additional tests using a segmented version of the curee...

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.

42

APPENDICES

43

APPENDIX A: Loading Frame Photos

44Loading Frame and Wall Specimen

Hydraulic Actuator Attached to Wall Sill Plate

45 Lateral Brace and Roller Assembly

46

APPENDIX B: Cyclic Loading Data Tables

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


Def. at P=0 (mm)

Peak Deflection

(mm) Load at δi

(kN) Max Force

(kN)


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)


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)


Energy(kN-mm)

EVDCycle Number


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)


Energy(kN-mm)

EVDCycle Number


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)


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


Def. at P=0 (mm)

Peak Deflection

(mm) Load at δi

(kN) Max Force

(kN)


Energy(kN-mm)

EVDCycle Number


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)


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)


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)


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)


Energy(kN-mm)

EVDCycle Number


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

60

APPENDIX C: Backbone Curves

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

)

66

APPENDIX D: Sheathing Nail Damage Details

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


69


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


70


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


71


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


72


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


73


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


74


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


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


Test: DA.1

Cycles: 25-28

Max Load (kN): 25.9

Drift (%): 0.94

Stiffness (%Ko): 46

78



Test: DA.1

Cycles: 29-31

Max Load (kN): 29.5

Drift (%): 1.25




= Pull-Through

Test: DA.1

Cycles: 32-34

Max Load (kN): 37.8

Drift (%): 2.22


79



= Pull-Through

Test: DA.1

Cycles: 35-37

Max Load (kN): 35.7

Drift (%): 3.2




= Pull-Through

= Fatigue Fracture

Test: DA.1

Cycles: 38-40

Max Load (kN): 13.6

Drift (%): 4.8


80


Test: DA.2

Cycles: 1-20

Max Load (kN): 18.8

Drift (%): 0.32



Test: DA.2

Cycles: 21-31

Max Load (kN): 31.6

Drift (%): 1.25


81



= Pull-Through

Test: DA.2

Cycles: 32-34

Max Load (kN): 38.7

Drift (%): 2.22




= Pull-Through

= Fatigue Fracture

Test: DA.2

Cycles: 35-37

Max Load (kN): 20.1

Drift (%): 3.2


82



= Pull-Through

= Fatigue Fracture

Test: DA.2

Cycles: 38-40

Max Load (kN): 12.2

Drift (%): 4.7


83

APPENDIX E: Damage Photos

84

Monotonic Tests: Pull-Through Sheathing Failures

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

96

APPENDIX F: Data Figures

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

)

100

Load (1) vs. Uplift (6)

-50

-40

-30

-20

-10

0

10

20

30

40

50

-15 -10 -5 0 5 10 15 20

Uplift (mm)

Load

(kN

)

Load (1) vs. Uplif t (7)

-50

-40

-30

-20

-10

0

10

20

30

40

50

-10 -5 0 5 10 15 20

Uplif t (mm)

Load

(kN

)

additional tests using a segmented version of the curee...

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