl

es

Ap

pro

x.

200

cycl

es

-50 50-100 1000-10

,00

010

,00

00

Axi

al f

orc

e （kN）

0-4

00

40

0A

xial

str

ess

(N

/mm

2)

Axial deformation（mm）

0-2.0 2.0 4.0-4.0Axial strain（％）

0-150 150Axial deformation（mm）

0-1

,50

01,

50

0A

xial

fo

rce （

kN）

0-1.5 1.5Axial strain（％）

0-3

00

30

0A

xial

str

ess

(N

/mm

2)

2001First BRB/UBB project in TaiwanTaipei County Government Building

2005First BRB/UBB project in ChinaTsinghua Science Park Building, Beijing

2005UBB performance test at UCSD.UCSD: University of California San Diego

Earthquake energy input

History of UBBTM