u.s. clt research update - woodworks€¦ · factor for nbcc and asce7 seismic retrofit (neessoft)...
TRANSCRIPT
U.S. CLT Research Update
John W. van de Lindt, November 6; 2014
Chicago, IL.
Disclaimer: This presentation was developed by a third party and is not funded by
WoodWorks or the Softwood Lumber Board.
Progress On The Development
Of Seismic Resilient Tall CLT
Buildings In The Pacific
Northwest
Shiling PeiColorado School of
Mines
Jeffrey BermanUniversity of Washington
John van de LindtColorado State
University
Hans-Erik Blomgren
Arup
Marjan Popovski
FP Innovations
Douglas Rammer
Forest Products Lab
Daniel Dolan
Washington State
University
James Ricles
Lehigh University
Richard Sause
Lehigh University
Background
New trend to build tall Cross Laminated Timber (CLT) buildings around the world. But mostly in relatively low seismic regions.
CLT system can be designed with force-based methods, but resiliency is not ensured during major earthquakes.
Cross Laminated Timber (CLT) is entering the North American market gradually.
• Great momentum for CLT implementation in Canada.
• Where is the market for CLT in the U.S.?• What should we expect: Performance expectations?• What is needed to be done to get there?
A Brief History of CLT Seismic Research
CLT
Invented
in early
1990’s
Research
in Slovenia
and
Macedonia
Wall tests,
Shake
table test
of wall
assembly
Trento
Province,
Italy
SOFIE
project
Over strength factor, Numerical
modeling methods, q factor
Research on
CLT
FPInnovation
& Forest
Products Lab
CLT
handbook
Estimation of R
factor for NBCC and
ASCE7
Seismic
Retrofit
(NEESSoft)
NEES CLT
Planning
Resilient Timber systems
in NZ
Wall tests,
Shake table
tests at NIED
3-story, 7-
story
P695 on CLT
shear wall
Resilient CLT
systems
NEES-CLT Planning Project
Objective: Conduct technical preparation for enabling design and testing of 8-20 story CLT buildings
Website: NEESCLT.mines.eduShiling Pei Dan Dolan James Ricles Richard Sauce Jeffrey Berman John van de Lindt
Marjan Popovski Michael Willford Hans-Erik Blomgren Douglas Rammer
Plan and Vision
Establish
Performance
Objectives
Resilient system
prototyping and
component
testing
Develop
Performance
Based Seismic
Design procedures
Full scale system
level tests
validation
Finalize and verify
design
methodology
Enable 8-20 story CLT building in high seismic regions in
the U.S.
Test verified prototype systems and design approaches,
taking market competitiveness into consideration
20
14
-20
16
20
16
-20
19
20
20
Tall CLT Building
Workshop
Seattle January 2014: Learn from practitioner and end-user communities
• About 60 Participants• Agenda: Societal needs,
Performance expectations, Engineering challenges
All workshop documents available at NEESCLT website
• White paper• All presentations• Contact info
Challenges for CLT in U.S.
First-cost still dominates decision making for adopting CLT
• Other traits (energy, carbon sequestration) adds to value but not as decisive
• Not cost competitive (first cost) at lower height
Challenges:• Fire related code provisions:
component level performance, system level performance
• Lack of experience: small implementations
• Lack of innovation and research funding
• Cost and performance
Performance Expectations
Not necessarily the higher the better. Balance of performance and cost
A three-tiered performance expectations for tall CLT buildings
A Road Map for Vision CLT2020Activity Description Action group
Continue growing local production of CLT Manufacturers
Ramp up engineering education and outreach
to architects and engineers, leveraging on the
Canadian experiences
Wood industry groups
Familiarize the public and contractors with the
use of CLT through component level
implementation, hybrid systems, etc.
Engineers and Architects
Developing methods to compare CLT building
system to conventional non-combustible
systems to provide a basis for fire safety
equivalency
Engineers, architects, and
building officials
Confirm and expand fire rating data and
methodology
Researchers (Material and fire
focus)
Research development of the prototype
resilient CLT systems
Researchers and design
professionals (Structural focus)
Continue working on CLT shear wall Code
adoption for ASCE7 via application of FEMA P-Researchers and code
regulatory committees
CLT Resilient System Testing
Introducing resilient energy dissipation lateral CLT system
Testing to be done later this year at WSU
Parallel CLT Project at WSU
USDA funded project on Smart Manufacturing
Combining whole-building concepts through the use of BIM, REVIT, RINO, and GRASSHOPPER to provide input to ABAQUS FEM analysis for smart manufacturing of panels
Move the connections and utilities into the interior of the wall through smart manufacturing and improve fire, energy, moisture, and structural performance.
FEMA P-695: Quantification of
Building Seismic Performance Factors
• A Methodology that allows a team to identify seismic performance factors for a new SFRS.
• The Methodology is consistent with the primary “life safety” performance objective of seismic regulations in model building codes.
So, then what is FEMA P-695?
• Peer review throughout is key
• Archetypes
• Design methodology
• Nonlinear time history analysis
• Performance evaluation
• CMR
Project Team and Review Panel MembersProject Team
Member Expertise Role
John W. van de Lindt, Ph.D.
George T. Abell Distinguished
Professor in Infrastructure
Colorado State University
Seismic reliability analysis
Earthquake engineering
Extreme loading on structures
Structural dynamics
Wood engineering
Project
Team Leader
Douglas R. Rammer, P.E.
Research General Engineer
Engineering Properties of
Wood, Wood Based Materials,
and Structures - RWU4714
Engineering Design Criteria
Mechanical Connection Behavior
Seismic and Wind Response of Wood
Structures
Condition Assessment
Project
Member
Marjan Popovski, Ph.D.
Principal Scientist and Quality
Manager
Advanced Building Systems
Department
FPInnovations
Cross laminated timber
Seismic behavior of wood systems
Wood connections
Project
Member
Philip Line, P.E.
Director, Structural
Engineering
American Wood Council
Codes and Standards
Seismic behavior of wood
Project
Member
Shiling Pei, Ph.D. P.E.
Assistant Professor
Department of Civil and
Environmental Engineering
Colorado School of Mines
Mechanistic models and non-linear
structural dynamics
Structural reliability
Earthquake engineering
Project
Member
M. Omar Amini
Ph.D. Student
Colorado State University
Student Project
Member
Peer Review Panel
Member Expertise Role
Charlie Kircher, Ph.D., P.E.
Principal and Owner
Charles Kircher & Associates
Structural and earthquake
engineering, focusing on
vulnerability assessment,
risk analysis and innovative
design solutions
Panel
Chair
J. Daniel Dolan, Ph.D., P.E.
Professor
Department of Civil and
Environmental Engineering
Washington State University
Dynamic Response of Light-
Frame Buildings
Full-Scale Static, Cyclic, and
Dynamic Testing of
Structural Assemblies
Numerical Modeling of
Structural and Material
Response to Static and
Dynamic Loading
Panel
Member
Kelly Cobeen, S.E.
Associate Principal
Wiss, Janney, and Elstner
Associates, Inc.
Peer Review
Wood Seismic Design and
Detailing
Seismic Performance
Evaluation
Structural Evaluation
Earthquake Engineering
Panel
Member
Archetype DevelopmentDesign Space
Archetype Configurations
Archetype Designs
Archetype Models
Mathematical idealization of the
proposed system
Index archetype configurations
Designed and detailed using the
design requirements
Prototypical representation of a
seismic-force-resisting system
Representative of typical
residential and commercial
structures in the U.S.
Configuration Design Variables Seismic Behavioral Effects
Occupancy and Use Strength
Elevation and Plan Configuration Stiffness
Building Height Inelastic-deformation Capacity
Structural Component Type Seismic Design Category
Seismic Design Category Inelastic-system Mobilization
Gravity Load
Archetype Development
Archetype Development (Residential)
Archetype Development (Multi-family)
Archetype Development (Multi-family)
Archetype Development (Commercial)
Design Methodology• Design for Shear
• Loads determined using ELF procedure
• Calculations performed using the design methodology
vs =CF* (NC x 3216)/bs
where:
CF= connector type factor: 1 for connector type A, and 2 for
connector type B
NC = number of connectors per CLT panel
bs = panel length, ft
• Assumptions
• Capacity based on the number of nails
• Brackets have capacity to transfer the loads
Design Methodology• Assumptions
1. Bearing capacity parallel to the grain of 1300 psi (SPF). Other
values can be used based on wood species used for the CLT.
2. Uniform distribution of the stresses in the compression zone.
3. Considering the assumed rocking behavior of each panel
making up the wall, the compression zone is contained within
the end panel. Size and behavior of the compression zone will
be investigated and refined during the testing.
4. Design options for controlling the length of the compression
zone include increasing bearing area such as by increasing wall
thickness.
5. Influence of floor stiffness above rocking panels is not explicitly
accounted for in the design process. Testing will evaluate if this
effect shall be included.
0
∗ ∗ ∗ ∗ 2 1.3 ∗ ∗ ∗ 2
1.3 ∗ ∗ ∗ 12"/vs=unit shear (kip/ft)
b= panel width (ft)
h= story height (ft)
t=panel thickness (in)
x= compression zone (ft)
w= gravity including weight of the wall (kip/ft)
Design Methodology
Modeling
Using CLT wall test data, Connector parameters can be calibrated to produce accurate wall response using the simplified kinematics model (wall data: Popovski et al, 2010)
• A simplified Kinematics model is used to
determine lateral response of CLT wall under
cyclic loading
• Assumptions
• Rocking behavior
• Limitations
• Inter-story drift
• Wall aspect ratio
• 16-parameter hysteretic model
• Developed at CSU and TAMU
• It allows more adaptive modeling of the degradation behavior of the wood shearwall components
Modeling
Backbone curve for EPHM hysteresis Degradation of loading paths
(Pei and van de Lindt, 2009)
Modeling
-6 -4 -2 0 2 4 6
-4
-3
-2
-1
0
1
2
3
4
Displacement (in.)
Forc
e (
kip
)
Test
Fit
Hysteresis for the 2ft CLT panel tested at CSU
0 1 2 3 4 5 6 7 8 9 100
0.5
1
1.5
2
2.5
3x 10
4
Roof Drift (in.)
Base S
hear
(lbs)
Static Pushover and Dynamic Analysis
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 50
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Fragility parameters (lognormal)µLn
=0.78492
σLn=0.64026
Pro
babili
ty
Sa
0 1 2 3 4 5 6 70
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Maximum Story Drift(%)
ST (
g)
Collapse
Margin Ratio
Overstrength factor
Period based ductility
Performance Evaluation
Sources of Uncertainty-Four Contributors
• Record-to-Record Variability
(βRTR = 0.4)
• Design Requirements
• Quality of Test Data
• Quality of Analytical Model
Adjusted Collapse Margin Ratio
Spectral Shape Factor
Collapse Margin Ratio
SSF to account for rare ground motions in the
Western United States with distinctive spectral shape
different from design spectrum in ASCE/SEI 7-05
Baker and Cornell (2006)
Sources of Uncertainty
Peer Panel
Tests Planned
Height, h Length, b h/b # Plys Thickness Number of
tests
Isolated wall tests
3.05 m (10’ 0”) 1.52 m (5’ 0”) 2.0 5 169 mm (6.65”) 2
2.44 m (8’ 0”) 0.61 m (2’ 0”) 4.0 3 99 mm (3.9”) 2
2.44 m (8’ 0”) 1.22 m (4’ 0”) 2.0 3 99 mm (3.9”) 2
2.44 m (8’ 0”) 2.44 m (8’ 0”) 1.0 3 99 mm (3.9”) 2
2.44 m (8’ 0”) 0.61 m (2’ 0”) 4.0 5 169 mm (6.65”) 2
2.44 m (8’ 0”) 2.44 m (8’ 0”) 2.0 5 169 mm (6.65”) 2
2.44 m (8’ 0”) 1.22 m (4’ 0”) 2.0 7 239 mm (9.41”) 2
Two wall tests2.44 m (8’ 0”) 8’ 0” 1.0 5 175 mm (6.9”) 2
Box type configuration2.44 m (8’ 0”) 2.44 m (8’ 0”) 1.0 5 175 mm (6.9”) 2
2.44 m (8’ 0”) 1.22 m (4’ 0”) 2.0 5 169 mm (6.65”) 2
2.44 m (8’ 0”) 0.61 m (2’ 0”) 4.0 5 169 mm (6.65”) 2
3-sided wall configuration
with a diaphram
2.44 m (8’ 0”) 0.61 m (2’ 0”) 4.0 5 169 mm (6.65”) 2
Isolated wall test setup (out-of-plane bracing not shown) Wall with multiple panels test setup (out-of-plane bracing not shown)
Two wall assemblies with a diaphragm (weight will be placed on the
diaphragm in lieu of force controlled actuators)Box type configuration with a diaphragm (cloverleaf loading)
Box type configuration with a diaphragm using 0.6 m x 2.4 m (2’x 8’)
panels
Box type configuration with an opening
Tests Planned
Test Type Objective
Isolated Wall Tests • Aspect ratio
• Range of connector thicknesses
• Connector spacing
• CLT wall thickness
• Holddowns
• Vertical joints
Two wall tests • Effect of diaphragm on wall behavior
• Diaphragm behavior
Box type
configuration
• Effect of out-of-plane loading on the connector
• Effect of bi-directional loading
• Holddowns in the corners
• Stability of the walls
Box type
configuration with
multiple panel walls
• Effect of out-of-plane loading on the connector
• Effect of bi-directional loading
• Holddowns in the corners
• Stability of the walls
• Vertical joints between perpendicular walls will
also be investigated
3-sided wall with a
diaphragm
• Effect of diaphragm rotation
• Combined loading on the connectors
Tests Planned
Test Performed at CSU
Test Performed at CSU
Tests Performed at CSU
Tests Performed at CSU
Tests Performed at CSU
Note: Gravity Load of 1.7 kip
Tests Performed at CSU
Illustrative example
ELF Design Methodology Modeling
Nonlinear Analysis
Static pushover and dynamic
analysis
Obtain parameters for the walls
and model the building using
SAPWood
Design the archetype model
using the design methodology
Obtain shear forces for the
archetype model
Performance evaluation
CMR and ACMR
Illustrative example
Illustrative example
-8 -6 -4 -2 0 2 4 6 8-20
-15
-10
-5
0
5
10
15
20
Displacement (in)
Forc
e (
kip
)
Test
16 Par. fit
Illustrative example
Ω ! 4.18
"#,%&& !'()* ∗ maxT, /0= 2.6 in.
10,2∑ 4510,560∑ 4560 10,57
μ9 :.:;<.7.:;<. 2.54
/0 0.76?@T 0.6?@
0 1 2 3 4 5 6 7 8 9 100
50
100
150
200
250
300
Roof Drift (in)
Forc
e (
kip
)
Vmax
=292 kip
0.8 Vmax
δu= 6.6 in.
V=69.68 kip
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 50
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Pro
babili
ty
Sa (g)
Illustrative example
SCT=2.37 g
A BCDBED
7.FG'0.H' 1.58
IA JJK ∗ A 1.17 ∗ 1.58 1.85
0 1 2 3 4 5 6 70
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Maximum Story Drift(%)
ST (
g)
SMT
=1.5 g
SCT
=2.37 g
Illustrative example
N9O9 NP9P7 NQP7 N9Q7 NRQS7 0.7
NP9P 0.1 0.1 ∗ T9 ≤ 0.4NP9P 0.1 0.1 ∗ 2.54 0.354
On average for
performance group
For any one
archetype
IA 1.85 > 1.8 ⇒ YZ
Illustrative example
Overstrength Factor
The value of the system overstrength factor, Ωo, for use
in design should not be taken as less than the largest average value of
calculated archetype overstrength, Ω, from any performance group
Deflection Amplification Factor
inherent damping may be assumed to be 5 percent of critical, and a
corresponding value of the damping coefficient, BI= 1.0
• Funding for the P695 study is provided by a cooperative agreement to Colorado State University from the USDA Forest Products Laboratory. That support is gratefully acknowledged. In-kind product has was provided by Structurlam and Nordic. The donation of that CLT is appreciated by the project team.
• Funding for the Smart Manufacturing project at WSU is provided by USDA.
• Funding for the NEES Tall CLT project is provided by the National Science Foundation through five collaborative grants.
Acknowledgements
