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AN ABSTRACT OF THE THESIS OF
Jeffrey D. Langlois for the degree of Master of Science in Civil Engineering and
Wood Science presented on January 31, 2002.
Title: Effects of Reference Displacement and Damage Accumulation in Wood
Shear Walls Subjected to the CUREE Protocol.
Abstract approved: ___________________ and __________________
Rakesh Gupta Thomas H. Miller
The objectives of this study are: (1) to evaluate the effect of reference
displacement on wall behavior under fully reversed cyclic loading using the
CUREE test protocol and (2) to assess damage accumulation (visible fastener
damage and stiffness degradation) for the imposed drift levels. All tests were
conducted on identical 2440 x 2440 mm (8 x 8 ft) wall specimens constructed of
Douglas-Fir studs and oriented strand board (OSB) panels. Sheathing was fastened
to the framing with pneumatically driven, SENCO annular ring shank nails. The
CUREE (Consortium of Universities for Research in Earthquake Engineering)
cyclic test protocol for ordinary ground motions was employed as a means to study
the racking response of the wood shear walls. Four sets of tests, each consisting of
two wall specimens, were conducted using four different reference displacements.
Results show that reference displacement can influence wall strength by up to 15%
while there was little or no effect on stiffness and area under the backbone curve. A
trend of increasing strength and ultimate displacement with increased reference
displacement was observed for the first three sets of tests. It was found however
that this trend did not hold true for the fourth set of tests with the largest reference
displacement.
Additional tests using a segmented version of the CUREE protocol
provided a way to correlate visible damage and stiffness degradation to imposed
drifts. Results show that while visible damage was minimal at drifts as high as 1%,
(8% of nails slightly damaged), a 52% reduction in secant stiffness had occurred. In
general, it was observed that significant softening of the wall could occur with only
minimal signs of visible damage to the sheathing fasteners.
Effects of Reference Displacement and Damage Accumulation in Wood Shear
Walls Subjected to the CUREE Protocol
by
Jeffrey D. Langlois
A THESIS
Submitted to
Oregon State University
in partial fulfillment of
the requirements for the
degree of
Master of Science
Presented January 31, 2002
Commencement June 2002
Master of Science thesis of Jeffrey D. Langlois presented on January 31, 2002 APPROVED: Co-Major Professor Representing Civil Engineering Co-Major Professor Representing Wood Science Head of Department of Civil, Construction and Environmental Engineering Head of Department of Wood Science and Engineering Dean of Graduate School I understand that my thesis will become part of the permanent collection of Oregon State University libraries. My signature below authorizes release of my thesis to any reader upon request.
Jeffrey D. Langlois, Author
ACKNOWLEDGEMENTS
It took the help and advice of a great many people to make this
accomplishment possible. While I cannot hope to thank everyone who assisted me
throughout my time at Oregon State, the following are acknowledged for their
support.
Milo Clauson for providing invaluable technical advice and endless hours
of help using the laboratory and hydraulic equipment.
Dr. Tom Miller and Dr. Rakesh Gupta for their guidance and enthusiasm in
designing and implementing this project.
Dr. Robert Leichti for a great deal of insightful counsel on wood mechanics
and the experimental research process.
Dr. David Rosowsky for his helpful advice and correspondence with
happenings within the CUREE-Caltech Woodframe Project.
Dr. Chris Higgins for his advice with modeling and analysis.
Dr. Jim Wilson for sharing his expert knowledge on structural wood panels
and steelhead fishing as well as the use of his function generator.
Dr. Dan Dolan of Virginia Polytechnic Institute for his guidance and
expertise in timber engineering.
Fellow graduate students Dana Lebeda, Eric Sakimoto, Rainer Staehle and
Alfred Tjahyadi for their assistance in fabricating wall specimens and help
with experiment preparation.
Louisiana Pacific Co. for donating the lumber and OSB panels.
Simpson Strong-Tie Co. for donating the hold-down and base plate
hardware.
TABLE OF CONTENTS
INTRODUCTION…………………………………………………………. 1 MATERIALS AND METHODS………………………………………….. 9 WALL SPECIMENS………………………………………………. 9 LOAD FRAME AND TEST EQUIPMENT………………………. 11 LOADING PROTOCOL……………………………………………13 Static Tests………………………………………………… 13 CUREE Protocol…………………………………………… 14 REFERENCE DISPLACEMENT STUDY………………………... 15 DAMAGE ACCUMULATION STUDY………………………….. 15 DATA ANALYSIS………………………………………………… 17 Load-Displacement Curves………………………………… 17 Stiffness………………………………………………….….17 Area Under Backbone Curve………………………………. 18 Qualitative Damage…………………………………………18 RESULTS AND DISCUSSION…………………………………………… 19 STATIC TESTS……………………………………………………. 19 CUREE TESTS……………………………………………………. 24 Reference Displacement Study…………………………….. 24 Damage Accumulation Tests……………………………… 31 CONCLUSIONS AND RECOMMENDATIONS…………………………37 BIBLIOGRAPHY………………………………………………….. ……... 40
TABLE OF CONTENTS, Continued
APPENDICES……………………………………………………………... 42 APPENDIX A: Loading Frame Photos……………………………………. 43 APPENDIX B: Cyclic Loading Data Tables………………………………. 46 APPENDIX C: Backbone Curves………………………………………….. 60 APPENDIX D: Sheathing Nail Damage Details…………………... ……... 66 APPENDIX E: Damage Photos……………………………………. ……... 83 APPENDIX F: Data Figures ………………………………………. ……... 96
LIST OF FIGURES
Figure Page 1 Shear Wall Specimen……………………………………………… 10 2 Load Frame and Shear Wall Specimen……………………………. 12 3 Data and Reference Displacements from Load-Displacement Curves……………………………………………………………… 13 4 CUREE Test Protocol for Ordinary Ground Motions…………….. 14 5 Segmented CUREE Protocol for Damage Accumulation Study…... 16 6 Load-Displacement Curves and Reference Displacements from Static Tests…………………………………………………………. 20 7 Reference Displacement Study, Backbone and Monotonic Curves.. 26 8 Damage at NEHRP Performance Levels in Segmented CUREE Protocol…………………………………………………………….. 34 9 Secant Stiffness at NEHRP Performance Level Drift Values from
Averaged Backbone Curve of the Damage Accumulation Tests….. 35
LIST OF TABLES
Table Page 1 Designations and Protocols for Wall Tests………………………… 16 2 Results from Monotonic Tests…………………………………….. 19 3 Strength Comparisons, Ring-Shank vs. Smooth-Shank Sheathing
Nails……………………………………………………………….. 22 4 Reference Displacement Values from Monotonic Tests…………... 25 5 Results from CUREE Tests……………………………………….. 27 6 Sheathing Nail Failure Modes as % of Total Nails from CUREE Tests……………………………………………………………….. 29 7 Damage Characteristics at NEHRP Performance Levels…………. 32 8 Mean Results of Tests DA.1 and DA.2……………………………. 33
1
Effects of Reference Displacement and Damage Accumulation in Wood Shear Walls Subjected to the CUREE Protocol
INTRODUCTION
In the United States, wood frame construction has long been the standard
for residential and low-rise commercial structures. Reducing the damage to these
structures caused by earthquakes would significantly reduce both the economic and
natural resource demands imposed by a growing population’s need for safe and
durable buildings. In general, low structural mass, ductility and overall redundancy
of these structures have contributed to wood’s generally favorable seismic track
record. However, losses in wood frame structures during the 1994 Northridge
earthquake resulted in 24 deaths and over $20 billion in property damage (Seible et
al. 1999). Better understanding the behavior of wood structures during earthquakes
by means of analytical and experimental research is essential to reducing losses
during seismic events of this nature.
In light-frame wood structures, shear walls are the primary lateral force
resisting system. As a result, studying their racking behavior under cyclic loading is
fundamental to understanding the response of wood buildings to earthquakes. Thus,
a great deal of experimental research using numerous standard and nonstandard
cyclic test methods has been conducted on wood shear wall systems. Due to the
vast amount of information available on how physical properties affect shear wall
behavior, no attempt is made here to provide a holistic review of the literature
available. Salenikovich (2000) provides a thorough overview of the physical
2attributes governing wall performance. In general, fastener type and spacing,
sheathing thickness, aspect ratio and hold-down anchorage are the most important
factors governing wall response to lateral loading.
Of particular interest is the fact that the lateral load capacities of wood shear
walls have generally been established from the results of monotonic tests (Dolan
1994). In these standard tests, wall specimens are subjected to a static,
unidirectional ramp loading not representative of the short duration, random,
reversing loads experienced during an earthquake. Following the Northridge
earthquake, it was decided by the City of Los Angeles, Department of Building and
Safety, that the allowable unit shears (design loads) for wood panel shear walls be
reduced by 25% (Rose 1998). The desire to fully understand whether or not this
reduction will improve the performance of wood structures during earthquakes has
spawned a great deal of research aimed at developing destructive tests more
representative of the loading actually experienced during a seismic event.
While monotonic tests have generally been the basis for establishing design
values, more realistic loading schemes have also been employed to study the
response of wood shear walls to seismic loads. Dolan (1989) conducted shake table
tests on twenty-five, 2440 x 2440 mm (8 x 8 ft.) wall specimens using acceleration
records from actual earthquakes. Results from these tests showed that panel type
(wafer board or plywood), and applied vertical load had little effect on wall
response. It was also noted that without significant scaling of the acceleration
records, shake table tests employing actual historic ground motion records
3generally do not fail the wall specimens and therefore do not provide information
regarding strength or overall ductility.
Dean et al. (1988) conducted dynamic shake table tests on 2440 x 2440 mm
shear walls to compare actual hysteretic behavior to that of an idealized single
degree of freedom model and check seismic provisions of the New Zealand
building code. They subjected four specimens to sinusoidal ground motions and
three specimens to the NS component of the 1940 El Centro earthquake scaled up
by 20%. They noted that walls sheathed with 12.7 mm (0.5 in.) plywood showed a
predominant damage mode of nail withdrawal from the framing members while
damage to walls sheathed with 7.5 mm (0.3 in.) plywood was characterized by
crushing of the sheathing around the nails.
More recently, shake table tests were conducted by Yamaguchi and Minowa
(1998). Their perforated shear wall specimens consisted of two 900 x 2700 mm (3
x 9 ft.) sheathed framing sections separated by a 1800 mm (6 ft.) opening
connected by the top and bottom plates. They noted that the dynamic tests
produced higher ultimate strength and lower ductility than observed in quasi-static
cyclic tests. The ultimate displacement of the dynamic tests was found to be 50% of
that in the quasi-static tests. They speculated that the slower loading rate associated
with quasi-static testing allowed walls to creep and therefore attain higher
displacements at peak load. Common failure mechanisms observed were nails
withdrawing from the framing and nail heads pulling through the sheathing.
4As an alternative to shake table testing, cyclic quasi-static test methods have
proved to be a relatively simple and economic means of experimentally
investigating the response of structural components to reversed loading. Generally,
tests are displacement controlled and consist of a gradually increasing, saw tooth
displacement schedule defined by a series of loading sequences. A sequence
consists of either several cycles of the same amplitude or a primary cycle followed
by several trailing cycles defined as a fraction of the primary cycle. In most cases,
these cycle amplitudes are explicitly related to a reference displacement based on
performance criteria extracted from static testing. A gradual increase of amplitude
from sequence to sequence provides a holistic behavioral record covering response
at low drifts as well as post-failure deformations.
In addition to reduced cost and simplicity, another advantage of quasi-static
testing over shake table tests is the potential to provide a consistent basis for the
development of design models and provisions for building codes (Leon and
Deierlein 1996). Currently however, the primary limitation of applying this
approach to wood shear walls has been the lack of a nationally recognized standard
cyclic test protocol. A positive aspect of this dilemma has been the movement by
several researchers to promote a general consciousness regarding the effects of
cyclic loading protocol characteristics on wall response.
Dinehart and Shenton (1998) compared the monotonic and cyclic response
of 2440 x 2440 mm plywood and OSB shear walls. They used ASTM E 564
(ASTM 2000) and the sequential phase displacement (SPD) cyclic protocol
5adopted by the Structural Engineers Association of Southern California (SEAOSC
1996). They concluded that the 30% drop in peak load observed between the first
and fourth cycle in each sequence of the SPD tests warranted a 25% reduction in
allowable unit shears based on monotonic tests.
Karacabeyli and Ceccotti (1998) tested 4880 x 2440 mm (16 x 8 ft)
plywood shear walls under 5 different cyclic protocols (SPD, CEN-Long, CEN-
Short, FCC and ISO), and compared them with monotonic and pseudo-dynamic
tests. The pseudo-dynamic tests consisted of displacement schedules based on
predictions from nonlinear time history analyses employing actual ground motion
records as input. They noted that long sequence protocols with the highest energy
demand, such as the SPD and the Forintek Canada Corporation (FCC) cyclic
procedure, result in lower displacements at peak load and generate nail fatigue
fractures, a failure mode never witnessed as a result of an actual earthquake or a
simulation on a shake table. They also found that using actual ground motion
records to conduct pseudo-dynamic tests gave wall strengths 15% higher than both
monotonic and cyclic tests. Based on this finding, and contrary to the
recommendations of Dinehart and Shenton (1998), they suggest that design
capacities for earthquake loading can safely be based on the first cycle envelope or
monotonic curve.
A similar study comparing cyclic test protocols was conducted by He et al.
(1998). They tested shear walls using two variations of the European cyclic tests
(CEN-Long and CEN-Short), the FCC protocol, as well as a new cyclic protocol
6they developed. They concluded that large amplitude, short sequence cyclic loading
such as the CEN-short and the new protocol results in strength values similar to the
monotonic curve and also produces failure modes comparable to those observed in
post earthquake inspections.
As part of the CUREE-Caltech Wood Frame Project, a recent draft report
by Uang (2001) provides a thorough overview of cyclic test protocols employed in
the past and compares the demands of two commonly used protocols (SPD and
ISO) to that of the newly developed CUREE protocol. They reported that schedules
with long sequence, equal amplitude cycles, such as SPD, impose unrealistic
energy demands and cause fatigue fractures of the sheathing nails. It was noted that
while the ISO protocol produced far fewer nail fatigues than the SPD tests, the
equal amplitude cycle groups in the displacement schedule may be too demanding
on the fasteners and give overly conservative estimates of strength and ductility.
They observed that the CUREE protocol appears to produce failure modes
consistent with observed seismic behavior and concluded that it is the most
appropriate for application to wood shear walls. Developed by Krawinkler et al.
(2000), the loading history captured in the CUREE protocol was derived from the
results of extensive nonlinear dynamic analyses. Time history responses were
transformed into deformations using cumulative damage techniques and served as
the basis for the displacement schedule presented (Krawinkler et al. 2000). The
CUREE protocol is the first of its type in that it is tailored specifically to wood
structural components and is based on the hysteretic response of wood frame
7structures. Thus, the author feels it is the most appropriate for application in
studying woodframe shear walls.
A key element of all cyclic test protocols in use (i.e. SPD, ISO, CEN, FCC,
CUREE, etc.) is the selection of a reference displacement governing the cycle
amplitudes throughout the entire test. In the case of the CUREE protocol, the
reference displacement is extracted from a monotonic load-displacement curve for
the wall specimen. Currently, the CUREE recommendation is to take the reference
displacement as 60% of the wall’s deformation capacity. The deformation capacity
is designated as the displacement at which the load drops to 80% of peak. While
this definition is provided in the CUREE report (Krawinkler et al. 2000), there is no
explanation provided for the selection of this value as the deformation capacity for
shear walls
Dolan (2001) provided an explanation for defining the displacement
capacity at the 80% post peak load position. The decision was based on the logic
that it is at this point that structural elements close to the overstressed wall system
(i.e. elements picking up load shed by the shear wall) would also be reaching
capacity. This criterion is also convenient in that it is consistent with European
standards as well as those found in steel and reinforced concrete testing standards
(Dolan 2001).
Uang (2001) concluded, “Even when a well defined procedure is provided
to determine reference displacement, considerable judgment is often required”.
Little is known about the effect of reference displacement on wall response.
8Because the reference displacement dictates the entire displacement schedule for
the protocol, it is important to understand the impact of the reference displacement
on wall performance.
With the increasing emphasis of performance-based seismic design comes a
need to accurately correlate damage symptoms to quantifiable performance
parameters of structural elements. To date, there have been few efforts to
experimentally develop such a relationship for wood shear walls. While much has
been experimentally noted regarding overall, end condition failure modes of shear
walls, no studies to our knowledge have been aimed to explicitly understand the
deterioration of sheathing-to-stud connections at various stages of loading.
Utilizing a modified, segmented version of the CUREE test, we were able to assess
both visible damage and stiffness degradation as a function of imposed story drifts,
a quantity likely to be used in evolving performance based design methods.
Specifically, the objectives of this study are:
1) To investigate the effect of reference displacement on wall behavior using
the CUREE cyclic protocol.
2) To correlate visible damage of the sheathing fasteners and stiffness
degradation to imposed story drifts for each individual loading sequence
within the CUREE protocol.
9MATERIALS AND METHODS
WALL SPECIMENS
All tests were conducted on identical wall specimens representative of
engineered construction practices in the U.S. A schematic of the wall construction
details is shown in Figure 1. Walls consisted of stud grade Douglas-Fir framing
members sheathed with 32/16 APA rated OSB. All framing and sheathing nails
were manufactured by SENCO pneumatically driven using a SENCO SN 65
framing nailer. Sheathing nails were full round head, strip cartridge, annular ring-
shank nails with a 2.87 mm (0.113 in.) diameter and 60.3 mm (2.38 in.) length.
Framing members were attached with short, full round head, strip cartridge,
smooth-shank nails with a 3.33 mm (0.131 in.) diameter and 82.6 mm (3.25 in.)
length. Sheathing nails were spaced at 102 mm (4 in.) around the panel edges and
305 mm (12 in.) along the field studs. To provide an effective 102 mm nailing
along the outer edges, the double end studs were each nailed at 204 mm (8 in) on
center and staggered to provide equal load transfer into both members. Due to
limited nailing space along the center stud, interior panel edge nailing clearance
was only 9.5 mm (0.375 in.) while all other edges received a clearance of 19 mm
(0.75 in.).
SIMPSON Strong-Tie HTT-16 type hold-downs were installed at the
bottom corners of each specimen. Hold-down brackets were fastened to the double
end studs with eighteen, hand driven, 16d sinker nails and were anchored through
10
Double Top SillAttached w/ 2-16d @ 305 mm o.c.
2440 mm
2440 mm
305 mm711 mm Stud to Sole Plate
Attached w/ 2-16d each(63.5 x 63.5 x 6.35 mm Base Plates)
1.22 by 2.44 m, 11.9 mm
OSB Panels
8d Ring Shank Sheathing Nails102 mm Edge, 305 mm Field
Double End StudsAttached w/ 2-16d
@ 610 mm o.c.
38 x 89mm Studs
@ 406 mm o.c.
Simpson HTT16 Tie-Downs,
18-16d Sinkers w/ 15.9 mm Bolt
15.9 mm A307 Anchor Bolts
Figure 1: Shear Wall Specimen
the sole plate using 15.9 mm (0.625 in.) diameter, Grade 5 steel bolts. Intermediate
anchor bolts installed with 63.5 by 63.5 by 6.35 mm (2.5 by 2 .5 by 0.25 in.)
SIMPSON base plates were symmetrically placed at 305 mm and 711 mm (28 in.)
from each end. While the installed anchorage far exceeds code requirements and
typical construction practice, it was employed as a means of eliminating movement
of the sole plate during testing.
The Uniform Building Code (ICBO 1997) lists the allowable unit shear for
a wall with 11.9 mm (0.47 in.) thick panels and a nail schedule of 102 mm / 305
mm as 5.55 kN/m (380 lb/ft). This value is based on the assumption that 8d
common nails are employed as the sheathing fasteners. Walls in this study were
11sheathed with 8d, annular ring shank nails with an effective diameter slightly
smaller than that of common nails. Since there is no mention of allowable unit
shears for walls employing fasteners other than common nails, it was assumed that
the walls had the same 5.55 kN/m allowable unit shear per UBC Table 23-II-I-1.
LOAD FRAME AND TEST EQUIPMENT
All tests were conducted at the Department of Wood Science and
Engineering’s, Gene D. Knudson Wood Engineering Laboratory at Oregon State
University. Figure 2 shows the test setup and photographs of the loading frame are
provided in Appendix A. Loading was achieved using a 49 kN (110 kip) capacity,
dynamic hydraulic actuator with a 254 mm (10 in.) stroke. The actuator was
mounted to the flange of a W10x112 steel beam vertically fastened to the reaction
wall. A 102 mm diameter hydraulic cylinder was used to support the actuator and
prevent any vertical loading of the walls during testing. A 2700 mm (9 ft.) long,
welded steel section was fitted to the actuator and attached to the double top sill
with 12.7 mm bolts and washers spaced at 305 mm. A lateral brace was used to
prevent any out-of-plane movement of the top sill during testing. All walls were
mounted to a stiff, welded steel fixture heavily bolted to the lab’s reaction floor.
The sole plates of each specimen rested upon a piece of steel channel such that the
sheathing panels were free to rotate in the plane of racking.
12
Wall Specimen Channels
1: Load Cell2: Lateral Displacement3: Diagonal LVDT4: Sill Slip LVDT5: Diagonal LVDT6: Uplift LVDT7: Uplift LVDT
47
3 5 6
1, 2
Roller Track with Lateral Bracing
49 kN MTS Actuator
W10 x 112 Beam
Support CylinderSteel Fixture
Figure 2: Load Frame and Shear Wall Specimen
The hydraulic actuator was driven using the MTS 407 controller. For cyclic
tests, an Analogic 2020 Polynomial Waveform Synthesizer was employed as the
signal source. Load and deflection data were logged from the actuator’s internal
position sensor and load cell. Additional linear variable differential transformers
(LVDTs) were installed to monitor panel racking, corner uplift and sole plate slip.
All data were acquired using a personal computer with an AMD 550 MHz
processor running National Instruments’ Lab View 6.1.
13LOADING PROTOCOLS
Static Tests
Monotonic tests were conducted such that the top sill was laterally
displaced at a rate of 0.25 mm/sec (0.01 in./sec) until failure occurred. Walls were
considered failed when the load dropped to 40% of ultimate. Generally, this
loading rate brought specimens to failure in 5 to 10 minutes. Data was logged at a
rate of 10 Hz during monotonic tests. Three static tests were conducted to
determine the reference displacements for the cyclic CUREE tests.
The reference displacement is taken as 60% of the wall’s monotonic
deformation capacity (∆f), defined as the deformation at which the applied load
drops, for the first time, to 80% of the maximum load that was applied to the
specimen (Krawinkler et al. 2000). Figure 3 shows how reference displacement
(∆ref) is determined from a monotonic load displacement curve.
Displacement
Loa
d
Pmax
0.8Pmax
∆f∆ref
Ko1
E0.4Pmax
0.6 ∆f
∆0.4Pmax
Figure 3: Data and Reference Displacement from Load Displacement Curves
14CUREE Protocol
The CUREE protocol for ordinary ground motion, as shown in Figure 4,
was used to study the cyclic racking behavior of the wall specimens. The protocol
consists of cyclic displacement sequences increasing in amplitude throughout the
test. Each sequence consists of a primary cycle, with amplitude defined as a
multiple of the reference displacement, and is followed by a series of trailing cycles
with amplitudes equal to 75% of the primary cycle. Sequences vary in length from
three to seven cycles. All tests were conducted such that the initial position of the
actuator was at half-stroke, allowing 127 mm (5 in.) maximum deflection in each
direction. All CUREE tests were conducted at a frequency of 0.1 Hz and data were
read at twenty-five times per second.
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
0 100 200 300 400
Time (seconds)
Dis
plac
emen
t (M
ultip
le o
f ∆
ref )
Figure 4: CUREE Cyclic Test Protocol for Ordinary Ground Motions
15REFERENCE DISPLACEMENT STUDY
Based on the results of three monotonic tests, four different reference
displacements were selected for investigating their effect on wall performance. For
each reference displacement, two walls were tested, for a total of eight tests
comprising the reference displacement study. The sample size of two walls is based
on the minimum recommended sample size of ASTM E 2126 (ASTM 2001). These
tests were stopped after forty-three cycles at which point the maximum experienced
deflection is equal to twice the reference displacement (2.0 ∆ref). In cases where this
value exceeded the stroke of the load cylinder, a displacement of 122 mm (4.8 in.)
was employed.
DAMAGE ACCUMULATION STUDY
Two walls were tested using a segmented version of the CUREE test shown
in Figure 5. Between each loading sequence the test was stopped for fifteen
minutes and walls were inspected. These tests were carried out in nine segments for
a total of forty cycles (up to 1.5∆ref).
Findings from both the reference displacement and damage accumulation
studies prompted us to perform a final wall test. The purpose of this test was to
investigate the point in the test where nail fractures were beginning to occur. For
this test the CUREE protocol was run for only thirty-seven cycles. Table 1
summarizes the different loading protocols for all walls tested in this study.
16
-1.5
-1
-0.5
0
0.5
1
1.5
Time (Not to Scale)
Dis
plac
emen
t (M
ultip
le o
f ∆r
ef)
Breaks in Loading Indicate 15 minute Inspection Periods
Figure 5: Segmented CUREE Protocol for Damage Accumulation Study
Table 1: Designations and Protocols for Wall Tests
Wall No. Designation Loading Protocol 1 Mono 1 2 Mono 2 3 Mono 3
Monotonic 0.25 mm/second
4 CUREE 1.1 5 CUREE 1.2 6 CUREE 2.1 7 CUREE 2.2 8 CUREE 3.1 9 CUREE 3.2 10 CUREE 4.1 11 CUREE 4.2
Ordinary CUREE 43 cycles at 0.1 Hz
12 DA.1 13 DA.2
Segmented CUREE 40 cycles at 0.1 Hz
14 CUREE 5 Ordinary CUREE 37 cycles at 0.1 Hz
17DATA ANALYSIS
Load-Displacement Curves
Load displacement curves or load envelopes are the most commonly
employed means of presenting the structural behavior of shear walls. For
monotonic tests, these curves are plotted directly from the acquired load-
displacement data. In the case of cyclic testing, plotting these data show the
hysteresis loops associated with each cycle of loading. From the hysteretic data, a
backbone curve is drawn representing the wall’s load response to the primary cycle
drifts. Points making up the backbone curve are the load at maximum displacement
of each sequence’s primary loading cycle. This provides a consistent basis for
comparing load envelopes from any test protocol. Performance quantities (Peak
Load Pmax, Initial stiffness Ko and area (energy) under the backbone curve E)
extracted from the load envelopes (monotonic or backbone curves) of each test are
outlined in Figure 3.
Stiffness
Initial stiffness (Ko) of the wall specimens was taken at 40% of the ultimate
strength (Fig. 3) such that;
Ko = 0.4 Pmax / ∆@0.4 Pmax
This value is provided as a definition of elastic stiffness in ASTM E 2126 (ASTM
2001) aimed to harmonize with European (CEN) conventions (Salenikovich 2000).
18For the damage accumulation study, secant stiffness from the backbone
curves was calculated at the various load levels associated with the designated
drifts.
Area Under the Backbone Curve Due to highly nonlinear response to lateral loading and lack of a distinct
yield criteria, traditional definitions of ductility based on a yield displacement
become somewhat arbitrary when applied to wood shear walls. As an alternative to
determining ductility, the absorbed energy was calculated as the area enclosed
under monotonic and backbone curves up to the deformation capacity (∆f). This
quantity, E, is shown as the striped region in Figure 3.
Qualitative Damage
Following each test, careful inspections of the sheathing fasteners and
framing connections were made. Figures depicting sheathing nail damage observed
in each test are provided in Appendix D. Damage modes of the sheathing fasteners
were classified into three categories: pull-through (PT) of the nail head through the
sheathing, withdrawal (W) of the nail shank from the sheathing and framing
member, and fatigue (F) fracture of the nail. To more specifically document failure
progression for the damage accumulation study, partial pull-through (PPT) was
defined as any visible recession of the nail head into the sheathing.
19RESULTS AND DISCUSSION
STATIC TESTS
Results from the three monotonic tests are presented in Table 2 and the
load-displacement curves are shown in Figure 6. Initially, two walls (MONO1 and
MONO 2) were tested per the recommendations of ASTM (ASTM 2001). While
these tests showed good agreement in terms of ultimate load (Pmax), initial stiffness
(Ko) and ultimate displacement (∆Pmax), the post peak behavior (∆f and E) of the two
varied considerably. Because of this, the reference displacements (∆ref) obtained
from each test were quite different (i.e. not within 15%). Therefore, a third test was
conducted as recommended by ASTM. Although the strength achieved in test
MONO 3 agreed well with the first two, this test revealed even more variability in
the performance of our specimen (i.e. ∆Pmax, ∆f, ∆ref, Ko and E).
Table 2: Results from Monotonic Tests
Pmax ∆Pmax ∆f K o Ε ∆ref Test kN mm mm kN/mm kN mm mm
Mono 1 41.4 72.2 78.0 2.27 2400 45.7
Mono 2 40.0 73.9 99.3 2.09 3040 61.0
Mono 3 42.9 89.3 125.7 1.54 4100 76.2
AVE 41.4 78.4 101.0 1.97 3180 61.0
20Looking at load displacement curves in Figure 6 and the values of Ko and E
in Table 2 shows that wall behavior varied from stiffer and less ductile (MONO1),
to softer and more ductile (MONO 3). MONO 2 exhibited similar initial stiffness to
MONO 1 only with higher deformation capacity and larger area under the
backbone curve. It appears that the inherent natural variation of wood and nailed
connections caused the three walls to incur damage and fail in different manners
and therefore exhibit different responses.
0
10
20
30
40
0 25 50 75 100 125 150Displacement (mm)
Load
(kN
)
∆ref3∆ref2∆ref1
MONO 1 MONO 2
MONO 3
Figure 6: Load-Displacement Curves and Reference Displacements of Static Tests
21Racking response of each wall was characterized by rotation of the
individual panels relative to the framing. This action induced flexural stresses and
visible double curvature of the top sill. Racking behavior was accompanied by a
tendency of the panels to move away from the framing. At higher load levels, the
uplift and compression forces associated with the lateral loading caused significant
separation of the end studs on the loading side of the specimen and crushing of the
sill plate on the opposite end.
The dominant failure mode of the sheathing nails for the monotonic tests
was pull-through. Photos depicting failures from the monotonic tests are provided
in Appendix E. In test MONO 1, essentially every sheathing nail along the bottom
of both panels completely pulled through the sheathing. Interestingly, little damage
was visible elsewhere on the wall. It appears that failing in this manner caused the
rapid drop in load carrying capacity following peak. Failure of MONO 2 also
appeared to be somewhat localized with severe pull-through damage along the
interior panel edges and top of the south panel. MONO 3 revealed the most evenly
distributed failure throughout the wall assembly with sheathing nail damage along
all four sides of both panels. Failing in this manner appears consistent with the high
deformation capacity observed.
Comparing the results of this study with those of previously published shear
wall tests suggests that the use of ring shank nails as sheathing fasteners can
significantly increase racking strength. Provided in Table 3 are published results
22from monotonic tests of wall configurations very similar to the one used here with
the exception that regular, smooth shank 8d nails were used as sheathing fasteners.
Table 3: Strength Comparison, Ring Shank Vs. Smooth Shank Sheathing Nails
Reported by No. of Walls Difference in Configuration
Mean Strength,
kN (min, max)
Langlois (2002) 3 - 41.4 (40.0, 42.9)
Dinehart and Shenton (1998) 2 8d smooth shank nails 31.9
(30.7, 33.1)
Salenikovich (2000) 2 11.1 mm OSB sheathing 8d smooth shank nails @
152 / 305 mm 24.2
(23.8, 24.7)
Staehle (2001) 3 8d smooth shank nails 29.1 (27.4, 32.1)
Uang (2001) 2
9.5 mm OSB sheathing 8d smooth shank nails
@ 51 mm along outer and top edges of panels
40.0 (38.9, 41.1)
Looking at the results of Dinehart and Shenton (1998) and Staehle (2001),
who tested 2440 x 2440 mm walls with framing configuration, hold down
hardware, nail density, sheathing size and thickness identical to the walls tested in
this study, it appears that ring shank sheathing nails can increase static wall
strength by as much as 40%. The larger difference in strength between walls in this
study and those tested by Salenikovich (2000) is attributed to the variation in
sheathing nail density as well as nail type. However, monotonic test results recently
23reported by Uang (2001) indicate that differences in strength of this magnitude may
occur without the benefit of ring shank nails. They tested walls with thinner OSB
panels and a higher nail density along the top and bottom edges and achieved
strengths comparable to those reported here.
Interestingly, of the studies mentioned in Table 3, only Uang (2001)
reported pull-through to be the dominant failure mode of the sheathing nails. The
other studies reported withdrawal of the nails from the framing members as the
dominant failure mode. The National Evaluation Service, Inc. (NES 1997) reports
that ring shank fasteners have a higher unit withdrawal resistance than smooth
shank fasteners (i.e. 5.25 N/mm of penetration vs. 4.90 N/mm of penetration for a
2.9 mm diameter nail). While the higher withdrawal strength of ring shank nails
may explain the differences between the strengths observed in this study with those
using the same sheathing thickness and nailing schedule, it does not explain the
higher strength and pull through failures reported by Uang (2001). One explanation
for this is the larger penetration depth (and therefore withdrawal capacity) of the
sheathing nails into the framing on account of the thinner sheathing panels.
However, the idea of increased shear resistance on account of thinner sheathing is
contrary to traditional design practice awarding higher design values to thicker
panels. Another possible reason for this discrepancy could be a variation in framing
lumber density, which is known to influence the withdrawal resistance of nails
(NES 1997).
24While comparing sheathing nail performances was not an original objective
of our study, it is important to note the strength increase observed when comparing
our results to those of other researchers reporting lower strength values due to
dominant withdrawal failures of the sheathing nails. Interestingly, an increase in
allowable shear loads for walls assembled with ring shank fasteners is not
permitted by the UBC (ICBO 1997). While future research on this topic is
necessary to further validate our observations, it is possible that the benefit in
performance far outweighs the minimal cost increase of deformed shank fasteners.
CUREE TESTS
Reference Displacement Study
Because the CUREE recommended method for selecting a reference
displacement is directly tied to their definition of deformation capacity (∆f), and we
obtained considerably different values of ∆f from each static test, the reference
displacements from each also differed substantially (∆ref in Table 2 and Figure 6).
For the purpose of investigating the effect of reference displacement on wall
performance, the variability in post-peak behavior we observed provided a good
basis for selecting a suitable range of values. However, it is perceived that such
variations are undesirable when a single appropriate value is sought. Eliminating
this element of judgment in reference displacement selection would not only
simplify the selection process but also improve the comparability of results from
25future research efforts. Monotonic tests performed in this study indicate that a
parameter such as ultimate displacement (∆Pmax) is more repeatable than post-peak
quantities such as the deformation capacity. It appears that using this drift level as a
basis for the reference displacement, (i.e. ∆ref = 0.8∆Pmax), may increase the
consistency of selecting a reference displacement.
Reference displacement values chosen for this study and their relation to the
monotonic results are shown in Table 4. This range (53 to 76 mm) represents the
variability of values from the set of three monotonic tests. The reference
displacement selected for the CUREE 2 tests was taken as the average of all three
tests and turned out to be the same value as averaging the values from tests MONO
1 and MONO 3. The highest value, obtained from test MONO 3, was also used for
the CUREE 4 tests. These tests were performed to investigate the effects of
employing relatively large reference displacements and also for comparison to the
CUREE tests performed by Uang (2001) where this value was used as well.
Additionally, this combination of values was convenient in that reference
displacements for each set of tests was approximately 8 mm (0.3 in.) greater than
that of the previous tests.
Table 4: Reference Displacement Values from Monotonic Tests
Test ∆ref SOURCE
CUREE 1 53 mm Average of MONO1 & MONO2 CUREE 2 61 mm Average of All 3 Tests CUREE 3 69 mm Average of MONO2 & MONO3 CUREE 4 76 mm MONO 3
26Figure 7 displays the average backbone curves (average load at peak
displacement in primary cycles) from each set of tests. This figure illustrates the
slight decrease in strength associated with cyclic testing compared to that of the
monotonic tests. This phenomenon is consistent with the findings of Dinehart and
Shenton (1998) and Dolan and Madsen (1992) investigating the difference of wall
response in cyclic and monotonic tests. The reduced strength of cyclically tested
walls is generally attributed to the more severe loading history associated with fully
reversed displacement cycles.
0
9
18
27
36
45
0 25 50 75 100 125
Displacement (mm)
Load
(kN
)
CUREE1CUREE2CUREE3CUREE4MONO
Figure 7: Reference Displacement Study, Backbone and Monotonic Curves
27A summary of the results from the eight wall tests is shown in Table 5.
Detailed quantitative results and backbone curves for all CUREE tests are provided
in Appendix B. As indicated by Figure 7 and the Pmax values in Table 5, strength
increased with reference displacement for the first three sets of tests. Because all
tests were conducted at the same frequency, the rate of loading for each cycle is
directly tied to the reference displacement. Therefore, it is logical that higher
strengths were achieved on account of the increased load rate associated with
higher reference displacements. Another trend observed for the first three pairs of
tests is that the strength was reached at the respective reference displacement
sequence (i.e. ∆Pmax = ∆ref). Apparently, the damage incurred during the 1.0 ∆ref
loading causes a significant drop in the load capacity observed in the following 1.5
∆ref sequence.
Table 5: Results from CUREE Tests
∆ref Pmax ∆Pmax Ko E TEST mm kN mm kN/mm kN mm
CUREE 1.1 32.6 53 1.9 2380 CUREE 1.2
53 33.9 53 2.1 2740
CUREE 2.1 37.6 61 1.6 2740 CUREE 2.2
61 37.9 61 2.4 3300
CUREE 3.1 38.7 69 2.8 2380 CUREE 3.2
69 39.2 69 2.1 2910
CUREE 4.1 36.0 73 1.8 2330 CUREE 4.2
76 37.9 54 2.4 1970
28Interestingly, both trends mentioned above did not hold true for the CUREE
4 tests. We found that these tests produced strengths lower than that of the CUREE
3 and CUREE 2 tests yet higher than that of CUREE 1. Also, the CUREE 4 tests
tended to fail specimens at displacements lower than the reference displacement
(i.e. ∆Pmax < ∆ref). It appears the higher demands associated with this reference
displacement during loading prior to the 1.0 ∆ref sequence cause more severe
damage than for other tests. Also unique to the CUREE 4 tests, and likely related to
the behavioral difference observed in these tests, was a failure of the center stud.
Because both interior panel edges are nailed to this framing member, it is the most
heavily nailed and therefore receives a high load demand when the wall is racked.
This observation of center stud failure is further discussed in the following text.
Table 6 displays the failure modes of the CUREE tests. Failure modes of
sheathing nails were consistent for all of the eight CUREE tests. Detailed figures
depicting observed failure modes for all CUREE tests are provided in Appendix D.
In 6 of the 8 tests, sheathing nail pull-through was the dominant mode of failure. In
tests CUREE 2.1 and CUREE 3.2, however, fatigue fracture of the nails was the
dominant failure mode. This failure mode was observed in all tests and was found
to be particularly high along the panel edges nailed to the center stud. The apparent
high demand imparted on these interior edges is consistent with recent findings by
Uang (2001). They observed that due to the double nailed exterior panel edges, the
sheathing’s center of rotation is offset towards the area of increased stiffness
(outward) causing increased deformation demand on the lighter nailed interior
29edges. Because the interior edges of both panels are nailed to the center stud, a
particularly high demand is imparted on this framing member. As mentioned
before, inspections following the CUREE 4 tests revealed a rupture of the center
stud at the sole plate connection. It appears that the increase in reference
displacement from the CUREE 3 tests to the CUREE 4 tests crosses a transition
point where rupture of the center stud becomes the controlling mode of failure.
This was particularly noticeable during test CUREE 4.1 where rupture of the center
stud at cycle 35 effectively eliminated the shear transfer capacity to the sole plate
and therefore prevented the heavy damage to interior edges observed in the other
Table 6: Sheathing Nail Failure Modes as % of Total Nails for CUREE Tests
TEST PT W F CUREE 1.1 46% 14% 19%
CUREE 1.2 42% 5% 21% CUREE 2.1 28% 14% 32%
CUREE 2.2 28% 13% 26% CUREE 3.1 35% 14% 22%
CUREE 3.2 35% 21% 39% CUREE4.1 36% 9% 8%
CUREE 4.2 44% 6% 23% PT = nail pull-through the sheathing panel W = withdrawal of the nail from the framing member F = fatigue fracture of the nail
30seven tests. This phenomenon of center stud damage on account of larger reference
displacements is a likely cause of the lower strength and ultimate displacement
values observed in the CUREE 4 tests.
Interestingly, a draft report presenting the results of recent tests conducted
at the University of California at San Diego (Uang 2001) highlights the fact that
nail fatigue was not observed in any of the CUREE tests they conducted. Potential
explanations for this discrepancy with our results include differences in sheathing
thickness and fastener types. Uang’s CUREE study (Uang 2001) tested walls with
an effective edge nailing density of 51mm (2 in.) and 9.5 mm (0.375 in.) thick OSB
sheathing. It is known that thinner sheathing panels are more susceptible to pull-
through while thicker panels are more likely to produce nail fractures (Salenikovich
2000). While the UCSD testing program included walls sheathed with plywood
similar in thickness to the specimens in this study (12.2 mm), the OSB walls tested
used 9.5 mm (0.375 in.) thick panels (Uang 2001). It is also possible that a lack of
nail slip on account of the higher withdrawal resistance of the ring shank nails
caused repeated flexural cycling at the same point along the nail’s shank. We
observed that the fatigued nails consistently fractured at the interface of the smooth
and deformed shank sections. Finally, it is known that the total number of cycles
experienced by the wall directly affects the failure mode of the sheathing nails (He
et al. 1998). It is possible that post failure cycling of the wall specimen can induce
nail fatigues that were not the actual failure mechanism of the wall. This issue was
investigated as part of the damage accumulation study presented next.
31
Damage Accumulation Tests For the damage accumulation tests, (DA.1 and DA.2 in Table 1), a reference
displacement of 76 mm was employed. This value was selected for the sake of
further investigating the center stud failures and relatively lower strength and
ultimate displacement values observed in the CUREE 4 tests.
Results of damage accumulation tests including sheathing nail damage,
shear load and stiffness loss associated with the various drift levels in the
segmented CUREE protocol are presented in Table 7. As shown in Table 7, for
loads as high as 1.3 times the allowable unit shear (0.3% drift), no damage to the
walls was visible even though 8% of the initial stiffness was lost. Interestingly, we
found this to be consistent throughout the tests, i.e. significant stiffness loss could
occur with minimal signs of qualitative damage.
Like the CUREE 4 tests, we found that both DA tests failed specimens at
displacements lower than the reference displacement as well as produced failure of
the center stud to sole plate connection. It appears that the higher drifts associated
with this large a reference displacement cause walls to fail in this manner.
To further highlight the usefulness of this type of segmented cyclic testing,
we have documented damage accumulation at drifts close to those outlined by the
National Earthquake Hazards Reduction Program (NEHRP) Guidelines for the
Seismic Rehabilitation of Buildings as typical performance level responses. Table
2-4 in the NEHRP Guidelines (FEMA 1997) provides transient drift values of 1, 2
and 3% as typical response parameters at the Immediate Occupancy (IO), Life
32Safety (LS) and Collapse Prevention (CP) performance levels, respectively. These
performance levels are provided by the NEHRP guidelines as criteria to designate
appropriate structural resistance to earthquakes of various intensity and probability.
Table 7 provides a brief description of the three limit states taken from the NEHRP
literature (FEMA 1997). Figure 8 illustrates the occurrence of the three limit state
drifts in the segmented CUREE test employing a reference displacement of 76 mm
(3 in.). Data from the damage accumulation study related to these performance
levels are highlighted by bold font in Table 8, with secant stiffness at the 3 drift
levels shown in Figure 9.
Table 7: Damage Characteristics at NEHRP Performance Levels (FEMA 1997)
Component: Collapse Prevention Life Safety Immediate Occupancy
General
Little residual stiffness and strength, but load bearing columns and walls functional. Large permanent drifts. Some exits blocked. Infills and unbraced parapets failed or at incipient failure. Building is near collapse.
Some residual strength and stiffness left in all stories. Gravity-load-bearing elements function. No out-of-plane failure of walls or tipping of parapets. Some permanent drift. Damage to partitions. Building may be beyond economical repair
No permanent drift. Structure substantially retains original strength and stiffness. Minor cracking of facades, partitions and ceilings as well as structural elements. All systems important to normal operation are functional.
Wood Stud Walls
(Primary)
Connections loose, nails partially withdrawn. Some splitting of members and panels. Veneers dislodged.
Moderate loosening of connections and minor splitting of members.
Distributed hairline cracking of gypsum and plaster veneers.
33Of particular interest are our findings regarding the IO performance level.
For a drift level of 0.9% (less than the NEHRP prescribed 1%), we found that while
only 8% of the total sheathing nails appeared damaged, the walls had endured a
mean stiffness (secant) loss of 52%. This is contrary to a description of the damage
expected at the IO performance level provided in Table 2-3 of the NEHRP
Guidelines stating “the structure substantially retains [its] original strength and
stiffness” (FEMA 1997).
Table 8: Mean Results of Tests DA.1 and DA.2
Total Drift v K PT PPT W F Total Cycles (%) (kN/m)
v/vallow (kN/mm)
%Ko (% total sheathing nails)
20 0.3 7.1 1.3 2.29 92% 0 0 0 0 0 24 0.6 9.6 1.7 1.53 61% 0 3 0 0 3 28 0.9 11.1 2.0 1.21 48% 0 7 1 0 8 31 1.2 12.5 2.3 1.03 41% 0 9 2 0 11 34 2.1 15.7 2.8 0.72 29% 2 8 3 0 14 37 3.1 11.8 2.1 0.38 15% 9 12 14 0 35 40 4.6 5.3 1.0 0.11 4% 21 14 16 9 60
v = shear load / wall length (2440 mm) at given drift level vallow = allowable unit shear from UBC Table 23-II-I-1 (5.55 kN/m) Drift = lateral displacement expressed as % of wall height (2440 mm) K = secant stiffness at designated drift Ko = average initial wall stiffness taken as secant at 40% Pmax from tests DA.1 and DA.2 Bold fonts display load history, stiffness and visible damage details at drifts at IO, LS and CP NEHRP performance levels
34
-1.5
-1
-0.5
0
0.5
1
1.5
Time (Not to Scale)
Dis
plac
emen
t (M
ultip
le o
f ∆
ref)
Immediate OccupancyLife Safety
Collapse Prevention
% Total Sheathing Nails Damaged: 8% 14% 35%
Figure 8: Damage at NEHRP Performance Levels in Segmented CUREE Protocol
Table 8 shows the shear load, stiffness loss and percent of the sheathing nails
damaged at the associated drift levels throughout the test.
Visible damage symptoms provided in NEHRP (FEMA 1997) at the IO
performance level pertain mostly to non-structural elements such as gypsum
wallboard. As performance based design methodologies continue to evolve, tests of
this type will be helpful in better assessing appropriate structural and nonstructural
performance criteria.
35
0
10
20
30
40
0 10 20 30 40 50 60 70 80 90 100 110 120 130
Displacement (mm)
Load
(kN
)
KCP
KLS
KO
KIO
Ko = 2.50 kN/mm - KIO = 1.20 kN/mm 48% KoKLS = 0.72 kN/mm 29% KoKCP = 0.36 kN/mm 15% Ko
Figure 9: Secant Stiffness at NEHRP Performance Level Drift Values from
Averaged Backbone Curve of the Damage Accumulation Tests
The damage accumulation study also provided the opportunity to better
understand at which point during the tests nails were beginning to fatigue. It was
observed in both tests (DA.1 and DA.2) that fatigue failures did not occur until
cycles 38 – 40 (1.5 ∆ref and trailing). This indicates that the fatigue failures in
earlier tests may have been occurring well after the wall had reached its load
capacity. It is also possible that fewer fatigues were occurring on account of the
time delay for inspection periods.
At this time, there is no recommendation provided in the CUREE protocol
report regarding the duration (total number of cycles) of the test. While pull-
36through and withdrawal failures have been observed in post-earthquake inspections
of wood shear walls (CUREE 2001), to our knowledge, fatigue fracture of the
sheathing nails has not. Therefore, in the name of achieving a realistic, cyclic
loading scenario for testing, it is desirable to minimize nail fatigue. To better
understand at which point in the test nails were fatiguing, a final wall was tested
(CUREE 5) using the ordinary CUREE protocol (∆ref = 76 mm) for a shorter
duration of thirty-seven cycles (up to 1.0 ∆ref). In this test, only 6% of the nail
failures observed were fatigue fractures (44% PT and 9% W) while on average
24% of the failures observed in the eight tests employing forty-three cycles (up to
2.0 ∆ref) were fatigue. This indicates that most nail fractures in the other CUREE
tests occurred at displacements of 1.5 ∆ref and higher. However, the limitation of
only conducting the test to 1.0 ∆ref is that the post-strength behavior is not captured
in the results. Therefore, a reasonable balance seems to be stopping the test after the
1.5 ∆ref and trailing cycle displacements. This displacement level is adequate to
observe the post-peak behavior of the wall and reduces nail fatiguing caused by
cycles with amplitudes higher than 2.0 ∆ref.
37CONCLUSIONS AND RECOMMENDATIONS
1. While it was shown that reference displacement does not drastically affect
the overall wall response to cyclic loading, the tests demonstrated that
strength and ultimate displacement are influenced by the selection of
reference displacement. For the first three CUREE tests employing
reference displacements of 53, 61 and 69 mm (2.1, 2.4 and 2.7 in.), strength
was shown to slightly increase with reference displacement. However, this
trend of increasing strength with reference displacement was not observed
in CUREE 4 tests employing a 76 mm (3 in.) reference displacement. Walls
tested with this reference displacement tended to reach peak load at lower
drifts (i.e. 0.7 ∆ref) and produced strengths similar to the 61 and 69 mm (2.4
and 2.7 in.) tests. One reason for this seems to be a transition in controlling
failure mechanism from the sheathing connections degrading to rupturing of
the center stud. Reference displacement was shown to have little effect on
initial stiffness and area under the backbone curve.
2. A modified, segmented version of the CUREE tests was used as a method
to track visible damage accumulated during the progressive failure of the
wall. However, due to the invisible nature of damage accumulation at low
drift levels, little can be said about a wall’s loading history based on visual
inspection of the structural components. It appears this method of
38correlating visual damage to load history would be more effective with the
presence of nonstructural elements such as gypsum wallboard that are
known to experience symptoms of visual damage at lower drifts.
3. The CUREE recommended method for obtaining a reference displacement
relies mostly on the wall’s over-strength response during monotonic tests.
Monotonic test results showed post-peak behavior of the three walls varied
considerably. As a result, vastly different reference displacements were
obtained from each test. Reducing variability in the reference displacement
selection process would simplify and enhance the overall objectivity of the
testing process. One possible approach to reducing this variability is that the
reference displacement be taken as a fraction of a quantity such as ultimate
displacement. Our tests show that this quantity is more repeatable than the
CUREE defined deformation capacity. Based on the small number of tests
performed in this study, it appears that using ultimate displacement as a
basis for selecting reference displacement, 0.8 ∆Pmax for example, would
improve the consistency of extracting reference displacements from the
monotonic loading curve.
4. The damage accumulation study suggests that as much as four times as
many nail fatigue failures were observed in the tests employing forty-three
cycles (up to 2.0 ∆ref) than for the one test employing only thirty-seven
39cycles (up to 1.0 ∆ref). This is a strong indication that the majority of
fatigues (75%) observed in the first eight CUREE tests were occurring after
the walls had reached peak load. While the wall tested with only thirty-
seven cycles provided far fewer fatigue failures, we found that terminating
the test at this low a drift level (1.0 ∆ref) did not provide enough information
about the wall’s post peak behavior. As a balance of the conflicting interests
of obtaining realistic failure mode as well as an overall response curve, it is
recommended that future tests be stopped following the 1.5 ∆ref
displacement sequence.
40BIBLIOGRAPHY
ASTM. (2000). “Standard method of static load test for shear resistance of framed walls for buildings.” ASTM E 564-95, West Conshohocken, Pa. ASTM. (2001). “Standard test methods for cyclic (reversed) load test for shear resistance of framed walls for buildings.” ASTM E 2126-01, ASTM, West Conshohocken, Pa. CUREE (2001). Woodframe Project Case Studies, CUREE Publication No. W-04. Consortium of Universities for Research in Earthquake Engineering, Richmond, CA. Dean, J. A., Stewart, W. G., and Carr, A. J. (1988). “The earthquake behaviour of plywood sheathed shear walls.” Proc., 1988 Int. Conf. On Timber Engrg., Vol. 2, Seattle, Wash. Dinehart, D. W. and Shenton, H. W. III (1998). “Comparison of static and dynamic response of timber shear walls.” J. Struct. Engrg., ASCE, 124 (6), 686-695. Dolan, J. D. (1989). “The dynamic response of timber shear walls,” PhD thesis, University of British Columbia, Vancouver, British Columbia, Canada. Dolan, J. D. (1994). “Proposed test method for dynamic properties of connections assembled with mechanical fasteners.” J. of Testing and Evaluation, ASTM, 22(6), 542-547. Dolan, J.D. (2001). Personal email. November 8, 2001. Dolan, J. D. and Madsen, B. (1992). “Monotonic and cyclic tests of timber shear walls” Can. J. Civ. Engrg., 19, 415-422. Federal Emergency Management Agency (FEMA). (1997). “NEHRP Guidelines for the Seismic Rehabilitation of Buildings.” Rep. 273, Washington, D.C. He, M., Lam, F. and Prion, H. G. L. (1998). “Influence of cyclic test protocols on performance of wood-based shear walls.” Can. J. Civ. Engrg., 25, 539-550. International Conference of Building Officials (ICBO). (1997). Uniform Building Code, Whittier, Calif.
41Karacabeyli, E. and Ceccotti, A. (1998). “Nailed wood-frame shear walls for seismic loads: test results and design considerations.” Proc., Struct. Engrs. World Congr., San Francisco, Calif. Krawinkler, H., Parisi, F. Ibarra, L., Ayoub, A. and Medina, R. (2000). “Final report, Development of a testing protocol for wood frame structures.” CUREE-Caltech Woodframe Project Report, Stanford University, Stanford, Calif. Leon, R. T. and Deierlein, G. G. (1996). “Considerations for the use of quasi-static testing.” Earthquake Spectra, 12(1), 87 – 109. National Evaluation Services (NES). (1997). “Power-driven staples and nails for use in all types of building construction” NER-272. International Staple, Nail and Tool Association, La Grange, IL. Rose, J. D. (1998). “Preliminary Testing of Wood Structural Panel Shear Walls Under Cyclic (Reversed) Loading.” APA Research Report 158. APA – The Engineered Wood Association, Tacoma, WA. Salenikovich, A. J. (2000). “The racking performance of light frame shear walls,” PhD thesis, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA. Seible, F., Filiatrault, A., and Uang, C-M. (1999). “Preface to the Proceedings of the Invitational Workshop on Seismic Testing, Analysis and Design of Woodframe Construction, Los Angeles, CA, March 1999.” CUREE Publication No. W-01, Consortium of Universities for Research in Earthquake Engineering, Richmond, CA. Staehle, R. (2001). “The Influence of Partial Submersion on Wood Shear Wall Performance.” Thesis, Universitat Karlsruhe, Karlsruhe, Germany. Structural Engineers Association of Southern California (SEAOSC). (1996). “Standard method of cyclic (reversed) load test for shear resistance of framed walls for buildings.” Whittier, Calif. Uang, C-M. (2001) “Draft report, Loading protocol and rate of loading effects.” CUREE-Caltech Woodframe Project Report, University of California, San Diego. Yamaguchi, N., and Minowa, C., 1998. “Dynamic performance of wooden bearing walls by shake table test.” Proc., World Conf. On Timber Engrg., Montreux, Switzerland.
47 Load-Displacement Values Displacement at zero load (δo,i), peak displacement (δi), load at peak
displacement (Pi) and maximum load in the cycle (Pmaxi) were recorded for each
loading cycle and are presented in the following tables.
Cyclic Stiffness
For each loading cycle, the cyclic stiffness was defined as;
Ki = (Pi+ - Pi
-)/(δi+ - δi
-)
The stiffness from the first cycle, K1 is used as a reference for stiffness degradation
noted in the %K1 columns.
Energy and Damping The work done or hysteretic energy dissipated by the wall during each cycle
of loading (Ei) was calculated as the area enclosed in each hysteretic loop. This
value was used to compare energy demands of the CUREE test using different
reference displacements. It was also used to calculate the equivalent viscous
damping ratio (ζi) for each cycle. Dolan (1994) provides the relation that:
ζi = Hysteretic Energy = Ei________ 2π Potential Energy 2π Area (ABC + CDE)
Energy quantities are taken as areas from the cyclic load-displacement
plots illustrated on the following page.
48
Performance Quantities from Cyclic Load Tests Provided in Tables
Displacement
Load
Pi+
Pi-
δi+
δi-
δo,i-
δo,i+ Ei
Ki1
Hysteretic and Potential Energy from Cyclic Load-Displacement Plots
Displacement
Load
A
BC
D
E
Hysteretic Energy (Ei)
Potential Energy (Area ABC + CDE)
Ei
49CUREE Test 1.1, June 19, 2001
Def. at P=0 (mm)
Peak Deflection
(mm) Load at δi
(kN) Max Force
(kN)
Cyclic Stiffness (kN/mm)
Energy(kN-mm)
EVDCycle Number
δ o,i+ δ o,i- δ i+ δ i− Pi+ Pi- Pmaxi+ δ o,i+ δ o,i- δ i+ δ i− 1 0.0 1.0 2.7 -2.7 9.84 -10.01 9.84 -10.01 3.64 100% 25.2 0.152 -0.9 1.0 2.7 -2.7 9.58 -10.01 9.69 -10.01 3.61 99% 22.8 0.143 -0.9 0.9 2.7 -2.7 9.69 -9.86 9.69 -9.86 3.58 98% 22.1 0.134 -0.9 1.0 2.7 -2.7 9.67 -9.78 9.67 -9.82 3.56 98% 21.4 0.135 -0.9 1.0 2.7 -2.8 9.52 -9.84 9.52 -9.84 3.54 97% 21.4 0.136 -0.9 1.0 2.7 -2.7 9.44 -9.80 9.44 -9.80 3.54 97% 21.4 0.137 -0.9 1.5 4.1 -4.0 12.18 -11.86 12.18 -12.14 2.96 81% 44.2 0.148 -1.3 1.1 3.0 -3.0 9.54 -9.31 9.54 -9.35 3.10 85% 26.5 0.159 -1.1 1.2 3.0 -3.0 9.48 -9.67 9.48 -9.67 3.14 86% 25.5 0.14
10 -1.2 1.2 3.0 -3.0 9.24 -9.24 9.39 -9.48 3.04 83% 25.5 0.1411 -1.0 1.2 3.0 -3.0 9.33 -9.48 9.33 -9.48 3.09 85% 24.8 0.1412 -1.1 1.1 3.1 -3.1 9.26 -9.39 9.41 -9.50 3.05 84% 24.8 0.1413 -1.1 1.2 3.1 -3.1 9.41 -9.48 9.41 -9.48 3.08 85% 24.8 0.1414 -1.0 1.9 5.4 -5.4 14.38 -13.69 14.38 -13.69 2.59 71% 68.3 0.1415 -1.7 1.7 4.1 -4.0 10.67 -10.41 10.67 -10.41 2.60 71% 40.4 0.1516 -1.5 1.6 4.1 -4.0 10.71 -10.35 10.71 -10.44 2.59 71% 38.4 0.1417 -1.4 1.6 4.1 -4.1 10.78 -10.37 10.78 -10.37 2.59 71% 38.1 0.1418 -1.5 1.7 4.1 -4.1 10.90 -10.69 10.90 -10.69 2.66 73% 37.4 0.1419 -1.4 1.6 4.1 -4.1 10.95 -10.69 10.95 -10.69 2.65 73% 37.4 0.1420 -1.4 1.5 4.1 -4.1 10.88 -10.56 10.88 -10.56 2.63 72% 37.0 0.1421 -1.3 4.9 10.8 -10.7 19.30 -18.72 19.30 -18.72 1.77 49% 221 0.1722 -3.6 3.9 8.1 -8.1 13.69 -13.25 13.69 -13.25 1.66 46% 101 0.1523 -3.0 3.6 8.1 -8.1 13.48 -13.14 13.48 -13.14 1.64 45% 94 0.1424 -2.8 3.7 8.1 -8.1 13.57 -13.40 13.57 -13.40 1.67 46% 92 0.1425 -2.7 8.5 16.2 -16.1 21.94 -21.38 21.94 -21.38 1.34 37% 367 0.1726 -6.2 6.1 12.2 -12.1 14.80 -14.27 14.80 -14.27 1.20 33% 164 0.1527 -5.0 6.4 12.1 -12.2 14.82 -14.31 14.82 -14.31 1.20 33% 153 0.1428 -5.0 6.1 12.1 -12.2 14.74 -14.55 14.74 -14.55 1.21 33% 151 0.1429 -4.8 11.5 21.5 -21.6 24.07 -23.45 24.45 -23.92 1.10 30% 512 0.1630 -9.8 9.2 16.3 -16.2 15.14 -14.74 15.14 -14.74 0.92 25% 228 0.1531 -7.5 8.7 16.2 -16.1 15.25 -14.84 15.25 -14.84 0.93 26% 214 0.1432 -6.9 25.1 37.7 -37.6 29.54 -28.94 30.88 -28.94 0.78 21% 1286 0.1933 -22.1 18.7 28.2 -28.3 15.78 -14.99 15.78 -14.99 0.55 15% 433 0.1634 -14.4 17.4 28.2 -28.3 15.91 -15.23 15.91 -15.23 0.55 15% 398 0.1435 -14.6 36.7 53.5 -53.7 31.99 -30.31 32.69 -30.63 0.58 16% 1727 0.1736 -33.5 27.9 40.2 -40.4 14.70 -13.33 14.70 -13.33 0.35 10% 589 0.1737 -24.1 29.8 40.4 -40.4 14.63 -13.50 14.63 -13.50 0.35 10% 536 0.1538 -24.1 56.0 80.8 -80.8 23.13 -25.17 29.56 -26.09 0.30 8% 2322 0.1939 -44.6 45.6 60.4 -60.6 10.31 -10.29 10.31 -10.29 0.17 5% 656 0.1740 -32.1 45.3 60.7 -60.6 9.88 -10.24 9.88 -10.24 0.17 5% 570 0.1541 -34.6 78.6 107.7 -107.7 12.76 -15.46 18.04 -16.85 0.13 4% 1856 0.2042 -53.6 63.0 80.9 -80.8 5.86 -8.99 6.11 -8.99 0.09 3% 563 0.1543 -45.7 64.9 80.8 -80.8 5.30 -8.24 6.05 -8.24 0.08 2% 492 0.00
50CUREE Test 1.2, June 20, 2001
Def. at P=0 (mm)
Peak Deflection
(mm) Load at δi
(kN) Max Force
(kN)
Cyclic Stiffness (kN/mm)
Energy(kN-mm)
EVDCycle Number
δ o,i+ δ o,i- δ i+ δ i− Pi+ Pi- Pmaxi+ Pmaxi- Ki %K1 Ei ζi 1 0.0 0.8 2.8 -2.7 8.99 -8.88 8.99 -8.88 3.27 100% 22.3 0.152 -1.0 0.8 2.8 -2.7 8.99 -8.75 8.99 -8.75 3.25 99% 20.8 0.143 -1.0 0.8 2.8 -2.7 8.65 -8.80 8.65 -8.80 3.18 97% 20.1 0.134 -0.9 0.8 2.8 -2.7 8.95 -8.67 8.95 -8.67 3.22 98% 19.7 0.135 -0.9 0.8 2.8 -2.7 8.86 -8.75 8.86 -8.75 3.22 98% 19.7 0.136 -0.9 0.8 2.8 -2.7 8.89 -8.54 8.89 -8.54 3.18 97% 19.3 0.137 -0.9 1.5 4.1 -4.0 11.05 -10.76 11.05 -10.76 2.68 82% 41.2 0.158 -1.2 1.5 3.1 -3.0 8.52 -8.56 8.52 -8.56 2.82 86% 24.9 0.159 -1.2 1.0 3.1 -3.0 8.60 -8.67 8.60 -8.67 2.83 86% 23.4 0.14
10 -1.2 1.1 3.1 -2.9 8.63 -8.58 8.63 -8.58 2.86 87% 23.0 0.1411 -1.1 1.1 3.1 -2.9 8.65 -8.63 8.65 -8.63 2.87 88% 23.0 0.1412 -1.1 1.0 3.1 -3.0 8.56 -8.52 8.56 -8.73 2.83 87% 22.7 0.1413 -1.2 1.0 3.1 -2.9 8.69 -8.65 8.69 -8.65 2.87 88% 22.7 0.1414 -1.1 2.0 5.3 -5.3 12.63 -12.78 12.63 -12.78 2.39 73% 64.7 0.1515 -2.0 1.5 4.1 -3.9 9.18 -9.86 9.18 -9.86 2.36 72% 37.2 0.1516 -1.5 1.4 4.1 -4.0 9.80 -9.75 9.80 -9.75 2.41 74% 35.3 0.1417 -1.4 1.4 4.1 -4.0 9.65 -9.95 9.65 -9.95 2.43 74% 34.9 0.1418 -1.4 1.6 4.1 -4.0 9.86 -9.63 9.86 -9.63 2.39 73% 34.2 0.1419 -1.6 1.4 4.1 -3.9 9.52 -9.71 9.52 -9.71 2.39 73% 33.8 0.1420 -1.4 1.4 4.1 -3.9 9.86 -9.73 9.86 -9.73 2.43 74% 33.8 0.1421 -1.6 5.0 10.6 -10.7 18.02 -18.10 18.02 -18.10 1.70 52% 208 0.1722 -4.5 3.7 8.1 -8.0 12.97 -12.23 12.97 -12.23 1.56 48% 94 0.1523 -3.5 3.5 8.2 -8.0 12.52 -12.31 12.52 -12.31 1.54 47% 88 0.1424 -3.2 3.3 8.2 -8.0 12.72 -12.27 12.72 -12.27 1.54 47% 86 0.1425 -3.2 8.0 16.2 -16.2 21.75 -23.13 21.75 -23.13 1.38 42% 348 0.1526 -6.5 5.7 12.2 -12.1 14.18 -13.97 14.18 -13.97 1.16 35% 154 0.1427 -5.3 5.7 12.1 -12.1 14.59 -14.27 14.59 -14.27 1.19 36% 144 0.1328 -5.1 5.4 12.2 -12.1 14.42 -14.29 14.42 -14.29 1.18 36% 141 0.1329 -4.9 11.0 21.5 -21.5 24.19 -26.11 24.54 -26.28 1.17 36% 505 0.1530 -9.7 8.4 16.2 -16.1 15.06 -14.91 15.06 -14.91 0.93 28% 218 0.1431 -7.8 8.3 16.2 -15.9 -15.14 15.08 -15.14 15.08 -0.94 -29% 205 -0.1432 -7.8 24.3 37.8 -37.6 31.07 -31.82 31.67 -32.33 0.83 26% 1332 0.1833 -21.6 16.2 28.2 -28.2 16.38 -16.23 16.38 -16.23 0.58 18% 433 0.1534 -15.3 17.6 28.3 -28.2 16.29 -16.59 16.29 -16.59 0.58 18% 399 0.1435 -15.3 36.2 53.8 -53.7 34.76 -34.01 35.23 -34.82 0.64 20% 1866 0.1636 -33.8 28.1 40.5 -40.5 15.08 -14.44 15.33 -14.44 0.36 11% 603 0.1637 -24.4 28.0 40.3 -40.4 15.10 -14.74 15.10 -14.74 0.37 11% 538 0.1438 -24.7 58.7 80.9 -80.7 30.35 -17.78 33.08 -20.32 0.30 9% 2345 0.1939 -48.4 43.6 60.6 -60.5 9.92 -8.29 10.88 -8.29 0.15 5% 591 0.1740 -37.0 41.7 60.7 -60.5 9.90 -8.07 10.12 -8.63 0.15 5% 517 0.1541 -37.0 71.8 107.8 -107.6 21.32 -12.10 23.81 -12.72 0.16 5% 1814 0.1642 -53.0 61.6 80.9 -80.8 7.88 -6.13 8.01 -6.45 0.09 3% 559 0.1643 -39.5 61.6 80.7 -80.8 7.75 -6.37 7.75 -6.37 0.09 3% 484 0.00
51CUREE Test 2.1, February 9, 2001
Def. at P=0 (mm)
Peak Deflection
(mm) Load at δi
(kN) Max Force
(kN)
Cyclic Stiffness (kN/mm)
Energy(kN-mm)
EVDCycle Number
δ o,i+ δ o,i- δ i+ δ i− Pi+ Pi- P +
maxi Pmaxi- Ki %K1 Ei ζi 1 0.0 0.7 3.1 -3.1 9.50 -8.07 9.50 -8.07 2.81 100% 15.0 0.092 -1.2 0.5 3.1 -3.1 9.46 -8.60 9.46 -8.60 2.90 103% 17.3 0.103 -1.3 0.5 3.1 -3.1 9.18 -7.99 9.18 -7.99 2.75 98% 16.3 0.104 -1.2 0.5 3.1 -3.1 9.18 -8.35 9.18 -8.35 2.83 101% 15.9 0.095 -1.1 0.5 3.1 -3.1 8.79 -7.86 9.16 -8.16 2.68 95% 15.4 0.106 -1.3 0.5 3.1 -3.1 9.09 -7.95 9.39 -7.95 2.73 97% 15.0 0.097 -1.2 1.0 4.6 -4.6 11.22 -10.03 11.69 -10.22 2.30 82% 32.7 0.118 -1.6 0.5 3.4 -3.5 9.01 -7.67 9.01 -7.67 2.41 86% 20.4 0.119 -1.3 0.8 3.5 -3.5 8.84 -7.58 9.03 -7.79 2.34 83% 19.5 0.1110 -1.3 0.6 3.4 -3.5 8.88 -7.67 9.09 -7.67 2.38 85% 18.6 0.1011 -1.3 0.7 3.4 -3.5 8.88 -7.69 9.09 -7.73 2.38 85% 18.2 0.1012 -1.3 0.6 3.5 -3.5 8.82 -7.56 9.69 -7.75 2.34 83% 17.3 0.1013 -1.3 0.5 3.5 -3.5 8.95 -7.82 8.95 -7.82 2.38 85% 17.3 0.0914 -1.2 1.2 6.2 -6.2 13.61 -11.99 13.61 -12.16 2.07 74% 49.5 0.1015 -2.2 1.0 4.6 -4.6 10.44 -8.56 10.44 -8.95 2.06 73% 31.3 0.1116 -1.8 1.0 4.6 -4.6 9.97 -8.92 10.09 -8.92 2.05 73% 28.6 0.1017 -1.6 0.9 4.6 -4.6 9.99 -9.18 10.25 -9.18 2.08 74% 27.7 0.1018 -1.8 0.9 4.6 -4.6 10.09 -8.90 10.20 -9.07 2.06 73% 27.7 0.1019 -1.8 1.0 4.6 -4.6 10.22 -8.79 10.33 -8.95 2.06 73% 27.2 0.1020 -1.6 4.1 4.6 -4.6 10.08 -8.75 10.22 -8.97 2.04 73% 26.8 0.1021 -4.1 2.4 12.3 -12.4 18.98 -17.80 19.15 -17.80 1.49 53% 182 0.1322 -3.5 2.7 9.2 -9.3 13.31 -11.75 13.33 -11.88 1.35 48% 83 0.1123 -3.3 1.9 9.2 -9.3 13.21 -11.84 13.54 -11.99 1.35 48% 74 0.1024 -3.2 6.8 9.2 -9.3 13.23 -12.04 13.33 -12.04 1.37 49% 73 0.1025 -7.4 5.5 18.5 -18.5 22.25 -20.81 22.28 -21.62 1.16 41% 314 0.1326 -5.6 4.4 13.8 -13.9 14.44 -13.46 15.01 -13.48 1.01 36% 145 0.1227 -5.6 3.9 13.8 -13.9 14.50 -13.40 14.72 -13.44 1.01 36% 128 0.1128 -5.7 11.2 13.8 -14.1 14.54 -13.52 14.54 -13.97 1.01 36% 125 0.1029 -11.5 6.5 24.6 -24.6 25.32 -24.41 25.32 -24.83 1.01 36% 447 0.1230 -9.2 7.2 18.5 -18.5 15.46 -14.21 15.46 -14.31 0.80 29% 209 0.1231 -8.4 22.4 18.5 -18.5 15.46 -14.38 15.46 -14.50 0.81 29% 188 0.1132 -24.1 16.6 43.1 -43.1 32.46 -32.39 33.29 -32.84 0.75 27% 1243 0.1433 -18.2 15.8 32.2 -32.4 17.02 -15.76 17.08 -15.76 0.51 18% 437 0.1334 -18.7 36.5 32.3 -32.3 17.06 -16.00 17.06 -16.40 0.51 18% 375 0.1135 -36.2 28.9 61.5 -61.5 36.31 -35.84 37.76 -36.31 0.59 21% 1768 0.1336 -27.8 28.4 46.2 -46.2 16.29 -14.14 16.40 -14.82 0.33 12% 517 0.1237 -28.3 60.4 46.1 -46.2 15.93 -14.17 16.04 -14.17 0.33 12% 501 0.1238 -52.3 47.4 92.3 -92.3 28.58 -13.38 31.29 -14.97 0.23 8% 2057 0.1739 -44.5 46.6 69.3 -69.2 9.84 -6.20 9.84 -6.60 0.12 4% 511 0.1540 -41.6 72.7 69.2 -69.2 9.07 -5.81 9.54 -6.50 0.11 4% 415 0.1341 -90.2 43.6 122.9 -123.0 15.51 -4.39 17.66 -8.31 0.08 3% 1442 0.1942 -66.6 47.1 103.8 -103.8 7.16 -2.43 7.62 -2.66 0.05 2% 527 0.1743 -34.9 0.0 103.7 -103.8 7.71 -2.53 7.86 -2.62 0.05 2% 419 0.00
52CUREE Test 2.2, February 20, 2001
Def. at P=0 (mm)
Peak Deflection
(mm) Load at δi
(kN) Max Force
(kN)
Cyclic Stiffness (kN/mm)
Energy(kN-mm)
EVDCycle Number
δ o,i+ δ o,i- δ i+ δ i− Pi+ Pi- Pmaxi+ Pmaxi- Ki %K1 Ei ζi 1 0.0 0.5 3.1 -3.1 10.12 -6.69 10.50 -6.96 2.68 100% 21.1 0.132 -1.5 0.3 3.2 -3.1 10.18 -6.58 10.24 -6.73 2.64 99% 19.7 0.123 -1.3 0.4 3.1 -3.1 10.16 -6.75 10.27 -7.18 2.72 102% 18.8 0.114 -1.3 0.4 3.1 -3.1 9.88 -6.69 10.20 -6.75 2.65 99% 18.8 0.125 -1.4 0.3 3.1 -3.1 9.97 -7.33 9.99 -7.33 2.77 103% 18.4 0.116 -1.4 0.4 3.1 -3.2 9.99 -7.13 9.99 -7.13 2.73 102% 17.9 0.117 -1.4 0.7 4.7 -4.8 12.57 -8.56 12.76 -9.09 2.24 84% 39.0 0.138 -2.0 0.6 3.5 -3.5 9.31 -6.60 10.18 -7.50 2.29 85% 22.9 0.139 -1.7 0.6 3.7 -3.6 9.65 -6.56 9.82 -6.88 2.24 84% 22.5 0.12
10 -1.6 0.6 3.5 -3.5 9.61 -6.67 10.41 -6.75 2.33 87% 22.0 0.1211 -1.5 0.6 3.5 -3.5 9.73 -6.56 9.86 -6.75 2.35 88% 22.0 0.1212 -1.6 0.5 3.5 -3.5 9.73 -6.60 10.76 -6.73 2.33 87% 21.6 0.1213 -1.5 0.6 3.5 -3.5 9.39 -6.65 10.03 -7.16 2.28 85% 21.1 0.1214 -1.5 1.4 6.2 -6.2 14.08 -10.65 14.36 -10.78 2.00 75% 61.5 0.1315 -2.1 0.9 4.7 -4.6 10.76 -7.73 11.10 -8.07 1.98 74% 34.0 0.1316 -1.9 0.8 4.6 -4.6 11.44 -7.52 11.44 -7.84 2.05 77% 31.7 0.1217 -2.0 0.7 4.6 -4.6 10.97 -7.75 11.20 -7.94 2.02 76% 32.1 0.1218 -1.8 0.9 4.6 -4.6 10.88 -7.73 10.97 -7.92 2.01 75% 31.2 0.1219 -2.0 0.8 4.7 -4.6 11.29 -7.77 11.29 -7.88 2.04 76% 31.2 0.1120 -2.1 1.0 4.6 -4.6 11.01 -7.62 11.01 -7.88 2.01 75% 31.2 0.1221 -2.0 4.4 12.3 -12.3 19.17 -15.82 19.81 -16.04 1.42 53% 219 0.1622 -4.6 3.3 9.2 -9.3 13.63 -10.86 13.63 -10.99 1.32 49% 90 0.1323 -3.9 3.3 9.2 -9.2 13.48 -11.50 13.50 -11.50 1.35 51% 83 0.1124 -3.0 3.3 9.3 -9.2 13.46 -11.33 13.69 -11.33 1.34 50% 80 0.1125 -3.5 7.7 18.5 -18.5 22.53 -19.85 23.17 -20.28 1.15 43% 376 0.1526 -8.3 5.8 13.9 -14.0 14.97 -12.91 14.99 -12.91 1.00 37% 155 0.1327 -6.4 5.4 13.9 -14.0 14.93 -12.99 15.21 -12.99 1.00 37% 145 0.1228 -6.0 5.3 13.9 -13.9 14.87 -13.08 14.95 -13.08 1.01 38% 140 0.1229 -5.6 11.1 24.7 -24.7 24.83 -22.98 25.86 -25.00 0.97 36% 543 0.1530 -12.0 8.2 18.5 -18.6 15.55 -13.80 15.72 -14.08 0.79 30% 228 0.1331 -9.3 8.0 18.5 -18.6 15.42 -14.10 15.70 -14.27 0.80 30% 207 0.1232 -8.9 25.5 43.1 -43.1 32.44 -31.80 33.33 -32.99 0.75 28% 1496 0.1733 -25.9 17.2 32.3 -32.3 17.42 -15.78 17.83 -16.38 0.51 19% 480 0.1434 -17.6 17.0 32.3 -32.3 17.25 -16.02 17.51 -16.59 0.51 19% 430 0.1335 -18.1 39.5 61.6 -61.6 36.80 -35.08 37.97 -36.80 0.58 22% 2180 0.1636 -40.1 30.1 46.2 -46.2 16.70 -14.61 17.27 -15.12 0.34 13% 678 0.1537 -29.6 30.9 46.3 -46.2 16.61 -14.63 16.97 -15.19 0.34 13% 592 0.1338 -29.9 63.0 92.3 -92.4 31.16 -17.49 34.27 -21.32 0.26 10% 2776 0.2039 -57.3 37.5 69.3 -69.3 10.16 -7.35 10.37 -8.22 0.13 5% 592 0.1640 -40.5 38.1 69.3 -69.3 10.03 -8.18 10.12 -8.18 0.13 5% 495 0.1341 -39.4 67.7 123.1 -123.2 13.74 -9.12 17.78 -10.10 0.09 3% 1625 0.1842 -66.5 65.7 103.9 -103.9 7.09 -5.67 7.84 -7.07 0.06 2% 547 0.1343 -66.2 69.2 104.0 -103.9 6.82 -5.73 7.60 -5.92 0.06 2% 488 0.00
53CUREE Test 3.1, April 19, 2001
Def. at P=0 (mm)
Peak Deflection
(mm) Load at δi (kN)Max Force
(kN)
Cyclic Stiffness (kN/mm)
Energy(kN-mm)
EVDCycle Number
δ o,i+ δ o,i- δ i+ δ i− Pi+ Pi- Pmaxi+ Pmaxi- Ki %K1 Ei ζi 1 0.0 1.3 3.5 -3.5 9.03 -9.31 9.18 -9.50 2.63 100% 29.4 0.152 -1.1 1.2 3.5 -3.5 8.86 -9.22 9.05 -9.29 2.59 99% 26.0 0.133 -1.1 1.2 3.5 -3.5 9.01 -9.24 9.05 -9.24 2.62 100% 24.7 0.124 -0.9 1.2 3.5 -3.5 8.77 -9.03 9.14 -9.26 2.55 97% 24.3 0.125 -1.1 1.1 3.5 -3.5 8.69 -9.03 9.05 -9.39 2.54 97% 23.9 0.126 -1.1 1.0 3.5 -3.5 9.05 -9.22 9.05 -9.22 2.62 100% 23.9 0.127 -1.0 1.9 5.2 -5.2 11.29 -11.91 11.46 -12.14 2.22 85% 49.8 0.138 -1.5 1.5 3.9 -4.0 8.88 -9.01 9.18 -9.22 2.27 86% 29.0 0.139 -1.3 1.3 3.9 -3.9 8.75 -8.86 9.01 -9.09 2.24 85% 28.1 0.13
10 -1.3 1.3 3.9 -3.9 8.95 -8.99 9.24 -8.99 2.29 87% 27.7 0.1311 -1.1 1.2 3.9 -3.9 8.88 -9.24 9.20 -9.24 2.31 88% 27.7 0.1212 -1.3 1.2 4.0 -3.9 8.84 -8.90 9.09 -9.12 2.25 86% 27.3 0.1213 -1.3 1.4 3.9 -3.9 8.88 -9.22 8.88 -9.22 2.31 88% 26.8 0.1214 -1.1 2.5 7.0 -7.0 13.46 -13.87 13.57 -13.87 1.96 75% 78.8 0.1315 -2.0 1.9 5.2 -5.2 9.84 -10.05 10.48 -10.05 1.91 73% 43.0 0.1316 -1.8 1.9 5.2 -5.2 9.95 -10.12 10.33 -10.22 1.93 73% 40.9 0.1217 -1.5 1.7 5.2 -5.3 10.18 -10.16 10.44 -10.16 1.94 74% 40.0 0.1218 -1.8 1.6 5.2 -5.2 10.12 -10.03 10.24 -10.24 1.93 74% 40.0 0.1219 -1.9 1.7 5.2 -5.2 10.03 -10.18 10.12 -10.18 1.94 74% 39.2 0.1220 -1.9 1.6 5.2 -5.2 10.33 -10.07 10.41 -10.27 1.96 75% 39.6 0.1221 -1.9 5.6 13.9 -13.9 18.61 -17.66 18.76 -18.25 1.30 50% 280 0.1822 -6.1 3.9 10.4 -10.5 14.21 -12.84 14.44 -13.08 1.29 49% 121 0.1423 -4.3 4.4 10.5 -10.4 14.29 -13.10 14.42 -13.10 1.31 50% 110 0.1224 -4.3 3.6 10.4 -10.4 14.31 -13.29 14.33 -13.29 1.32 50% 108 0.1225 -4.3 10.4 20.8 -20.9 21.87 -21.19 22.21 -21.19 1.03 39% 487 0.1726 -11.1 6.1 15.6 -15.7 15.48 -14.06 15.53 -14.33 0.94 36% 206 0.1427 -7.9 5.4 15.7 -15.7 15.70 -14.27 15.80 -14.46 0.96 36% 188 0.1328 -8.0 7.1 15.7 -15.7 15.95 -14.33 15.95 -14.33 0.97 37% 183 0.1229 -7.2 14.5 27.9 -27.9 24.15 -23.81 25.54 -24.22 0.86 33% 686 0.1630 -15.5 8.9 20.9 -20.9 15.31 -15.02 15.42 -15.21 0.73 28% 300 0.1531 -11.0 10.1 20.9 -20.9 15.74 -15.38 15.78 -15.38 0.74 28% 271 0.1332 -11.7 30.3 48.7 -48.7 32.22 -31.22 33.16 -30.82 0.65 25% 1732 0.1833 -30.1 22.0 36.5 -36.5 16.74 -14.55 17.00 -14.55 0.43 16% 593 0.1734 -25.0 23.2 36.5 -36.5 16.61 -16.10 16.72 -16.10 0.45 17% 532 0.1435 -23.9 47.1 69.5 -69.5 34.95 -26.96 38.88 -29.92 0.45 17% 2357 0.1736 -49.4 35.8 52.2 -52.2 13.08 -11.67 13.44 -11.97 0.24 9% 693 0.1737 -36.1 33.4 52.2 -52.2 12.27 -11.35 12.59 -11.50 0.23 9% 569 0.1538 -36.1 71.7 104.3 -104.3 18.25 -11.18 21.68 -12.25 0.14 5% 2047 0.2139 -73.1 61.8 78.0 -77.9 6.75 -4.88 7.03 -5.03 0.07 3% 544 0.1940 -59.9 44.4 78.0 -77.9 6.45 -4.98 6.90 -4.98 0.07 3% 475 0.1741 -57.1 94.2 125.6 -125.7 2.41 -4.49 12.50 -5.71 0.03 1% 1095 0.4042 -95.2 59.2 103.9 -103.8 2.09 -2.34 2.90 -3.22 0.02 1% 280 0.1943 -79.5 63.2 103.8 -103.9 1.77 -2.15 2.77 -2.66 0.02 1% 239 0.00
54CUREE Test 3.2, April 26, 2001
Def. at P=0 (mm)
Peak Deflection
(mm) Load at δi
(kN) Max Force
(kN)
Cyclic Stiffness (kN/mm)
Energy(kN-mm)
EVDCycle Number
δ o,i+ δ o,i- δ i+ δ i− Pi+ Pi- P +maxi P -maxi Ki %K1 Ei ζi 1 0.0 1.0 3.5 -3.5 11.20 -11.15 11.20 -11.15 3.20 100% 34.2 0.142 -1.0 0.9 3.5 -3.5 11.19 -11.13 11.19 -11.13 3.22 100% 29.3 0.123 -1.1 1.1 3.5 -3.5 11.13 -10.85 11.13 -10.85 3.15 98% 27.8 0.124 -0.9 1.1 3.5 -3.5 10.98 -10.98 10.98 -10.98 3.16 99% 27.3 0.115 -0.9 1.1 3.5 -3.5 10.79 -10.85 10.79 -10.85 3.11 97% 26.8 0.116 -0.9 1.1 3.5 -3.5 10.94 -10.79 10.94 -10.79 3.11 97% 26.4 0.117 -1.0 1.9 5.3 -5.2 13.64 -14.19 14.43 -14.19 2.65 83% 56.6 0.128 -1.6 1.4 3.9 -3.9 10.68 -10.53 10.68 -10.53 2.73 85% 33.7 0.139 -1.3 1.5 3.9 -3.9 10.81 -10.68 10.81 -10.68 2.75 86% 31.7 0.12
10 -1.3 1.4 3.9 -3.9 10.72 -10.68 10.72 -10.68 2.72 85% 31.7 0.1211 -1.2 1.4 3.9 -3.9 10.72 -10.74 10.72 -10.74 2.74 86% 30.7 0.1212 -1.1 1.4 3.9 -3.9 10.68 -10.72 10.68 -10.72 2.74 85% 31.2 0.1213 -1.0 1.4 3.9 -3.9 10.66 -10.72 10.66 -10.72 2.72 85% 30.7 0.1214 -1.2 2.5 7.0 -7.0 15.82 -16.24 16.13 -16.24 2.29 71% 90.3 0.1315 -2.2 2.0 5.2 -5.2 11.56 -12.19 11.79 -12.19 2.28 71% 50.7 0.1316 -1.5 1.8 5.2 -5.2 11.90 -12.19 11.90 -12.19 2.30 72% 46.8 0.1217 -1.5 2.2 5.2 -5.2 11.83 -12.15 11.83 -12.15 2.30 72% 45.9 0.1218 -1.5 1.8 5.2 -5.2 11.83 -12.23 11.83 -12.23 2.30 72% 45.4 0.1219 -1.5 1.9 5.2 -5.2 11.79 -12.09 11.79 -12.09 2.29 71% 45.4 0.1220 -1.7 2.0 5.2 -5.2 11.77 -12.09 11.77 -12.09 2.29 71% 45.4 0.1221 -1.6 6.7 13.9 -13.9 20.69 -21.52 21.05 -21.52 1.52 47% 311 0.1722 -4.4 4.7 10.4 -10.4 14.58 -14.81 14.58 -14.81 1.41 44% 136 0.1423 -3.7 4.7 10.4 -10.4 14.41 -14.75 14.41 -14.75 1.40 44% 122 0.1324 -3.8 4.2 10.4 -10.4 14.47 -14.83 14.47 -14.83 1.41 44% 121 0.1325 -3.4 10.8 20.7 -20.7 23.84 -24.93 23.84 -24.93 1.18 37% 516 0.1626 -9.3 8.3 15.7 -15.6 15.62 -15.68 15.62 -15.68 1.00 31% 232 0.1527 -6.1 8.2 15.7 -15.7 15.94 -16.17 15.94 -16.17 1.02 32% 207 0.1328 -5.5 8.2 15.7 -15.7 15.62 -16.00 15.62 -16.00 1.01 32% 203 0.1329 -5.4 17.0 27.9 -27.9 26.70 -27.57 27.25 -28.00 0.97 30% 720 0.1530 -14.0 12.0 20.9 -20.8 16.01 -15.90 16.01 -15.90 0.77 24% 326 0.1631 -9.1 12.0 20.8 -20.9 16.20 -16.15 16.20 -16.15 0.78 24% 291 0.1432 -9.2 32.7 48.6 -48.8 35.98 -35.66 35.98 -36.11 0.74 23% 1846 0.1733 -28.3 26.7 36.6 -36.6 17.33 -16.84 17.33 -16.84 0.47 15% 621 0.1634 -19.8 25.5 36.5 -36.5 17.31 -17.56 17.31 -17.56 0.48 15% 535 0.1335 -21.2 50.0 69.6 -69.5 39.33 -36.83 39.33 -37.49 0.55 17% 2538 0.1536 -43.0 38.4 52.3 -52.2 14.52 -13.83 15.60 -13.83 0.27 8% 828 0.1837 -29.5 37.3 52.2 -52.2 13.98 -13.32 13.98 -13.32 0.26 8% 674 0.1538 -30.1 80.3 104.4 -104.5 24.27 -11.04 29.06 -16.86 0.17 5% 2519 0.2239 -62.4 65.8 78.1 -78.0 6.81 -6.12 6.96 -6.44 0.08 3% 607 0.1940 -43.7 65.7 78.0 -78.0 6.47 -5.76 6.85 -5.93 0.08 2% 487 0.1641 -34.1 96.5 125.7 -125.7 12.07 -7.57 13.43 -8.68 0.08 2% 1266 0.1642 -75.4 80.7 104.0 -104.0 5.14 -4.84 5.61 -4.84 0.05 1% 548 0.1743 -30.4 80.5 104.0 -104.0 4.38 -4.57 4.95 -4.89 0.04 1% 433 0.00
55CUREE Test 4.1, June 25, 2001
Def. at P=0 (mm)
Peak Deflection
(mm) Load at δi
(kN) Max Force
(kN)
Cyclic Stiffness (kN/mm)
Energy(kN-mm)
EVDCycle Number
δ o,i+ δ o,i- δ i+ δ i− Pi+ Pi- Pmaxi+ Pmaxi- Ki %K1 Ei ζi 1 0.0 1.4 3.9 -3.8 9.58 -9.11 9.58 -9.11 2.44 100% 33.0 0.152 -1.0 1.4 3.9 -3.8 9.44 -9.03 9.44 -9.03 2.40 99% 29.1 0.133 -1.0 1.4 3.8 -3.8 9.50 -8.87 9.50 -8.87 2.39 98% 27.8 0.134 -1.0 1.3 3.8 -3.8 9.38 -8.91 9.38 -8.91 2.39 98% 27.4 0.135 -1.1 1.4 3.8 -3.8 9.32 -8.79 9.32 -8.79 2.37 97% 27.0 0.126 -1.0 1.4 3.9 -3.8 9.50 -8.87 9.50 -8.87 2.39 98% 27.0 0.127 -1.1 2.1 5.7 -5.7 12.16 -10.97 12.16 -10.97 2.03 83% 58.7 0.148 -1.7 1.7 4.4 -4.4 9.56 -8.69 9.56 -8.69 2.08 86% 35.1 0.149 -1.3 1.6 4.4 -4.4 9.54 -8.60 9.54 -8.60 2.08 85% 33.4 0.13
10 -1.4 1.6 4.4 -4.3 9.67 -8.77 9.67 -8.77 2.11 87% 33.0 0.1311 -1.4 1.6 4.4 -4.4 9.46 -8.66 9.46 -8.66 2.07 85% 33.0 0.1312 -1.5 1.6 4.4 -4.3 9.40 -8.62 9.40 -8.62 2.09 86% 33.0 0.1413 -1.4 1.6 4.4 -4.3 9.60 -8.73 9.60 -8.73 2.11 87% 32.5 0.1314 -1.4 3.0 7.6 -7.5 14.24 -12.45 14.24 -12.45 1.77 73% 91.2 0.1415 -2.2 2.5 5.8 -5.8 10.42 -9.42 10.42 -9.42 1.72 71% 52.2 0.1516 -1.9 2.4 5.8 -5.7 10.50 -9.56 10.50 -9.56 1.74 72% 50.5 0.1417 -1.9 2.4 5.8 -5.7 10.48 -9.54 10.48 -9.54 1.74 71% 50.1 0.1418 -1.9 2.4 5.8 -5.8 10.54 -9.58 10.54 -9.58 1.75 72% 49.2 0.1419 -1.9 2.5 5.8 -5.8 10.57 -9.63 10.57 -9.63 1.75 72% 49.2 0.1420 -1.9 2.4 5.8 -5.8 10.59 -9.77 10.59 -9.77 1.76 72% 48.8 0.1321 -2.0 7.3 15.3 -15.2 19.84 -17.88 19.84 -17.88 1.24 51% 313 0.1722 -6.3 5.6 11.5 -11.5 13.43 -11.98 13.43 -11.98 1.11 45% 136 0.1523 -4.8 5.5 11.6 -11.5 13.28 -11.91 13.28 -11.91 1.09 45% 128 0.1424 -4.9 5.6 11.6 -11.6 13.32 -12.14 13.32 -12.14 1.10 45% 128 0.1425 -4.9 11.5 23.0 -22.8 23.99 -22.93 23.99 -22.93 1.02 42% 535 0.1626 -11.1 8.8 17.3 -17.3 14.63 -13.45 14.63 -13.45 0.81 33% 227 0.1527 -8.4 8.7 17.3 -17.3 14.80 -13.45 14.80 -13.45 0.82 34% 212 0.1428 -8.7 8.9 17.3 -17.3 14.82 -13.59 14.82 -13.59 0.82 34% 209 0.1429 -8.6 16.2 30.5 -30.2 27.06 -26.69 27.06 -26.69 0.88 36% 766 0.1530 -16.3 12.6 23.1 -23.0 15.31 -14.00 15.31 -14.00 0.64 26% 317 0.1531 -12.4 11.9 23.0 -23.1 15.43 -14.35 15.43 -14.35 0.65 26% 299 0.1432 -11.7 35.7 53.3 -53.4 34.90 -33.70 34.90 -33.70 0.64 26% 2026 0.1833 -33.7 26.6 40.4 -40.4 15.55 -14.26 15.55 -14.26 0.37 15% 613 0.1634 -24.9 26.7 40.5 -40.3 15.49 -14.45 15.49 -14.45 0.37 15% 559 0.1535 -25.0 54.4 76.5 -76.5 34.82 -26.46 36.05 -27.38 0.40 16% 2484 0.1736 -47.4 38.0 57.2 -57.2 10.20 -10.85 10.20 -10.85 0.18 8% 656 0.1737 -33.6 37.7 57.4 -57.4 9.99 -11.18 9.99 -11.18 0.18 8% 581 0.1538 -33.7 68.2 115.5 -115.5 10.57 -11.59 15.57 -11.59 0.10 4% 1593 0.2039 -54.1 44.8 85.9 -86.1 5.03 -6.31 5.03 -6.31 0.07 3% 475 0.1640 -34.2 43.2 85.9 -86.4 4.60 -5.80 4.60 -5.80 0.06 2% 394 0.1441 -29.8 60.7 123.1 -122.9 7.17 -10.30 7.17 -10.30 0.07 3% 757 0.1142 -58.2 43.0 115.4 -115.2 5.48 -7.32 5.48 -7.32 0.06 2% 554 0.1243 -47.1 34.5 115.4 -115.2 5.48 -6.93 5.48 -6.93 0.05 2% 488 0.00
56
CUREE Test 4.2, July 19, 2001
Def. at P=0 (mm)
Peak Deflection
(mm) Load at δi
(kN) Max Force
(kN)
Cyclic Stiffness (kN/mm)
Energy(kN-mm)
EVDCycle Number
δ o,i+ δ o,i- δ i+ δ i− Pi+ Pi- Pmaxi+ Pmaxi- Ki %K1 Ei ζi 1 0.0 1.6 3.8 -3.8 11.82 -11.68 11.82 -11.68 3.09 100% 46.8 0.172 -1.3 1.4 3.8 -3.8 11.92 -11.34 11.92 -11.34 3.03 98% 39.0 0.143 -1.3 1.4 3.8 -3.8 11.67 -11.24 11.67 -11.24 2.99 97% 36.7 0.134 -1.3 1.4 3.8 -3.8 11.57 -11.24 11.57 -11.24 2.99 97% 35.8 0.135 -1.4 1.4 3.8 -3.8 11.63 -11.24 11.63 -11.24 3.00 97% 34.9 0.136 -1.2 1.4 3.8 -3.8 11.43 -11.21 11.43 -11.21 2.97 96% 34.4 0.137 -1.1 2.2 5.6 -5.7 14.88 -14.46 14.88 -14.46 2.61 85% 73.0 0.148 -1.7 1.8 4.3 -4.3 11.55 -11.01 11.55 -11.01 2.62 85% 42.7 0.149 -1.4 1.7 4.3 -4.3 11.22 -11.13 11.22 -11.13 2.60 84% 40.4 0.1310 -1.4 1.8 4.3 -4.3 11.33 -11.01 11.33 -11.01 2.59 84% 39.9 0.1311 -1.4 1.8 4.3 -4.3 11.53 -11.17 11.53 -11.17 2.64 85% 39.5 0.1312 -1.3 1.8 4.3 -4.4 11.29 -11.28 11.29 -11.28 2.61 84% 39.9 0.1313 -1.4 1.7 4.4 -4.4 11.26 -11.26 11.26 -11.26 2.58 83% 39.0 0.1314 -1.4 3.3 7.6 -7.6 16.72 -16.77 16.72 -16.77 2.19 71% 112.5 0.1415 -2.1 2.5 5.8 -5.7 12.35 -12.18 12.35 -12.18 2.14 69% 62.4 0.1416 -1.8 2.5 5.7 -5.7 12.29 -12.28 12.29 -12.28 2.15 70% 59.2 0.1317 -1.7 2.3 5.8 -5.7 12.41 -12.42 12.41 -12.42 2.16 70% 58.3 0.1318 -1.7 2.5 5.8 -5.8 12.31 -12.28 12.31 -12.28 2.13 69% 58.8 0.1319 -1.7 2.5 5.8 -5.8 12.53 -12.40 12.53 -12.40 2.16 70% 57.9 0.1320 -1.6 2.4 5.8 -5.8 12.51 -12.44 12.51 -12.44 2.16 70% 57.4 0.1321 -1.7 7.8 15.1 -15.1 22.77 -22.58 22.77 -22.58 1.50 49% 379 0.1822 -5.2 6.1 11.5 -11.5 14.94 -15.24 14.94 -15.24 1.31 42% 156 0.1423 -3.4 5.4 11.5 -11.5 15.41 -15.36 15.41 -15.36 1.34 43% 145 0.1324 -3.3 5.6 11.6 -11.6 15.02 -15.24 15.02 -15.24 1.31 42% 142 0.1325 -3.1 13.0 22.8 -22.6 26.35 -26.54 26.35 -26.54 1.16 38% 614 0.1626 -7.7 10.4 17.3 -17.2 15.80 -16.10 15.80 -16.10 0.93 30% 252 0.1527 -5.9 9.9 17.3 -17.1 16.03 -16.24 16.03 -16.24 0.94 30% 234 0.1328 -6.1 10.3 17.3 -17.3 16.09 -16.41 16.09 -16.41 0.94 30% 228 0.1329 -5.5 19.2 30.6 -30.5 29.45 -29.61 29.45 -29.61 0.97 31% 843 0.1530 -13.8 14.6 22.9 -23.1 15.99 -16.18 15.99 -16.18 0.70 23% 339 0.1531 -7.4 14.5 22.9 -23.2 16.19 -16.47 16.19 -16.47 0.71 23% 316 0.1332 -7.3 37.7 53.1 -53.1 37.97 -36.66 37.97 -36.66 0.70 23% 2168 0.1733 -29.5 29.7 40.5 -40.4 16.31 -15.59 16.31 -15.59 0.39 13% 620 0.1534 -19.5 29.5 40.4 -40.3 16.09 -16.06 16.09 -16.06 0.40 13% 546 0.1335 -19.2 56.4 65.7 -66.7 32.58 -17.33 32.58 -17.33 0.38 12% 1959 0.1936 -19.9 43.0 57.1 -57.6 9.90 -8.39 9.90 -8.39 0.16 5% 499 0.1537 -19.0 43.4 57.6 -57.6 9.47 -8.44 9.47 -8.44 0.16 5% 424 0.1338 -3.6 86.4 102.8 -90.3 23.71 -15.24 23.71 -15.24 0.20 7% 2243 0.1939 -50.9 67.1 86.5 -86.1 8.20 -7.15 8.20 -7.15 0.09 3% 632 0.1540 1.7 69.6 86.5 -86.5 7.83 -7.15 7.83 -7.15 0.09 3% 521 0.1341 -6.3 92.3 115.8 -121.8 13.74 -11.09 13.74 -11.09 0.10 3% 1140 0.1242 11.2 94.3 115.4 -115.2 5.54 -6.92 5.54 -6.92 0.05 2% 620 0.1443 34.3 87.5 113.3 -112.7 5.24 -6.17 5.24 -6.17 0.05 2% 554 0.00
57CUREE Test DA.1, August 2, 2001
Def. at P=0 (mm)
Peak Deflection
(mm) Load at δi
(kN) Max Force
(kN)
Cyclic Stiffness (kN/mm)
Energy(kN-mm)
EVDCycle Number
δ o,i+ δ o,i- δ i+ δ i− Pi+ Pi- Pmaxi+ Pmaxi- Ki %K1 Ei ζi 1 0.0 1.7 3.8 -3.8 10.89 -11.02 10.89 -11.02 2.88 100% 42.1 0.162 -1.1 1.6 3.8 -3.8 10.83 -10.90 10.83 -10.90 2.86 99% 38.6 0.153 -1.0 1.5 3.8 -3.8 10.73 -10.81 10.73 -10.81 2.82 98% 34.3 0.134 -1.0 1.4 3.8 -3.8 10.66 -10.59 10.66 -10.59 2.80 97% 32.6 0.135 -1.0 1.5 3.8 -3.9 10.93 -10.65 10.93 -10.65 2.81 98% 31.8 0.126 -1.0 1.5 3.8 -3.8 10.54 -10.53 10.54 -10.53 2.75 96% 31.8 0.137 -1.0 2.3 5.7 -5.6 13.77 -13.53 13.77 -13.53 2.40 83% 80.7 0.178 -1.3 1.9 4.3 -4.3 10.30 -10.28 10.30 -10.28 2.39 83% 38.2 0.149 -1.2 1.9 4.3 -4.3 10.42 -10.45 10.42 -10.45 2.42 84% 36.5 0.1310 -1.1 1.7 4.3 -4.3 10.50 -10.32 10.50 -10.32 2.41 84% 36.1 0.1311 -1.0 1.9 4.3 -4.3 10.42 -10.28 10.42 -10.28 2.40 83% 35.6 0.1312 -1.1 1.8 4.3 -4.3 10.38 -10.36 10.38 -10.36 2.41 84% 35.6 0.1313 -1.1 1.9 4.3 -4.3 10.48 -10.45 10.48 -10.45 2.43 84% 35.2 0.1214 -1.1 3.2 7.6 -7.6 15.88 -15.80 15.88 -15.80 2.08 72% 101.7 0.1315 -1.8 2.5 5.8 -5.8 11.71 -11.65 11.71 -11.65 2.03 70% 55.8 0.1316 -1.5 2.6 5.8 -5.7 11.67 -11.65 11.67 -11.65 2.03 70% 53.2 0.1317 -1.4 2.6 5.7 -5.7 11.73 -11.65 11.73 -11.65 2.04 71% 52.4 0.1218 -1.4 2.4 5.7 -5.8 11.69 -11.73 11.69 -11.73 2.04 71% 52.4 0.1219 -1.4 2.5 5.8 -5.7 11.69 -11.82 11.69 -11.82 2.05 71% 51.9 0.1220 -1.3 2.6 5.8 -5.7 11.75 -11.69 11.75 -11.69 2.04 71% 51.5 0.1221 -1.5 7.9 15.3 -15.2 21.94 -21.38 21.94 -21.38 1.42 49% 351 0.1722 -4.5 5.9 11.4 -11.5 14.63 -14.57 14.63 -14.57 1.27 44% 140 0.1323 -2.6 5.9 11.5 -11.4 14.55 -14.70 14.55 -14.70 1.28 44% 130 0.1224 -2.5 5.9 11.5 -11.5 14.79 -14.70 14.79 -14.70 1.28 45% 127 0.1225 -2.5 13.4 22.5 -22.8 25.87 -25.96 25.87 -25.96 1.14 40% 594 0.1626 -7.8 10.3 17.3 -17.1 15.71 -15.64 15.71 -15.64 0.91 32% 233 0.1427 -4.7 10.2 17.3 -17.2 16.06 -15.76 16.06 -15.76 0.92 32% 216 0.1328 -4.0 10.1 17.3 -17.2 15.85 -15.88 15.85 -15.88 0.92 32% 212 0.1229 -4.9 19.4 29.8 -30.1 29.47 -29.88 29.47 -29.88 0.99 34% 835 0.1530 -11.8 15.1 23.0 -22.9 16.20 -16.15 16.20 -16.15 0.70 24% 324 0.1431 -7.0 14.9 23.1 -23.0 16.39 -16.39 16.39 -16.39 0.71 25% 300 0.1332 -7.1 38.7 53.3 -53.4 37.80 -35.81 38.31 -36.26 0.69 24% 2181 0.1833 -26.0 30.1 40.4 -40.1 16.57 -15.68 16.57 -15.68 0.40 14% 625 0.1534 -16.7 30.3 40.3 -40.1 16.51 -16.07 16.51 -16.07 0.40 14% 555 0.1435 -16.8 58.3 76.6 -75.8 35.66 -33.74 37.54 -33.74 0.46 16% 2708 0.1636 -43.6 46.8 57.8 -57.4 13.32 -12.94 13.32 -12.94 0.23 8% 809 0.1737 -28.3 47.1 57.8 -57.5 12.73 -13.02 12.73 -13.02 0.22 8% 690 0.1538 -25.0 79.2 115.4 -114.8 13.63 -13.10 25.32 -14.51 0.12 4% 2159 0.2239 -19.3 65.2 86.9 -86.4 5.29 -7.44 5.29 -7.44 0.07 3% 508 0.1540 10.5 64.4 86.9 -86.3 4.96 -7.32 4.96 -7.32 0.07 2% 415 0.12
58CUREE Test DA.2, August 3, 2001
Def. at P=0 (mm)
Peak Deflection
(mm) Load at δi
(kN) Max Force
(kN)
Cyclic Stiffness (kN/mm)
Energy(kN-mm)
EVDCycle Number
δ o,i+ δ o,i- δ i+ δ i− Pi+ Pi- Pmaxi+ Pmaxi- Ki %K1 Ei ζi 1 0.0 1.5 3.8 -3.8 12.81 -12.82 12.81 -12.82 3.37 100% 47.1 0.152 -1.4 1.2 3.8 -3.8 12.85 -13.04 12.85 -13.04 3.40 101% 39.0 0.133 -1.3 1.1 3.8 -3.8 12.85 -12.43 12.85 -12.43 3.31 98% 36.9 0.124 -1.3 1.1 3.8 -3.8 12.56 -12.31 12.56 -12.31 3.25 97% 35.2 0.125 -1.2 1.0 3.9 -3.8 12.54 -12.10 12.54 -12.10 3.21 95% 34.8 0.126 -1.3 1.0 3.8 -3.8 12.59 -12.26 12.59 -12.26 3.26 97% 34.3 0.127 -1.3 1.7 5.7 -5.7 16.22 -15.17 16.22 -15.17 2.75 82% 76.3 0.148 -2.0 1.2 4.3 -4.3 12.42 -11.57 12.42 -11.57 2.79 83% 43.3 0.139 -1.6 1.2 4.3 -4.3 12.28 -11.47 12.28 -11.47 2.76 82% 41.1 0.1310 -1.5 1.2 4.3 -4.3 12.42 -11.61 12.42 -11.61 2.78 83% 40.3 0.1211 -1.6 1.3 4.3 -4.3 12.40 -11.63 12.40 -11.63 2.79 83% 40.3 0.1212 -1.6 1.2 4.3 -4.3 12.34 -11.69 12.34 -11.69 2.79 83% 39.9 0.1213 -1.6 1.2 4.3 -4.3 12.52 -11.67 12.52 -11.67 2.80 83% 39.9 0.1214 -1.6 2.3 7.6 -7.5 18.82 -17.23 18.82 -17.23 2.39 71% 117.0 0.1415 -3.0 1.7 5.8 -5.7 14.14 -12.63 14.14 -12.63 2.34 70% 63.2 0.1316 -2.3 1.6 5.8 -5.7 14.06 -12.65 14.06 -12.65 2.32 69% 60.6 0.1317 -2.3 1.7 5.8 -5.8 14.06 -12.63 14.06 -12.63 2.31 69% 59.4 0.1218 -2.3 1.6 5.8 -5.7 14.00 -12.63 14.00 -12.63 2.32 69% 58.5 0.1219 -2.3 1.6 5.7 -5.7 14.22 -12.67 14.22 -12.67 2.35 70% 58.5 0.1220 -2.2 1.7 5.7 -5.7 14.08 -12.78 14.08 -12.78 2.34 70% 58.1 0.1221 -2.3 6.7 15.2 -15.1 24.83 -22.87 24.83 -22.87 1.58 47% 399 0.1822 -6.8 4.9 11.5 -11.4 16.96 -15.27 16.96 -15.27 1.41 42% 166 0.1423 -5.1 4.5 11.5 -11.4 17.16 -15.21 17.16 -15.21 1.41 42% 154 0.1324 -5.0 4.4 11.5 -11.5 17.18 -15.33 17.18 -15.33 1.41 42% 151 0.1325 -5.1 11.5 22.8 -22.5 28.50 -26.96 28.50 -26.96 1.22 36% 656 0.1726 -10.4 8.6 17.3 -17.1 17.86 -16.25 17.86 -16.25 0.99 29% 275 0.1527 -8.0 8.7 17.3 -17.4 18.08 -16.52 18.08 -16.52 1.00 30% 253 0.1328 -7.4 8.8 17.3 -17.2 17.98 -16.47 17.98 -16.47 1.00 30% 249 0.1329 -8.0 17.4 30.4 -30.4 31.55 -29.39 31.55 -29.39 1.00 30% 911 0.1630 -16.2 13.0 23.0 -22.8 18.06 -16.09 18.06 -16.09 0.75 22% 370 0.1531 -11.7 13.3 23.0 -22.9 17.98 -16.52 17.98 -16.52 0.75 22% 345 0.1432 -12.1 35.9 53.2 -53.4 38.68 -34.25 38.68 -34.93 0.68 20% 2220 0.1833 -33.4 28.5 40.4 -40.0 16.94 -14.90 16.94 -14.90 0.40 12% 653 0.1634 -23.3 27.9 40.4 -40.2 16.96 -15.08 16.96 -15.08 0.40 12% 599 0.1535 -23.8 52.0 76.4 -76.3 20.09 -11.82 36.27 -14.10 0.21 6% 2009 0.2636 -30.0 36.4 57.8 -57.4 8.23 -7.40 8.23 -7.40 0.14 4% 467 0.1737 -18.5 35.4 57.5 -57.4 8.36 -7.38 8.36 -7.38 0.14 4% 398 0.1438 -19.9 62.3 113.8 -114.1 12.18 -9.38 13.73 -10.55 0.09 3% 1333 0.1739 -16.9 51.5 86.9 -86.3 5.76 -5.97 5.76 -5.97 0.07 2% 449 0.1440 -11.7 51.5 86.7 -86.3 5.96 -6.03 5.96 -6.03 0.07 2% 430 0.13
59CUREE Test 5, August 9, 2001
Def. at P=0 (mm)
Peak Deflection
(mm) Load at δi
(kN) Max Force
(kN)
Cyclic Stiffness (kN/mm)
Energy(kN-mm)
EVDCycle Number
δ o,i+ δ o,i- δ i+ δ i− Pi+ Pi- Pmaxi+ Pmaxi- Ki %K1 Ei ζi 1 0.0 1.5 3.8 -3.7 11.05 -11.10 11.05 -11.10 2.96 100% 44.4 0.172 -1.4 1.3 3.7 -3.8 11.11 -10.73 11.11 -10.73 2.92 99% 38.2 0.153 -1.4 1.2 3.8 -3.8 11.03 -10.77 11.03 -10.77 2.85 96% 35.7 0.144 -1.4 1.2 3.8 -3.8 10.95 -10.59 10.95 -10.59 2.82 95% 34.9 0.145 -1.4 1.1 3.8 -3.8 11.05 -10.61 11.05 -10.61 2.83 96% 33.5 0.136 -1.5 1.1 3.8 -3.8 11.11 -10.65 11.11 -10.65 2.86 97% 33.5 0.137 -1.5 1.7 5.7 -5.7 14.14 -13.43 14.14 -13.43 2.40 81% 70.6 0.148 -2.3 1.3 4.3 -4.3 11.13 -10.02 11.13 -10.02 2.47 83% 41.0 0.149 -1.9 1.1 4.3 -4.3 11.18 -10.08 11.18 -10.08 2.47 84% 39.1 0.14
10 -1.9 1.2 4.3 -4.3 11.20 -10.14 11.20 -10.14 2.47 83% 38.5 0.1311 -1.8 1.1 4.3 -4.3 11.11 -10.08 11.11 -10.08 2.45 83% 38.5 0.1312 -1.9 1.1 4.3 -4.3 11.11 -10.22 11.11 -10.22 2.48 84% 37.9 0.1313 -1.8 1.1 4.3 -4.3 11.09 -10.24 11.09 -10.24 2.48 84% 37.4 0.1314 -1.8 2.3 7.5 -7.5 16.57 -15.53 16.57 -15.53 2.13 72% 108.8 0.1415 -3.3 1.6 5.8 -5.8 12.52 -11.08 12.52 -11.08 2.05 69% 60.8 0.1416 -2.6 1.7 5.7 -5.8 12.52 -11.20 12.52 -11.20 2.06 70% 58.6 0.1417 -2.7 1.5 5.7 -5.8 12.52 -11.22 12.52 -11.22 2.07 70% 57.5 0.1318 -2.6 1.5 5.8 -5.8 12.59 -11.24 12.59 -11.24 2.07 70% 56.6 0.1319 -2.7 1.5 5.8 -5.8 12.63 -11.22 12.63 -11.22 2.07 70% 56.6 0.1320 -2.7 1.5 5.7 -5.8 12.69 -11.28 12.69 -11.28 2.08 70% 55.2 0.1321 -2.6 6.2 15.3 -15.2 22.54 -21.20 22.54 -21.20 1.44 49% 372 0.1822 -7.7 4.1 11.5 -11.5 15.73 -13.57 15.73 -13.57 1.28 43% 157 0.1523 -6.0 3.6 11.5 -11.5 15.79 -13.65 15.79 -13.65 1.28 43% 146 0.1424 -6.0 3.8 11.4 -11.5 15.90 -13.78 15.90 -13.78 1.30 44% 142 0.1325 -5.9 10.6 22.9 -22.9 26.52 -24.87 26.52 -24.87 1.12 38% 614 0.1726 -13.2 7.6 17.2 -17.2 17.12 -14.14 17.12 -14.14 0.91 31% 256 0.1527 -10.4 7.6 17.3 -17.1 17.18 -14.47 17.18 -14.47 0.92 31% 240 0.1428 -10.2 7.3 17.2 -17.1 17.24 -14.55 17.24 -14.55 0.93 31% 235 0.1429 -10.4 16.0 30.4 -30.4 30.41 -27.73 30.41 -27.73 0.96 32% 846 0.1530 -18.5 11.0 23.0 -22.9 17.41 -14.45 17.41 -14.45 0.69 23% 351 0.1531 -14.2 11.2 22.9 -22.9 17.69 -14.59 17.69 -14.59 0.71 24% 328 0.1432 -14.1 33.5 53.6 -53.5 39.11 -33.31 39.11 -33.74 0.68 23% 2153 0.1833 -36.9 24.3 40.4 -40.3 18.16 -13.72 18.16 -13.72 0.40 13% 649 0.1634 -29.2 24.1 40.4 -40.3 17.82 -13.65 17.82 -13.65 0.39 13% 579 0.1535 -29.3 51.7 76.3 -76.3 33.25 -20.50 35.13 -22.71 0.35 12% 2289 0.1836 -55.9 34.8 57.6 -57.6 12.07 -8.48 12.07 -8.48 0.18 6% 627 0.1737 -45.5 34.4 57.8 -57.6 11.73 -8.48 11.73 -8.48 0.18 6% 554 0.15
61Description of Backbone Curve Properties
For each test conducted in this study, hysteretic load-displacement data were reduced to backbone curves representing the overall wall response to cyclic loading. For each primary loading cycle, the peak displacement and load at peak displacement was plotted making up the backbone curve. In instances where the peak load occurred at displacements notably lower than peak, an additional point was plotted to illustrate the drop in load carrying capacity of the wall.
62
Backbone Curves for CUREE 1 Tests (∆ref = 53 mm)
0
10
20
30
40
0 10 20 30 40 50 60 70 80 90 100 110 120 130
Displacement (mm)
Load
(kN
)
Backbone Curves for CUREE 2 Tests (Dref = 61 mm)
0
10
20
30
40
0 10 20 30 40 50 60 70 80 90 100 110 120 130
Displacement (mm)
Load
(kN
)
63
Backbone Curves for CUREE 3 Tests (∆ref = 69mm)
0
10
20
30
40
0 10 20 30 40 50 60 70 80 90 100 110 120 130
Displacement (mm)
Load
(kN
)
Backbone Curves for CUREE 4 Tests(∆ref = 76mm)
0
10
20
30
40
0 10 20 30 40 50 60 70 80 90 100 110 120 130
Displacement (mm)
Load
(kN
)
64
Backbone Curves for 8 CUREE Tests, Reference Displacement Study
0
10
20
30
40
0 10 20 30 40 50 60 70 80 90 100 110 120 130
Displacement (mm)
Load
(kN
)
Backbone Curves for Damage Accumulation Tests Segmented CUREE Protocol
(∆ref = 76 mm)
0
10
20
30
40
0 10 20 30 40 50 60 70 80 90 100 110 120 130
Displacement (mm)
Load
(kN
)
65
Backbone Curve for Test CUREE 5 37 Cycles (D = 76mm)
0
10
20
30
40
0 10 20 30 40 50 60 70 80 90 100 110 120 130
Displacement (mm)
Load
(kN
)
67
Description of Sheathing Nail Damage Figures
Presented next are figures illustrating sheathing nail failure modes for each of the quasi-static cyclic tests performed in this study. The first figure for each test shows the quantity of fatigue, withdrawal and pull-through damage modes expressed as a percentage of the total number of sheathing nails (approximately 170 sheathing nails were used per wall). The second figure shown for each test illustrates the distribution of failure modes for panel edges that sustained a particularly high level of damage (i.e. edges where more than 80% of the sheathing nail connections were visibly degraded). Failure mode percentages shown along interior edges pertain to the total damage to both interior edges combined.
Sheathing Nail Failure Modes: Test CUREE 1.1
68
Test 1.1∆ref = 53 mm
0%
10%
20%
30%
40%
50%
% o
f Tot
al N
ails
Fatigue Withdrawal
Pull-through
60%
F
2
0% P
T
20
% W
75% F 15% PT 10% W
90% F 10% PT55% F 15% PT 15% W
40% F 40% PT 20% W
Sheathing Nail Failure Modes: Test CUREE 1.2
69
Test 1.2∆ref = 53 mm
0%
10%
20%
30%
40%
50%%
of T
otal
Nai
ls
Fatigue
Withdrawal
Pull-through
75%
F
2
0% P
T
5%
W
70% F 15% PT 15% W55% F 35% PT 0% W
Sheathing Nail Failure Modes: Test CUREE 2.1
70
Test 2.1∆ref = 61 mm
0%
10%
20%
30%
40%
50%
% o
f Tot
al N
ails Fatigue
Withdrawal
Pull-through
45%
F
2
5% P
T
20
% W
15% F 50% PT 25% W
60% F 30% PT 10% W60% F 15% PT 25% W
90% PT 10% W
Sheathing Nail Failure Modes: Test CUREE 2.2
71
Test 2.2∆ref = 61 mm
0%
10%
20%
30%
40%
50%
% o
f Tot
al N
ails
Fatigue
Withdrawal
Pull-through
60%
F
30
% P
T
10%
W
40% F 60% PT
60%
F
2
5% P
T
15%
W
35%
F
50%
PT
1
5% W
75% F 25% PT75% PT 25% W
15% F 45% PT 40% W
Sheathing Nail Failure Modes: Test CUREE 3.1
72
Test 3.1∆ref = 69 mm
0%
10%
20%
30%
40%
50%
% o
f Tot
al N
ails
FatigueWithdrawal
Pull-through
45%
F
35%
PT
2
0% W
45% F 15% PT 40% W
10%
F
85%
PT
5%
W
65%
PT
15
% W
10% F 85% W10% F 80% PT 10% W
30% F 40% PT 25% W
Sheathing Nail Failure Modes: Test CUREE 3.2
73
Test 3.2∆ref = 69 mm
0%
10%
20%
30%
40%
50%
% o
f Tot
al N
ails
Fatigue
Withdrawal
Pull-through
45%
F
3
0% P
T
10%
W
55% F 30% PT 15% W
80%
PT
10% F 75% PT
40% F 45% PT 15% W
Sheathing Nail Failure Modes: Test CUREE 4.1
74
Test 4.1∆ref = 76 mm
0%
10%
20%
30%
40%
50%
% o
f Tot
al N
ails
Fatigue
Withdrawal
Pull-through
70% PT 30% W
30%
F
50
% P
T
10%
W
60% PT 40% W
Sheathing Nail Failure Modes: Test CUREE 4.2
75
Test 4.2 ∆ref = 76 mm
0%
10%
20%
30%
40%
50%
% o
f Tot
al N
ails
Fatigue
Withdrawal
Pull-through
60%
F
30%
PT
1
0% W
40% F 60% PT
80% PT 10% W
30% F 55% PT 15% W
Damage Accumulation Tests Damage and Failure Modes, Number of Damaged Nails at Various Cycles
76
TEST # Cycles Damage PT PPT W 0 2 0 0 10 4 0 17 6 8 14 11
19 18 39 34 31 39 0 7 0 0 13 0 0 13 0 0 13 0
11 24 8 37 17 17 54 15 19
28 46 16
28 0.9 0 12 2 0
37 3.1 15 21 24 0
Fatigue DA 1 24 2 0
28 14 0 31 23 0 34 33 0 37 76 0 40 132 28
DA 2 20 7 0 24 13 0
28 13 0 31 13 0 34 43 0 37 72 1 40 89 1
CUREE 5 37 100 10 Damage and Failure Modes, Average Number of Damaged Nails at Various Drift Levels from Tests DA.1 and DA.2
# Cycles Drift (%) PT PPT W Fatigue
24 0.6 0 5 0 0
31 1.2 0 15 3 0
34 2.1 4 14 6 0
40 4.6 36 24 28 15
77
= Withdrawal Apparent
Test: DA.1
Cycles: 1-24
Max Load (kN): 21.9 Drift (%): 0.64
Stiffness (%Ko): 57.3
= Partial Pull-Through
= Withdrawal Apparent
Test: DA.1
Cycles: 25-28
Max Load (kN): 25.9
Drift (%): 0.94
Stiffness (%Ko): 46
78
= Partial Pull-Through
= Withdrawal Apparent
Test: DA.1
Cycles: 29-31
Max Load (kN): 29.5
Drift (%): 1.25
Stiffness (%Ko): 39.6
= Partial Pull-Through
= Withdrawal Apparent
= Pull-Through
Test: DA.1
Cycles: 32-34
Max Load (kN): 37.8
Drift (%): 2.22
Stiffness (%Ko): 28.4
79
= Partial Pull-Through
= Withdrawal Apparent
= Pull-Through
Test: DA.1
Cycles: 35-37
Max Load (kN): 35.7
Drift (%): 3.2
Stiffness (%Ko): 18.6
= Partial Pull-Through
= Withdrawal Apparent
= Pull-Through
= Fatigue Fracture
Test: DA.1
Cycles: 38-40
Max Load (kN): 13.6
Drift (%): 4.8
Stiffness (%Ko): 4.7
80
= Partial Pull-Through
Test: DA.2
Cycles: 1-20
Max Load (kN): 18.8
Drift (%): 0.32
Stiffness (%Ko): 98.9
= Partial Pull-Through
Test: DA.2
Cycles: 21-31
Max Load (kN): 31.6
Drift (%): 1.25
Stiffness (%Ko): 41.5
81
= Partial Pull-Through
= Withdrawal Apparent
= Pull-Through
Test: DA.2
Cycles: 32-34
Max Load (kN): 38.7
Drift (%): 2.22
Stiffness (%Ko): 29.1
= Partial Pull-Through
= Withdrawal Apparent
= Pull-Through
= Fatigue Fracture
Test: DA.2
Cycles: 35-37
Max Load (kN): 20.1
Drift (%): 3.2
Stiffness (%Ko): 10.5
82
= Partial Pull-Through
= Withdrawal Apparent
= Pull-Through
= Fatigue Fracture
Test: DA.2
Cycles: 38-40
Max Load (kN): 12.2
Drift (%): 4.7
Stiffness (%Ko): 4.3
85
Monotonic Tests: Field Studs Detached from Sole Plate
Monotonic Test: Heel End-Post Separation from Sole Plate
86
Monotonic Tests: Pull-Through Failure along Bottom Edge Nailing
Monotonic Tests: Pull-Through Failure along Interior Edge Nailing
87
CUREE 1 Tests: Pull-Through and Fatigue along Interior Edge Nailing.
CUREE 1 Tests: Withdrawal and Fatigue along Bottom Edge Nailing
88
CUREE 1 Tests: Withdrawal of Sill-to-Stud Nailing
CUREE 1 Tests: Pull-Through and Fatigue of Top Interior Nailing
89
CUREE 2 Tests: Fatigue Fractures of Interior Edge Nailing
CUREE 2 Tests: Withdrawal and Pull-Through of Bottom Edge Nailing
90
CUREE 3 Tests: Damage to Bottom Edges
CUREE 3 Tests: Nail Withdrawal, Pull-Through and Buckling of Sheathing
91
CUREE3 Tests: Withdrawal and Pull-Through along Interior Edges
CUREE3 Tests: Withdrawal and Fatigue along Bottom Edges
92
CUREE 4 Tests: Withdrawal along Bottom Edge
CUREE 4 Tests: Rupture at Center Stud – Sole Plate Connection
93
CUREE 4 Tests: Heavy Damage to Interior Sheathing Nailing
CUREE 4 Tests: Separation of Center Stud from Sole Plate
94
Test DA 1: Pull-Through at Bottom Corner
Test DA 1: Rupture at Center Stud – Sole Plate Connection
95
Test DA 2: Pull-Through along Bottom Edge
Test DA 2: Rupture of Center Stud at Sole Plate Connection
97
Data Figures In addition to lateral load and drift data, several other LVDTs were installed to monitor movement of various wall components (see below). This data was used only to check the symmetry of the wall’s response and as a means of spotting any points of significant behavioral change. Provided here is a figure showing the LVDT locations on the wall specimen along with the designated channel number. Following are plots from these data as a function of applied lateral load. (Note: Positive load indicates outward stroke of the cylinder and negative load values indicate inward stroke).
Channels1: Load 2: Displacement3: Diagonal LVDT4: Sill Slip LVDT5: Diagonal LVDT6: Uplift LVDT7: Uplift LVDT
47
3 5 6
1, 2 INOUT
98
Load (1) vs. Displacement (2)
-50
-40
-30
-20
-10
0
10
20
30
40
50
-130 -120 -110 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130
Displacement (mm)
Load
(kN
)
Load (1) vs. Bottom Sill Slip (4)
-50
-40
-30
-20
-10
0
10
20
30
40
50
-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0
Slip (mm)
Load
(kN
)
99
Load (1) vs. Diagonal (3)
-50
-40
-30
-20
-10
0
10
20
30
40
50
-60 -40 -20 0 20 40 60 80
Diagonal (mm)
Load
(kN
)
Load (1) vs. Diagonal (5)
-50
-40
-30
-20
-10
0
10
20
30
40
50
-60 -40 -20 0 20 40 60
Diagonal (mm)
Load
(kN
)