effect of gravity framing on earthquake-induced...
TRANSCRIPT
1 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Effect of Gravity Framing on Earthquake-Induced
Losses and Collapse Risk of Steel Frame
Buildings in Seismic Regions
June 23-24 2016, Hydra, Greece
DIMITRIOS G. LIGNOS
SWISS FEDERAL INSTITUTE OF TECHNOLOGY, LAUSANNE (EPFL)
2 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Motivation
The next generation of performance-based earthquake
engineering (PBEE) has formalized a framework for assessing the
seismic performance of frame buildings.
The same framework can be employed to assess the earthquake-
induced losses in frame buildings (FEMA P-58).
Important for stakeholders, building owners:
Informed decisions for effective designs (new buildings)
Effective seismic retrofits (existing buildings)
Evaluation of repair actions in the aftermath of earthquakes
3 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Overview of PBEE Methodology
l DV( ) = G DV DM( )dG DM EDP( )dG EDP IM( )dl IM( )allDMs
òallEDPs
òallIMs
ò
Image adopted by Zareian (2006)
4 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Overview of PBEE Methodology (2) -Impact of Analytical Model Representation on EDPs (and losses)
Perimeter SMF
Equivalent
gravity frameRigid
link
4.6 m
4.0 m
4.0 m
4.0 m
6.1m 6.1m 6.1m
(a)
3 bays @ 6.10 m
I I I I
I
I
I
I
I
I
I
I
30.5
0 m
42.70 m
I
I
I
I
I
I
I
I
I
I
I
I
I I I I
I
I
I
I
Interior gravity
framingPerimeter SMF
Historically, “bare frame” models have been utilized for nonlinear response
history analysis of frame buildings (e.g., Composite action, gravity framing is
ignored).
5 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Motivation (2) -Examples from Christchurch Earthquakes 2010, 2011
Total cost to insurers of rebuilding was approximately NZ$40Billion.
Significant portion of the estimated dollar loss is from damage to non-
structural components.
New Zealand: developed country with long tradition in earthquake
engineering research and practice!
Source: Bruneau et al. (2011)
6 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Northridge 1994 Hyogoken-Nanbu 1995 Tohoku 2011
Motivation (3) -Collapse Risk During Extreme Earthquakes
Hyogoken-Nanbu 1995 Loma Prieta 1989 Loma Prieta 1989
Images Source: NISEE, E-Library
7 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Motivation (4) -Residual Deformations and Demolition Actions
With the evolution of design provisions, code-conforming frame
buildings may not collapse (easily) but it is likely to experience large
residual deformations after a large earthquake.
Examples of steel and RC buildings with residual displacements leading to demolition (San
Fernando and Tohoku earthquakes)
9 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Utilize loss metrics in order to quantify the seismic-induced
losses in steel frame buildings designed in urban California.
Assess the effect of analytical model representation of a
steel frame building on earthquake-induced losses under
various seismic intensities.
Quantify the effect of residual deformations on the loss
assessment of steel frame buildings with steel SMFs or
SCBFs.
Assess the effect of seismic design parameters (e.g., SCWB
ratio) on the earthquake-induced losses of steel frame
buildings in highly seismic regions.
Objectives and Scope
10 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Overview of Loss Estimation Methodology
: Expected total repair costs conditioned on seismic intensity IM.
: Probability of having no-collapse given IM
: Probability of having no-collapse given IM but the building
will be demolished.
: Probability of having collapse given IM.
E LT IMéë ùû
P NCÇR IM( )
P C IM( )
P NCÇD IM( )
Source: Ramirez and Miranda (2013)
P D NC, IM( ) = P D RSDR( )dP RSDR NC, IM( )0
¥
ò
Probability of demolition given IM but no collapse (Assumed μ=1.5% and σ=0.30) :
11 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Archetype office steel buildings (2- to 20-stories) with perimeter steel
special moment frames designed in Urban California (IBC 2009, AISC-
2010)
(Sources: Elkady and Lignos 2014*)
Example: Steel Frame Buildings with Special Moment
Frames
*Elkady, A. and Lignos, D.G. (2014). "Modeling of the Composite Action in Fully Restrained Beam-to-Column Connections:
Implications in the Seismic Design and Collapse Capacity of Steel Special Moment Frames". Earthquake Engineering and
Structural Dynamics (EESD). Vol. 43(13), pp. 1935-1954, DOI: 10.1002/eqe.2430.
12 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Source: National Seismic Hazard Map (USGS 2008)
Seismic Hazard in Design Location of Interest
13 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Fragility and Cost Distribution Functions
To compute realistic loss estimations for steel frame
buildings architectural layouts were developed.
Steel frame buildings with SMFs: rectangular footprint of
14,000ft2
Cost estimates were developed based on the RS Means
Cost Estimating Manuals.
Non-structural components (both drift- and acceleration-
sensitive) were considered to compute the replacement cost
estimates per building.
Structural components (e.g., beam-to-column connections,
columns, slabs, base plates, etc) were also considered.
Base case replacement cost was estimated to be $250/ft2.
15 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Steel Frame Buildings with Moment Resisting Frames -Modeling of Composite Action and Interior Gravity Framing
*Elkady, A. and Lignos, D.G. (2014). "Modeling of the Composite Action in Fully Restrained Beam-to-Column Connections:
Implications in the Seismic Design and Collapse Capacity of Steel Special Moment Frames". Earthquake Engineering and
Structural Dynamics (EESD). Vol. 43(13), pp. 1935-1954, DOI: 10.1002/eqe.2430.
Source: Elkady and Lignos (2014)*
Perimeter SMF
Equivalent
gravity frameRigid
link
4.6 m
4.0 m
4.0 m
4.0 m
6.1m 6.1m 6.1m
-0.08 -0.04 0 0.04 0.08
Mom
ent
(kN
-m)
-2000
-1000
0
1000
2000
3000
Chord Rotation θ (rad)
(b)
Exp. DataSimulation
-0.1 0 0.1
-450
0
450
Chord Rotation θ (rad)
(c) M
om
ent
(kN
-m)
Exp. DataSimulation
θbind
bindM
maxM
maxM
θu
θu
Joint panel zone model
Lumped plasticity model
Elastic beam-column element
Equivalent gravity beam & column
Composite shear-tab connection model
(a)
16 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Experimental Data
Simulation
Experimental Data
Simulation
Steel Frame Buildings with Special Moment Frames
-Modeling of steel columns
Source: Suzuki and Lignos (2015)*
*Suzuki, Y., Lignos, D.G. (2015). ”Large Scale Collapse Experiments of Wide Flange Steel Beam-Columns”, Proceedings 8th
International Conference on Behavior of Steel Structures in Seismic Areas, Shanghai, China, July 1-3, 2015.
17 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
0.5 1 1.5 20
0.5
1
1.5
2
2.5
Sa[g
]
Period T [sec]
Design Spectrum
Mean Spectrum
Individual GM
0 0.05 0.1 0.150
0.5
1
1.5
2
2.5
Maximum Story Drift Ratio [rad]
Sa (
T1, 5%
) [
g]
Median Collapse Capacity ŜCT
Collapse
Collapse Risk of Steel Frame Buildings with SMFs
-Ground Motion Sets and Process to Trace Collapse
Source: Elkady and Lignos (2014)*
Ground Motion Set from FEMA P695
Far-Field Set of 44 Ground Motions
Incremental Dynamic Analysis
to Trace Dynamic Instability
*Elkady, A. and Lignos, D.G. (2014). "Modeling of the Composite Action in Fully Restrained Beam-to-Column Connections:
Implications in the Seismic Design and Collapse Capacity of Steel Special Moment Frames". Earthquake Engineering and
Structural Dynamics (EESD). Vol. 43(13), pp. 1935-1954, DOI: 10.1002/eqe.2430.
18 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Collapse Risk of Steel Frame Buildings with SMFs
*Elkady, A. and Lignos, D.G. (2015). ”Effect of Gravity Framing on the Overstrength and Collapse Capacity of Steel Frame
Buildings with Perimeter Special Moment Frames”, Earthquake Engineering and Structural Dynamics (EESD), Vol. 44(8),
1289-1307, DOI: 10.1002/eqe.2519.
19 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Collapse Risk of Steel Frame Buildings with Special
Concentrically Braced Frames (SCBFs)
21 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Expected Losses Conditioned on Seismic Intensity
-Utilization of Bare Frame Analytical Models
Due to P-Delta
effects
Hazards: Service Level, Design Basis (DLE) & Maximum Considered Event (MCE)
Minimum monetary loss due to business interruption is not considered
Due to P-Delta
effects
22 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
8-story SMF: B-Model
Bare Frame Only 8-story SMF: CG-Model
Composite Action & Gravity Framing
Expected Losses Conditioned on Seismic Intensity
-Effect of Analytical Model Representation: Steel SMFs
Earthquake-induced loss assessment at discrete levels of intensity may be over-
conservative when it is based on “bare frame” model representations of the building.
23 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Expected Losses Conditioned on Seismic Intensity
-Effect of Analytical Model Representation: Steel SCBFs
Earthquake-induced loss assessment at discrete levels of seismic intensity may be
over-conservative when it is based on “bare frame” model representations of the
building.
B CG B CG B CG B CG B CG B CG
Illustration: 6-story Steel Frame Building with SCBFs
E[L
T/IM
]
24 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Expected Losses Conditioned on Seismic Intensity
Effect of Strong-Column-Weak-Beam Ratio on Expected Losses
Hazards: Service Level, Design Basis (DLE) & Maximum Considered Event (MCE)
Minimum monetary loss due to business interruption is not considered
25 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Expected Annual Losses (EAL) as a Loss Metric
E LT( ) = E LT IM( )dl IM( ) =0
¥
ò E LT IM( )dl IM( )
dIMdIM
0
¥
ò
Sa(T
1, 5%) [g]
10-2
10-1
100
101
6S
a [
1/y
ear]
10-5
10-4
10-3
10-2
10-1
100
3-Story SCBF12-Story SCBF4-Story SMF12-Story SMF
EAL weights all possible levels of the seismic hazard by taking into
account their probability of occurrence.
26 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Expected Annual Losses (EALs)
27 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Concluding Remarks At seismic intensities associated with service and design-basis
earthquakes damage to non-structural content dominates steel frame
building earthquake induced losses regardless of the selected numerical
model and loss metric.
Earthquake induced loss estimates at discrete seismic intensities:
overestimated when building EDPs are based on “bare-frame”
models.
Composite action and the interior gravity framing reduce the
earthquake-induced loss estimates due to demolition by more than
50%. Loss estimates due to collapse risk reduce by 75%.
EALs: practical not affected by the choice of the numerical model
representation (Bare model or Composite-Gravity included).
Actions to reduce losses due to collapse risk (i.e., employed SCWB)
should be based on “better” building model representations as well as
discrete seismic intensities.
28 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Thank you for your kind attention!
For more information visit: resslab.epfl.ch
29 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Acknowledgements-Research Sponsors
30 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Backup Slides
31 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Archetype office steel buildings (2- to 12-stories) with perimeter steel
special concentrically braced frames designed in Urban California (IBC
2009, AISC-2010)
(Sources: NIST 2010)
Steel Frame Buildings with Special Concentrically
Braced Frames
32 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Fragility and Cost Distribution Functions (2)
-Examples of Damageable Components and Damage States
Story Drift Ratio, SDR [rad]0 0.01 0.02 0.03 0.04
Pro
bab
ility
of
Exce
ed
en
ce
0
0.2
0.4
0.6
0.8
1
Flexural BucklingLocal BucklingFracture
(Source: Lignos and Karamanci 2013*)
*Lignos, D.G., and Karamanci, E. (2013). “Drift-based and Dual-Parameter Fragility Curves for Concentrically Braced Frames in
Seismic Regions". Journal of Construnctional Steel Research, Vol. 90, pp. 209-220.
34 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Braced Frame Collapse Specifics
35 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
-0.04 -0.02 0 0.02 0.04-2000
0
2000
Rotation, [rad]
Eq
. S
hea
r F
orc
e, V
[k
N]
2
yV
p
Vy
Kp
Ksh
Vcol
Vcol
deff-
V
V V
V
Mb-Mb
+deff
+
ts
drib
Steel Frame Buildings with Special Moment Frames
-Modeling of panel zone shear distortion
W27x94
W24x84
W2
4x
13
1
W2
4x
13
1
W2
4x
13
1
W2
4x
13
1W24x84
W21x68
W2
4x
94
W2
4x
94
W2
4x
94
W2
4x
94
W30x108
W30x116
W30x116
W27x94
W2
4x
14
6
W2
4x
19
2
W2
4x
19
2
W2
4x
14
6
H =
32
.60
m
W2
4x
13
1
W2
4x
17
6
W2
4x
17
6
W2
4x
13
1
3 bays @ 6.10m
4.6
m4
.0m
4.0
m4
.0m
4.0
m4
.0m
4.0
m4
.0m
Perimeter
SMF
Rigid links
Equivalent
gravity frame
*Elkady, A. and Lignos, D.G. (2014). "Modeling of the Composite Action in Fully Restrained Beam-to-Column Connections:
Implications in the Seismic Design and Collapse Capacity of Steel Special Moment Frames". Earthquake Engineering and
Structural Dynamics (EESD). Vol. 43(13), pp. 1935-1954, DOI: 10.1002/eqe.2430.
Source: Elkady and Lignos (2014)*
36 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Steel Frame Buildings with Special Concentrically Braced Frames -Modeling of Steel Braces: Flexural Buckling and Fracture due to Low-Cycle Fatigue
*Karamanci, E., and Lignos, D.G. (2014). ”Computational Approach for Collapse Assessment of Concentrically Braced Frames
in Seismic Regions.” ASCE, Journal of Structural Engineering, Vol. 15(A401419), pp. 1-15.
Source: Karamanci and Lignos (2014)*
e0 = 0.748kL
r
æ
èç
ö
ø÷
-0.399D
t
æ
èç
ö
ø÷
-0.628E
Fy
æ
èçç
ö
ø÷÷
0.2
D
t
Calibrated with over 270 tests from steel braces
37 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions *Karamanci, E., and Lignos, D.G. (2014). ”Computational Approach for Collapse Assessment of Concentrically Braced Frames
in Seismic Regions.” ASCE, Journal of Structural Engineering, Vol. 15(A401419), pp. 1-15.
Source: Karamanci and Lignos (2014)*
Steel Frame Buildings with Special Concentrically Braced Frames -Modeling of Steel Braces: Flexural Buckling and Fracture due to Low-Cycle Fatigue
38 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
-0.1 0 0.1
-450
0
450
Rotation [rad]
Mom
ent
[kN
.m]
Exp. Data
Simulation
Mmax
+
u
bind
Mmax
-
u
Mbind
-
W27x94
W24x84
W2
4x
13
1
W2
4x
13
1
W2
4x
13
1
W2
4x
13
1W24x84
W21x68
W2
4x
94
W2
4x
94
W2
4x
94
W2
4x
94
W30x108
W30x116
W30x116
W27x94
W2
4x
14
6
W2
4x
19
2
W2
4x
19
2
W2
4x
14
6
H =
32
.60
m
W2
4x
13
1
W2
4x
17
6
W2
4x
17
6
W2
4x
13
1
3 bays @ 6.10m
4.6
m4
.0m
4.0
m4
.0m
4.0
m4
.0m
4.0
m4
.0m
Perimeter
SMF
Rigid links
Equivalent
gravity frame
Steel Frame Buildings with SMFs or SCBFs
-Modeling of gravity framing system and its connections
Image source: Liu and Astaneh (2002)
Source: Elkady and Lignos (2015)*
*Elkady, A. and Lignos, D.G. (2015). ”Effect of Gravity Framing on the Overstrength and Collapse Capacity of Steel Frame
Buildings with Perimeter Special Moment Frames”, Earthquake Engineering and Structural Dynamics (EESD), Vol. 44(8), pp.
1289-1307, DOI: 10.1002/eqe.2519.
39 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Tracing Sidesway Collapse of Frame Buildings -Example of definition of dynamic collapse due to earthquake shaking
40 D. G. Lignos – Effect of Gravity Framing on Earthquake-Induced Losses & Collapse Risk of
Steel Frame Buildings Designed in Seismic Regions
Expected Losses Conditioned on Seismic Intensity
-Effect of Analytical Model Representation: Steel SCBFs
12-story SCBF: B Model
Brace Frame Only 12-story SCBF: CG Model
Composite Action + Gravity Framing
Hazards: Service Level, Design Basis (DLE) & Maximum Considered Event (MCE)
Minimum monetary loss due to business interruption is not considered