Steel Plate Shear Wall Design

Transcription

8/12/2012
STEEL PLATE SHEAR WALLS (SPSW),
TEBF, CFST, SF,
AND OTHER SHORT STORIES
Michel Bruneau, Ph.D., P.Eng
Professor
Department of Civil, Structural, and Environmental
Engineering
Introduction
Focus on SPSW (incl. P-SPSW, SC-SPSW), CFST, CFDST
(and maybe a bit more)
Broad overview (References provided in NASCC paper for
more in-depth study of specific topics)
Additional technical information can also be found at
www.michelbruneau.com and in “Ductile Design of Steel
Structures, 2nd Edition” (Bruneau et al. 2011)*.
* Subliminal message: This book will give you ultimate reading pleasure –buy 100 copies now!
Acknowledgments - 1
Acknowledgments - 2
Graduate students:
Sponsors:
Samer El-Bahey (Stevenson & Associates)
National Science Foundation (EERC and NEES
Programs)
Jeffrey Berman (University of Washington, Seattle)
Daniel Dowden (Ph.D. Candidate, University at Buffalo)
New York State
Pierre Fouche (Ph.D. Candidate, University at Buffalo)
Federal Highway Administration,
Shuichi Fujikura (ARUP)
American Institute of Steel Construction
Michael Pollino (Case Western Reserve University)
Engineer Research and Development Center (ERDC) of
the U.S. Army Corps of Engineers
Ronny Purba (Ph.D. Candidate, University at Buffalo)
MCEER, NCREE, Star Seismic, and Corus Steel.
Bing Qu (California Polytechnic State University)
Ramiro Vargas (Technological University of Panama)
Darren Vian (Parsons Brinkerhoff)

See others at www.michelbruneau.com
This support is sincerely appreciated. Opinions presented
are those of the author.
Example of
Implementation
(USA)
Steel Plate Shear Walls
(SPSW)
(
)
Infill (Web)
Column (VBE)
Beam (HBE)
CourtesyTony Harasimowicz, KPFF, Oregon
1
8/12/2012
Examples of Implementation
(USA)

Examples of Implementation
(USA)
LA Live
56 stories
Courtesy Lee Decker – Herrick Corporation, Stockton, CA
Analogy to TensionTension-only
Braced Frame

Flat bar brace
Very large brace
slenderness
l d
(e.g.
(
in
i
excess of 200)
Courtesy of GFDS Engineers, San Francisco, and Matthew Eatherton, Virginia Tech

V

Braced Frame

Steps to “transform”
into a SPSW
1)) Replace
p
braces byy
infill plate (like adding
braces)
Braced Frame

V

Anchor Beam
Pinched
hysteretic curves
Increasing drift
to dissipate
further hysteretic
energy
Not permitted by
AISC Seismic
Provisions
Permitted by
CSA-S16 within
specific limits of
application
Steps to “transform”
into a SPSW
1)) Replace
p
braces byy
infill plate (like adding
braces)
2) For best seismic
performance, fully
welded beam-column
connections
V
2
8/12/2012
Berman/Bruneau June 12 2002 Test
End--Result
End

Cyclic (Seismic)
behavior of SPSW
Sum of
z
z
V
Fuller hysteresis
provided by moment
connections
Stiffness and
redundancy provided
by infill plate
L/tw = 3740
h/L = 0.5
(centerline
dimensions)
Example of Structural Fuse
600
Base Shear (kN)
400
200
0
-200
-400
Specimen F2
Boundary Frame
-600
600
-3
-2
-1
0
Drift (%)
1
2
3
-3
-2
-1
0
Drift (%)
1
2
3
Base Shear (kN)
400
200
0
-200
-400
-600
Forces from Diagonal Tension Field
ωV = σ t cos2(α)
ωH = σ t sin(α) cos(α) = ½ σ t sin(2α)
FH = ωH L = ½ σ L t sin(2α)
Knowing L, σy, and α,
Can calculate needed
thickness (t)
σ ·t
Brace and Strip Models
α
PANEL TENSION FIELD
STRESS ACROSS UNIT
UNIT PANEL WIDTH
ALONG DIAGONAL
V =P··cos α
DIAGONAL WIDTH,
α
P = σ · t · ds
H =P·sin α
σ
θ
RESULTANT TENSION FIELD
FORCE, P AND COMPONENTS
tw i =
ds
α
ωV =V /dx
SPSW WEB
PLATE
ωH =H /dx
dx
UNIT
LENGTH
ALONG BEAM
HORIZONTAL, ωH, AND
VERTICAL, ωV,
DISTRIBUTED LOADING
SPSW
HBE
2 Ai sin θi sin 2 θi
L sin 2 2 αi
hs
hs
L
Equivalent Brace Model (Optional)
L
Strip Model
3
8/12/2012
Strip Model

Strips models in retrofit project
using steel plate shear walls
Developed by Thorburn, Kulak, and
Montgomery (1983), refined by Timler and
Kulak (1983))
V ifi d experimentally
Verified
i
t ll by
b
z
z
z
Elgaaly et al. (1993)
Driver et al. (1997)
Many others
Courtesy of Jay Love, Degenkolb Engineers
AISC Guide Design of SPSW
(Sabelli and Bruneau 2006
2006))
Recent Observations on SPSW
(Bruneau et al. 2011)

Review of implementations to date
Review of research results
Design requirements and process
Design examples
z
z

Region of moderate seismicity
Region of high seismicity
Other design considerations (openings, etc.)
Capacity design from Plastic
Analysis
z
Demands on VBEs
z
Demands on HBEs

Flexibility Factor
Factor’ss purpose
HBE in-span yielding
RBS connections in HBEs
P-SPSW (reduced demands)
Repair and drift demands
Plastic Analysis Approach

Yielding strips
Plastic Hinges
Used to develop
Free Body Diagrams
of VBEs and HBEs
For design
strength,
neglect
plastic hinges
4⋅M p
1
contribution V = 2 ⋅ Fy ⋅ t ⋅ L ⋅ sin 2α + h
4
8/12/2012
Capacity Design of VBE
Capacity Design of VBE
Flexibility Limit Issue
Importance of
Capacity Design
Lubell et al. (2000)
observed poor
behavior of some
SPSWs (pull-in of
columns)
Others suggested
flexibility limit
desirable to prevent
slender VBEs

SPSW-4 UBC Test (Lubell et al. 2000)
SPSW-2 UBC Test (Lubell et al. 2000)
Flexibility Limit (cont’d)

Plate girder analogy

Flexibility factor
o
ηo
o
Steel Plate Shear Wall
Plate Girder
(ηu −ηo )max =
where
ωt = 0.7hsi 4
twi
2Ic L
δ
ηu
hs
V
Flange can be modeled as a continuous
beam on elastic foundation
⎛
⎛ω
sin ⎜ t
εgL ⎜
⎝ 2
⎜1 −
sin 2 α ⎜
⎛ ωt
⎜ sin ⎜ 2
⎝
⎝
⎞
⎛ ωt ⎞
⎛ ωt ⎞
⎛ ωt
⎟ cosh ⎜ 2 ⎟ + cos ⎜ 2 ⎟ sinh ⎜ 2
⎠
⎝ ⎠
⎝ ⎠
⎝
⎞
⎛ ωt ⎞
⎛ ωt ⎞
⎛ ωt
⎟ cos ⎜ 2 ⎟ + sinh ⎜ 2 ⎟ cosh ⎜ 2
⎠
⎝ ⎠
⎝ ⎠
⎝
⎞⎞
⎟⎟
⎠⎟
⎞⎟
⎟⎟
⎠⎠
Increase in streess
Infill Panel
I-Beam Plate Girder
Empirically based
flexibility limit:
ωt = 0.7hsi 4
0.9
x
xu
Flange
ωt ≤ 2.5
1.0
L
u
ω t = 3.35
Other specimens
that behaved well:
α
Stiffner
Infill Panel
UBC SPSW-2 and SPSW-4:
0.8
07
0.7
twi
≤ 2.5
2I c L
Solving
0.6
0.5
0.00307twi hsi 4
L
Introduced in the
CAN/CSA S16-01 and
2005 AISC Seismic
Provisions
Ic ≥
0.4
0.3
0.2
20%
0.1
0.0
0
0.5
1
1.5
2
ωt
2.5
3
3.5
4
5
8/12/2012
Column Design Issues (cont’d)

Prevention of In-Plane Shear Yielding

SPSWs tested by Tsai and Lee (2007) exceeded flexibility
limit, yet performed comparably to SPSWs meeting limit
Evaluation of previous specimens
z
Case
Specimen
Number of
identification
stories
Researcher
ωt
Vn
Vsap 2000
Vu − design
(kN)
(kN)
(kN)
Shear Yielding
(i) single-story specimen
1Driver Lubell
al (2000)ω =1.73SPSW2 Park
et al,et1997,
t
2
Berman and Bruneau (2005)
F2
3.35
et1 al, 2007
1
1.01
ωt=1.58
75
108
113
932
259
261
Yes
No
766
1361
1458
Yes
(ii) multi-story specimen-a
3
Driver et al (1998)
-b
4
1 73
1.73
4
Park et al (2007)
SC2T
3
1.24
Park et al, 2007, ωt=1.62
676
1011
5
SC4T
3
1.44
999
984
1273
No
6
SC6T
3
1.58
999
1218
1469
Yes
7
WC4T
3
1.62
560
920
1210
Yes
8
WC6T
3
1.77
560
1151
1461
Yes
9
Qu and Bruneau (2007)
b
-
2
1.95 2881
1591
2341
No
10
Tsai and Lee (2007)
SPSW N
2
2.53
968
776
955
No
SPSW S
2
3.01
752
675
705
No
11
a
b
SPSW S (ωt=3.01>2.5)
SPSW N (ωt=2.53>2.5)
999
For multi-story specimens, VBEs at the first story are evaluated.
Not applicable.
Lubell et al, 2000, ωt=3.35
1.2
Excessive flexibility example
1F Drift = 0.2%
σ / fy
1.0
σ / fy
0.8
0.6
0.4
0.2
8.0E+005
0.0
1.2
6.0E+005
1F Drift = 0.3%
1.0
4.0E+005
Specimen: Two-story SPSW (SPSW S)
Flexibility factor: ωt=3.01
=3 01
Researchers: Tsai and Lee (2007)
2 0E+005
2.0E+005
0.0E+000
σ / fy
Base Shear (N)
1.0E+006
0.8
0.6
0.4
0.2
0.0
1.2
3.5E+006
o
lα
x
1F Drift = 0.6%
1.0
3.0E+006
2.5E+006
0.8
0.6
0.4
0.2
2.0E+006
0.0
1.2
1.5E+006
1F Drift = 2.0%
1.0
Specimen: Four-story SPSW
Flexibility factor: ωt=1.73
Researcher: Driver (1997)
1.0E+006
0.8
0.6
Lee and Tsai (2008)
0.4
Driver (1997)
0.2
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
1F Drift (%)
0.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
x/lα
HBE Moment Diagram
SPSW
2.0
ωybi+1
Compression ω
strut between
columns
Resultant forces
from yielding (x)
of strips
fish plate
web of intermediate beam
flange of intermediate beam
d
(B)
xbi
ωybi
L
V
+
V
V
-
V
ωybi-ωybi+1
o
Vv
κ=0.0
κ=0.5
κ=1.0
κ=1.5
κ=2.0
Maximum
1.5
ωxbi+1

0.4
1.2
0.0E+000

0.6
0.0
1.2E+006
5.0E+005
HBE
FBD
0.8
0.2
σ / fy

Tension Fields
σ / fy

Theoretically, with infinitely elastic beam/columns, could
purposely assign high L/h ratio and low stiffness to the
boundary elements (Bruneau and Bhagwadar 2002)
Truss members 1 to 8 in compression as a result of beam and
column deflections induced by the other strips in tension –
entire tension field is taken byy the last four truss members.
Behavior even worse if bottom beam free to bend.
This extreme (not practical) example nonetheless illustrates
how non-uniform
yielding can occur
Base Shear (N)

1F Drift = 0.1%
1.0
+
(ωybi+ωybi+1)(d+2hf )/2
Normalized Moment:: M(x) / (ωL2/8)

No
1.0
0.5
Optional Alternative:
RBS at HBE ends
In-Span HBE
Hinging
0.0
-0.5
-1.0
-1.5
o
-2.0
V h(x )
-
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Fraction of span from left support
0.8
0.9
1
Design for
wL2/4
6
8/12/2012
Case Study: Design Outputs
W16x36
W18x76
(0.88)
(0.99)
Monotonic Pushover
Sway and Beam Combined Mechanism
L1θ / L2 + θ
L1θ / L2 + θ
ns
∑V H
W16x89
(0.98)
tplate = 0.036 in
S
= 19.69 in
Astrip = 0.72 in2
(0.98)
W16x89
W16x40
(0.96)
(0.96)
W16x40
10 ft
tplate = 0.036 in
S
= 19.69 in
Astrip = 0.72 in2
L2
L1
Δi+2
Vi+2
i =1
i
i
⎛ Lp ⎞
⎟
=2⎜
⎜
⎟
⎝ L p − L1 ⎠
ns
∑M
i =0
pbi
Plastic Hinge on the HBEs
Δi+1
ns
ns
1
1
+ ∑ Fyp L p (t wi − t wi +1 ) sin (2α ) H i − ∑ Fyp t wi L1 sin (2α ) H i
i =1 2
i =1 2
x76
W18x
(0.99
9)
Vi+1
tplate = 0.059 in
S
= 19.69 in
Astrip = 1.17 in2
(0.99
9)
tplate = 0.059 in
S
= 19.69 in
Astrip = 1.17 in2
x76
W18x
W14x61
(0.99)
x50
W18x
(0.91
1)
(0.91
1)
10 ft
W18x
x50
W12x22
(0.98)
ωb
Hi+2
ωc
Horizontal component of the strip yield forces
(0.95)
tplate = 0.072 in
S
= 19.69 in
Astrip = 1.42 in2
(0.96)
tplate = 0.072 in
S
= 19.69 in
Astrip = 1.42 in2
W24x62
(0.91)
W24x117
(0.98)
20 ft
20 ft
Hi+1
θ
α
L2
L1
L1 ns
L
+ ∑ Fyp (t wi L2 − t wi +1 L p ) cos 2 α 1
2 i =1
2
Vertical component of the strip yield forces
Hi
Plastic Hinge
SPSW-CD
SPSW-ID
+ Fyp t w1 L2 cos 2 α
Vi
W24x146
(0.96)
(0.92)
W24x146
W12x45
W24x62
(0.99)
10 ft
W24x62
(0.99)
Δi
W12x19
Strips remained
elastic
Lp
Case Study: Strength per this
plastic mechanism is 13% less
than per sway mechanism
Design HBEs for wL2/4
Cyclic Pushover Analysis
• Monotonic: in-span plastic hinge + significant HBE vertical deformation
• Cyclic: to investigate whether phenomenon observed in monotonic
analysis may lead to progressively increasing deformations
4%
10.8
3%
7.2
2%
3.6
1%
0
0%
-3.6
-1%
-7.2
-2%
Vertical Displac
cement (in) .
14.4
Lateral Drift (%)
Top Floor Displacement, Δ (in)
• Loading history:
-4%
-3%
2
3
4
Number of Cycles, N
5
Æ Significant
accumulation of plastic
incremental deformation
on SPSW-ID
• Maximum Rotations:
SPSW-ID = 0.062 radians
SPSW-CD = 0.032 radians
SPSW-CD
-2.5
SPSW-ID
-3.0
10.8
14.4
SPSW-ID

0.0

-1.0
HBE2
Yielding strips
Plastic Hinges
1.0 SPSW-CD

M/M p
0.5
0.0
-0.5
deserve more attention
in future research
-7.2 -3.6
0
3.6
7.2
Lateral Displacement (in)
HBE3 Vertical Displacements
6
-0.5
• AISC 2005 Seismic Specifications:
Ordinary-type connections be
used in SPSW
ÆTime history analyses
show same behavior, with
vertical displacements
increasing with severity of
ground excitation level
0.5
M/M p
• Curves bias toward one direction
1.0
4%
-2.0
• Comparing rotation demands at
beam to column connection
3%
-1.5
15
-4%
1
2%
-1.0
-3%
-14.4
Lateral Drift
-1%
0%
1%
-0.5
-14.4 -10.8
-10.8
-2%
0.0
-1.0
-2.5
HBE2
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
θ / θ 0.03
Normalized Moment Rotation (θ/0.03)
For design
strength,
neglect
plastic hinges
4⋅M p
1
contribution V = 2 ⋅ Fy ⋅ t ⋅ L ⋅ sin 2α + h
7
8/12/2012
Single Story SPSW Example

Design
Interpretation #2:
Lateral load Vu=
α
h

Interpretation #1:
Lateral load Vu=
L
Force assigned to infill panel
V =
4⋅M p
1
⋅ Fy ⋅ t ⋅ L ⋅ sin 2α +
2
h
κ ⋅Vdesign =
Single Story SPSW Example
2.25
2.00
50000
Overstrength from
capacity design
40000
1.50
Weighht (lb)
Vplastic/ Vd
design
1.75
Case Study
α = 45D
β = 1.0
L/h=0.8
L/h=1.00
L/h=1.5
L/h=2
L/h=2.5
1
f yp t w Lh sin ( 2α )
2
1 25
1.25
30000
20000
1.00
Balance point
0.75
⎡
κ balance = ⎢1 +
⎢⎣
0.50
⎤
1L
β
⋅
⎥
2 h 1 + 1 − β 2 ⎥⎦
10000
−1
0
AISC
Design force to be assigned
to boundary moment frame
0.25
PROPOSED
Panel HBE
VBE
75%
Total
40%
0.00
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
κ
Quantifying
Performance
Seismic Performance Factors
Parameter
• Time history analyses of SPSWs
designed with various k value
revealed different drift response
• Need to rigorously quantify
significance in terms of seismic
performance
• FEMA P695 procedure is a
useful tool for that purpose
SW320
SW320K
Reference
1. Design Stage
R
7
7
ATC63 Design 3-Story SPSW Big Size 100%.xls
176
176
Vmax
495
226
δy,eff
1.80
1.8
δu
8.86
8.64
Ω = Vmax/Vdesign
2.81
1.29
μT = δu/δy,eff
4.92
4.80
SCT
3.60
2.29
IDA Curve for SW320 Sa PDGravity+Leaning.xls
SMT
1.50
1.50
IDA Curve for SW320K Sa PDGravity+Leaning.xls
CMR = SCT/SMT
2.40
1.53
Vdesign
2. Nonlinear Static (Pushover) Analysis
Pushover Curve for SW320 and SW320K.xls
Included SH = 2%, Ωd = 1.2 and φ = 0.9
3. Incremental Dynamic Analysis (IDA)
8
8/12/2012
Typical Archetype Model
Component Degradation Model
OPENSEES Model:
M
• Fiber Hinges on HBE and
VBE ends
My
P
Mcap
SH =
2%
Py
EI
• Axial Hinges on Strips
EA
-θy θy
Symmetri
c
• Gravity loads applied on
SPSW according to its
tributary area.
0.081
0.039 0.064
θ
δy
No
Compression
Strength
-My
(a) Boundary
Elements
• Remaining loads applied on
Leaning columns
Pcap
SH =
2%
9.0δy 10.7δ
δ
y
0.015 0.018
(Axial
Strain)
(b) Strips
Failure mode developed based on 33 previously tested SPSW specimens
Degradation model verified on 1 to 4 story SPSW specimens
Dual Strip Model
P-Δ Leaning
Column
Incremental Dynamic Analysis (IDA) Results - Sa
Seismic Performance Factors
SW0320
Parameter
SW320
SW320K
Reference
1
1. Design Stage
R
Probability off Collapse
0.8
SW0320K
7
7
176
176
Vmax
495
226
δy,eff
Vdesign
2. Nonlinear Static (Pushover) Analysis
0.6
1.80
1.8
δu
8.86
8.64
SW320
Lognormal SW320
Ω = Vmax/Vdesign
2.81
1.29
SW320K
Lognormal SW320K
μT = δu/δy,eff
4.92
4.80
SCT
3.60
2.29
IDA Curve for SW320 Sa PDGravity+Leaning.xls
SMT
1.50
1.50
IDA Curve for SW320K Sa PDGravity+Leaning.xls
CMR = SCT/SMT
2.40
1.53
0.4
0.2
0
0
5
Spectral Acceleration, ST (Tn = 0.36 Sec.), g
Seismic Performance Factors, Cont.
10
Pushover Curve for SW320 and SW320K.xls
Included SH = 2%, Ωd = 1.2 and φ = 0.9
3. Incremental Dynamic Analysis (IDA)
Fragility Curve: DM (Inter(Inter-story Drift) for SW320
1
Parameter
SW320
SW320K
Reference
4. Performance Evaluation
0.36
0.36
SDC
Dmax
Dmax
FEMA P695 (ATC63) Table 5-1
SSF (T, μT)
1.25
1.25
FEMA P695 (ATC63) Eq. 5-5
FEMA P695 (ATC63) Table 7-1b
1.91
ACMR = SSF (T, μT) x CMR
3.00
βRTR
0.4
0.4
FEMA P695 (ATC63) Section 7.3.1
βDR
0.2
0.2
FEMA P695 (ATC63) Table 3-1: (B - Good)
βTD
0.35
0.35
FEMA P695 (ATC63) Table 3-2: (C - Fair)
FEMA P695 (ATC63) Table 5-3: (B - Good)
βMDL
0.2
0.2
βtot = sqrt (βRTR + βDR + βTD + βMDL )
0.60
0.60
ACMR20% (βtot)
1.66
1.66
ACMR10% (βtot)
2.16
2.16
Statusi
Pass
Pass
FEMA P695 (ATC63) Eq. 7-6
StatusPG
Pass
2
2
2
2
0.8
Probability off Exceedance
T
0.6
DM: 1% Drift
DM: 2% Drift
DM: 3% Drift
0.4
DM: 4% Drift
DM: 5% Drift
DM: 6% Drift
0.2
DM: 7% Drift
NOT Pass FEMA P695 (ATC63) Eq. 7-7
DM: Collapse Point
5. Final Results
R
7
Try Again
0
Try Again
Design Level
Sa = 1.5g
Ω
2.8
μT
4.9
Try Again
7
Try Again
Cd = R
0
2
4
6
8
10
Spectral Acceleration, S T (Tn = 0.36 Sec.), g
9
8/12/2012
Fragility Curve: DM (Inter(Inter-story Drift) for SW320K
1
Perforated Steel Plate Shear
Walls (P
(P--SPSW)
Probability off Exceedance
0.8
0.6
DM: Drift 1%
(to reduce tonnage of steel
in low
low--rise SPSWs)
DM: Drift 2%
DM: Drift 3%
0.4
DM: Drift 4%
DM: Drift 5%
DM: Drift 6%
0.2
DM: Drift 7%
DM: Collapse Point
0
0
Design Level
Sa = 1.5g
2
4
6
8
10
Spectral Acceleration, ST (Tn = 0.36 Sec.), g
Infill Overstrength

Available infill plate material might be
thicker or stronger than required by design.
Several solution to alleviate this concern
z
z
z
Light-gauge cold-rolled steel
Low Yield Steel (LYS) steel
Perforated Steel Plate Shear Wall
Perforated Wall Concept
4
3
2
1
A
Specimen P at 3.0% Drift
B
C
D
E
F
Perforated Layout, Cont.
Sdiag
θ
“Typical”
diagonal strip
10
8/12/2012
Typical Perforated Strip ((Vian
Vian 2005)
Typical Strip Analysis Results (ST1)
At monitored strain emax = 20%, D = 100 mm (D/S
(D/Sdiag = 0.25)
Sdiag = 400 mm
2δ
ABAQUS S4 “Quadrant” Model
D
(a) Strip Mesh and Deformed Shape (Deformation Scale Factor = 4)
L = 2000 mm
½L
δ
(b) Maximum In-Plane Principal Stress Contours
t = 5 mm
not actual mesh
D = variable
Sdiag
½ Sdiag
(c) Maximum In-Plane Principal Strain Contours
FLTB Model
FLTB Model: Typical Panel Results
At monitored strain εmax = 20%, D = 200 mm (D/
(D/S
Sdiag = 0.471)
5.0
Strip emax = 20%
Strip emax = 15%
Strip emax = 10%
Strip emax = 5%
Strip emax = 1%
Total Uniform Strrip Elongation, ε un (%)
4.5
4.0
3.5
Panel emax = 20%
Panel emax = 15%
Panel emax = 10%
Panel emax = 5%
Panel emax = 1%
3.0
2.5
2.0
1.5
1.0
0.5
0.0
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Perforation Ratio, D/S diag
Maximum In-Plane Principal Strain Contours
Shear Strength vs. Frame Drift
3000
Infill Shear Strength: RF
Model
0.9
0.8
2000
1500
1000
500
51.5%
0.7
emax = 20%
emax = 15%
emax = 10%
emax = 5%
emax = 1%
Solid
D050 (D/Sdiag = 0.12)
D100 (D/Sdiag = 0.24)
D150 (D/Sdiag = 0.35)
D200 (D/Sdiag = 0.47)
D250 (D/Sdiag = 0.59)
D300 (D/Sdiag = 0.71)
Bare
Vyp.perf / V yp
Total Shear Sttrength, Vy (kN)
1.0
2500
0.6
0.5
0.4
0.3
⎡
D ⎤
⋅ V yp
V yp. perf = ⎢1 − α
Sdiag ⎥⎦
⎣
Predicted (Eq. 4.3)
γ = 5%
γ = 4%
γ = 3%
γ = 2%
γ = 1%
Linear Reg.
0.2
0.1
correction factor:
0.0
0
0.0
0.0
1.0
2.0
3.0
Frame Drift, γ
4.0
5.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
α = 0.7
1.0
D/S diag
11
8/12/2012
Implementation of P
P--SPSW
Replaceability of Web Plate
in SPSW
Courtesy of Robert Tremblay, Ecole Polytechnique, et Eric Lachapelle, Lainco Inc, Montreal
Experimental Program

Phase I: Pseudo-dynamic load to an
earthquake having a 2% in 50 years
probability of occurrence.
(Chi Chi CTU082EW--2╱50 PGA=0.67g)
(Chi_Chi_CTU082EW--2╱50
PGA=0 67g)
Cut-out and replace webs at both levels
Phase II: Repeat of pseudo-dynamic load to
an earthquake having a 2% in 50 years
probability of occurrence.
Subsequently cyclic load to failure.
Pseudo--dynamic Test (cont’d)
Pseudo
Web replacement

Buckled web plate
from first pseudodynamic test cut out
and new web plate
welded in place
Pseudo--dynamic Test (cont’d)
Pseudo
1st story
2nd story
Specimen after the maximum peak drifts of 2.6% at lower
story and 2.3% at upper story in pseudo-dynamic test.
12
8/12/2012
Subsequently Cyclic Test
Subsequently Cyclic Test (cont’d)

Severe plate damage and intermediate beam damage also
occurred at drifts between 2.5% and 5%
2nd story after interstory drift of 5%
1st Story after interstory drift of 5%
Self-Centering SPSW
Self-Centering
Self(Resilient) SPSWs
(SC--SPSWs)
(SC
Concept:
Replace rigid HBE to VBE joint connections
of a conventional SPSW with a rocking
connection combined with Post-Tension
elements.
y Energy dissipation provided by yielding
of infill plate only (not shown in figure)
y HBE, VBE and P.T. components
designed to remain essentially elastic
y Elastic elongation of P.T. about a rocking
point provides a self-centering
mechanism
UB Test-Setup (Full Infill Plate Frames)
UB Specimen (Rocking about Flanges)
13
8/12/2012
Accommodating Beam Growth with
Large Columns
Courtesy of Greg MacRae, University of Canterbury, New Zealand
NewZ-BREAKSS Rocking Connection
Rocking Point (Ea. End of HBE)
W6x VBE
Radius Cut-Out
Flange Reinf. Plate
UB Test Frame:
Additional Test Frame
Configurations:
Test Frames w/
Infill Strips
New Zealand-inspired – Buffalo
Resilient Earthquake-resistant
Auto-centering while Keeping
Slab Sound (NewZ-BREAKSS)
Rocking Connection
Frame w/ NewZBREAKSS Conn.
Light Gage
Web Plate
W8x HBE
Continuity Plate
VBE Web Dblr Plate
Post-Tension
(Ea. Side of HBE Web)
P tT i
Post-Tension
Eccentricity
Stiffener Plates (Typ.)
Cant HBE Web (Ea. End of HBE)
Shear Plate w/
Horiz. Long Slotted Holes
Comments:
¾Schematic detail shown of UB 1/3 test frame connection currently being tested at UB
¾Eliminates PT Frame expansion by HBE rocking at the beam top flanges only
14
8/12/2012
UB NewZ-BREAKSS Test Frame
UB NewZ-BREAKSS Test Frame
UB NewZ-BREAKSS Test Results
NewZ-BREAKSS Hysteresis
Full Infill Plates
-3.4
60
-2.7
50
40
Base Shear (kips)
-2.0
0.167Δy
0.33Δy
0.67 Δy
1.0Δy
2Δy
3Δ
3Δy
30
20
-1.4
Top Story Drift (%)
-0.7 0.0 0.7 1.4
2.0
2.7
3.4
4Δy
2% drift
2.5% drift
3% drift
Comments:
¾Displacement control at top
level actuator with a slaved
Force control at level 1 & 2
2.
10
¾Force control load pattern of
1, 0.658, 0.316 at level 3, 2, 1
actuators used based on
approximate first mode shape.
0
-10
-20
-30
-40
-50
-60
-5
-4
-3
-2
-1
0
1
2
Top Story Displacement (in)
3
4
5
Discrete Strips Alternative
NewZ-BREAKSS Hysteresis
Full Infill Plates - SAP2000
Top Story Drift (%)
-4.5
-3
-1.5
0
1.5
3
4.5
80
Base Shear (k
(kips)
60
40
20
1)
2)
3)
4)
Test Frame - 2x0.5" strds
APT = 4x0.5" strds
APT = 6x0.5" strds
APT = 6x0.6" strds
0
-20
*Residual Drift
1) 1.85%
2) 1.0%
3) 0.85%
4) 0.58%
*modify HBE/VBE
sizes as required
-40
-60
-80
-8
-6
-4
-2
0
2
4
6
8
15
8/12/2012
UB Test Results – NewZ-BREAKSS
Top Story Drift (%)
-6 -4.5 -3 -1.5
0
1.5
3
4.5
6
No separation of the
infill strips occurred
(also observed with
the flange rocking
case).
Testing stopped to
be able to reused
VBEs for subsequent
shake table testing.
60
Base Shear (kips)
SAP2000: 10% Comp.
40
20
0
-20
PT Yielding Occured At
Approx. 4.5% Top Story
Drift
-40
-60
-10.5 -7.5
-4.5
-1.5
1.5
4.5
7.5
10.5
Eccentrically Braced Frame
Tubular-link Eccentrically
TubularBraced Frames (TEBF)
a.k.a.
EBF with BuiltBuilt-up Box Links
Proof--of
Proof
of--Concept Testing
Tubular--link EBF
Tubular

EBFs with wide-flange (WF) links require
lateral bracing of the link to prevent lateral
torsional buckling
Lateral bracing is difficult to provide in
b
bridge piers
Development of a laterally
Fyf
tw
stable EBF link is warranted
Fyw
Consider rectangular crosstf
section – No LTB
d
16
8/12/2012
Finite Element Modeling of
Proof--of
Proof
of--Concept Testing
Link Testing – Results
Large Deformation Cycles of Specimen X1L1.6
Hysteretic Results for Refined ABAQUS Model and Proof-of-Concept
Experiment
Design Space
Stiffened Links
Unstiffened Links
0.64
1.67
E
Fyw
Implementation
of TEBF
b
tf
0.64
ρ = 1.6
E
Fyw
d
tw

E
Fyf
ρ
Some slenderness limits
accidentally missing
from AISC 341-10
Towers of temporary
structure to support
and provide seismic
resistance
i t
to
t deck
d k off
self-anchored
suspension segment of
East Span of SanFrancisco-Oakland Bay
Bridge during its
construction
Earthquakes
Multi--Hazard Design Concept
Multi
Why Multi-Hazard Engineering Makes Sense?
17
8/12/2012
Storm Surge or Tsunami
Collision
http://www.dot.state.mn.us/bridge/Manuals/LRFD/June2007Workshop/10%20Pier%20Protection.pdf
Fire
Blast
Suicide truck-bomb collapsed the Al-Sarafiya bridge and sent cars
toppling into the Tigris River (AP, (Baghdad, Iraq, April 2007)
Multi--hazard solution
Multi

A true multi-hazard engineering solution is a
concept that simultaneously has the desirable
characteristics to protect and satisfy the multiple
(contradicting) constraints inherent to multiple
hazards
Needs holistic engineering design that address all
hazards in integrated framework
A single cost single concept solution (not a
combination of multiple protection schemes)
Pay-off: Reach/protect more cities/citizens
Concrete--Filled Steel Tubes
Concrete
(CFST)
for blast and seismic
performance
18
8/12/2012
CFST Piles

“The Loma Prieta and
Northridge earthquakes in
California and the Kobe,
Japan quake, along with reexamination of largediameter cylinder-pile
cylinder pile
behavior in the Alaskan
earthquake of 1964, have
demonstrated the superior
ductility of concrete-filled
steel tubular piles.”
(Ben C. Gerwick Jr., ASCE Civil
Engineering Magazine, May 1995)

CFST Column Specimen (1st Series)
CFST Column Test Results
Test 5: Bent 1, C5 (1.3X, W, Z=0.75m)
16.5”
164”
CAP-BEAM
C5
C4
68.5”
69.5”
6”
6
5”
5
59”
C6
Bridge carrying Broadway Ave. over the railroad in City of Rensselaer, NY
Built 1975. No major rehab, although joints and wearing surface were redone
4”
4
Dmax
= 76 mm
32”
FOUNDATION
BEAM
Gap
= 3 mm
164”
Concrete-Filled Steel
Tube
Concrete (no rebars)
Damage Progress of CFST Column
(Column Deformations)
1.2 deg
(0.021 rad)
2.2 deg
(0.038 rad)
4.9 deg
(0.085 rad)
18.7 deg
(0.327 rad)
Fracture of
Column
Seismically
Designed
Ductile Column

10.5 deg
(0.182 rad)
5.0 deg
(0.088 rad)
21.9 deg
(0.382 rad)
Buckling of
Steel Tube
Explosion
3.8 deg
(0.067 rad)
8.3 deg
(0.144 rad)
17.0 deg
(0.297 rad)
Fracture of
Steel Tube
Covered
Concrete
Plastic
Deformation
(Test 6 : B2-C4)

Blew
Away
Plastic
Deformation
(Test 9 : B2-C6)
On-set of
Column Fracture
(Test 10 : B2-C5)
Post-fracture
of Column
(Test7 : B2-C4)
Shear Failure
Seismic Design
Alone is not a
Guarantee of MultiHazard Performance
Need Optimal
Seismic/Blast
Design
19
8/12/2012
Comparison of Blast Parameters
Jacketed NonNonDuctile Column
(Seismic Retrofit)

CFST Tests
0.10W
Test 5
Test 4
250
750
Test 3
Test 9,10
Test 7
Test 6
Comparison of Column Damage
Horizontal
Deformation
(mm)
Test 1,3 Test 2,4
1
1
1
38
3
59
5
80
7
6
6
10
10
17
15
102
123
144
165
8
19
19
11
21
23
12
24
27
12
28
31
188
13
32
35
216
14
37
39
242
15
40
44
263
16
45
49
285
16
50
52
309
15
52
56
328
16
57
61
347
15
62
65
367
14
67
71
379
All longitudinal
bars fractured.
Test 6 CFST C4
(x = 1.6 X)
Test 1 RC1
(x = 2.16 X)
0.7 deg
(0.012 rad)
All longitudinal
71
bars fractured.
75
13
74
Standoff
Distance
(in X)
3
3.25
Calibration Work
Fracture of
Column
Explosion
Blew
Away
250
3.8 deg
(0.067 rad)
18
Test 2
Test 1
0.8 1.3
2
0.6 1.1 1.6 2.16
24
(Max)
W
0.55W
Reaction
Frame
Again Shear Failure
Same conclusions
1.2 deg
(0.021 rad)
RC, SJ Tests
W
79
2.9 deg
(0.051 rad)
Test 2 RC2
(x = 3.25 X)
Test 3 SJ2
(x = 2.16 X)
Test 4 SJ1
(x = 3.25 X)
Blast Simulation Results
e
)
Post-fracture
of Column
(Test7 : B2-C4)
Proposed Multi Hazard Concept
• Analysis of concrete filled double skin tubes (CFDST)
showed they can offer similar performance as CFST
• CFDST concentrates materials where needed for higher
strength-to-weight ratio
20
8/12/2012
Blast Test Results
S1 @ 3% Drift
S1 @ 7.5% Drift
S1 @ 10% Drift
S5 @ 3% Drift
S5 @ 6% Drift
S5 @ 7.5% Drift
Enhanced Steel Jacketed Column
21
8/12/2012
ERDC Test on ESJC
• Results
Structural Fuses (SF)
Analogy

structural fuse, d
mass, m
Sacrificial element to protect the rest of the
system.
frame f
frame,
braces, b
Ground Motion, üg(t)
Model with
Nippon Steel BRBs
Benefits of Structural Fuse Concept:

Seismically induced damage is
concentrated on the fuses V
V
Following a damaging
earthquake only the fuses V
would need to be replaced VV
Once the structural fuses are
removed, the elastic structure
returns to its original position
(self-recentering capability)
Total
Eccentric Gusset
Gusset--Plate
p

αK1 = Kf
y
Structural Fuses
K1
yd
yf

Ka
Δya
Frame
Kf
Δyf
u
22
8/12/2012
Test 1
First Story BRB
Test 1
(PGA = 1g)
40
1st Story Axiaal Force (kips)
30
20
10
0
-0.5
-0.4
-0.3
-0.2
-0.1
-10
0
0.1
0.2
0.3
0.4
0.5
-20
-30
-40
Axial Deformation (in)
Test 1 (Nippon Steel BRB Frame)
First Story Columns Shear
1st Story Column
ns Shear (kN)
100
-5
75
50
25
0
-4
-3
-2
-1
-25
0
1
2
3
4
5
-50
-75
-100
Inter-Story Drift (mm)
ABC Bridge Pier with
Structural Fuses
Specimen S2S2-1
New “Short Length” BRB
Developed by Star Seismic
23
8/12/2012
Specimen with BRB Fuses
Specimen with BRB Fuses
Controlled Rocking/Energy
Dissipation System

Rocking Frames (RF)

Absence of base of leg
connection creates a rocking
bridge pier system partially
isolating the structure
Installation of steel yielding
devices (buckling-restrained
braces) at the steel/concrete
interface controls the rocking
response while providing
energy dissipation
Retrofitted Tower
Existing Rocking Bridges
South Rangitikei Rail Bridge
Lions Gate Bridge North Approach
Static, Hysteretic Behavior of Controlled
Rocking Pier
FPED=0
FPED=w/2
Device Response
24
8/12/2012
Design Procedure
Design Chart:
Design Constraints
z
h/d=4
10
Acceleration
⇒
Limit forces through
vulnerable members
using structural “fuses”
8
6
z
Velocityy
Control impact energy to
foundation and impulsive
loading on tower legs
by limiting velocity
⇒
Displacement Ductility
Limit μL of
specially detailed,
4
2
⇒
ductile “fuses”
z
Auub
z
Aub ((in2)

0
0
β<1 Inherent re-centering (Optional)
⇒
100
200
Lub
300
400
Lub (in.)
constraint1
constraint2
constraint3
constraint4
constraint5
Synthetic EQ 150% of Design – Free Rocking
Synthetic EQ 150% of Design
Free Rocking
Synthetic EQ 150% of Design
TADAS Case ηL=1.0
Synthetic EQ 175% of Design - Viscous Dampers
Conclusions

Recent research has enhanced understanding
of seismic behavior of SPSW
z
z
z
z
z

Enhanced FBD for capacity design of HBEs/VBEs
Revisited purpose of flexibility factor
Significance of HBE in
in-span
span hinging
Implication of “balanced design”
Post-EQ replaceability and expected drift demands
P-SPSW: Cost-effective for low-rise SPSWs
SC-SPSW: Promising resilient system
TEBF, CFST, CFDST, SF, Rocking strategies
25