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Comparison of lateral performance: Residential light wood framing versus cold-formed steel framing

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Comparison of lateral performance: Residential light wood framing versus cold-formed steel framing

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COMPARISON OF LATERAL PERFORMANCE:
RESIDENTIAL LIGHT WOOD FRAMING VERSUS COLD-FORMED STEEL
FRAMING
by
Fang Sui
A Thesis Presented to the
Faculty of THE SCHOOL OF ARCHITECTURE
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirem ents for the D egree of
MASTER OF BUILDING SCIENCE
May 2002
May 2002 Fang Sui
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UNIVERSITY OF SOUTHERN C A LIFO R ^
The Graduate School
University Park
LOS ANGELES, CALIFORNIA 90089-169!
This th esis, w ritten b y
U nder th e d irectio n o f h M J C . Thesis
C om m ittee, an d a p p ro ved b y a ll its m em bers,
has been p resen ted to an d accepted b y The
G raduate School, in p a rtia l fu lfillm en t o f
requirem ents fo r th e degree o f
Dean o f Graduate Studies
Da te May 10. 20Q2 _ _
IS COMMITTEE
Chairperson
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DEDICATION
This thesis is dedicated to my parents and my husband. Thank you for
always being there and for teaching me the importance of hard work and
determination.
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ACKNOWLEDGEMENTS
There are too many people to whom I owe thanks for helping me complete
this project to name all individually. I am very appreciative of everyone who
assisted me in my research, as well as my graduate career.
First of all, I would like to thank my committee members: Prof. Schierle
(Chairman), Prof. Schiler and Prof. Vergun for the guidance and expertise provided
to me during the course of this project. I would also like to thank Prof. Gerry
Pardoen of University of California, Irvine, and Mr. Roger Brockenbrough who
offered me much information on previous shear wall test data.
I would also like to thank everyone who assisted me in the planning and
testing phase of this study. I would like to thank Prof. Schierle and Prof. Schiler for
their help with the test apparatus and test instrumentation. I would also like to thank
my husband, HaiFeng, and Ray, the woodshop supervisor in the School of
Architecture for their assistance in building the test frames and test specimens.
HaiFeng also helped me to do some tests during his busy final exam weeks.
Finally, I would like to express my gratitude to the graduate students in the
Building Science Program for their help in all aspects of this study. They have
helped me complete this project and make graduate school the most rewarding and
educational experience of my life.
HI
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TABLE OF CONTENTS
DEDICATION ii
ACKNOWLEDGEMENTS ....................................................................................iii
LIST OF TABLES vii
LIST OF FIGURES viii
LIST OF GRAPHS x
ABSTRACT xii
HYPOTHESIS xiii
Part I: Background Research 1
Chapter 1. Introduction 1
1.1. Definitions 1
1.2. Background 4
1.3. Thesis Objective 6
1.4. Design Codes 6
1.5. Application 7
1.6. Thesis Organization ............................................................................ 7
1.7. Limitation of Study ............................................................................ 8
Chapter 2. Literature Review 10
2.1. Introduction 10
2.2. Properties of Wood Studs and CFS Studs .................................... 10
2.3. Properties of Fasteners .................................................................. 11
2.4. Fastener Test Review ..........................................................................12
2.5. Monotonic Test Protocol of Shear Walls ...................................... 15
2.6. Cyclic Test Protocol of Shear Walls 16
2.7. Comparison Review of Wood and CFS Framing 17
Part H: Fastener Tests ......................................................................................... 19
Chapter 3. Fastener Test Description and Procedure 19
3.1. Introduction 19
3.2. Test Specimens ..................................................................................19
iv
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3.3. Test Apparatus ................................................................................ 22
3.4. Instrumentation ................................................................................ 27
3.5. Test Procedure ................................................................................ 28
3.6. Definition of Properties .................................................................28
Chapter 4. Fastener Parallel Test Results ......................................................... 31
4.1. Introduction ...................................................................................... 31
4.2. Results ....................................................................................... 31
4.3. Strength Limit State and Yield Strength State 36
4.4. Effective Shear Stiffness and Initial Shear Stiffness 37
4.5. Behaviors .............................................................................................38
Chapter 5. Fastener Perpendicular Test Results 42
5.1. Introduction .......................................................................................42
5.2. Results 42
5.3. Strength Limit State and Yield'Strength State 46
5.4. Effective Shear Stiffness and Initial Shear Stiffness .....................47
5.5. Behaviors ..........................................................................................49
Chapter 6. Fastener Test Discussion ..................................................................51
6.1. Introduction .........................................................................................51
6.2. Parallel Test Discussion ...................................................................51
6.3. Perpendicular Test Discussion 52
6.4. Perpendicular Test Comparison to Past Studies 53
6.5. Comparison o f Parallel Test and Perpendicular Test 55
Part HI. Shear Wall Test Comparison (Previous Tests) 59
Chapter 7. Monotonic Test Comparison (Previous Tests) ..............................59
7.1. Introduction .........................................................................................59
7.2. Specimen Description and Test Protocol 60
7.3. Behaviors Comparison ......................................................................61
7.4. Shear Wall vs. Fastener Test ............................................................ 63
7.5. Discussion .........................................................................................67
Chapter 8. Cyclic Test Comparison (Previous Tests) .........................................68
8.1. Introduction 68
8.2. Behavior Comparison .........................................................................68
8.3. Shear Wall vs. Fastener Test ......................................................... 69
8.4. Discussion 72
Part IV. Conclusion and Recommendation 73
V
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Chapter 9. Conclusion and Recommendation 73
9.1. Conclusions 73
9.2. Recommendation 74
Bibliography ..........................................................................................................76
Appendix A. Fastener Parallel Test Results 78
Appendix B. Fastener Perpendicular Test Results 83
Appendix C. Monotonic Test Results (Previous Tests) ..................................86
Appendix D. Cyclic Test Results (Previous Tests) 87
vi
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LIST OF TABLES
Table 2.1. Wood Stud versus CFS stud Comparison .........................................11
Table 2.2. Nail and screw Comparison ............................................................... 12
Table 3.1. Tested Specimens ................................................................................20
Table 4.1. Parallel Test Summary ........................................................................35
Table 5.1. Perpendicular T est Summary ............................................................ 46
Table 6.1. Monotonic Test Results for Failure Load (Serrette, 1997) 54
Table 6.2. Wood and CFS Fastener Test Results ................................................55
vii
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LIST OF FIGURES
Figure 1.1. Earthquake Acceleration of 1994 Northridge Earthquake ................I
Figure 1.2. Fastener Behavior under Lateral Force .................................... 2
Figure 1.3. Timber Cost Six Year Trend ............................................................. 5
Figure 1.4. Building Codes .................................................................................... 7
Figure 2.1. Sheathing Connection Test Specimen Configurations(Dolan, 1992) 13
Figure 2.2. Small-Scale Test Specimen in Serrette’s Test (Serrette, 1997) 14
Figure 2.3. ASTM E564 (Dinehart, 1998) 16
Figure 2.4. SPDWave ..........................................................................................17
Figure 3.1. Test Specimen Elevation ................................................................. 21
Figure 3.2. Snap-Cap Insulation .....................................................................22
Figure 3.3. Parallel Test Apparatus ....................................................................23
Figure 3.4. Parallel Test Apparatus ....................................................................23
Figure 3.5. Perpendicular Test Apparatus ........................................................... 24
Figure 3.6. CFS Stud with Wood Blocks ........................................................... 25
Figure 3.7. Steel Pipe Lever and Load ................................................................26
Figure 3.8. Steel Ruler to Measure Displacement.....................................................28
Figure 3.9. NAHB Method for Determining the YLS from Test Data ...............29
Figure 4.1. Parallel Test Specimen W8 and WIO ...............................................39
Figure 4.2. Second Parallel Test of Specimen WIO..................................................40
Figure 4.3. Parallel Tests o f Specimen S8 and S10............... ...................................41
viii
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Figure 5.1. Perpendicular Tests of Specimen W8 and WIO ................................49
Figure 5.2. Perpendicular Tests of Specimen S8 and S10 50
Figure 5.3. Broken OSB Panels after Failures ...................................................50
Figure 6.1. Failure Nails ...................................................................................... 53
Figure 7.1. Wood Stud Test Shear Wall 8ft x 8ft (Shah, 2001) 61
Figure 7.2. CFS Stud Test Shear Wall 8ft x 8ft (Shah, 2001) 61
IX
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LIST OF GRAPHS
Graph 4.1. Load-displacement Curves of Specimen W8 Parallel Test ......32
Graph 4.2. Load-displacement Curves of Specimen WIO Parallel Test .........33
Graph 4.3. Load-displacement Curves of Specimen S8 Parallel Test .........33
Graph 4.4. Load-displacement Curves of Specimen S10 Parallel Test ......... 34
Graph 4.5. Load-displacement Curves of 4 Specimens in Parallel Tests .......35
Graph 4.6. FSLS of 4 Parallel Test Specimens ..............................................36
Graph 4.7. Effective Shear Stiffness of 4 Parallel Test Specimens .............. 37
Graph 4.8. Initial Shear Stiffness of 4 Parallel Test Specimens 38
Graph 5.1. Load-displacement Curves of Specimen W8 Perpendicular Test „43
Graph 5.2. Load-displacement Curves of Specimen WIO Perpendicular Test ...43
Graph 5.3. Load-displacement Curves o f Specimen S8 Perpendicular Test ...44
Graph 5.4. Load-displacement Curves of Specimen S10 Perpendicular Test ...44
Graph 5.5. Load-displacement Curves o f 4 Specimens in Perpendicular Tests ..45
Graph 5.6. FSLS of 4 Perpendicular Test Specimens .........................................47
Graph 5.7. Effective Shear Stiffness o f 4 Perpendicular Test Specimens ....... 48
Graph 5.8. Initial Shear Stiffness of 4 Perpendicular Test Specimens ............48
Graph 6.1. FSLS of Parallel Test and Perpendicular Test .................................56
Graph 6.2. Effective Shear Stiffiiess o f Parallel Test and Perpendicular Test ...57
Graph 6.3. Initial Shear Stiffiiess of Parallel Test and Perpendicular Test ........57
X
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Graph 7.1. Fastener Parallel Test Strength vs. Shear Wall Strength ...............64
Graph 7.2. Fastener Parallel Test Stiffiiess vs. Shear Wall Stiffiiess ...............64
Graph 7.3. Fastener Parallel Test Strength vs. Shear Wall Strength ............... 65
Graph 7.4. Fastener Parallel Test Stiffiiess vs. Shear Wall Stiffiiess ............... 65
Graph 7.5. Fastener Parallel Test Strength vs. Shear Wall Strength ............... 66
Graph 7.6. Fastener Parallel Test Stiffiiess vs. Shear Wall Stiffiiess ............... 66
Graph 8.1. Fastener Parallel Test Strength vs. Shear Wall Strength ............... 70
Graph 8.2. Fastener Parallel Test Stiffiiess vs. Shear Wall Stiffiiess ............... 70
Graph 8.3. Fastener Parallel Test Strength vs. Shear Wall Strength ............... 71
Graph 8.4. Fastener Parallel Test Stiffiiess vs. Shear Wall Stiffiiess ................71
xi
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ABSTRACT
Cold-formed steel (CFS) framing is recently being used for load bearing wall,
floor, and roof framing in residential construction; as an alternative for wood. How
does CFS framing compare to wood in resisting seismic forces? This thesis seeks to
answer this question.
Both wood and CFS walls usually have sheathing applied to resist shear.
Several past tests on wood and CFS shear walls showed that fastener failure is a
common failure mode. The objective of this thesis was to test CFS and wood
fasteners and compare results to fastener and shear wall tests by others, including
monotonic and dynamic tests.
Tests show fasteners had different failure modes when load is applied parallel
or perpendicular to panel edges (refereed to as Parallel Test and Perpendicular Test,
respectively in this thesis). Parallel tests are better to simulate actual load conditions.
A test protocol for single fastener was also developed. The test results show higher
strength but a tendency of stud buckling of CFS walls. Tests o f a device to break the
thermal bridge of CFS studs, were unsatisfactory. This requires more research.
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HYPOTHESIS
Cold-formed steel (CFS) framing resists earthquake forces better than light
wood framing.
xiii
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Part I. Background Research
Chapter 1. Introduction
1.1. Definitions
• Lateral Force
Wind and Seismic are the two primary lateral forces considered in building
design. Wind is usually a one-directional force while earthquake force is multi
directional force. Figure 1.1 shows the typical earthquake acceleration.
NORTH RIDGE CA 1994 01 17 0400 PST
SMDB station: NRG
Owner USC
17645 saticoy St., north
2 Q .o
Peakacc: -4414
Component: 180
34.209, -118.517
450.0
0 10 20 30 40 50 80
sec
Figure 1.1. Earthquake Acceleration of 1994 Northridge Earthquake
• Shear Wall Test
Shear walls, acting as vertical diaphragms, comprise one of the primary
lateral-load resisting components in wood and CFS construction. Tests are usually
l
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done on 8ft x 8ft or 4ft x 8ft shear walls, called full-size shear wall. In this thesis,
“full-size shear wall” is briefly called “shear wall”.
• Fastener Test
Fastener tests provide a qualitative measure of fastener performance to verify
shear wall tests.
• Parallel and Perpendicular Force
Referring to Fig. 1.2, lateral load applied to a shear wall is resisted by
fasteners parallel to the load. The resulting shear wall rotation causes perpendicular
fasteners to resist rotation and thus lateral load. However, their perpendicular
resistance is ineffective due to stud bending.
Load on fastener
Lateral Force ^
Fastener O ^
*
Tension Compression
Figure 1.2. Fastener Behavior under Lateral Force
2
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• Parallel Test and Perpendicular Test
For this thesis, two direction loads are both tested separately. Tests under
parallel and perpendicular loads are briefly called Parallel Test and Perpendicular
Test, respectively in this thesis.
• Light Wood Framing
Most houses in the United States are of wood-frame construction: a system of
wood wall studs, floor joists, plywood wall and floor sheathing and finish sheathing
attached to wall.
The chief advantage o f platform construction is that the floor system provides
a working platform upon which the walls and partitions for the next storey are built.
Since the studs are one storey in height, walls can be easily fabricated one storey at a
time, and for all but the highest walls, can be lifted into place manually.
• CFS Framing
CFS framing is an alternative to platform wood framing, replacing wood
studs and joists by steel studs and joists.
• Abbreviations
For convenience, abbreviations of Specimens are used in this thesis.
The first letter presents:
• “W” = wood
• “S” = CFS
The second letter presents:
• “8” = 8d nail or #8 screw
3
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• “10” = lOd nail or #10 screw.
For example, “W8” means wood frame with 8d nail and “S10” means CFS
frame with #10 screw.
1.2. Background
Steel is a good building material because of its high strength-to-section-area
ratio and it is the most recycled material. Cold-formed steel (CFS) framing has been
widely used as non-load bearing interior partitions and exterior enclosures in
commercial and institutional construction for decades in United States. Sharp
increases in lumber cost since 1993 and pressure from environmental groups to
preserve forests has caused CFS framing to become an alternative to lumber wood
framing, which were widely used for American suburban houses. A poll conducted
at the NAHB convention in 1995 indicated that 22% of builders on the West Coast
were planning to use cold-formed steel (Bateman, 1997). This thesis investigates the
effectiveness of CFS framing to resist earthquake forces as a substitute for light
wood framing.
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Timber Cost
H 9 90 91 92 93 94
Ye*or
Figure 1.3. Timber Cost Six Year Trend
As early as the 1950’s, the building code controlling timber shear wall design
had been based on “monotonic” tests; e.g., shear loads were applied in the plane of
the wall, acting in one direction only. Until the early 1990’s, little research had been
done on timber shear walls and diaphragms utilizing a reversed-cyclic testing
procedure. While monotonic loading may be appropriate for evaluating shear wall
performance under lateral loads caused by wind, ground motion during a seismic
event cause severe cyclic (reversed) forces on the shearwall. Wind may also cause
repeated load applications, although usually not at peak load levels.
The research of modeling earthquake response of timber shear walls indicate
that the connection between the sheathing and the framing of the wall is the primary
factor controlling the response of the structural assembly (Dolan, 1992). The
analysis of shear wall performance shows that the fastener mainly resist load parallel
to the edge of panel. However, some researchers performed tests on fastener
applying perpendicular load to the edge of panel. More tests should be done on
fastener behaviors.
5
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1.3. Thesis Objective
The objectives of the thesis are:
• To compare the lateral performance of wood framed vs. CFS framed
shear walls.
• To evaluate the performance of CFS framing compared to wood framing.
The fastener test results include not only static load-displacement curves but
also quantitative data on limit states of static behavior, including the load and
displacement level at the Yield Limit State (YLS) and the Strength Limit State
(SLS). Quantitative data include behavior parameters such as Initial Shear Stiffiiess
and Effective Shear Stiffiiess based on the NAHB method for all the groups of test
specimens. The loads parallel and perpendicular to the edge of the panel will be
applied to the fastener and tested.
The results of the fastener tests were used to:
• Determine load-displacement curves of a single fastener.
• Compare the performance of nail and screw.
• Compare the fastener behavior in Parallel Test and Perpendicular Test.
• Determine the comparison of shear walls.
Comparison o f shear wall test results of monotonic and cyclic tests will be
presented and discussed. Shear wall in tests will be compared to the single fastener
tests.
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1.4. Design Codes
Current design values for shear walls in the codes are based on results
obtained from full size, static, one-directional tests performed on shear walls. Wind
or seismic loads, determined by building codes, are compared with the resistance that
the shear walls provide per unit length.
Nr R mM mIW C m t irm m m *
ItMlNMtag
|IIW i
Figure 1.4. Building Codes
1.5. Application
The result of this thesis is to better understand the behaviors o f fasteners
under lateral forces. It will provide owners, architects, engineer and contractors
basic knowledge about seismic performance o f CFS framing in residential
construction.
1.6. Thesis Organization
Part I is a literature review regarding:
Seismic design;
7
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Coin:
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Wood platform framing;
SFS platform framing.
Since the fastener behavior determines the shear wall response, it is important
to understand the behaviors of the fasteners before comparing it to the shear wall
performance. The second part of the thesis presents the test objectives, test method,
results of fastener Parallel Tests and Perpendicular Tests that predict the performance
of full-scale shear walls. This part also compares the test results of fastener Parallel
Tests and Perpendicular.
The third part of the thesis is to compare the test results of shear walls
monotonic and cyclic tests from past studies. Shear wall behaviors are discussed and
compare to fastener test results. SLS and stiffiiess of single fastener are compared to
test results from the faster Parallel Test.
Conclusions are covered in the last part. Additionally, the test data from
fastener Parallel Test are included in Appendix A. The test data from fastener
Perpendicular Test are included in Appendix B. Monotonic and cyclic test results
from pass studies are provided in Appendix C and D.
1.7. Limitation of study
Only two or three specimens were tested for each variable configuration
being investigated in fastener tests. Considering the variability present in wood as a
material, additional tests are needed to support these results. The numerical results
reported are limited to one brand of APA rated sheathing OSB, although the trends
observed in this thesis can be applied to other types o f APA rated sheathing OSB.
8
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Test instruments and procedures of different researchers might get different
test results.
9
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Chapter 2. Literature Review
2.1. Introduction
This chapter serves as a summary of relevant research that has been
conducted to date. Two fastener Perpendicular Tests are presented. In the past, the
majority of research was focused on monotonic performance of timber shear walls.
More recently, research has been focused on the performance o f timber shear walls
under cyclic and dynamic loading. Only a few researchers paid attention to the
performance of CFS shear wall that is becoming an alternative material to wood
structures in recent ten years. The test protocols o f shear wall are presented.
2.2. Properties of Wood studs and CFS studs
Wood is a natural, energy efficient and the only renewable building material.
Moisture, decay, termites, and fire effect the long-term performance and durability of
wood. The common size of wood studs used in residential construction is 2 x 4 in
(nominal size).
Cold-formed steel is made by a cold-forming process where sheets of steel
are passed through a series of roll forming dies to create the desired shape. The
design strength is defined by a combination of the thickness of the steel utilized as
well as the shape of the member. Various bends in the member’s cross-section add
to the stiffness an ultimate strength o f the piece. CFS has some advantages
compared to wood: lighter components, durability, noncombustible, termite-proof,
no warp or crack, recyclable. The disadvantages are thermal conduction, rust,
10
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buckling under lateral load, and being less unfamiliar to construction industry.
Exterior load-bearing steel studs are usually built of 18 or 20 gauge steel. The
common size of CFS studs used in residential construction is 3-1/2 x 1-5/8-in with
1/2-in lip.
The allowable loads from calculations according to UBC are shown in Table
2.1. The bending and shear stress of CFS stud is about two and half times as wood
stud. In theory, CFS studs are stronger than wood studs, depending on gage of steel,
etc..
Table 2.1. Wood Stud versus CFS stud Comparison
Wood stud CFS stud (CFS/Wood)%
Nominal size (in) 2 x 4 1-5/8 x 3-1/2
Actual size width (in) 1.5 1.625
Actual size length (in) 3.5 3.5
D (in) 1.3715
Thickness (in) 0.033
Area (in*) 5.25 0.1956 3.73%
Unit weight (lb/ft3) 43 520 1200.09%
Weight (lb/ft) 1.5677 0.75 47.84%
Ix (in4) 5.3594 0.47 8.77%
Iy (in4) 0.9844 0.1519 15.43%
Sx (in3 ) 3.0625 0.2686 8.77%
Sy(inJ) 1.3125
Fb (psi) 1200 33000 2750.00%
M (#") 3675 8864 241.19%
Ft or Fu (psi) 675 45000 6666.67%
T (#) 3544 8802 248.38%
Fv (psi) 95 14000 14736.84%
V(#)
499 1267 254.09%
2.3. Properties of Fasteners
The most common fasteners used in wood framing are nails, bolts and lag
bolts, while CFS fasteners are screws and bolts. Normally, the screws are made of
1 1
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high strength steel. The allowable loads from calculation according to UBC are
shown in Table 2.2.
Table 2.2. Nail and Screw Comparison
8d Common
Bright Nail
lOd Common
Bright Nail
8d Flat Head Screw
Diameter (in) 0.135 0.148 0.164
Actual diameter (in2 ) 0.135 0.148 0.120
Length (in) 2.5 3 I
Area (in2 ) 0.014 0.017 0.011
I(in4 ) 0.0000163 0.0000236 0.0000355
S (inJ) 0.0002415 0.0003183 0.0004330
Fy (psi) 33000 33000 50000
M (#”) 7.971 10.503 21.652
Fu (psi) 45000 45000 65000
T(#)
644 774 735
Fv (psi) 14000 14000 22000
Shear (#) 200 241 249
2.4. Fastener Test Review
AISI “Standard Test Methods for Determining the Tensile and Shear Stress
of Screws” provides the method of testing the shear or tensile design strength for
screws. This method is applied to connections of two steel components. However,
there is no standard method to test the fastener performance of sheathing attached to
framing.
As a part o f an extensive experimental and analytical study to investigate the
behaviors of timber shear walls subjected to earthquakes, Dolan (1992) investigated
the nailed connection performance under monotonic and cyclic loads. The load was
applied perpendicular to the panel edge. The nonlinear load-deflection curves were
used for modeling the nail connection between the sheathing and the framing o f the
12
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shear walls. The premise that the hysteresis for the nail connection is contained
within an envelope defined by the monotonic load-displacement curve was
confirmed.
f
25*25*250 mm
Slitltners Attached Hero
To Prtvtnt Bending
Of Plywood Sheathing
(Boih Edges of Sheathing)
(b)
OopiacemenU
Measured - - L
Each Side 1
of framing
Steel Bar
Displacements
— Measured
EachStde
of Framing
Figure 2.1. Sheathing Connection Test Specimen Configurations (Dolan, 1992)
Figure 2.1 shows the specimen configuration. Plywood specimens usually
failed by the nail-head pulling through the sheathing. Dolan concludes that the nail
properties are the primary factor in determining the load-displacement behavior of
sheathing connections using 8d hot-dipped galvanized common nails. The hysteresis
of the nail connection is constrained in the envelope defined by the monotonic test
load-displacement curve.
13
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Serrette (1997) did full-scale static racking tests and small-scale lateral shear
test on various sheathings attached to CFS steel studs. A procedure similar to that
described in ASTM D 1761-88 was used for the small-scale tests. Failure resulted
from the fastener breaking the edge of the panel. Normalized lateral shear
connection resistances were found to be relatively close to the corresponding
normalized racking shear values for the full-scale test. Figure 2.2 shows the
specimen configuration.
Figure 2.2. Small-Scale Test Specimen in Serrette’s Test (Serrette, 1997)
These fastener tests are good for predicting the performance of shear walls.
However, these tests only test the behavior o f multi-fastener, which could not present
the behavior of single fastener. Moreover, the loads were applied perpendicular to
14
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the edge of the panel. As described in Chapter 1, the fastener resisted not only
perpendicular load under lateral force, but also parallel load. Therefore, single
fastener test should be done under both parallel load and perpendicular load.
2.5. Monotonic Test Protocol of Shear Wall
Most of the shear wall tests based on two test protocols: ASTM E72 or
ASTM E564. ASTM E72, “Conducting Strength Tests of Panels for Building
Construction”, is the first test protocol developed by ASTM for determining the
structural properties of segments of wall, floor, and roof constructions. In the
specification, the specimen is loaded at a constant rate to7901b (99plf), 15701b
(196plf), and 23601b (295plf) with complete unloading between each load increment.
After the 23601b load is applied, the specimen is unloaded and then reloaded
monotonically until failure. ASTM E72 is intended to evaluate the strength of the
panel materials (Serrette, 1995)
ASTM E564, “Static Load Test for Shear Resistance of Framed Walls for
Buildings”, is another racking strength standard developed due to controversy over
steel tie-down rods present in the ASTM E72 tests. The specimen is preloaded to
10% of the expected ultimate load to “seat” the connections and then unloaded.
Three increments of one-third the expected ultimate load are then applied. At each
test increment the specimen is unloaded before application o f the next higher load
increment. ASTM E564 is intended to evaluate the strength of the entire wall system
(Serrette, 1995)
15
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so -
30 -
30 -
IO -
400 o 200 ■oo tooo 1200
T im e (s e e )
a. Static Test Load History
Figure 2.3. ASTM E564 (Dinehart, 1998)
2.6. Cyclic Test Protocol of Shear Walls
Sequential Phased Displacement test protocol (SPD) is modified and adopted
by the Structure Engineers Association of Southern California (SEAOSC). The
protocol is based on the so-called First Major Event (FME), which can generally be
considered as the displacement corresponding to the Yield State of the specimen.
Prior monotonic testing must be performed to determine the FME for this cyclic
protocol.
The displacement history is composed of groups o f stabilization and
degradation cycles that are repeated at higher amplitudes. Test frequencies are lower
than would typically be expected in an earthquake.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
300
200
100
5
- 0
-100
-200
-300
0 10 20 30 40 50
Cycle No.
Figure 2.4. SPD Wave
2.7. Comparison Review of Wood and CFS Framing
• “Shear Resistance of Oriented Strand Board and Plywood-Sheathed, Light-
Gauge Steel and Wood Stud Walls”, Neal N. Shah, UCI (2001)
This thesis focus on the comparisons between:
• Two groups having a nail at 6, 4, and 2-inches-on-center with plywood
sheathing, one group attached to CFS stud framing and the other group
attached to wood stud framing,
• Two groups with nails at density o f 6, 4, and 2-inches-on-center and oriented
strand board (OSB) sheathing with one group attached to CFS stud framing
and the other group attached to wood stud framing.
The experimental results indicate that: (i) increased nail density increases
panel strength and stiffness for the light-gauge steel and wood-framed stud walls, but
not linearly, (ii) although the measured maximum resistance of the plywood and
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
OSB attached to the LGS-ffamed stud walls was higher than that for the plywood
and OSB attached to the wood-framed stud walls, in general, the differences between
the values were not significant, (iii) the light-gauge steel stud framed shear walls
were generally found to have higher overstrength and ductility factors compared to
wood-stud framed shear walls, (iv) the wood-framed assembly performed better than
the steel framed assembly (not 100%, but marginally better) since the steel framed
assembly had pinched hysteresis loops and therefore less hysteretic damping.
• “Steel vs. Wood Cost and Short Term Energy Comparison**, NAHB (2001)
This report addresses the site in Valparaiso, Indiana, including a house
framed with conventional dimensional lumber and a second one framed with cold-
formed steel. Blower door tests were conducted for both houses to determine the
levels of infiltration for each house. Similarly, co-heat tests were performed to
compare short-term energy consumption for both houses.
The results indicated that the costs o f certain framing components of steel-
framed-homes are comparable with those framed with wood. Blower door test
concluded that both steel-framed and wood-framed homes have approximately the
same leakage rate. Co-heat test results showed that the tested UA value of the wood
house was 5.8% better than that of an identical steel house.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Part II. Fastener Tests
Chapter 3. Fastener Test Description and Procedure
3.1. Introduction
The objective of fastener test is to better understand the fastener behavior and
predict the force-displacement behavior of shear walls, so as to compare the different
behaviors of different fastener types. The different types o f fasteners tested, material
used in the construction o f the specimens, instrumentation, and testing procedures
followed for testing the specimens are described in this chapter.
3.2. Test Specimens
Four different specimens, described in Table 3.1, were tested monotonically
under parallel and perpendicular loads. At least four specimens were tested for each
specimen configuration: two Parallel Tests and two Perpendicular Tests. Additional
Specimen S8+ was tested perpendicularly once to compare to past studies, which had
the similar configuration as Specimen S8. The only different is that the distance
from fastener to the sheathing edge is 3/8-in.
19
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Table 3.1. Tested Specimens
Specimen W8 Specimen W10 Specimen S8 Specimens 10
Stud Kiln dried D.F.
2x4-in
Kiln dried D.F.
2x4-in
CFS 20g
l-5/8x3-l/2-in
CFS 20g
l-5/8x3-l/2-in
Stud
Manufactur
er
Roseburg
Forest Products,
Inc.
Roseburg Forest
Products, Inc.
Western Metal
Lath, Inc.
Western Metal
Lath, Inc.
Sheathing APA rated
Sheathing
7/16-in OSB
APA rated
Sheathing
7/16-in OSB
APA rated
Sheathing
7/16-in OSB
APA rated
Sheathing
7/16-in OSB
Fastener Bright common
nail 8d x 2-1/2-
in
Bright common
nail lOd x 3-in
Flat head self
piercing zinc
screw #8 x 1-in,
10 coarse
threads
Flat head self
piercing zinc
screw #10 x 1-
1/2-in, 15
coarse threads
Fastener
Manufactur
er
Primesource
Building
Products, Inc.,
Dallas, TX
Primesource
Building
Products, Inc.,
Dallas, TX
Crown Bolt Inc.,
Corritos, CA
Crown Bolt Inc.,
Corritos, CA
Note 1/2-in Expanded
Polystyrene
(EPS) added
between some
CFS stud and
OSB panel
All materials in the tests were bought from Home-Depot Supermarket. All
sheathings in the specimens were APA rated Sheathing 7/16-in Oriented Strand
Board (OSB). The size of the sheathings in Parallel test was 8-in high by 12-in wide
while the size in Perpendicular Test was 12-in tall by 16-in wide, as illustrated in
Figure 3.1. The Types of fasteners varied between Specimens. However, the
distances from fastener to the sheathing edge were all 1/2-in, which is the common
edge distance in shear wall tests.
20
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2x4" wood stud or
l-5/8x3-l/2" CFS stud 2x4" wood stud or
1-5/8X3-1/2" CFS stud
— Fastener
7/16" OSB
//-Fastener . -------7/16"OSB
f
■ , < ■ ■
I
Figure 3.1. Test Specimen Elevation
Left: Parallel Test; Right: Perpendicular Test
Specimen W8 and WIO consisted of different fasteners while the other
components are the same, which were constructed using kiln dried Douglas-Fir stud
2x4-in (nominal size) and 7/16-in OSB. Specimen S8 was constructed using #8 flat
head screw and 20g 1-5/8 x 3-1/2-in CFS stud.
One disadvantage of CFS shear wall is the thermal bridge in the position of
the CFS stud. U.S. Building Technology (USBT) developed the thermal barrier of
Flat-Cap and Snap-Cap Insulated Framing™ that is applied outside the CFS stud to
get better insulation for CFS shear wall, as shown in Figure 3.2. Unfortunately, the
company could not be reached during the writing of this thesis. It was known from
the introduction of the company that the products are manufactured from modified
Type II expanded polystyrene (EPS), which can be purchased from the store.
Therefore, in this test, Specimen S10 had 1/2-in EPS between the sheathing panel
21
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and framing stud, to investigate the performance of shear wall with polystyrene
insulation. The fastener is #10 flat head screw.
Heat Flow through a Wall
Thermal Barrier — ;
Thermal Bridge
■! i ! ?'i ,!l
Figure 3.2. Snap-Cap Insulation
3.3. Test Apparatus
Because the design codes for North America are based on the monotonic
racking strength of shear walls, the tests in this thesis are monotonic tests. Dolan
(1992) and Serrette (1997) both tested multi-fastener under perpendicular force.
However, tests of this thesis were on single fastener under both parallel and
perpendicular load. Specimens were tested in a perpendicular position.
Parallel Test: Figure 3.3 shows the configuration used for four specimens.
The wood studs and CFS studs were fixed perpendicularly on one side o f a wood
table by several screws to restrict drift of the studs. In the tests, no deformation of
the studs was observed. The studs were placed 1/4-in from the table edge to assure
the sheathing is only fixed to the stud. Another big-size restricted the sheathing to
22
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move in 2-D direction along the stud flange. During the tests, the sheathing always
moved in 2-D direction as required. Figure 3.4 is a photo of the test apparatus.
#16 screw
#16 screw
#16 screw
Figure 3.3. Parallel Test Apparatus
Figure 3.4. Parallel Test Apparatus
23
Steel pipe to apply load
Fastener -
A r
7/16-in OSB
#16 screw works as axial
2x4” wood stud or
1-5/8 x 3-1/2" CFS stud
Fixed table
L
2x4-in wood stud
8dor lOdnail
7/16-in OSB
' I -*•
Specimen W8 and WIO section A-A
CFS stud
#8 screw -
7/16-in OSB- m l
CFS stud-
710 screw-
1/2-in EPS -
7/16-in OSB -
Specimen S8 section A-A
, r
Specimen S10 section A-A
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Perpendicular Test: Figure 3.5 shows the configuration used for four
specimens. The wood studs and CFS studs were fixed horizontally on the top of a
wood table by several screws. In the tests, no lift of the studs was observed. The
studs were placed 1/4-in from the table edge to assure the sheathing is only fixed to
the stud. A #16 screw drilled into the table assured the sheathing to move in 2-D
direction along the flange of studs. During the tests, the sheathing was observed
only shift in 2-d direction as required.
Fastener
Steel pipe to apply load
2x4" wood stud or
1-5/8* 3-1/2" C FS stud
7/16-in O SB
Fixed able
B
n
416 screw w orks as uial *
Bdor lOdnail
2x4-m wood stud
7/16-in O SB
- I
B
Specim en W 8 and W 10 lection B -B
*8 screw -
CFS stud
7/16-inOSB
— 5 *
I
1/2-in EPS-
S 1 0 screw -
CFSstud-
7/16-iaOSB-
Spccim cn S8 section B -B
i
Specim en SIO section B -B
Figure 3.5. Perpendicular Test Apparatus
24
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Wood studs are solid, but the CFS studs are hollow. The flange o f CFS stud
would buckle during tests. To prevent buckling of CFS stud during testing, 1-1/2 x
1-1/2-in wood blocks were attached to both ends of the CFS stud, shown in Figure
3.6.
Wood block
Figure 3.6. CFS Stud with Wood Blocks
In both test setups, to get more accurate test results, some tools were used as
complement. A smaller hole was drilled on the panel, so that the distance between
the fastener and the edge of the panel could be exactly one half inch and to avoid
panel edge splitting. Before hammering the nail into the wood stud, a hole was
drilled into the stud to avoid splitting the stud.
To determine the condition of each fastener after specimen failure, the nails
were removed from the panels using a cat’s paw and hammer and screws were
removed using a screw gun. The condition o f the fastener was then observed and
recorded. The removal of nail/screw was necessary to determine the type o f damage,
if any, which had occurred.
25
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Lever theory was used to apply the load on the fasteners, which was
developed by Schierle in UC Berkeley. Two levers used in the tests, one o f which
was on the sheathing (Figure 3.3 and 3.5) and the other was a steel pipe (Figure 3.7).
Lead blocks on one end of the pipe apply 10 times greater load on the fastener, using
10:1 lever ratio.
In following formula, Puad B lo c k is the gravity load of lead blocks. Psteei p ip e is
the compression load on the intersection of steel pipe and panel. P F astcner is the load
applied on the fastener. The sum o f Moments must be zero for static equilibrium.
Parallel Test: PS te e i p ip e x 3-in - P ^ d B lo c k x 35.28-in = 0
Axial
Lead Block
Figure 3.7. Steel Pipe Lever and Load
Psteei Pipe = 11.76 X P L ead Block
P F astener X 8.5-in - P S teel Pipe X 10-in = 0
PFastener= 0.85 X P S teel Pipe
— 0.85 X 11.76 X PLead Block
10 X PLead Block
26
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Hence the load on the fastener in Parallel Test equals 10 times the gravity
load of lead blocks.
Perpendicular Test: Psteei p ip e x 5-in - P L ead B lo c k x 25-in = 0
Psteei Pipe = 5 X P L ead Block
P F astener X 6-in - Psteei Pipe X 12-in = 0
P F astener 2 X Psteei Pipe
= 2 X 5 X P L ead Block
— 10 X P L ead Block
Hence the load on the fastener in Perpendicular Test equals 10 times the
gravity load of lead blocks.
3.4. Instrumentation
Typical fastener instrumentation included the measurements of the:
• Weight o f the lead blocks and steel balls.
• Displacement of the sheathing relative to the stud.
The weight of the lead blocks was measured using a weight scale. Because
the load was applied from the top of the panel, the panel would shift down
perpendicularly relative to the fixed stud. Displacement between the panel and a
reference point on the stud would change with increasing loads. A ruler was used to
measure the displacement (Figure 3.8).
27
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Figure 3.8. Steel Ruler to Measure Displacement
3.5. Test Procedure
A one-directional static load-controlled test was used (Monotonic Test).
Load was increased by 101b per step, which means lib lead block was added at the
steel pipe lever. Every step was at least thirty seconds before displacement reading
was taken. Two tests were performed for each Specimen configuration. However, if
load-displacement differed more than 15%, a third test was performed.
3.6. Definition of Properties
To calculate the displacement and load levels at the Yield Limit State, NAHB
method (National Association o f Home Builders) was used. Jay Crandell of the
National Association of Home Builders and the researchers associated with the
CUREe-Caltech Woodframe Project both contributed to the creation o f this method.
Figure 3.9 explains the method and its parameters graphically.
28
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Jay Crandell N
,NAHB Research Center;
Figure 3.9. NAHB Method for Determining the YLS from Test Data
In Figure 3.9, A = Displacement at Lateral Load F (inches)
= Yield Displacement (inches)
Au = Ultimate Displacement (inches)
Fy= Load at Yield (lbs)
Fu = Ultimate Capacity of Shear Wall (lbs)
p = 0.60
The load-displacement curve shown in Figure 3.9 is an approximate fit to the
data of various shear wall tests. It was developed by NAHB, Virginia Tech,
Simpson Strong-tie and other labs. This method uses the trapezoidal method to find
the area under Crandell’s non-linear curve and set it equal to the area under the bi
linear curve. The yield load o f this curve was arbitrarily set at the ultimate wall load
29
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value, predicted by Crandell’s equation, divided by 1.5. The 1.5 divisor was based
on prior test results. The yield displacement (Ay ), which is 0.6 times the
displacement of Crandell’s curve at the Yield State of the bi-linear curve, is an
unknown quantity. The ( 3 factor is a degree of freedom value, which was determined
so that the area under the non-linear curve is equal to the area under the bi-linear
curve.
The initial shear stiffness is determined using the YLS. It is the average of
the slope of the load-displacement between the origin and the YLS.
The effective shear stiffness is determined from the load and displacement at
SLS. It is the average slope of the load-displacement between zero and the SLS.
The initial shear stiffness and effective shear stiffness of panels is determined
by:
V _ F y L S _ tr _ ^ S L S
K ‘ ~ — o r K * ~ —
YLS SLS
where
K, = initial shear stiffness for the envelope being considered
Ke ff = effective shear stiffness for the envelope being considered
F y l s - force at YLS
A yls = displacement at YLS
F s l s =force at SLS
A s l s — displacement at SLS
30
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Chapter 4. Fastener Parallel Test Results
4.1. Introduction
Results of the fastener Parallel Test are presented in this chapter. In all, nine
monotonic tests were performed, three of which were for Specimen W10 while two
for each of the other specimens. The load-displacement equivalent elastic-plastic
curves and the qualitative behavior o f the fasteners under parallel load are discussed
in this chapter. Load resistance and elastic stiffness values of the fasteners are
reported. The NAHB method is used to determine the yield point of the walls. The
overall behavior and failure modes of the specimen are also discussed.
4.2. Results
Results were obtained from analyzing the load-displacement curves of the
fastener parallel tests performed. Curves for the static one-directional monotonic
tests were derived from data sampled continuously while a displacement was applied
at a constant rate. Because data points are taken every thirty seconds for each 10 lbs
incremental load, these thirty-second points were extracted from the continuously
recorded data obtained during testing.
Values presented in this chapter represent averages of the values obtained
from each specimen. Actual values obtained can be found in Appendix A. Load-
displacement curves for the four specimen configurations are presented in Graphs
4.1 to 4.4. Curves in these graphs represent the static test data.
31
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Two tests were performed for Specimen W8, S8 and S10 configuration. A
third test was performed for Specimen W10, because the capacity of second test
exceeded the first test by 15%. However, the third test conformed the first test with
equivalent results.
700
600
500
€■ 400
*
■ J 300
200
100
0.00 0.10 0.20 0.30 0.40 0.50 0.60
D isp lacem en t (in)
Graph 4.1. Load-displacement Curves of Specimen W8 Parallel Test
32
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L oad (lb) L oad (lb)
700
600
500
400
300
200
100
0.60 0.50 0.40 0.00 0.10 0.20 0.30
♦ ■ Test 1
-■— Test 2
D isp la c e m e n t (In)
Graph 4.2. Load-displacement Curves of Specimen W10 Parallel Test
700
600
500
400
300
200
100
0
•Test 1
-Test 3
Test 2
i
0.00 0.10 0.20 0.30 0.40
D isp la c e m e n t (in)
0.50 0.60
Graph 4.3. Load-displacement Curves of Specimen S8 Parallel Test
33
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700
600
500
2 *
=- 400
m
■ 3 300
200
100
0
0.00 0.10 0.20 0.30 0.40 0.50 0.60
Displacem ent (in)
Graph 4.4. Load-displacement Curves o f Specimen S10 Parallel Test
Graph 4.5 shows test results of the first test of each specimen to easily
compare the behavior o f the four specimens. Graph 4.5 shows that Specimen W8,
W10 and S8 have similar load-displacement curves from 0 to 0.05 in displacement.
Specimen S10 was designed to solve the thermal bridge problem of CFS shear walls.
Specimen S10 with #10 screw has significantly different load-displacement curve
than Specimen W8 with #8 screw.
34
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0.00 0.10 0.20 0.30 0.40 0.50 0.60
D isplacem ent (In)
Graph 4.5. Load-displacement Curves o f 4 Specimens in Parallel Tests
Strength and stiffness values at the point o f yield, failure, and maximum load
resistance, using NAHB method, are presented in Table 4.1. Variation between tests
is probably due to the inherent variability o f wood stud and sheathing.
Table 4.1. Parallel Test Summary
Specimen W8 Specimen W10 Specimen S8 Specimen S10
Fsls (lbs) 575 690 580 665
Asls (in) 0.277 0.189 0.234 0.572
Kcff (lbs/in) 2192 3702 2475 1162
Ffailure (lbs) 585 700 590 675
Fyls (lbs) 383 460 387 443
Ayls (in)
0.051 0.036 0.048 0.163
K, (lbs/in) 7624 13355 8369 2731
F y l s = Force at YLS, 4 sis — Displacement at SLS, K ^ = Effective Shear Stiffness,
F failure = Force at failure, F y l s =Force at YLS\ A y l s - Displacement at YLS,
K e J g r = Effective Shear Stiffness
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Values of maximum load resistance (SLS) ranged from 575 lbs to 690 lbs.
Values of load resistance at catastrophic failure ranged from 585 lbs to 700 lbs.
Values of load resistance at yield (YLS) ranged from 383 lbs to 460 lbs. F sls is 1.5
times F yls-
4.3. Strength Limit State and Yield Strength State
Graph 4.6 shows that Specimen W10 has the highest capacity in four
specimen configurations. Specimen W8 has similar capacity as Specimen S8.
Replacing 8d nail by lOd nail, increase the capacity by 20%. Specimen S10 was
designed to solve the thermal bridge problem of CFS shear walls. The #10 screw
increased the capacity of Specimen S10 by 15%.
700
600
500
£ 400
300
200
100
0
3
W8 W10 S8
690 ' "
------------------------------------------------ 003
575
B i g
580
*->1
« j j |
|& |
tf*
H
B B S S
S10
Graph 4.6. F sls o f 4 Parallel Test Specimens
Using the NAHB method, the load at yield limit state point has similar
relationship among the four specimens.
36
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4.4. Effective Shear Stiffness and Initial Shear Stiffness
The data of effective shear stiffness and initial shear stiffness of the four
specimens are presented in Graph 4.7 and 4.8. The Effective Shear Stiffness ranges
from 1162 to 3702 lb/in. The Initial Shear Stiffness ranges from 2731 to 13355 lb/in.
10000
9000
8000
7000
~ 6000
| 5000
5 4000
3000
2000
1000
0
Graph 4.7. Effective Shear Stiffness of 4 Parallel Test Specimens
Graph 4.7 shows the effective shear stiffness of Specimen W10 is
significantly higher than other specimens. Increasing nail size increased the
effective shear stiffness of specimens. W8 and S8 have similar effective shear
stiffness. However, the stiffness of Specimen S10 is only third of Specimen S8.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
10000
9000
8000
7000
_ 6000
e
1 5000
3 4000
3000
20 0 0
1000
0
Graph 4.8. Initial Shear Stiffness of 4 Parallel Test Specimens
Graph 4.8 shows the initial shear stiffness of Specimen W10 is also
significantly higher than other specimens. Increasing nail size increased the initial
shear stiffness of specimen. W8 and S8 also have similar initial shear stiffness.
However, the stiffness of Specimen S10 is only half of Specimen S8.
4.5. Behaviors
Most of Specimens W8 and W10 had similar behaviors in the tests. Only a
few displacements were observed in the beginning. Along the increase of loads, the
displacement was obvious. The nail head tilted as shown in Figure 4.1 (left). The
tilt made the nail head press into the OSB panel. Then some cracks were heard and
the splits of panels were observed and getting larger. Suddenly, the nail was pulled
through the panel and the specimen failed as shown in Figure 4.1 (right). The reason
that the panel shifted was the bending of the nail, which could be seen now. The tip
38
13355
-'I i n
4 1 1 1
1 1 1
- - O O O b
7 l f i 2 d
1 M
*
J t
c
H
m m m
t o B W t
i l l
B
IjgB
iB s s
III ^ S I 2 7 3 1
m
* 3 1
> ■ i
liitiii
r
L | 5 | |
E R a U u f l H s i H D I I p y B *
P i ^
r f\
1
i
W B W 10 S8 S10
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
of the nail was restricted by the solid wood and kept straight, but the head was pulled
out and whole nail bent.
Figure 4.1. Parallel Test Specimen W8 and W10
Left: Tilted Nail Head; Right: Specimen Failure
The second Specimen W10 test had a different failure mode. A sudden large
displacement of 0.14-in was observed at 625 lbs load, but the specimen could still
take the load. Figure 4.2 shows that the nail was pulled out and the panel was
separated from the stud. After adding 50 lbs loads, the nail was pulled out of the
wood stud and the specimen failed. This shows the inherent variability o f wood
studs. The failure load of this test is similar as the other test results, but the
displacement was very different.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Figure 4.2. Second Parallel Test of Specimen W10
Specimen S8 and S10 experienced distinguished deformation compared to
other wood specimens. The fastener had similar behaviors but the displacements
were different. Specimen S8 had very few displacement at the beginning while
Specimen SIO showed great displacement from beginning to end.
Because there was no restriction on the other side of the flange, the screw
ends were not restricted. Screws tilted (Figure 4.3, left). Tilting resulted in the head
and shank of the screw pressing into the panel and bending of the flange material
immediately around the screw. However, the flange clipped the threads of screws to
restrain it. Some cracks could also be heard and splitting o f panels were observed
getting larger (Figure 4.3, right). All failures were similar: the screws were pulled
through the panel. However, none of screws suffered any significant bending but
none of the screws fractured from fatigue.
40
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Figure 4.3. Parallel Tests of Specimen S8 and S10
Left: Screw Rotates; Right: Panel Splits
Buckling of CFS studs requires more investigation. As described in chapter 3
of Test Setup, two wood blocks were installed to resist flange buckling. In real
construction projects, studs are only braced at both ends and mid-height. Therefore,
flange buckling would be more likely. More research should be done on this topic.
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Chapter 5. Fastener Perpendicular Test Results
5.1. Introduction
Results of the fastener Perpendicular Test are presented in this chapter. In
all, eight monotonic tests were performed, two for each of the specimens. The load-
displacement equivalent elastic-plastic curves and the qualitative behavior of the
fasteners under parallel load are discussed in this chapter. Load resistance and
elastic stiffness values of the fasteners are reported. NAHB method is used to
determine the yield point of the walls. The overall behavior and failure modes of the
specimen are also discussed.
5.2. Results
Results were obtained from analyzing the load-displacement curves of the
fastener perpendicular tests performed. Curves for the static one-directional
monotonic tests were derived from data sampled continuously while a displacement
was applied at a constant rate. Because data points are taken every thirty seconds for
each 10-lb incremental load, these thirty-second points were extracted from the
continuously recorded data obtained during testing.
Values presented in this chapter represent averages of the values obtained
from each specimen. Actual values obtained can be found in Appendix B. Load-
displacement curves for the four specimen configurations are presented in Graphs
5.1 to 5.4. Curves in these graphics represent the static test data.
42
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700
600
500
| 400
300
200
100
0 I
0
Graph 5.1. Load-displacement Curves of Specimen W8 Perpendicular Test
700
600
500
= ■ 400
*0
3
J 300
200
100
0
0.00 0.10 0.20 0.30 0.40 0.50 0.60
D isplacem ent (in)
Graph 5.2. Load-displacement Curves of Specimen W10 Perpendicular Test
43
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•Test 1
•Test 2
•Test 1 |
-Test 2 j
0.10 0.20 0.30 0.40
Displacement (in)
0.50 0.60
700
600
500
s
=• 400
8
-i 300
200
100
0
0.00 0.10 0.20 0.30 0.40 0.50 0.60
Displacement (in)
Graph 5.3. Load-displacement Curves of Specimen S8 Perpendicular Test
700
600
500
S'
— 400
«
■ 3 300
200
100
0
0.00 0.10 0.20 0.30 0.40 0.50 0.60
Displacainant (in)
Graph 5.4 Load-displacement Curves of Specimen S10 Perpendicular Test
Graph 5.5 shows test results of the first test of each specimen to easily
compare the behavior o f the four specimens. Graph 5.5 shows that Specimen W8
and W10 has similar load-displacement curve from 0 to 0.15-in displacement.
44
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•Test 1 |
■Test 2!
•Test 1
-Test 2
Specimen S10 is designed to solve the thermal bridge problem of CFS shear walls.
Specimen S10 with #10 screw has significantly different load-displacement curve
than Specimen W8 with #8 screw.
700
600
0.00 0.10 0.20 0.30 0.40 0.50 0.60
Displacement (in)
Graph 5.5. Load-displacement Curves of 4 Specimens in Perpendicular Test
Strength and stiffness values at the point of yield, failure, and maximum load
resistance, using the NAHB method, are presented in Table 5.1. The variation
between tests is probably due to the inherent variability of wood stud and sheathing.
Values of maximum load resistance (SLS), ranged from 200 lbs to 400 lbs.
Values of load resistance at catastrophic failure ranged from 206 lbs to 410 lbs.
Values of load resistance at yield (YLS) ranged from 133 lbs to 266 lbs. Fsls is 1.5
times Fyls*
45
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Table 5.1. Perpendicular Test Summary
Specimen W8 Specimen W10 Specimen S8 Specimen S10
Fsls (lb) 375 305 400 200
Asls (in)
0.234 0.164 0.112 0.264
K c fr (lb/in) 2192 3702 2475 1162
Ffailure (lb) 380 312 410 206
Fyls (lb) 250 203 267 133
Ayls (in) 0.072 0.043 0.026 0.105
K i (lb/in) 3478 4775 10391 1284
F y l s — Force at YLS, A s l s = Displacement at SiIS, Keff= Effective Shear Stiffness,
F f auure = Force at failure, F yls - Force at YLS A y ls = Displacement at YLS,
Ke ff= Effective Shear Stiffness
5.3. Strength Limit State and Yield Strength State
Graph 5.6 shows that Specimen S8 has the highest lateral capacity in four
specimen configurations. Specimen W8 has a little lower capacity than Specimen S8.
It was surprised that, replacing 8d nail by lOd nail decreases the by 17. Specimen
S10 was designed to solve the thermal bridge problem of CFS shear walls. The #10
screw decreased the capacity o f Specimen S10 by 15%.
Using the NAHB method, the load at yield limit state point has similar
relationship for the four specimens.
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Graph 5.6. F sls of 4 Perpendicular Test Specimens
5.4. Effective Shear Stiffness and Initial Shear Stiffness
The data of effective shear stiffness and initial shear stiffness of the four
specimens are presented in Graph 5.7 and 5.8. The Effective Shear Stiffness ranges
from 761 to 3578 lb/in. The Initial Shear Stiffness ranges from 1284 to 10391 lb/in.
Graph 5.7 shows the effective shear stiffness of Specimen S8 is significantly
higher than other specimens. Increasing nail size increased the effective shear
stiffness and initial shear stiffness o f specimens. However, the stiffness of Specimen
S10 is only one-fifth of Specimen S8.
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Graph 5.7. Effective Shear Stiffness of 4 Perpendicular Test Specimens
1 0 3 9 1
10000
9000
8000
7000
? 6000
1 5000
2 4000
3000
2000
1000
0
W8 W10 S8 S10
Graph 5.8. Initial Shear Stiffness of 4 Perpendicular Test Specimens
Graph 5.8 shows that the initial shear stiffness of Specimen S8 is also
significantly higher than other specimens. Increasing nail size also increased the
initial stiffness of specimen. However, the stiffness of Specimen S10 is only one-
eight of Specimen S8.
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5.5. Behaviors
Specimen W8 and Specimen W10 have similar behavior. As in the Parallel
Test, only a small displacement was observed at the beginning. With increasing
load, displacement increased (Figure 5.1 left). Also panel splitting was observed.
Suddenly, the edge o f OSB panel was broken and the nail pulled through the panel as
shown in Figure 5.1. Panel shifting, caused by nail bending was observed after the
specimen failed. Variability of wood panels caused the different test values.
Figure 5.1. Perpendicular Tests of Specimen W8 and WIO
Left: Specimen Deflected; Right: Specimen Failure
Specimen S8 and SIO experienced unique deflection and failure (Figure 5.2).
It was difficult to see the panel displacement of S8 at the beginning of the test, while
significant deflection was observed for Specimen SIO. In both S8 and SIO, the
screws tilted but did not suffer significant bending and none of the screws fractured
from fatigue. Two wood blocks were also installed to resist bending of the flange.
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Figure 5.2. Perpendicular Tests of Specimen S8 and SIO
Left: Screw Rotates; Right: Panel Edge Breaks
Variability of the OSB panel caused breaking o f the panel edge. In some
tests, the broken section was oblique to the edge of the panel as shown in Figure 5.3
(left). In other tests, it was perpendicular to the panel edge as shown in Figure 5.3
(right).
Figure 5.3. Broken OSB Panels after Failures
Left: Oblique Broken Section; Right: Perpendicular Broken Section
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Chapter 6. Fastener Test Discussion
6.1. Introduction
Some fundamental parameters that can be used to characterize the behavior
of fasteners were defined in the previous two chapters including the Yield Limit
State, Ultimate Limit State, Initial Shear Stiffness, Effective Shear Stiffness.
This chapter discusses the fastener test results and behaviors including
Parallel Test and Perpendicular Test. The comparisons of these tests are also
discussed. Moreover, results obtained from this investigation are compared
quantitatively with results obtained from past studies of monotonic and cyclic
performance o f fastener with wood studs and CFS studs.
6.2. Parallel Test Discussion
The inherent variability of wood could cause different failures in tests: nails
pulling out of the stud or nails pulling through the panel. Comparably, CFS studs
have more consistent qualities than wood, although the OSB panel caused variability.
The two test results of Specimen S8 have only two-percent different capacities,
which is very accurate.
In the Parallel Test, Specimen WIO performed much better than the other
specimens. It has the highest strength and stiffness. Increasing nail size increased
the resistance capacity for the parallel force to increase the capacity o f full-size shear
wall.
51
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Specimens W8 and S8 have similar strengths and stiffness. CFS framing
with #8 screws might be the perfect alternative to wood framing with 8d nail. More
tests on shear wall will be discussed later.
The strength of Specimen SIO is a little higher than Specimen S8. However,
the displacement of SIO is about double that of S8. The stiffness o f Specimen SIO is
a big concern.
6.3. Perpendicular Test Discussion
As calculated in Chapter 2, lOd nail was supposed to have better shear and
bending resistance than 8d nail. However, the Perpendicular Tests showed that 8d
nail had higher capacity than lOd nail. The reason is that lOd nail has higher
bending capacity than 8d nail. When load increased, lOd nail could resist much
more bending than the 8d nail. Figure 6.1 shows that the deform angle of failed lOd
nail is smaller than that of 8d nail. The behavior of Specimens W8 and WIO was, at
first, the nail was bend and pulled out, and then the panel edge broke. Therefore, the
shear walls with greater diameter nails might not perform better than smaller
diameter nail under perpendicular load. However, Specimen WIO has greater
stiffness than Specimen W8.
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Figure 6.1. Failure of Nails
CFS with snap-cap insulation might not be a good way to solve the thermal
bridge problem, because polystyrene is ineffective to resist shear. The screw
cantilevers from the CFS stud and the bending moment of Specimen SIO is higher
than S8, therefore, screw tends to tilt. Table 5.1 shows that Specimen SIO deforms
about twice as much as Specimen S8.
6.4. Perpendicular Test Comparison to Past Studies
Several tests where used to compare the monotonic and cyclic performance
of fastener with wood studs and CFS studs under perpendicular forces. Tests
performed by other researchers on fasteners help to compare the performance of
wood and CFS specimens.
Serrette (1997) performed fastener tests using five different sheathings on 20
gauge CFS framing. The edge distance was 3/8-in (Table 6.1).
53
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Table 6.1. Monotonic Test Results for Failure Load (Serrette, 1997)
Sheathing material Test# Failure load / screw (lbs)
1/2-in gypsum wall board (papered edge) 3 92.96
1/2-in gypsum wall board (non-papered edge) 3 50.60
15/32-in plywood - APA rated sheathing 3 269.13
7/16-in OSB - APA rated sheathing 3 232.77
'/2-in FiberBond wall board 3 103.45
Dolan (1992) investigated nailed connection performance in wood framed
shear walls under the monotonic and cyclic loads. No difference between the test
results for the slow and rapid cyclic connection tests could be found. The reversed
bending shape after testing indicated that there has been significant yielding o f the
nails in cyclic test.
In this thesis, Specimen S8+ was tested perpendicularly to compare to the test
results of other researchers. The capacity o f 3/8-in edge distance (Specimen S8+) is
about 75% of the capacity of l/2-in edge distance (Specimen S8), which means that
the edge distance is very important for the shear capacity of shear walls.
In Table 6.2, if the capacity of Specimen W8 is multiplied by 75% to account
for smaller edge distance, the values are similar Dolan’s result (Dolan, 1992). Also
Serrette (1997) results are similar to test results from o f thesis (Table 6.2). Table 6.2
also shows that, for wood framing, the test results for monotonic and cyclic are the
similar.
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Table 6.2. Wood and CFS Fastener Test Results
Stud Panels Fasteners Edge
(in)
Protocol Max.
load
Drift
(in)
Specimen
W8
D.F. 7/16-in rated
OSB
8dx 2-1/2-in
bright common
nails
1/2 Monotonic 375 0.234
Specimen
WIO
D.F. 7/16-in rated
OSB
lOd x 3-in bright
common nails
1/2 Monotonic 305 0.164
Dolan
(1992)
SPF 3/8-in
Canadian soft
plywood
8d x 2-1/2-in
galvan. common
nails
Monotonic 296 0.354
Dolan
(1992)
SPF 3/8-in
Canadian soft
plywood
8dx 2-1/2-in
galvan. common
nails
Cyclic 308 0.354
Specimen
S8
20g
CFS
7/16-in rated
OSB
#8 x 1-in flat
head screw
1/2 Monotonic 400 0.112
Specimen
S8+
20g
CFS
7/16-in rated
OSB
#8 x 1-in flat
head screw
3/8 Monotonic 265 0.099
Serrette
(1997)
20g
CFS
7/16-in rated
OSB
#6 x 1-in bugle
head self-drilling
screw
3/8 Monotonic 233
Serrette
(1997)
20g
CFS
15/32-in rated
plywood
#6 x 1-in bugle
head self-drilling
screw
3/8 Monotonic 269
The table shows that the test protocol for single fastener in this thesis is
acceptable. Because no single fastener Parallel Tests were done before, no data
exists to compare the Parallel Tests with other test results. More Parallel Tests are
recommended for future research.
6.5. Comparison of Parallel Test and Perpendicular Test
The load-displacement curves of fastener Parallel and Perpendicular Test
show different aspects of four specimens (Graph 4.1 - 4.4 and Graph 5.1— 5.4).
55
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• Strength Limit State and Yield Strength State
Graph 6.1 shows Perpendicular Test capacities are all less than Parallel Test
capacities. Specimens W8 and S8 reduced one third, Specimen SIO reduced half and
Specimen WIO reduced two thirds o f Parallel Test capacities. Large fasteners have
greater difference than small fasteners. The yield capacities have the similar
relationship as ultimate capacities.
! 0 Perpendicular Test | 375
I Parallel Test
Graph 6.1. Fsls o f Parallel Test and Perpendicular Test
• Effective Shear Stiffness And Initial Shear Stiffness
Graphs 6.2 and 6.3 show effective and initial shear stiffness, respectively. In
both testes, Specimen SIO has the lowest stiffness among four specimens. Effective
Parallel shear stiffness is 37% to 98% greater than Perpendicular stiffness (except for
Specimen S8). Initial Parallel shear stiffness is 113% to 180% greater than
Perpendicular stiffness.
56
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10000
8000
W8 W10
□ Perpendicular Test
Parallel Test
Graph 6.2. Effective Shear Stiffness of Parallel Test and Perpendicular Test
£
10000
{□Perpendicular Test j 3478 4775 10391 1284
P Parallel Test 7624 13355 8369 2731
Graph 6.3. Initial Shear Stiffness o f Parallel Test and Perpendicular Test
• Behaviors
At the beginning, both Parallel and Perpendicular tests behaved similar, but
the failure modes o f Parallel and Perpendicular Test were different. In the Parallel
Test, the fastener pulled through OSB panel, except one pulled out the wood stud.
The quality o f wood and CFS mainly determined the failure mode. The quality of
57
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OSB panel partly caused failure. In the Perpendicular Test, all failure was caused by
breaking of the OSB panel edge.
Quality of sheathing and wood is very important for shear walls. In the tests,
the edge distances were strictly controlled to get accurate results. However, in real
construction, it is hard to accurately control the edge distance. As described in this
chapter, the reduced edge distance could cause reduced capacity. In the case studies
after Northridge Earthquake, lack o f quality control is the most common problem
(Schierle, 2001).
Life safety and repair costs are two items that should be considered in design
for lateral forces. That brings the conflicts of the ductility and stiffness of structure
components. Structure design should get the balance between them.
Several case studies after Northridge Earthquake commented that greater
stiffness at lower levels may increase seismic forces on upper levels and may cost
more to repair (Schierle, 2001).
However, less stiffness means more displacement under lateral force.
Schierle found that, in 1994 Northridge Earthquake, non-structural damage is a much
greater percentage of the total damage than structural damage in most case studies
where itemized repair cost were available (Schierle, 2001). CFS shears walls similar
to Specimen S10 might cost more to repair after earthquake damage than wood
framing, because drilling screws is slower and less familiar than nailing. EPS
insulation between sheathing and CFS studs is not satisfactory for lateral resistance;
but EPS outside the sheathing would not effect shear resistance.
58
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Part III. Shear Wall Test Comparison (Previous Tests)
Chapter 7. Monotonic Test Comparison (Previous Tests)
7.1. Introduction
Comparisons of monotonic tests of wood and CFS shear walls are presented
in this chapter. The main focus will be on single fastener behavior of APA rated
7/16-in OSB sheathed shear sheathing. The overall behavior and failure modes of
the walls are discussed and compared to the fastener tests. Values of average
strength and effective shear stiffness of single fastener in walls are presented, and
also compared to the test results o f fastener tests.
The compared test results from other researchers are listed below:
APA Report 154 (Tissell, 1993) provides the historical record of wood shear
wall tests conducted by APA - The Engineered Wood Association. Most walls was
tested per FHA Circular 12. This test protocol can potentially result in higher
ultimate loads than are reached when the wall is tested to full design load on the first
cycle and to twice design load on the second cycle.
Dinehart and Shenton (1998) conducted both static and dynamic tests on
wood frame shear wall to determine the wall resistance to lateral loading and
compare the static and dynamic performance. The traditional ASTM E-564 test
procedure was used in the static tests.
59
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Serrette (1996) conducted tests to investigate the behavior of light gauge steel
shear walls sheathed with plywood, oriented strand board, and gypsum wallboard.
The first and second phases were to investigate the static behavior of shear walls.
Sponsored by USBT, Serrette (1998) also performed some tests to determine
how the Snap-Cap Insulated Framing System impacted the lateral resistance of the
sheathed wall to wind and seismic loads. In the tests, the screw fastener schedule,
fastener size and head insulation were varied.
More detailed description are included in Appendix C.
7.2. Specimen Description and Test Protocol
The shear wall specimens presented in this study were similar to each other,
with framing type and sheathing material being the only difference. This provided
an opportunity to directly compare and analyze the wood and CFS shear walls of
similar configurations.
The static and cyclic tests used 8ft x 8ft or 4ft x 4ft specimens. Narrow shear
walls (less than 1:3) are not considered. Figures 7.1 and 7.2 show the basic
configuration of an 8ft x 8ft shear wall. The material and fasteners might be
different for tests of different researchers. Instrumentation and apparatus might also
be different.
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Test wall (96"x96")
2 -2x4
2x4 (typ) 16" o.c.
4x4 (typ)
3x4 Plywood or OSB
wall sheathing
^Hold-downs (typ)
Figure 7.1. Wood Stud Test Shear Wall 8ft x 8ft (Shah, 2001)
Plywood or OSB
wall sheathing
-Top Track /-T -tw oipr***")
1 J - - M *
•M '
M " — • > U " * •-
C-Shaped Studs (typ) 24" o.c.
shaped studs (back-to-back)
-C-shaped stud
y~Hold-downs (typ)
Figure 7.2. CFS Stud Test Shear Wall 8ft x 8ft (Shah, 2001)
7.3. Behavior Comparison
Dinehart and Shenton (1997) described the behavior o f wood framing shear
wall in the monotonic tests as following: first, sheathing tended to pull away from
the frame, pulling the nails along with it. The nails were pulled out o f the stud. In
61
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only a few instances were nails pulled through the sheathing. This lifting of the
sheathing away from the frame occurred only along the edges of the sheathing.
Second, the bottom plate spit parallel to the grain at the uplift comer. Finally, some
interior studs were observed to twist along their length, and split at their top or
bottom along the line of the sheathing nails in the stud.
The first-step behavior of wood framing shear wall is the same as the fastener
Parallel Test of W8 and W10: the nails were pulled out or pulled through the
sheathing. The behavior of shear wall implies that parallel force governed most of
the fastener behaviors. Because Dinehart and Shenton (1997) built the shear walls
using Spruce-Pine-Fir stud of different quality than Douglas Fir. Most nails were
pulled out, while most of the nails were pulled through the panel in the fastener
Parallel Test.
In Serrette (1996) CFS framed shear wall tests, racking of the wall resulted in
the screw fasteners tilting about the plane of the stud flange. Tilting resulted in the
head and shank of the screw pressing into the panel and bending of the flange
material immediately around the screw. As the lateral displacement of the wall
increased, the panel pulled over the screw heads and became unzipped. The wall
responded to unzipping by a sudden drop in load carrying capacity. No screws
pulled out of the stud flanges. For more dense screw schedule, the chord studs
crippled, which advanced the pull-over behavior of the panels. Crippling typically
initiated in the non-sheathed flange o f the chord stud member.
62
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In Serrette's tests of Snap-Cap Insulated Framing System, failure was
initiated by deformation of the OSB around the screw head as the head pressed into
the OSB and screws tilted with respect to the plane o f the stud flange. Buckling in
the compression chord was the ultimate failure mode. The above descriptions of
initial fastener behavior and failure mode are the same as the fastener behavior of
Specimens S8 and S10 fastener Parallel Test.
Overall, parallel force governed the fastener behavior at the edge of the
panel. Average values of single fasteners shear wall tests will be compared to the
test results of faster Parallel Tests.
7.4. Shear Wall vs. Fastener Test
Ultimate Strength State and Effective Shear Stiffness are compared. To
verify sample test, results of similar shear wall tests are compared. Since no test
results are available for S10 shear walls, S12 test is compared. All sheathings are
7/16-in OSB and most of the specimens are 8ft x 8ft except for those mentioned.
Fastener capacities is computed, divide shear wall capacities by number o f nails at
one edge. Effective shear stiffness is computed by the NAHB method.
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• 6-inch Fastener Spacing (Graphs 7.1 & 7.2)
= ■ 400
Q Shear W a N Test
■ Fastener Parallel Test
W 8 W 10 S8 S10orS12
□Shear W all Test | 456 442
B Fastener Parallel Test 575 600 580 665
Graph 7.1. Fastener Parallel Test Strength vs. Shear Wall Strength
Shear wall SI 0 is 4ft x 8ft.
Shear walls S8 and SI 2 have similar strength.
Shear wall strengths are lower than fastener Parallel Test strengths.
O Shear W a N lest
■ Fastener Parallel Test
W 8 W10 S8 i S10crS12
□Shear W all Test 4566 ! 1210
■FastenerParallel Test 2192 3702 2475 j 1162
Graph 7.2. Fastener Parallel Test Stiffness vs. Shear Wall Stiffness
Shear wall S8 stiffness is higher than shear wall S I2 stiffness.
4ft x 8ft CFS shear wall stiffness is similar to fastener Parallel Test stiffness.
4ft x 8ft shear wall is more ductile than 8ft x 8ft shear wall.
64
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• 4-inch Fastener Spacing (Graphs 7.3 & 7.4)
□ Shear W all Test 299 | 4 71
■ Fastener Parallel Test 575 000 ! 500 066
Graph 7.3. Fastener Parallel Test Strength vs. Shear Wall Strength
Shear wall W8 is 1/2-in OSB sheathing. Shear wall S8 is 4ft x 8ft.
Shear wall W8 strength is lower than S8 strength.
Shear wall strength is lower than fastener Parallel Test strength.
S8 | S10crS12
□ Shear W all Test_______ 2306 j _________ j 242* j
a Fastener Parallel Test | 2192 j 3702 j 2475 ' 1162
Graph 7.4. Fastener Parallel Test Stiffness vs. Shear Wall Stiffness
Shear wall W8 stiffness is similar to S8 stiffness.
8ft x 8ft wood shear wall stiffness is similar to fastener Parallel Test stiffness.
4ft x 8Ji CFS shear wall stiffness is similar to fastener Parallel Test stiffness.
65
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3-inch Fastener Spacing (Graphs 7.5 & 7.6)
0
W8 W 10 S8 | S10crS12
□Shear W ail Test 372 406 | 434 466
n Fastener Parallel Test 575 600 | 560 I 666
Graph 7.5. Fastener Parallel Test Strength vs. Shear Wall Strength
Shear wall W10 is I /2-in OSB sheathing. Shear walls S8 and S I 0 are 4ft x 8ft.
Shear wall W8 strength is the lowest and shear wall S I 2 strength is the highest.
□ Shear W a N Test
■ Fastener P a raN e t Test
j □ Shear W a H Test I
■ Fastener Parallel Test
2000
/
H H I
f l -
/
W8 W 10 | S8 | S10orS12
□ShearWall Test | 3338 i 1863
n Fastener Parallel Test 2192 3702 | 2475 j 1162
Graph 7.6. Fastener Parallel Test Stiffness vs. Shear Wall Stiffness
Shear wall W8 stiffness is higher than S8 stiffness.
4ft x 8ft CFS shear wall stiffness are higher than fastener Parallel Test stiffness.
66
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7.5. Discussion
Strengths of wood shear walls are lower than CFS shear walls under
monotonic tests. Shear walls W8 and S10 are more ductile than S8, which is good
for life safety, but not for repair cost.
Wood shear wall strengths range only 52% to 64% of fastener Parallel Test
strengths. The reason is that, in shear wall tests, fasteners had different behaviors in
the comer or the middle of the panel edge when shear wall failed. Shear wall
strength is the average value.
CFS shear wall strengths range 66% to 81% of fastener Parallel Tests
strength, which is higher than wood framed shear wall. The reason is that some CFS
shear walls failed due to stud buckling, which could absorb some energy. Effective
shear wall stiffness is higher than fastener Parallel Tests stiffness.
Fastener Parallel Test is more valuable than Perpendicular Test. The test
results could predict shear wall test.
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Chapter 8. Cyclic Test Comparison (Previous Tests)
8.1. Introduction
Cyclic tests of wood and CFS shear walls are presented in this chapter, based
on shear walls of APA rated 7/16-in OSB sheathing. Overall behavior and failure
modes of the walls are discussed and compared to the fastener tests. Ultimate
strength and effective shear stiffness of walls are presented and compared fastener
test results. Test results of the following three researchers, using SPD protocol, are
compared:
Rose (1998) tested eight specimens dynamically, sponsored by APA - The
Engineered Wood Association. The tests were conducted at the Structural
Laboratory, Department of C ivil, University of California - Irvine.
In COLA-UCI (City of Los Angeles - University of California, Irvine) project,
Pardoen investigated 36 groups of 8’ x 8’ shear walls using cyclic testing under
displacement control, of which, six groups are CFS framing while the rest groups are
wood framing (2000).
Serrette (1996) as phase three of his testing program conducted cyclic testing
using OSB and plywood sheathing (one side of the wall sheathed). Specimen
descriptions are included in Chapter 7.2 with detailed in Appendix D.
8.2. Behavior Comparison
In the cyclic tests by Rose (1998), the observed failure mode was fastener
fatigue, with nails breaking within the lumber framing about 3/8-in to 1/2-in below
68
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the framing surface. Fastener fatigue failures occurred near the comers of the panels
after near-maximum shear loads were reached, and progressed further along the top
and bottom and vertical edges of the panels, away from the comers, as the load-
displacement cycles continued. The wood framed tests in COLA-UCI project had
the similar failure mode. Unlike the monotonic test, the fastener behavior in the
cyclic tests of wood framed shear walls had some different behavior from the faster
Parallel Test and Perpendicular Test presented in this thesis. However, the test
results from Parallel Test are still comparable.
For CFS shear walls the bottom of the compression chord buckled due to
high compressive stresses from the racking effect. In general, racking of the wall
resulted in the screw fasteners rocking (tilting) about the plane of the stud flange.
Rocking resulted in the head and shank of the screw pressing into the panel and
bending of the flange material immediately around the screw. The screws along the
edge o f the wall had no damage or failure. Like the monotonic test, the fastener
behavior in the cyclic tests of CFS shear walls had similar behavior as the Parallel
Test o f this thesis, although the tests in this thesis are monotonic.
8.3. Shear Wall vs. Fastener Test
Ultimate Strength State and Effective Shear Stiffness are compared. To
verify sample test, results of similar shear wall tests are compared. Data o f shear
wall cyclic tests is very limited. Some test data of two distinct framing types and
fasteners, Specimens W8 and S8 will be discussed. All sheathings are 7/16-in OSB
and most of the specimens are 8ft x 8ft except for those mentioned. Fastener
69
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strength is computed, divided shear wall strength by number of nails at one edge.
Effective shear stiffness was calculated by the NAHB method.
• 4-inch Fastener Spacing (Graphs 8.1 & 8.2)
■ Shear Wall Test
□ Fastener Parallel Test
■ Shear Wall Test
□ Fastener Parallel Test
Graph 8.1. Fastener Parallel Test Strength vs. Shear Wall Strength
Shear wall S8 strength is higher than shear wall W8.
Shear wall strengths are lower than fastener Parallel Tests.
□ Shear Wall Test |
■ Fastener Parallel Test I
6000 '
l a Shear Wall Test 6093 j 6229
■ Fastener Parallel Test_________2192_______ j _______2475
Graph 8.2. Fastener Parallel Test Stiffness vs. Shear Wall Stiffness
Shear walls W8 and S8 have similar stiffness.
Shear wall stiffness are much higher than fastener Parallel Tests.
70
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• 3-inch Fastener Spacing (Graphs 8.3 & 8.4)
■ Shear Wall Test |
□ Fastener Parallel Test |
□ Fastener Parallel Test I
Graph 8.3. Fastener Parallel Test Strength vs. Shear Wall Strength
Shear wall S8 is 4ft x 8ft.
Shear wall S8 strength is higher than shear wall W8.
Shear wall strengths are lower than fastener Parallel Tests.
OShearW all Test
■ Fastener Parallel Test
2000
□ ShearW all Test
■ Fastener Parallel Test I
Graph 8.4. Fastener Parallel Test Stiffness vs. Shear Wall Stiffness
Shear walls W8 stiffness is higher than S8 stiffness.
Wood shear wall stiffness is higher than fastener Parallel Test stiffness.
4ft x 8ft CFS shear wall stiffness is similar to fastener Parallel Test stiffness.
71
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8.4. Discussion
Wood shear wall strengths of cyclic tests are lower than CFS shear wall
strengths. Both 8ft x 8ft shear walls have the similar stiffness. Narrower shear wall
has more ductility, which is good for life safety, but not good for repair cost.
Wood shear wall strengths range 44% to 47% of fastener Parallel Tests
strengths. The reason is that, in shear wall tests, fasteners had different behaviors in
the comer or the middle of the panel edge when shear wall failed. Shear wall
strength is the average value.
CFS shear wall strengths range 61% to 72% of fastener Parallel Tests
strength, which is higher than wood framed shear wall. The reason is that some CFS
shear walls failed due to stud buckling, which could absorb some energy. Effective
shear wall stiffness is higher than fastener Parallel Tests stiffness.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Part IV Conclusion and Recommendation
Chapter 9. Conclusion and Recommendation
9.1. Conclusions
The results of the testing program described in this thesis provide several
important behavioral characteristics of fasteners in Parallel and Perpendicular Tests.
Some fundamental parameters used to characterize the lateral behavior o f these
fasteners include the data for the Yield Limit State, Strength Limit State, Effective
Shear Stiffness, and Initial Shear Stiffness. Another significant behavioral
characteristic observed and recorded during the testing procedure was the different
failure mechanisms. General observations obtained in this study are as follows:
• Strengths under parallel loads are higher than that under perpendicular
load.
• Stiffness under parallel loads is higher than under perpendicular load.
• The variability o f wood and OSB sheathing strength requires attention.
Strong-Wall™ Shearwall developed by Simpson Strong-Tie Co., Inc.
uses steel strips at the edge of OSB sheathing to prevent the nails pulling
through sheathing, which got higher strength in the cyclic tests.
• Fastener tests alone provided no answer if wood or CFS walls are better.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
• Quality control is very important during construction (Schierle, 1993).
Pre-fabricated shearwall like Simpson Strong-Wall™ Shearwall might be
a good solution.
• Life safety and earthquake repair costs should be balanced in design.
UBS 1997 deals only with life safety.
• CFS is more labor intensive, because screws are driven individually.
• The Parallel Test is more valuable than the Perpendicular Test, because
studs subject to bending are not effective to resist perpendicular load.
• CFS shear walls have higher strength than wood shear walls.
• Narrower shear walls are more ductile than long shear walls.
• Stud buckling of CFS shear walls critically affects strength and stiffness.
9.2. Recommendation
• Fastener performance should be based on parallel rather than
perpendicular test, both in monotonic and cyclic mode.
• A realistic protocol should be developed for dynamic tests of CFS shear
walls.
• More tests are needed on Snap-Cap system to improve their performance.
• New means should be developed to solve the thermal bridge problem of
CFS framing, such as adding insulation outside the sheathing.
• Considering the constant quality o f steel, a lower safety factor could be
considered for CFS framing.
• Stud buckling of CFS shear walls, requires more research.
74
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• Dynamic tests should be conducted on CFS shear walls, because screws
tend to tilt and dynamic test may result in three-dimensional tilting.
75
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Bibliography
Ambrose, J. and Vergun, D., 1999. Design fo r Earthquakes. John Wiley & Sons, Inc.
ASTM, 1995. ASTM E72-95 Standard Method o f Conducting Strength Tests o f
panels fo r Building Construction. Annual Book of ASTM Standards: pp. 392-402.
ASTM, 1995. ASTM E564-95 Standard Practice fo r Static Load Test fo r Shear
Resistance o f Framed Walls fo r Buildings. Annual Book o f ASTM Standards: pp.
556-559.
Bateman, B. W., 1997. Light-Gauge Steel Verses Conventional Wood Framing In
Residential Construction. Journal of Construction Education. Vol. I, No. 4, pp. 327-
338
Breyer, D. E., Kenneth J. F. and Kelly E. C., 1993. Design o f Wood Structures, ASD,
Fourth Edition. McGraw-Hill, Inc., New York.
Charlson, J., 1998. Shear Wall Performance of Snap-Cap Insulated Framing System.
USBT, Framingham, MA
Dinehart, D. W. and Shenton, H. W., 1998. Comparison o f Static and Dynamic
Response o f Timber Shear Walls. Journal of Structural Engineering, ASCE Vol. 124,
No. 6, June, pp. 686-695.
Dolan, J. D. and Madsen B., 1992. Monotonic and Cyclic N ail Connection Tests.
Canadian Journal of Civil Engineering, Vol. 19, No. 1, February, pp. 97-104.
Charlson, J., 1998. Shear Wall Performance o f Snap-Cap Insulated Framing System.
USBT, Framingham, MA.
ICBO, 1997. Uniform Building Code, Volume 2. International Conference of
Building Officials, Whittier, CA.
NASFA, 2000. Prescriptive Method fo r Residential Cold-formed Steel Framing,
Year 2000 Edition. North American Steel Framing Alliance, Washington, DC,
Publication NT3.00.
NAHB, 2001. Steel vs. Wood Cost and Short Term Energy Comparison. National
Association of Home Builder Research Center
76
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Pardoen, G.C., 2001. Report O f A Testing Program O f Light-Framed Walls With
Wood-Sheathed Shear Panels. The City o f Los Angeles Department of Building and
Safety
Roger, B., 1998. Shear Wall Design Guide. North American Steel Framing Alliance,
Washington, DC, Publication RG-9804.
Rose, J. D., 1998. Research Report 158 — Preliminary Testing o f Wood Structural
Panel Shear Walls Under Cyclic (Reversed) Loading. APA — The Engineered Wood
Association, Tacoma, WA.
Shah, Neal N., 2001. Shear Resistance o f Oriented Strand Board and Plywood-
Sheathed, Light-Gauge Steel and Wood-Framed Stud Walls. University of
California, Irvine
SEAOSC, 1997. Standard Method o f Cyclic (Reversed) Load Test fo r Buildings.
Technical report, Structural Engineers Association o f Southern California, Whittier,
CA.
Serrette, R, G. Hall and J. Ngyen, 1997. Additional Shear Wall Values fo r Light
Weight Steel Framing. American Iron and Steel Institute, Washington, DC.
Serrette, R, G. Hall and J. Ngyen, 1996. Shear Wall Values fo r Light Weight Steel
Framing. American Iron and Steel Institute, Washington, DC.
Serrette, R, Encalada, J., Juadines, M. and Nguyen, H., 1997. Static Racking
Behavior o f Plywood, OSB, Gypsum, and FiberBond Walls with Metal Framing.
Journal of Structural Engineering, pp. 1097-1086.
Schierle, Goetz G., 2001. Woodframe Project Case Studies - the CUREE-Caltech
Woodframe Project. Consortium of Universities for Research in Earthquake
Engineering
Schierle, Goetz G., 2002. Northridge Earthquake Field Investigations: Statistical
Analysis o f Woodframe Damage - the CUREE-Caltech Woodframe Project.
Consortium of Universities for Research in Earthquake Engineering
Tissell, J. R., 1993. Research Report 154 — Wood Structural Panel Shear Walls.
APA - The Engineered Wood Association, Tacoma, WA.
USBT, 1998. Shear Wall Performance o f Snap-Cap Insulated Framing System.
http://users.erols.com/usbt
Yu, W.W., 2000. Cold-formed Steel Design. John Wiley & Sons, Inc., New York.
77
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Appendix A. Fastener Parallel Test Results
1. Specimen W8 and W10
Specimen W8 S pecimen W1L O
Test 1 Test 2 Test 1 Test 2 Test 3
Load (lb) A(in) A(in) A(in) A(in) A(in)
0 0.000 0.000 0.000 0.000 0.000
5 0.000 0.000 0.000 0.000 0.000
15 0.001 0.001 0.001 0.001 0.000
25 0.002 0.002 0.002 0.002 0.000
35 0.003 0.003 0.003 0.003 0.000
45 0.004 0.004 0.004 0.004 0.000
55 0.005 0.004 0.005 0.006 0.001
65 0.006 0.004 0.006 0.008 0.002
75 0.007 0.004 0.007 0.010 0.003
85 0.008 0.004 0.008 0.012 0.004
95 0.009 0.005 0.009 0.014 0.004
105 0.010 0.006 0.010 0.016 0.004
115 0.011 0.007 0.011 0.018 0.004
125 0.012 0.008 0.012 0.0120 0.004
135 0.013 0.010 0.013 0.021 0.005
145 0.014 0.012 0.014 0.023 0.006
155 0.015 0.014 0.015 0.025 0.007
165 0.016 0.016 0.016 0.027 0.008
175 0.017 0.017 0.016 0.028 0.008
185 0.018 0.018 0.016 0.029 0.008
195 0.019 0.019 0.016 0.030 0.008
205 0.020 0.020 0.016 0.031 0.008
215 0.021 0.021 0.017 0.033 0.010
225 0.021 0.021 0.018 0.035 0.012
235 0.022 0.022 0.019 0.037 0.014
245 0.023 0.023 0.020 0.039 0.016
255 0.025 0.029 0.021 0.043 0.018
265 0.027 0.035 0.021 0.047 0.020
275 0.031 0.039 0.022 0.050 0.021
285 0.035 0.043 0.023 0.055 0.023
295 0.037 0.045 0.025 0.059 0.023
305 0.039 0.047 0.027 0.063 0.023
315 0.045 0.048 0.029 0.066 0.025
325 0.051 0.050 0.031 0.070 0.027
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
(Continued)
Specimen W8 S pecimen WlL O
Test 1 Test 2 Test 1 Test 2 Test 3
Load (lb) A(in) A(in) A(in) A(in) A(in)
335 0.057 0.056 0.031 0.074 0.029
345 0.063 0.063 0.031 0.078 0.031
355 0.072 0.070 0.033 0.082 0.032
365 0.082 0.078 0.035 0.086 0.035
375 0.086 0.088 0.035 0.090 0.036
385 0.090 0.098 0.035 0.094 0.035
395 0.094 0.102 0.037 0.098 0.037
405 0.098 0.105 0.039 0.102 0.039
415 0.104 0.111 0.043 0.109 0.042
425 0.110 0.117 0.047 0.117 0.043
435 0.117 0.121 0.049 0.125 0.046
445 0.125 0.125 0.051 0.133 0.051
455 0.148 0.145 0.057 0.141 0.054
465 0.164 0.148 0.063 0.148 0.055
475 0.172 0.156 0.068 0.152 0.059
485 0.188 0.164 0.074 0.156 0.063
495 0.191 0.176 0.080 0.164 0.068
505 0.195 0.184 0.086 0.168 0.070
515 0.207 0.191 0.090 0.180 0.076
525 0.234 0.195 0.094 0.188 0.086
535 0.250 0.203 0.098 0.195 0.091
545 0.270 Failure 0.102 0.203 0.094
555 0.285 0.109 0.211 0.102
565 0.293 0.113 0.219 0.105
575 0.301 0.117 0.227 0.113
585 0.316 0.121 0.234 0.117
595 0.328 0.125 0.242 0.129
605 0.344 0.132 0.250 0.137
615 0.352 0.141 0.254 0.137
625 Failure 0.145 0.258 0.148
635 0.148 0.398 0.152
645 0.156 0.414 0.156
655 0.160 0.430 0.160
665 0.164 0.469 Failure
675 0.176 0.484
685 0.188 Failure
695 0.195
705 0.203
715 0.211
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Continued)
Specimen W8 S lecimen W1 0
Test 1 Test 2 Test 1 Test 2 Test 3
Load (lb) Alin) A(in) A(in) A(in) A(in)
725 0.219
735 Failure
Fsls (lb) 615 535 725 655 675
Ke n r (lb/in) 1749 2634 3314 4090 1394
Fyls (lb) 410 357 483 437 450
K, (lb/in) 6793 8455 10854 15856 5486
2. Specimen S8 and S10
Specimen S8 Specimen S10
Test 1 Test 2 Test 1 Test 2
Load (lb) A(in) A(in) A(in) A(in)
0 0.000 0.000 0.000 0.000
5 0.000 0.000 0.001 0.000
15 0.001 0.001 0.004 0.001
25 0.002 0.002 0.007 0.002
35 0.003 0.003 0.009 0.003
45 0.004 0.004 0.012 0.004
55 0.005 0.005 0.017 0.007
65 0.006 0.006 0.021 0.010
75 0.007 0.007 0.026 0.013
85 0.008 0.008 0.031 0.016
95 0.010 0.010 0.034 0.018
105 0.012 0.012 0.037 0.020
115 0.014 0.014 0.040 0.021
125 0.016 0.016 0.043 0.023
135 0.017 0.019 0.045 0.030
145 0.018 0.021 0.047 0.037
155 0.019 0.024 0.049 0.044
165 0.020 0.027 0.051 0.051
175 0.021 0.029 0.058 0.057
185 0.021 0.031 0.064 0.063
195 0.022 0.033 0.071 0.068
205 0.023 0.035 0.078 0.074
215 0.024 0.037 0.085 0.082
225 0.025 0.039 0.092 0.090
235 0.026 0.041 0.099 0.098
245 0.027 0.043 0.105 0.105
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
(Continued)
Specimen S8 Specimen S10
Test 1 Test 2 Test 1 Test 2
Load (lb) A(in) A(in) Alin) A(in)
255 0.027 0.047 0.115 0.115
265 0.027 0.051 0.125 0.125
275 0.029 0.055 0.141 0.129
285 0.031 0.059 0.156 0.133
295 0.033 0.063 0.160 0.139
305 0.035 0.066 0.164 0.145
315 0.037 0.068 0.170 0.146
325 0.039 0.070 0.176 0.148
335 0.043 0.076 0.182 0.154
345 0.047 0.082 0.188 0.160
355 0.051 0.084 0.193 0.168
365 0.055 0.086 0.199 0.176
375 0.057 0.092 0.219 0.178
385 0.059 0.098 0.250 0.180
395 0.061 0.104 0.262 0.191
405 0.063 0.109 0.277 0.203
415 0.068 0.113 0.281 0.209
425 0.074 0.117 0.281 0.215
435 0.080 0.125 0.293 0.223
445 0.086 0.133 0.297 0.230
455 0.094 0.148 0.305 0.238
465 0.098 0.156 0.309 0.258
475 0.105 0.160 0.320 0.266
485 0.113 0.168 0.332 0.273
495 0.121 0.176 0.344 0.289
505 0.133 0.180 0.352 0.301
515 0.141 0.184 0.359 0.309
525 0.156 0.188 0.367 0.320
535 0.172 0.191 0.387 0.336
545 0.184 0.195 0.398 0.344
555 0.195 0.203 0.438 0.352
565 0.211 0.207 0.453 0.355
575 0.234 0.219 0.480 0.363
585 0.250 Failure 0.508 0.371
595 Failure 0.512 0.379
605 0.516 0.387
615 0.539 0.418
625 0.570 0.426
635 Failure 0.465
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
(Continued)
Specimen S8 Specimen S10
Test 1 Test 2 Test 1 Test 2
Load (lb) A(in) A(in) A(in) A(in)
645 0.496
655 0.527
665 0.535
675 0.547
685 0.555
695 0.570
705 0.574
715 Failure
FsLs(lb) 585 575 625 705
Kefr (lb/in) 2340 2629 1096 1228
Fyls (lb)
390 383 417 470
K, (lb/in) 10196 6542 2469 2993
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Appendix B. Fastener Perpendicular Test Results
1. Specimen W8 and W10
Specimen S8 Specimen S10
Test 1 Test 2 Test 1 Test 2
Load (lb) A(in) A(in) A(in) A(in)
0 0.000 0.000 0.000 0.000
5 0.004 0.004 0.000 0.002
15 0.006 0.006 0.002 0.005
25 0.008 0.008 0.004 0.007
35 0.010 0.010 0.007 0.009
45 0.012 0.012 0.009 0.011
55 0.015 0.015 0.011 0.013
65 0.018 0.017 0.013 0.016
75 0.021 0.020 0.015 0.020
85 0.023 0.022 0.017 0.023
95 0.025 0.025 0.020 0.027
105 0.027 0.028 0.022 0.031
115 0.029 0.031 0.024 0.035
125 0.031 0.033 0.029 0.039
135 0.035 0.040 0.033 0.043
145 0.039 0.047 0.037 0.047
155 0.043 0.052 0.042 0.051
165 0.047 0.058 0.046 0.055
175 0.051 0.064 0.050 0.059
185 0.055 0.069 0.055 0.063
195 0.059 0.075 0.063 0.070
205 0.063 0.081 0.071 0.078
215 0.070 0.090 0.076 0.086
225 0.078 0.098 0.082 0.094
235 0.094 0.112 0.086 0.102
245 0.109 0.126 0.091 0.109
255 0.125 0.132 0.100 0.120
265 0.141 0.137 0.109 0.130
275 0.156 0.143 0.117 0.141
285 0.160 0.148 0.134 0.151
295 0.164 0.154 0.142 Failure
305 0.164 0.163 0.154
315 0.172 0.174 0.168
325 0.184 0.185 0.176
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
(Continued)
Specimen S8 Specimen S10
Test 1 Test 2 Test 1 Test 2
Load (lb) A(in) A(in) A(in) A(in)
335 0.199 0.192 Failure
345 0.207 0.202
355 0.211 0.219
365 0.219 0.241
375 Failure 0.249
385 0.250
395 Failure
FsLs(lb) 365 385 325 285
Keff (lb/in) 1669 1540 1844 1887
Fyls (lb) 243 257 217 190
K, (lb/in) 3708 3248 4782 4769
2. Specimen S8 and S10
Specimen S8 Specimen S10
Test 1 Test 2 Test 1 Test 2
Load (lb) A(in) A(in) A(in) A(in)
0 0.000 0.000 0.000 0.000
5 0.000 0.000 0.008 0.004
15 0.001 0.002 0.027 0.018
25 0.002 0.003 0.047 0.031
35 0.003 0.005 0.063 0.041
45 0.004 0.006 0.073 0.051
55 0.005 0.008 0.083 0.059
65 0.006 0.009 0.094 0.067
75 0.007 0.011 0.099 0.072
85 0.008 0.012 0.104 0.078
95 0.009 0.014 0.109 0.082
105 0.011 0.015 0.117 0.086
115 0.013 0.017 0.124 0.094
125 0.014 0.018 0.133 0.109
135 0.015 0.020 0.156 0.125
145 0.016 0.021 0.167 0.141
155 0.016 0.023 0.188 0.180
165 0.016 0.024 0.206 0.188
175 0.018 0.026 0.216 0.211
185 0.020 0.027 0.227 0.234
195 0.021 0.029 0.237 0.281
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
'Continued)
Specimen S8 Specimen S10
Test 1 Test 2 Test 1 Test 2
Load (lb) A(in) A(in) A(in) A(in)
205 0.023 0.030 0.247 Failure
215 0.027 0.032 Failure
225 0.027 0.035
235 0.031 0.038
245 0.031 0.041
255 0.035 0.044
265 0.039 0.047
275 0.043 0.050
285 0.047 0.053
295 0.051 0.056
305 0.055 0.059
315 0.063 0.062
325 0.070 0.063
335 0.078 0.064
345 0.086 0.067
355 0.094 0.070
365 0.102 0.076
375 0.109 0.080
385 Failure 0.083
395 0.086
405 0.092
415 0.102
425 0.114
435 Failure
Fsls (lb) 375 425 205 195
Ketr (lb/in) 3429 3722 829 693
Fyls (lb) 250 283 137 130
Kr (lb/in) 11852 8930 1458 1109
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Appendix C. Monotonic Test Results (Previous Tests)
In below table,
• The sheathing material are all 7/16-in OSB Rated Sheathing except for marked
with*
• All fastener spacing in the field of the panel are 12-in
• Fsls is the ultimate load per foot
Edge
Spacing
Stud Protocol Stud
Spacing
Specimen
Size
Fastener
Size
F sls
(lb)
A (in) Keir
(lb/in)
6-in Serrette
(1997)
CFS
20g
ASTM
E564
24-in 8ftx8ft Screw
#8 1-in
7288 1.585 4598
Serrette
(1998)
CFS
20g
ASTM
E564
24-in 4ftx8ft Screw
#12 x 1-
1/2-in
3532 2.92 1210
4-in Dinehart
(1998)*
SPF ASTM
E564
16-in 8ftx8ft Nail 8d 7169 3.11 2305
Serrette
(1996)
CFS
20g
ASTM
E564
24-in 4ftx8ft Screw
#8 1-in
5648 2.33 2424
3-in Tissell
(1993)
D.F. 16-in Nail 8d 11888
Tissell
(1993)*
D.F. 16-in Nail lOd 12992
Serrette
(1996)
CFS
20g
ASTM
E564
24-in 4ftx8ft Screw
#8 1-in
6944 2.08 3338
Serrette
(1998)
CFS
20g
ASTM
E564
24-in 4ftx8ft Screw
#12x1-
1/2-in
7452 4.00 1863
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Appendix D: Cyclic Test Results (from Previous Tests)
In below table,
• The sheathing material are all 7/16-in OSB Rated Sheathing
• All fastener spacing in the field of the panel are 12-in
• F s l s is the ultimate load per foot
Edge
Spacing
Stud Protocol Stud
Spacing
Specimen
Size
Fastener
Size
F sls
(lb)
A (in) K eff
(lb/in)
4-in COLA/
UCI
(2000)
D.F. SPD 16-in 8ftx8ft Nail 8d
x2-l/2in
6081 0.998 6093
COLA/
UCI
(2000)
CFS
20g
SPD 24-in 8ftx8ft Bugle
head
Screw
#8x1-in
8521 1.368 6229
3-in APA
(1998)
D.F. SPD 16-in 8ftx8ft Nail 8d 8700 1.16 7500
Serrette
(1996)
CFS
20g
SPD 24-in 4ftx8ft Screw
#8x1-in
6710 2.308 2908
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University of Southern California Dissertations and Theses

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Asset Metadata

Creator Sui, Fang (author)

Core Title Comparison of lateral performance: Residential light wood framing versus cold-formed steel framing

School School of Architecture

Degree Master of Building Science / Master in Biomedical Sciences

Degree Program Building Science

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag Architecture,engineering, civil,engineering, materials science,OAI-PMH Harvest

Language English

Contributor Digitized by ProQuest (provenance)

Advisor Schierle, G. Goetz (committee chair), Schiler, Marc E. (committee member), Vergun, Dimitry (committee member)

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c16-296210

Unique identifier UC11337587

Identifier 1411808.pdf (filename),usctheses-c16-296210 (legacy record id)

Legacy Identifier 1411808.pdf

Dmrecord 296210

Document Type Thesis

Rights Sui, Fang

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the au...

Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus, Los Angeles, California 90089, USA