1
Chapter 1: Composition and history of Buckling‐restrained Braces
Buckling‐restrained Braces and Applications1
BUCKLING-RESTRAINED BRACEHISTORY, DESIGN and APPLICATIONS
Toru Takeuchi, Akira WadaRyota Matsui, Ben Sitler, Pao-Chun Lin,
Fatih Sutcu, Hiroyasu Sakata, Zhe Qu
2
Chapter 1: Composition and history of Buckling‐restrained Braces
Buckling‐restrained Braces and Applications2
Concept of Buckling-restrained Brace
Types of restrainerAppearance of typical BRB
1.1 Composition of buckling‐restrained Braces (BRB)
Mortar
3
Chapter 1: Composition and history of Buckling‐restrained Braces
Buckling‐restrained Braces and Applications3
-600-400-200
0200400600
-40 -20 0 20 40Axial deformation (mm)
Axi
al fo
rce
(kN
)
Hysteresis of well‐designed BRB
Clearance and eccentricity
Development of higher buckling mode
RestrainerCore plate
4
Chapter 1: Composition and history of Buckling‐restrained Braces
Buckling‐restrained Braces and Applications4
1972: Takeda et al. tried to improve the post-buckling behaviour ofH-section braces by encasing the steel section in reinforcedconcrete. However, because no debonding mechanism wasprovided, the restrainer received a significant compressiveforce, cracked and ultimately experienced overall buckling.
1979: Motizuki et al. proposed introducing a debonding layerbetween the core plate and reinforced concrete restrainer.However, the system tended to buckle at the unrestrained coreextension
1988: The first practical buckling-restrained brace was achieved bySaeki, Wada, et al. employed rectangular steel tubes with in-filled mortar for the restrainer, and determined the optimaldebonding material specifications to obtain stable andsymmetric hysteresis behaviour.
1.2 History of Development
5
Chapter 1: Composition and history of Buckling‐restrained Braces
Buckling‐restrained Braces and Applications5
The first application of Buckling‐restrained Brace (Unbonded Brace, 1987)
Nippon Steel Headquarter No.2 (Tokyo) BRB installation
BRB experiment 1987
M Fujimoto, A Wada, E Saeki, T Takeuchi, A Watanabe: Development of Unbonded Braces, Quarterly Column, No.115, pp.91‐96, 1990.1
1.2 History of Development
6
Chapter 1: Composition and history of Buckling‐restrained Braces
Buckling‐restrained Braces and Applications6
Plant & Environmental Sciences, UC Davis Bennett Federal BuildingRetrofit/ Salt Lake City
Early US applications in 2000’s
7
Chapter 1: Composition and history of Buckling‐restrained Braces
Buckling‐restrained Braces and Applications7
1.3 BRB TYPES (Mortar in‐filled type)
Restrainer
Core Plate
Spacer
Slit
Connection
RestrainerRestrainer
Core Plate
8
Chapter 1: Composition and history of Buckling‐restrained Braces
Buckling‐restrained Braces and Applications8
1.3 BRB TYPES (Dry type)
Restrainer Tube
Core Tube
Pin End
Solid End
Bolt End Restrainer Tube
Core Tube
Restrainer TubeCore Tube
Core Tube
Restrainer Tube
Core Plate
RestrainerUnbonded Sheet
Slit
Core Plate
Core Plate
Bolt
Restrainer Bolt
9
Chapter 2: Restrainer Design and Clearances
Buckling‐restrained Braces and Applications9
Quality Requirement for Hysteresis models
Inappropriate clearance
Plastic strainconcentration
Local buckling Local bulging
Uneven stiffness
Degradationin compression side
Unevenstrength
Unevenstrength Local bulging Degradation
in compression sideBulging-induced failure
Tearing
FractureSlack
(pin connection)
Buckling
Buckling-induced failure
10
Chapter 2: Restrainer Design and Clearances
Buckling‐restrained Braces and Applications10
2.1 Restrainer Design
Global Stability, including:
Restrainer End
Higher Mode Buckling
Connection Strength
Fatigue Fracture
ConnectionsRestrainer
BRB Stability and Strength
1.Restrainer successfully suppresses core first‐mode buckling (Chapter 2)2.Debonding mechanism decouples axial demands and allows for Poisson effects (Chapter 2)3.Restrainer wall bulging due to higher mode buckling is suppressed (Chapter 3)4.Global out‐of‐plane stability is ensured, including connection (Chapter 4)5.Low‐cycle fatigue capacity is sufficient for expected demands (Chapter 5)
11
Chapter 2: Restrainer Design and Clearances
Buckling‐restrained Braces and Applications11
Ecr c
c c Ecr cu
N aa yN N
2( )
1 1cuB Bcu c
cu c c yB Bcu cr cu cr
N a s eN aM N a y MN N N N
a: Fabrication tolerances of core and/or brace s:Clearance or thickness of debonding material (per face)e:Eccentricity of the axial forceMB
y:flexural strength of the restrainerNcu= da Ny:core yield force amplified by overstrength and strain hardening
da =1.4~1.5NB
cr :Euler buckling strength of the restrainer, given by:2
2B Bcr
B
EINl
Where initial imperfections ec/lB ≤ 1/500, a relatively slender restrainerwith lB/Dr > 20 and with an overall safety factor of eα ≥ 1.5;
2
2B Bcr e cu
B
EIN Nl
12
Chapter 3: Local Bulging Failure
Buckling‐restrained Braces and Applications12
in‐plane local bulging failure
out‐of‐plane local bulging failure
(Tokyo Institute of Technology)
(National Center for Research on Earthquake Engineering)
3.1 Failure Caused by High Mode Buckling
13
Chapter 3: Local Bulging Failure
Buckling‐restrained Braces and Applications13
3.1 Failure Caused by High Mode Buckling
core strain
axial force
Compression
Tension
mortarsteel core steeltube wall
section s‐s
Bc
section w‐w
srs
srwtc
debondinglayer
Bc Br
Dr
BrBc
tc
Dr
srw
srs
ww
s
s
14
Chapter 3: Local Bulging Failure
Buckling‐restrained Braces and Applications14
3.1 Failure Caused by High Mode Buckling
core strain
axial force
Compression
Tension
ww
s
s
section s‐s
section w‐w
N N
N N
Compression is initially applied
Flexural buckling waves form in both the in‐plane and out‐of‐plane directions
15
Chapter 3: Local Bulging Failure
Buckling‐restrained Braces and Applications15
srs+0.5γp Bc ɛt
srw+0.5 γp tc ɛt
core strain
axial force
Compression
Tension
ww
s
s
Bc
tc
srw
srs
ɛt
section s‐s
section w‐w
Maximum tensile strain is applied
γp =0.5, Poisson ratio of steel inelastic deformation Clearances increase because of the Poisson effect
3.1 Failure Caused by High Mode Buckling
16
Chapter 3: Local Bulging Failure
Buckling‐restrained Braces and Applications16
lp,s
lp,w
Bc
tc
core strain
axial force
Compression
Tension
ww
s
s
Ny
Ny
Ny
Ny
Ny
2srs+γp Bc ɛt
2srw+ γp tc ɛt
section s‐s
section w‐w
Compression reaches yield strength Ny
High mode buckling waves form and generating the outward forces.
outward force
outward force
3.1 Failure Caused by High Mode Buckling
17
Chapter 3: Local Bulging Failure
Buckling‐restrained Braces and Applications17
Pd,s
Pd,w Pd,w
Pd,w Pd,w
core strain
axial force
Compression
Tension
ww
s
s
Ncu
lp,w
core strain
axial force
Compression
Tension
Ncu
Ncu
Ncu
Ncu
2srs+γp Bc ɛt
2srw+ γp tc ɛt
section s‐s
section w‐w
lp,s
Compression reaches maximum compressive capacity Ncu
High mode buckling wavelengths remain, the maximum outwards are fully developed.
3.1 Failure Caused by High Mode Buckling
18
Chapter 3: Local Bulging Failure
Buckling‐restrained Braces and Applications18
ww
s
s
out‐of‐plane local bulging failure
in‐plane local bulging failure
in‐plane bulging
out‐of‐plane bulging
section s‐s
section w‐w
core strain
axial force
Compression
Tension
Ncu
Local bulging failure when restrainer is too weak in sustaining outward forces
3.1 Failure Caused by High Mode Buckling
19
Chapter 3: Local Bulging Failure
Buckling‐restrained Braces and Applications19
3.2 Estimation on Outward Force (demand)
0.5Pd,s
0.5Pd,s0.5lp,s
Bc
,
,
4 2cu rs p c td s
p s
N s ν B εP
l
,
,
4 2cu rw p c td w
p w
N s ν t εP
l
In‐plane outward force Pd,s
Out‐of‐plane outward force Pd,w
Ncu
Ncu
2srs+γp Bc ɛt
0.5Pd,w
Ncu
0.5Pd,w
0.5lp,w
tc
2srw+ γp tc ɛtNcu
Apply moment equilibrium condition on the free body,
20
Chapter 3: Local Bulging Failure
Buckling‐restrained Braces and Applications20
B
A’
B’
Bc
D
D’
x
Pc,w
Pc,w
Ab
b
x
External work = Pc,wδw
t
w
section w‐w
section t‐ta
Br
δw
3.4 Estimation on Steel Tube Resistance (capacity)out‐of‐plane bulging failure
Bc
A
D
B
B’
A’
D’
2x
3‐D view
Bc
t
w
δw
21
Chapter 3: Local Bulging Failure
Buckling‐restrained Braces and Applications21
small deformation curvature
3.4 Estimation on Steel Tube ResistanceYield line patterns
B
A’
B’
D’
A
α
D
B
A’
B’
D’
A D
45。
B
A’
B’
D’
A D
45。
B
A’
B’
D’
A D
Condition 1
Yield lines AD and A’D’ ignored residual stress at tube corners
Condition 2 Condition 3 Condition 4
α
(Yoshida et al. 2010) (Lin et al. 2010)
Internal energy: E9(9 yield lines)α = 45°
Internal energy: E9(9 yield lines)α: minimizing E9
Internal energy: E5(5 yield lines)α = 45°
Internal energy: E5(5 yield lines)α: minimizing E5
2,
2,
41
41
c w r ry
c r
c s r ry
c r
P t σB B
P t σt D
2,
2,
4 214 21
c rc w r ry
c r
c rc s r ry
c r
B BP t σ
B Bt D
P t σt D
2,
2,
21
21
c w r ry
c r
c s r ry
c r
P t σB B
P t σt D
2,
2,
2121
c rc w r ry
c r
c rc s r ry
c r
B BP t σ
B Bt D
P t σt D
A D
(resistance factor) (resistance factor) (resistance factor) (resistance factor)
22
Chapter 3: Local Bulging Failure
Buckling‐restrained Braces and Applications22
3.5 Test Results and Evaluations
,exp2
,
,exp2
,
4 2out‐of‐plane:
4 2in‐plane:
cu rw p c t
p w r ry
cu rs p c t
p s r ry
N s ν t ε
l t σ
N s ν B ε
l t σ
Experimental resistance factor
● 15 specimens without bulging× 14 out‐of‐plane bulged specimens ▲ 5 in‐plane in‐plane bulged specimens
resistan
ce fa
ctor
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1Bc/Br or tc/Dr
0
2
4
6
8
10
12
14
Condition 2Condition 1
Condition 3
Condition 4
resis
tance factor
Bc/Br or tc/Dr
example:●
●
× ▲
× ▲
Appropriate: bulging did not occur in test and was not in expectation
Conservative: bulging is in expectation but did not occur in test
Appropriate: bulging occurred in test and was in expectation
Dangerous: bulging occurred in test but was not in expectation
(9 dangerous estimation)
(9 dangerous estimation)
(over‐conservative)
(recommended)
23
Chapter 3: Local Bulging Failure
Buckling‐restrained Braces and Applications23
3.5 Test Results and EvaluationsProposed design method:
0
2
4
6
8
10
12
14
resistan
ce fa
ctor
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1Bc/Br or tc/Dr
,2
, ,
,2
, ,
4 21.0
2
4 21.0
2
cu rw p c td w r cw
c w r c r ry p w
cu rs p c td s r cs
c s r c r ry p s
N s ν t εP B BDCR
P B B t σ l
N s ν B εP D tDCR
P D t t σ l
0.85
7.7
in‐plane bulgingtcDr
BrBc
0.85c
r
BB
0.85c
r
tD
● 15 specimens without bulging× 14 out‐of‐plane bulged specimens ▲ 5 in‐plane in‐plane bulged specimens
out‐of‐plane bulging
24
Chapter 3: Local Bulging Failure
Buckling‐restrained Braces and Applications24
3.6 Required Mortar Strength for Local Pressure
3.7 Local Bulging Criteria for Circular Restrainer
Bc
lc
Pd,wcontact surface
steel core
restrainer
, 'd wc
c c
Pf
l B
,
, ,
4 221.0cu rs p c td s r r
scc s m m c r r ry p s
N s ν B εP B tDCR
P c t t πt B σ l
25
Chapter 4: Connection Design and Global Stability
Buckling‐restrained Braces and Applications25
The AIJ Recommendations provide rigorous evaluation methods for BRB connection out‐of‐plane buckling. Two concepts below are presented:
AIJ (2009) Recommendations for stability design of steel structures. Architectural Institute of Japan.
4.2 Design Concepts
Moment transfercapacity is lost at the
end of restrainer
EIB
JEIB
JEIB
L0
L0
lB L0
Connectionzone
Connectionzone
Restrainedzone
=Plasticzone
EIB
>
Bendingmomenttransfer
Gusset plate
JEIB EIB
>JEIB EIB
KRg
KRg
Restrainer-endzone
Connectionzone
Connectionzone
Restrainer-endzone
Plasticzone
Restrainedzone
1: Cantilevered gusset 2: Restrainer end continuity
26
Chapter 4: Connection Design and Global Stability
Buckling‐restrained Braces and Applications26
Type A Type B Type C(a) low stiffness
(US/NZ detailes)(b) high stiffness
(JP details)
(a) One-way (b) ChevronBRB configurations in frame
BRB configurations
Not rotationallybraced
27
Chapter 4: Connection Design and Global Stability
Buckling‐restrained Braces and Applications27 Toru Takeuchi, Tokyo Institute of Technology
Tsai and Nakamura’s proposal (2002) Koetaka and Inoue’s proposal (2008)
2
20
(1 2 )(2 )
J Bcr
r EINL
* *
(1 2 )( )( )
Ncr R
N N
lN Kl d l d l
1 2
1 2 0
1(1 )cr RN K
L
Stability assessment
0r
c
Li
28
Chapter 4: Connection Design and Global Stability
Buckling‐restrained Braces and Applications28 Toru Takeuchi, Tokyo Institute of Technology
Hikino and Okazaki’s proposal (2013)*
1 1 2*
1 1 2 1 2 0
11 21 (1 )
R Rcr R
K L K dN KL L L l d L
Takeuchi’s proposal (2013)0
10
( )( ) ( ) 1
r r rp r cr
lim cur r Bp r cr
M M a NN N
M M a N
2
2 20
(1 2 )(2 ) 24 /
Rgr J Bcr
Rg
EIN
L
0Rg
RgJ B
K LEI
20 24 /2
(1 2 )Rg
rc Rg
Li
point of rotation
LinDneck
a) mortar‐filled BRB
yielding
b) steel tube‐in‐tube BRB
Lin
29
Chapter 4: Connection Design and Global Stability
Buckling‐restrained Braces and Applications29 Toru Takeuchi, Tokyo Institute of Technology
Takeuchi’s proposal (cont’d)
0 02
0 0
(1 2 )
(1 2 ) ( ) 1
g r r rp p r
lim cug r r r Bp p r cr
M M M M aN N
M M M M a N
In case of plastic hinges produced at joint ends
Stable Unstable
30
Chapter 4: Connection Design and Global Stability
Buckling‐restrained Braces and Applications30
4.6 In‐plane pinching
(a) Frame pinching (b) Frame opening
horizontal stiffener
verticalstiffener
Expected Failure Recommended Proposal
31
Chapter 5: Cumulative Deformation Capacity until Fracture
Buckling‐restrained Braces and Applications31
Expected Plastic Zone
Plastic Zone
(a) Ordinary Tube Brace
(b) Incomplete Buckling-restrained Brace
(c) Complete Buckling-restrained Brace
Local Buckling Mechanism
Plastic stress concentration
Mild local buckling and averaged strain distribution along plastic zone
Friction
Local buckling distribution until fracture
Cumulative energy‐dissipation capacity
32
Chapter 5: Cumulative Deformation Capacity until Fracture
Buckling‐restrained Braces and Applications32
1 21 2
m mt f fC N C N
0.1
1
10
100
0.01 1 10 100 100
01000
010000
0
LY100SS400LY235
Steel material fatigue performance4)
Cycle Number Nf
Stra
in Am
pilitu
deΔε
eq(%
)
BRB < Steel Material
BRB fatigue performance6),7)
Exp. Data5)
4) Saeki, E et al. 1995. A Study on Low Cycle Fatigue Characteristics of Low Yield Strength Steel, J. Struct. Constr. Eng., AIJ, No. 472, 139‐1475) Nakamura, H., Takeuchi, T., et al. 2000. Fatigue Properties of Practical Scale Unbonded Braces, Nippon Steel Technical Report, Nippon Steel Corporation, No. 82, 51‐576) Takeuchi, T. et al. 2008. A. Estimation of Cumulative Deformation Capacity of Buckling Restrained Braces, J. Struct. Eng., ASCE, Vol. 134, No. 5, 822‐8317) Takeuchi, T. et al. 2006. Cumulative Deformation Capacity and Damage Evaluation for Elasto‐plastic Dampers at Beam Ends, J. Struct. Constr. Eng., AIJ, No. 600, 115‐122
Elastic region
Plastic region
Manson‐CoffinFatigue Formula
Steel material fatigue performance4)
BRB Fatigue Performance under Cyclic Loading
33
Chapter 5: Cumulative Deformation Capacity until Fracture
Buckling‐restrained Braces and Applications33
s0=1.0mm, tc=25mm
s0=2.0mm, tc=25mm
s0=5.0mm, tc=25mm
s0=0mm (Steel material)
1 10 100 1000 10000
Strain amplitu
de Δε n
(%)
0.1
1
10
100
0.01Fracture cycle Nf
s0=2.0mm, tc=12mm
5) Nakamura, H., Takeuchi, T., et al. 2000. Fatigue Properties of Practical Scale Unbonded Braces, Nippon Steel Technical Report, Nippon Steel Corporation, No. 82, 51‐579) Takeuchi, T., Ohyama, T., and Ishihara, T. 2010. Cumulative Cyclic Deformation Capacity of High Strength Steel Frames with Energy Dissipation Braces (Part 1), Journal of Structural and Constructional Engineering, Architectural Institute of Japan, Vol. 75, No. 655, 1671‐1679 (in Japanese)
Experiment s0=1mm, tc=25mm5)
Experiment s0=2mm, tc=12mm9)
SN400B
Fatigue performance of BRBdecreases as clearance between core plate and restrainer increases
Fatigue Performance of BRB using Plastic Strain Concentration Mechanism
34
Chapter 5: Cumulative Deformation Capacity until Fracture
Buckling‐restrained Braces and Applications34
0 0.5 1 1.5 2
Damage Index
Gradually Increasing
FatigueShaking Table
(Theory)
05
1 02 04 06 08 0
1 0 01 2 0
0.52
5
1.22
5
1.92
5
2.62
5
3.32
5
4.02
5
4.72
5
5.42
5
6.12
5
6.82
5
7.52
5
8.22
5
8.92
5
9.62
5
10.3
2
11.0
2
11.7
3
12.4
3
F r e q u e n c y Nfi
( c y c l e s )
S t r a i n A m p l i t u d e i ( % )
0.001
0.01
0.1
1
10
100
1 10 100 1000 104 105 106
Constant Amp.
Strain Amp. Δε (%)
Failure Cycles Nf (cycles)
εe=0.5・N
f
-0.14
εp=54.0・N
f
-0.71
Estimation by Miner’s Method
Strain Amplitude Frequency
Fatigue Curve under Constant Amplitude
Accuracy by Miner’s Method
35
Chapter 6: Performance Test Specification for BRB
Buckling‐restrained Braces and Applications35
Single Brace test
Single Brace test with rotational deformation(ANSI/AISC 341-05)
6.1 Test Configurations1) Uniaxial test
36
Chapter 6: Performance Test Specification for BRB
Buckling‐restrained Braces and Applications36
2) Inclined test
Inclined layout with column
Inclined layout with initial out-of-plane drift
37
Chapter 6: Performance Test Specification for BRB
Buckling‐restrained Braces and Applications37
3) In‐frame test
38
Chapter 6: Performance Test Specification for BRB
Buckling‐restrained Braces and Applications38
(a) ANSI/AISC 341-05 and US practiceCycle Inelastic Deformation Cumulative strain Cumulative
(Story drift angle) ( bm = 4 by ) ( by =0.25%) Inelastic strain
by ×2 =2×4× by - by ) =0 by =2×4×0.25=2% =2×4×0=0%0.5 bm ×2 =2×4× by - by ) =8 by =2×4×0.5=4% =2×4×0.25=2%1.0 bm ×2 =2×4× by - by ) =24 by =2×4×1.0=8% =2×4×0.75=6%1.5 bm ×2 =2×4× by - by ) =40 by =2×4×1.5=12% =2×4×1.25=10%
.0 bm ×2 =2×4× by - by ) =56 by =2×4×2.0=16% =2×4×1.75=14%1.5 bm ×4 =4×4× by - by ) =80 by =4×4×1.5=24% =4×4×1.25=20%
Total =208 by =56% =52%
(b) BCJ and Japanese practiceCycle Inelastic Deformation Cumulative strain Cumulative
(Plastic length strain) ( by =0.25%) ( by =0.25%) Inelastic strain
by ×3 =3×4× by - by ) =0 by =3×4×0.25=3% =3×4×0=0%0.5%×3 =3×4× by - by ) =8 by =3×4×0.5=6% =3×4×0.25=3%1.0% ×3 =3×4× by - by ) =36 by =3×4×1.0=12% =3×4×0.75=9%
.0% ×3 =3×4× by - by ) =84 by =3×4×2.0=24% =3×4×1.75=21%
×3 =3×4× by - by ) =132 by =3×4×3.0=36% =3×4×2.75=33%
Total =264 by =81% =66%
(1.5 bm until fracture)
(3.0% until fracture)
Example BRB testing protocol
39
Chapter 6: Performance Test Specification for BRB
Buckling‐restrained Braces and Applications39
6.4 Post Earthquake InspectionKoriyama Big-Eye, a 24-story, 133m building complete in 1998 in Fukushima experienced
Tohku Earthquake 2011 at 234km from epicenter. The cumulative deformationmeasurements and earthquake record were used to calibrate a finite element model,indicated a peak ductility demand of µ ≈ 4 and a cumulative plastic strain of ∑εp ≈ 20%(∑δp/δy ≈ 100) in the Y direction, still 6% of their capacity.
cumulative def. meter
max def. meterFukushima Koriyama Big-EyeInaba Y, Morimoto S, Tsuruta S, Takeuchi T, Matsui R. Damage record of buckling restrained braces that received actual ground motion. AIJ Kanto Branch Research Report Collection 2017
40
Chapter 7.1: Damage Tolerant Concept
Buckling‐restrained Braces and Applications40
7.1.1 Damage Tolerant Concepts
Damage Tolerant StructureEarthquake Ground Motion and Seismic Design in Japan
Wada A, Connor J, Kawai H, Iwata M, Watanabe A: Damage Tolerant Structure, ATC-15-4, Proc. 5th
US-Japan WS on the Imprement of Building Structural Design and Construction Practices, 1992.9
41
Chapter 7.1: Damage Tolerant Concept
Buckling‐restrained Braces and Applications41
0.005(1/200)
0.00125(1/800)
0.01(1/100)
0.00125(1/800)
0.01(1/100)
BRB EnergyDissipationZone
Main FrameDamage Zone
BRB EnergyDissipationZone
Main Frame(Normal Steel)
BRB
Main Frame(High-strengthSteel)
BRB
Max Response Max Response
Story DriftAngle
Story DriftAngle
ShearForce
ShearForce
System of Main Structure and DamperStrain Distribution along the beam
(a) Ordinary Concept (b) Damage Tolerant ConceptShear force-Story Drift Relationship of Damage Tolerant Structure
42
Chapter 7.1: Damage Tolerant Concept
Buckling‐restrained Braces and Applications42
Triton Square Project
43
Chapter 7.1: Damage Tolerant Concept
Buckling‐restrained Braces and Applications43
Grand Tokyo North Tower Election of Large BRBF
Following Damage Tolerant Projects
44 Toru Takeuchi Tokyo Tech
Grid-skin structures with BRBs
BRB is suitable for Grid-skin structures
Ductile elements, Less bending loss, Free internal space, Design with facades
45
Cg南側
Toru Takeuchi Tokyo Tech
Energy-dissipation Skins with Solar Cells2. Disaster Prevention and Environmental Sustainability
46
Solar-panel Envelope StructureFlexible and Lightweight structure over the main frame
Main FrameSpiral Layout of Energy-dissipation Fuses around Perimeter zones
Open Space
Energy Dissipation Brace
Energy-dissipation Skins with Solar Cells2. Disaster Prevention and Environmental Sustainability
47
Chapter 7.3: Seismic retrofit with BRBs
Buckling‐restrained Braces and Applications47
Midorigaoka-1st Building Retrofit concept
48
Chapter 7.3: Seismic retrofit with BRBs
Buckling‐restrained Braces and Applications48
-800
-600
-400
-200
0
200
400
600
800
-30 -20 -10 0 10 20 30
Experiment
(kN
)
(mm)
Calculation -800
-600
-400
-200
0
200
400
600
800
-30 -20 -10 0 10 20 30
Experiment
(kN
)
(mm)
Calculation
(a) Before retrofit (b) After RetrofitReduced mock-up test for 2nd floor frame
49
Chapter 7.3: Seismic retrofit with BRBs
Buckling‐restrained Braces and Applications49
Detail for the connections between frame and BRB
Maximum story drift obtained by time‐history analyses
50
Chapter 7.3: Seismic retrofit with BRBs
Buckling‐restrained Braces and Applications50
summer spring/fall winter
Environmental effect of outer skins
51
Chapter 7.3: Seismic retrofit with BRBs
Buckling‐restrained Braces and Applications51
Perimeter work process
Carbon fiber reinforcement BRB Attachment
52
Chapter 7.3: Seismic retrofit with BRBs
Buckling‐restrained Braces and Applications52
53
Chapter 7.3: Seismic retrofit with BRBs
Buckling‐restrained Braces and Applications53
(a) Exterior appearance (b) Interior viewApplication for Seismic retrofit (Administer Build. Tokyo Tech)
Retrofit with Diagonal BRB Louver
Takeuchi T, Yasuda K, Iwata M: Seismic Retrofitting using Energy Dissipation Façades, ATC-SEI09(San Francisco), 2009.12
54
Chapter 7.3: Seismic retrofit with BRBs
Buckling‐restrained Braces and Applications54
7.4.1 BRB application on RC frame with elastic steel frame
55
Chapter 7.3: Seismic retrofit with BRBs
Buckling‐restrained Braces and Applications55
A
B
C
D
E
F
1 2 3 4 5 6 8 9 107 12 1311
A
B
C
D
E
F
Typical RC school building in Turkey
56
Chapter 7.3: Seismic retrofit with BRBs
Buckling‐restrained Braces and Applications56
‐80
‐40
0
40
80
120
160
0 20 40 60 80 100 120
Inter‐story displacemen
t (mm)
Time (sec)
RC onlyRC+BRBRC+BRB+SF
≈1/1000 story drift≈1/3000 story drift
≈1/30 story drift
Residual displacement
RC only
RC + BRB
RC + BRB + SF
57
Chapter 7.3: Seismic retrofit with BRBs
Buckling‐restrained Braces and Applications57
0
0.5
1
1.5
2
0.000 0.005 0.010 0.015 0.020 0.025
"First M
ode" Spe
ctral A
cceleration S A
(T1, 5%
) (g)
Maximum inter‐story drift (rad)
RC onlyRC+CB+SFRC+BRB+SFtarget drift (1/150)
(a)
0
0.5
1
1.5
0 0.00025 0.0005 0.00075 0.001"First M
ode" Ape
ctral A
cceleration S A
(T1, 5%) (g)
Maximum Residual Drift (rad)
RC+CB+SFRC+BRBRC+BRB+SF
(b)
Increment Dynamic Analyses curves
58
Chapter 7.3: Seismic retrofit with BRBs
Buckling‐restrained Braces and Applications58
Cyclic Loading Test for RC retrofit with BRB+SF(Istanbul Technological University)
59
Chapter 7.6: Applications for truss and spatial structures
Buckling‐restrained Braces and Applications59
7.5.2 Types of Spatial Structure Applicationsa) Truss structures
△ △ △ △ △ △
Buckling BRB -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
y
軸歪み [%]
ForceLimitingFunction
Devices
Response Control for Truss Structures
Device Layout Types for Response-controlled Truss Structures
60
Chapter 7.6: Applications for truss and spatial structures
Buckling‐restrained Braces and Applications60
Horizontal Acceleration
Vertical Acceleration
Horizontal Input
(R‐1) Roof with Dampers (R‐2) Base IsolatedRoof
(R‐3) Substructure with Dampers (R‐4) Entire Base Isolation
Seismic Response of Raised Roof
Device Layout for Response-controlled Roof Structures
61
Chapter 7.6: Applications for truss and spatial structures
Buckling‐restrained Braces and Applications61
Seismic retrofit of communication towers
62
Chapter 7.6: Applications for truss and spatial structures
Buckling‐restrained Braces and Applications62
Deck
Horizontal Tie
Thrust Brace
Vibration Control Brace (Deck)
Main Arch
Horizontal Brace
Vibration Control Brace (Roof)
5.7
5.7
108.
3m
5.7
5.7
Toyota Stadium
Shimokita Dome
63
Chapter 7.6: Applications for truss and spatial structures
Buckling‐restrained Braces and Applications63
BRBs
Buckling‐restrained Braces
Retrofit of Hanshin highway bridge
Bridge girder with BRBs on RC peer
7.5.3 Applications to Bridge Structures
Seismic retrofit of steel arch bridge with BRBs
Celik O, Bruneau M: Skewed Slab‐on‐Girder Steel Bridge Superstructures with Bidirectional‐Ductile End Diaphragms, ASCE Journal of Bridge Engineering, Vol.16, No.2, pp.207‐218, 2011
64
Chapter 7.7: Spine frame concepts
Buckling‐restrained Braces and Applications64
7.6.2. Dual spine systemBRB or Damper
BRB or Damper(a) Conventional BRB distribution (b) Dual spine concept
ElasticBrace
Taga K, Koto M, Tokuda Y, Tsuruta J, Wada A. Hints on how to design passive control structure whose damper efficiency is enhanced, and practicality of this structure, Proc. Passive Control Symposium 2004, 105‐112, Tokyo Tech, 2004.11
65
Chapter 7.7: Spine frame concepts
Buckling‐restrained Braces and Applications65
Retrofit of Suzukake G3 Tokyo Tech 2010Akira Wada, Qu Zhe et al.
Qu Z, Wada A, Motoyui S, Sakata H, Kishiki S: Pin-supported walls for enhancing the seismic performance of building structures. Earthquake Engineering and Structural Dynamics 2012
66
Chapter 7.7: Spine frame concepts
Buckling‐restrained Braces and Applications66
7.6.4. Non-uplifting Hinged Spine Frame System (Material Research Building)
67
Chapter 7.7: Spine frame concepts
Buckling‐restrained Braces and Applications67
(a) Conventional BRBF (SD)
(b) Lift‐up Rocking Frame (LU)
(c) Non‐uplifting Spine Frame (NL)
7.6.5. Comparison of Spine Frame Systems
Takeuchi T, Chen X, Matsui R. Seismic performance of controlled spine frames with energy‐dissipating members, Journal of Constructional Steel Research, Vol.115, 51‐65, 2015.11
68
Chapter 7.7: Spine frame concepts
Buckling‐restrained Braces and Applications68
BRC
PT wire
BRC BRC
1
2
3
4
5
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
1
2
3
4
5
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
1
2
3
4
5
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
1
2
3
4
5
0 0.03 0.06 0.09 0.12 0.15
1
2
3
4
5
0 0.03 0.06 0.09 0.12 0.15
1
2
3
4
5
0 0.03 0.06 0.09 0.12 0.15
Residual Story Drift Angle (%)Max. Story Drift Angle (%)
0.8% rad.(1/125)
0.8% rad.(1/125)
0.8% rad.(1/125)
0.05% rad.(1/2000)
0.05% rad.(1/2000)
0.05% rad.(1/2000)
Shear DamperSystem
Lift-upSpine
System
Non Lift-upSpine
System
69
Chapter 7.7: Spine frame concepts
Buckling‐restrained Braces and Applications69
680 Folsom Street, SF, US
7.6.7 Application ExamplesRetrofit of Steel Frame with RC core wall spine
Janhunen B., Tipping S., Wolfe J., Mar T. Seismic Retrofit of a 1960s steel moment-frame highrise using a pivoting spine, SEAOC 2013 Convention Proceedings
70
Chapter 7.7: Spine frame concepts
Buckling‐restrained Braces and Applications70
BRBs
RC core
Wilshire Grand Tower, LA, US
Damped Outrigger concept
Joseph LM, Gulec C, Schwaiger K Justin M: Wilshire Grand: Outrigger Designs and Details for a Highly Seismic Site, International Journal of High‐Rise Buildings, Vol.5, Issue 1, 2016, pp.1‐12
71
Chapter 7.7: Spine frame concepts
Buckling‐restrained Braces and Applications71
atR
Optimization Method
2 2 2
2 2 2
3.28 0.75 (1 ) 0.57(1 )6.75 1.81 (1 ) 0.63(1 )
tr at tr at at at
tr at tr at at topt
a
S R S R R RS R S R R R
,, ,
2
4 2 2
0.20 0.59 0.61 ,2.01 ( 2)
b
t
at optat opt d op
r trtS
R ck R
S
Exclusive Optimization
Res
pons
e
Outrigger position
Dam
per
B.Huang, T.Takeuchi: Dynamic Response Evaluation of Damped-Outrigger Systems with Various Heights, Earthquake Spectra, Vol.33, No.2, pp.665-685, 2017.5
72
Chapter 7.6: Applications for truss and spatial structures
Buckling‐restrained Braces and Applications72
The latest knowledge is overviewed in
Buckling-Restrained Braces and Applications
T. Takeuchi and A. Wada, Japan Society of Seismic Isolation, 2017
mail to [email protected]
30-years from the first application, BRBs are still actively researched andexpanding applications. I am looking forward to further development inthe future.
73
Thank you very much for your kind attention