Update on the Development of CLT Seismic Design

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 Pei
Colorado School of
Mines
Jeffrey Berman
University of
Washington
Daniel Dolan
Hans-Erik Blomgren
Washington State
University
Arup
James Ricles
John van de Lindt
Lehigh University
Colorado State
University
Richard Sause
Lehigh University
Marjan Popovski
FP Innovations
Douglas Rammer
Forest Products Lab
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
Over strength factor, Numerical
modeling methods, q factor
CLT
Invented
in early
1990’s
Research
in Slovenia
and
Macedonia
Wall tests,
Shake
table test
of wall
assembly
Trento
Province,
Italy
SOFIE
project
Wall tests,
Shake table
tests at NIED
3-story, 7story
Estimation of R
factor for NBCC and
ASCE7
Research on
CLT
FPInnovation
& Forest
Products Lab
P695 on CLT
shear wall
Seismic
Retrofit
(NEESSoft)
CLT
handbook
NEES CLT
Planning
Resilient Timber systems
in NZ
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.edu
Shiling Pei
Dan Dolan
Marjan Popovski
James Ricles
Richard Sauce
Michael Willford Hans-Erik Blomgren
Jeffrey Berman
John van de Lindt
Douglas Rammer
Plan and Vision
Develop
Performance
Based Seismic
Design procedures
Resilient system
prototyping and
component
testing
2014-2016
Finalize and verify
design
methodology
Full scale system
level tests
validation
2016-2019
Establish
Performance
Objectives
2020
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
Tall CLT Building
Workshop
Seattle January 2014: Learn
from practitioner and enduser 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 CLT2020
Activity Description
Action group
Continue growing local production of CLT
Manufacturers
Ramp up engineering education and outreach
to architects and engineers, leveraging on the
Wood industry groups
Canadian experiences
Familiarize the public and contractors with the
use of CLT through component level
Engineers and Architects
implementation, hybrid systems, etc.
Developing methods to compare CLT building
system to conventional non-combustible Engineers, architects, and
systems to provide a basis for fire safety
building officials
equivalency
Confirm and expand fire rating data and Researchers (Material and fire
methodology
focus)
Research development
resilient CLT systems
of
the
prototype
Continue working on CLT shear wall Code
adoption for ASCE7 via application of FEMA P-
Researchers and design
professionals (Structural focus)
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 Members
Project Team
Peer Review Panel
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
Shiling Pei, Ph.D. P.E.
Assistant Professor
Department of Civil and
Environmental Engineering
Colorado School of Mines
Codes and Standards
Seismic behavior of wood
Project
Member
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
Member
Charlie Kircher, Ph.D., P.E.
Principal and Owner
Charles Kircher & Associates
Expertise
Structural and earthquake
engineering, focusing on
vulnerability assessment,
risk analysis and innovative
design solutions
Role
Panel
Chair
J. Daniel Dolan, Ph.D., P.E.
Professor
Department of Civil and
Environmental Engineering
Washington State University
Dynamic Response of LightFrame Buildings
Panel
Member
Full-Scale Static, Cyclic, and
Dynamic Testing of
Structural Assemblies
Numerical Modeling of
Structural and Material
Response to Static and
Dynamic Loading
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 Development
Design Space
Representative of typical
residential and commercial
structures in the U.S.
Archetype Configurations
Prototypical representation of a
seismic-force-resisting system
Archetype Designs
Index archetype configurations
Designed and detailed using the
design requirements
Archetype Models
Mathematical idealization of the
proposed system
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.
Design Methodology
0
∗
∗
∗
∗
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)
∗
2
Modeling
• 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
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)
Modeling
• 16-parameter hysteretic model
• Developed at CSU and TAMU
• It allows more adaptive modeling of the degradation
behavior of the wood shearwall components
Backbone curve for EPHM hysteresis
(Pei and van de Lindt, 2009)
Degradation of loading paths
Modeling
4
3
Force (kip)
2
1
0
-1
-2
-3
Test
Fit
-4
-6
-4
-2
0
2
Displacement (in.)
4
6
Hysteresis for the 2ft CLT panel tested at CSU
Static Pushover and Dynamic Analysis
4
3
x 10
Overstrength factor
2.5
Base Shear (lbs)
2
Period based ductility
1.5
1
0.5
0
0
1
2
3
4
5
6
Roof Drift (in.)
7
8
9
10
5
1
4.5
0.9
4
0.8
Fragility parameters (lognormal)
0.7 µLn=0.78492
σ Ln=0.64026
3.5
Probability
S T (g)
3
2.5
2
0.6
0.5
0.4
1.5
0.3
1
0.2
0.5
0.1
0
Collapse
Margin Ratio
0
0
1
2
3
4
Maximum Story Drift(%)
5
6
7
0
0.5
1
1.5
2
2.5
Sa
3
3.5
4
4.5
5
Performance Evaluation
Collapse Margin Ratio
Spectral Shape Factor
Adjusted 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-Four Contributors
• Record-to-Record Variability
(βRTR = 0.4)
• Design Requirements
• Quality of Test Data
• Quality of Analytical Model
Sources of Uncertainty
Peer Panel
Tests Planned
Height, h
Length, b
h/b
# Plys
Thickness
Number of
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 tests
2.44 m (8’ 0”)
8’ 0”
1.0
5
175 mm (6.9”)
2
Box type configuration
2.44 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
2.44 m (8’ 0”)
0.61 m (2’ 0”)
4.0
5
169 mm (6.65”)
2
Isolated wall tests
3-sided wall configuration
with a diaphram
Tests Planned
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
Effect of diaphragm on wall behavior
Diaphragm behavior
•
•
•
•
Effect of out-of-plane loading on the connector
Effect of bi-directional loading
Holddowns in the corners
Stability of the 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
•
•
Effect of diaphragm rotation
Combined loading on the connectors
Two wall tests
Box type
configuration
Box type
configuration with
multiple panel walls
3-sided wall with a
diaphragm
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
Obtain shear forces for the
archetype model
Design Methodology
Design the archetype model
using the design methodology
Nonlinear Analysis
Performance evaluation
Static pushover and dynamic
analysis
CMR and ACMR
Modeling
Obtain parameters for the walls
and model the building using
SAPWood
Illustrative example
Illustrative example
20
15
Force (kip)
10
5
0
-5
-10
-15
-20
-8
Test
16 Par. fit
-6
-4
-2
0
2
Displacement (in)
4
6
8
Illustrative example
300
Vmax=292 kip
250
0.8 Vmax
Force (kip)
200
150
100
V=69.68 kip
50
δ u= 6.6 in.
0
0
1
2
3
4
5
6
7
8
9
Roof Drift (in)
Ω
"#,%&&
!
μ9
4.18
!
'
()*
∑6
0 45 10,5
10,2 6
7
∑0 45 10,5
∗ max T, /0 = 2.6 in.
T
/0
:.:;<.
7.:;<.
2.54
0.6 ?@
0.76 ?@
10
Illustrative example
1
4.5
0.9
4
0.8
3.5
0.7
Probability
5
ST (g)
3
SCT=2.37 g
2.5
2
SMT=1.5 g
0.6
0.5
0.4
0.3
1.5
SCT=2.37 g
0.2
1
0.1
0.5
0
0
0
1
2
3
4
5
6
7
Maximum Story Drift(%)
A
I
A
BCD
BED
JJK ∗
7.FG'
0.H'
A
1.58
1.17 ∗ 1.58
1.85
0
0.5
1
1.5
2
2.5
Sa (g)
3
3.5
4
4.5
5
Illustrative example
NP9P
0.1
NP9P
0.1
0.1 ∗ T 9 ≤ 0.4
0.1 ∗ 2.54
N9O9
7
NP9P
I
1.85 > 1.8 ⇒ YZ
A
7
NQP
0.354
7
N9Q
7
NRQS
0.7
On average for
performance group
For any one
archetype
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
Acknowledgements
• 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.
Thank you.
Contact information:
Prof John W. van de Lindt
[email protected]

Download Report