ASTM D5055-19e1

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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Designation: D5055 − 19
Standard Specification for
Establishing and Monitoring Structural Capacities of
Prefabricated Wood I-Joists
This standard is issued under the fixed designation D5055; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Corrected editorially in January 2020.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 General—This specification gives procedures for
D198 Test Methods of Static Tests of Lumber in Structural
establishing, monitoring, and reevaluating structural capacities
Sizes
of prefabricated wood I-joists. Capacities considered are shear,
D245 Practice for Establishing Structural Grades and Re-
reaction, moment, and stiffness. Procedures for establishing
lated Allowable Properties for Visually Graded Lumber
common details are given and certain design considerations
D1990 Practice for Establishing Allowable Properties for
specific to wood I-joists are itemized.
Visually-Graded Dimension Lumber from In-Grade Tests
1.2 Contents of the Standard—An index and brief descrip-
of Full-Size Specimens
tion of the main features of this specification are given in
D2559 Specification for Adhesives for Bonded Structural
X2.1.1.
Wood Products for Use Under Exterior Exposure Condi-
tions
1.3 Development of the Standard—The development and
D2915 Practice for Sampling and Data-Analysis for Struc-
intent of this specification is discussed in Appendix X2.
tural Wood and Wood-Based Products
1.4 The values stated in inch-pound units are to be regarded
D4761 Test Methods for Mechanical Properties of Lumber
as standard. The values given in parentheses are mathematical
and Wood-Based Structural Materials
conversions to SI units that are provided for information only
D5456 Specification for Evaluation of Structural Composite
and are not considered standard.
Lumber Products
D5457 Specification for Computing Reference Resistance of
1.5 This standard does not purport to address all of the
Wood-Based Materials and Structural Connections for
safety concerns, if any, associated with its use. It is the
Load and Resistance Factor Design
responsibility of the user of this standard to establish appro-
D7247 Test Method for Evaluating the Shear Strength of
priate safety, health, and environmental practices and deter-
Adhesive Bonds in Laminated Wood Products at Elevated
mine the applicability of regulatory limitations prior to use. A
Temperatures
specific precautionary statement is given in 6.1.1.5.
D7480 Guide for Evaluating the Attributes of a Forest
1.6 This international standard was developed in accor-
Management Plan
dance with internationally recognized principles on standard-
E4 Practices for Force Calibration and Verification of Test-
ization established in the Decision on Principles for the
ing Machines
Development of International Standards, Guides and Recom-
E529 Guide for Conducting Flexural Tests on Beams and
mendations issued by the World Trade Organization Technical
Girders for Building Construction
Barriers to Trade (TBT) Committee.
E699 Specification for Agencies Involved in Testing, Quality
Assurance, and Evaluating of Manufactured Building
Components
This specification is under the jurisdiction of ASTM Committee D07 on Wood
and is the direct responsibility of Subcommittee D07.02 on Lumber and Engineered
Wood Products. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 1, 2019. Published May 2019. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1990. Last previous edition approved in 2016 as D5055–16 DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D5055-19E01. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D5055 − 19
IEEE/ASTM SI 10 Standard for Use of the International 4. Design Considerations
System of Units (SI): The Modern Metric System
4.1 Design Value Adjustments:
2.2 U.S. Product Standards:
4.1.1 Duration of Load—With the exception of reaction
PS-1 Structural Plywood
design values limited by compression perpendicular to grain,
PS-2 Performance Standard for Wood-Based Structural-Use
prefabricated wood I-joists shall be designed using the strength
Panels
adjustment for load duration used in sawn lumber. This
PS-20 American Softwood Lumber Standard
adjustment is determined in accordance with the section on
2.3 Other Standards:
Duration of Load Under Modification of Allowable Properties
CSA O86 Engineering Design in Wood
for Design Use in Practice D245.
CSA Standards for Wood Adhesives O112 Series
4.1.2 Repetitive Members—The repetitive member factor
CSA O121 Douglas-fir Plywood
for prefabricated I-joists shall be taken as 1.0.
CSA O141 Softwood Lumber
NOTE 2—Committee D07 chose to reduce the repetitive member factor
CSA O151 Canadian Softwood Plywood
to unity primarily for purposes of design simplicity. A discussion of this
CSA O325 Construction Sheathing
decision is given in Appendix X2.
CSA O437.0 OSB and Waferboard
4.1.3 Treatments—Some pressure treatments affect material
Lumber Grading Rules Approved by American Lumber
strength and the quality of prefabricated wood I-joists. Treated
Standards Committee (ALSC) or Canadian Lumber Stan-
5 I-joists shall not be used without evaluation of such effects.
dards Accreditation Board (CLSAB)
6 4.1.4 Environment—The capacities developed in this speci-
SPS-1 Fingerjoined Structural Lumber
fication are applicable to prefabricated wood I-joists used
SPS-4 Fingerjointed Flange Stock Lumber, 2001
under dry service conditions defined in the governing code-
ISO/IEC 17020 General Criteria for the Operation of Vari-
referenced design standards, such as in most covered struc-
ous Types of Bodies Performing Inspection
tures. Appropriate adjustments for uses in other environments
ISO/IEC 17025 General Requirements for the Competence
shall be made.
of Testing and Calibration Laboratories
ISO/IEC 17065 Conformity Assessment–Requirements for
4.2 Shear Design:
Bodies Certifying Products, Processes and Services
4.2.1 Neglecting loads within a distance from the support
equal to the depth of the member shall not be permitted.
3. Terminology
4.2.2 Adjustments to the shear design value near the support
3.1 Definitions: or at locations of continuity or where reinforcements are
3.1.1 prefabricated wood I-joist—a structural member provided must be substantiated by independent testing to the
manufactured using sawn or structural composite lumber general intended criteria for shear capacity herein.
flanges and structural panel webs, bonded together with exte-
rior exposure adhesives, forming an “I” cross-sectional shape. 5. Materials
These members are primarily used as joists in floor and roof
5.1 General—The following I-joist components meet the
construction.
definition of a biobased product in accordance with 3.3.1 of
3.2 Definitions of Terms Specific to This Standard:
Guide D7480:
3.2.1 capacity (or structural capacity)—the numeric result
5.1.1 Lumber flange materials complying with USDOC
of certain calculations specified in this specification.
PS-20, CSA O141, NLGA SPS-1, or NLGA SPS-4.
5.1.2 Structural composite lumber flange materials comply-
3.2.2 design value—the numeric value claimed by the
ing with Specification D5456.
manufacturer as appropriate for use in structural analysis.
5.1.3 Web materials complying with USDOC PS-1,
NOTE 1—A brief discussion of this issue is found in X2.9.
USDOC PS-2, CSA O121, CSA O151, CSA O325, or CSA
3.2.3 structural composite lumber—a composite of wood
O437.0.
elements (for example, wood strands, strips, veneer sheets, or
5.2 Flange Stock:
a combination thereof), bonded with an exterior grade adhesive
5.2.1 All flange material shall conform to the requirements
and intended for structural use in dry service conditions.
of 6.4. In addition, when the flange material is structural
composite lumber, the following properties shall be determined
Available from APA—The Engineered Wood Association, 7011 South 19th in accordance with Specification D5456: modulus of elasticity
Street, Tacoma, WA 98466, http://www.apawood.org; and TECO, 2902 Terra Court,
(flat or edge, depending on flange orientation in the I-joist),
Sun Prairie, WI 53590, http://www.tecotested.com.
compression (parallel and perpendicular to grain), and nail
Available from Canadian Standards Association (CSA), 5060 Spectrum Way,
design values.
Mississauga, ON L4W 5N6, Canada, http://www.csa.ca.
Available from American Lumber Standard Committee (ALSC), P.O. Box 210,
5.2.2 End joints in purchased flange stock are permitted
Germantown, MD 20874, http://www.alsc.org; and Canadian Lumber Standards
provided such joints conform to the general intent and Section
Accreditation Board (CLSAB), 960 Quayside Drive, Suite 406, New Westminster,
10 of this specification.
BC V3M 6G2, Canada, http://www.clsab.ca.
Available from National Lumber Grades Authority (NLGA), 302–960 Quay-
5.3 Web Material—Panels shall conform to manufacturing
side Drive, New Westminster, BC V3M 6G2, Canada, http://www.nlga.org.
or performance standards recognized by the applicable govern-
Available from International Organization for Standardization (ISO), 1, ch. de
la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org. ing code. Examples are PS-1 (or CSA O151) and PS-2 (or CSA
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D5055 − 19
O325). In addition, all panels shall meet the equivalent of equal to or higher than the lower 95 % confidence interval on
Exposure I requirements as specified in PS-1 or PS-2. the mean residual shear strength ratio for the solid wood
control specimens.
5.4 Adhesives—Adhesives used to bond together compo-
nents of the finished product shall conform to the requirements
6. Qualification
in Specification D2559 (or, in Canada, shall conform to an
6.1 General—This section describes procedures, both em-
appropriate standard from the CSA Standards for Wood
pirical and analytic, for initial qualification of the structural
Adhesives, O112 Series, stipulated in CSA O86). In addition,
capacities of prefabricated wood I-joists. Qualification is re-
adhesives used for web-to-web, web-to-flange, and flange-to-
quired for certain common details of I-joist application since
flange joints shall be qualified for heat durability performance
they often influence structural capacities. All capacities are to
in accordance with 5.4.3. Appendix X4 gives additional
be reported with three significant digits. Any time significant
information and standards that shall be considered when
changes in joist or application details, manufacturing processes
qualifying adhesives and adhesive-bonded materials.
or material specifications occur, qualification is required, as for
a new manufacturer or product line.
NOTE 3—Heat durable performance implies that a bonded joint will
6.1.1 Testing—Qualification tests shall be conducted or
exhibit similar material resistance to solid wood in an elevated tempera-
ture environment where the wood material surrounding the joint does not
witnessed by a qualified agency as defined in 8.1. All test
provide thermal protection.
results are to be certified by the qualified agency.
6.1.1.1 Sample Size—The number of specimens specified in
5.4.1 Adhesives and binder systems used in the fabrication
6.2, 6.3, 6.4, 6.5, and 6.6 are minimums. The producer wishing
of Structural Composite Lumber products shall be evaluated in
to evaluate the validity of the sample size will find a procedure
accordance with Specification D5456.
in 4.7 of Practice D2915.
5.4.2 Adhesives and binder systems used in the fabrication
6.1.1.2 Test Specimens—Materials and fabrication proce-
of panel products used as a web shall be evaluated in
dures of test specimens shall be as typical of intended
accordance with PS-2 (or, in Canada, CSA O325) with the
production as can be obtained at the time of manufacturing
Exposure 1 classification.
qualification specimens. Minimum specimen temperature at
5.4.3 Adhesives—Heat durability:
the time of test shall be 40°F (4°C). Specimens shall be tested
5.4.3.1 Adhesives used for web-to-web, web-to-flange, and
at the as-received moisture content.
flange-to-flange joints shall be qualified for heat durability
NOTE 4—It is desirable to conduct preliminary tests to aid the selection
performance through testing in accordance with Test Method
of representative specimens.
D7247. The test temperature and heat exposure duration for
6.1.1.3 Test Accuracy—Tests in accordance with this speci-
specimens tested at elevated temperature (7.2 of Test Method
fication are to be conducted in a machine or apparatus
D7247) shall meet the requirements of Items 1, 2, 3, and 4
calibrated in accordance with Practices E4 except that the
below.
percentage error shall not exceed 62.0.
(1) The solid wood control specimen and both pieces of the
6.1.1.4 Test Methods—Methods generally applicable to the
bonded specimen shall be prepared from the same commercial
full-section joist tests required herein are in Guide E529, with
species group of Douglas Fir, Southern Pine, or the predomi-
the following exceptions: (1) the methods are applicable to
nate commercial species group used in the flange. The adhesive
both qualification and quality control, (2) load rate shall be as
formulation used in the test shall be the same as the adhesive
specified in the following sections, and (3) delays between load
formulation used in the production process.
increments are not required. Required tension and compression
(2) For the bonded specimens, the minimum target bond-
tests shall be substantially in accordance with Test Methods
line temperature shall be 428°F (220°C). For the matched solid
D198 or Test Methods D4761 with load rates as specified in the
wood control specimens, the minimum target temperature at
following sections. All test report formats and content shall be
the shear plane shall be 428°F (220°C).
in keeping with the intended use of the results and be agreed
(3) The minimum target temperatures of Item 2 shall be
upon by all involved parties prior to the test.
maintained for a minimum of 10 min or until achieving a
6.1.1.5 Test Safety—All full-scale structural tests are poten-
residual strength ratio for the solid wood control specimens of
tially hazardous and appropriate safety precautions must be
30 6 10 %, whichever is longer.
observed at all times. One particular concern is the potential for
(4) Block shear testing shall be conducted immediately
lateral buckling during full-section I-joist tests and appropriate
after removal from the oven such that the specimen bondline or
lateral restraint must be maintained at all times.
shear plane temperature does not drop more than 9°F (5°C)
after leaving the oven and prior to failure. This provision is
6.2 Shear Capacity Qualification:
satisfied when the time interval from the removal of the
6.2.1 Initial capacity shall be established from either test
specimen from the oven to the failure of the block shear
results or calculations. The equations used for the calculation
specimen does not exceed 60 s for each specimen tested and
method shall be confirmed by a test program; the details of
the room temperature of the test laboratory at the time of
which are beyond the scope of this specification. Explanations
testing is not less than 60°F (15.5°C).
of the statistics used in the analysis of test results, with an
5.4.3.2 For adhesives tested in accordance with 5.4.3.1, the example, are given in Appendix X5.
residual shear strength ratio for the bonded specimens, as 6.2.2 Factors which influence shear capacity include web
calculated in accordance with Test Method D7247, shall be type, thickness, and grade; web to flange joint; joint type in
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D5055 − 19
web (machined, butted, glued or not, reinforced, etc.). Each 6.2.3 must be repeated. If the second test set fails to meet the
combination of these web factors must be tested separately in criteria, all depths which have been skipped must also be
accordance with 6.2.3, unless the critical combination in a tested. (A check of the regression criteria is given in X5.4.5.)
proposed grouping is first established by test. Flange stiffness
6.2.11.1 Data from joist depths where failure is web buck-
influences shear strength: if a range of flange sizes is to be used
ling shall be excluded from the regression analysis, if: (1)
with a given combination of web factors, all sizes must be
including the results causes failure to meet the criteria of
tested unless all values are to be based on tests with the
6.2.11; or (2) the producer determines the reduction in regres-
smallest flange. When a range of species or grades of either
sion line slope is unacceptable. In either case, all depths greater
sawn or composite lumber is to be grouped, preliminary tests
than the shallowest excluded, shall be tested.
shall be conducted to determine which is critical. Joists with
NOTE 5—Depending on joist details and material, there will be some
structural composite lumber flanges, such as laminated veneer
depth where web buckling appears as a mode of failure. Further increases
lumber (LVL), must be tested separately from joists with sawn
in depth will result in consistent web buckling, and at some point ultimate
lumber flanges.
strength will reduce compared to shallower joists.
6.2.3 For each web factor combination, a minimum of ten
6.2.11.2 When no more than three depths are to be qualified,
specimens shall be tested for each critical joist depth. Critical
the correlation is not necessary, but each depth must be tested.
joist depths are minimum and maximum product depths with
6.2.12 The shear capacity of the product shall be limited to
approximate 4-in. (102-mm) depth increments between. If the
that calculated by taking into account sample size, test result
installation of specific reinforcement as defined in the manu-
variability, and reduction factors. Data from tests at different
facturer’s literature is required at a certain depth to maintain
joist depths included in regression analysis are permitted to be
product performance in the progression of a series of depths
combined to obtain a pooled estimate of variability.
within a combination, the product must be tested at this depth
6.2.12.1 Combining Data—The regression equation from
plus the adjacent depth which does not require specific
6.2.11 provides the expected mean shear strength (P ) for depth
e
reinforcement.
(d ):
i
6.2.4 Specimen length shall be that which usually produces
P 5 A1Bd (1)
failures in shear and shall not extend past each bearing support e i
more than ⁄4 in. (6.4 mm). The bearing length shall be
where A and B are intercept and slope of the equation.
adequate to usually produce shear failure instead of a bearing
6.2.12.2 Where too few depths are involved for correlation
failure but shall not exceed 4 in. (102 mm), unless justified.
in 6.2.11, when the tests fail the regression criteria, or where
There shall be a minimum horizontal distance of 1 ⁄2 times the
depths are excluded from the correlation, no combining is
joist depth between the face of the support and the edge of the
allowed and each such depth shall be evaluated separately.
load pad.
6.2.12.3 The mean and standard deviation of the data from
6.2.5 On one end of the specimen, a vertical web joint, if
¯
each depth tested are (P ) and (S ). The coefficient of variation
i i
used, shall be located approximately 12 in. (305 mm) from the
is:
face of the support or ⁄2 the distance between the support and
¯
the load pad.
v 5 S /P (2)
i i i
6.2.6 The load shall be applied to the top flange either as a
Let n be the number of tests for each depth (d ) tested and
i i
single point load at center span or as two point loads of equal
included in the regression analysis. Then the coefficient of
distance from the center span. Load pads shall be of sufficient
variation in the combined data sets is:
length to prevent local failure.
6.2.7 The load shall be applied at a uniform rate so that 2
@ n 2 1 v #
~ !
( i i
v 5 (3)
Œ
anticipated failure will occur in not less than 1 min.
n 2 J
i
(
6.2.8 Any required web reinforcements developed in 6.7.1
Where J is the number of depths included in the regression
shall be installed at supports. When required to prevent failure
analysis and the summation is from i = 1 to J.
at a load point, additional reinforcement shall be installed,
provided such reinforcement is not wider than the load pad. 6.2.12.4 Shear Capacity—The shear capacity is calculated
as follows:
6.2.9 Ultimate load and mode of failure shall be recorded in
addition to product and test setup descriptions. If any specimen
P 5 C P 2 KvP /2.37 (4)
~ !
s e e
fail in bending, the data shall be excluded. However, for
where:
purposes of evaluating shear capacity, bearing failure is con-
K = factor for one-sided 95 % tolerance limit with 75 %
sidered a mode of shear failure. Appendix X6 discusses some
confidence for a normal distribution. Values for this
of the modes of shear failure and offers a possible coding
factor are given in Appendix X5, Eq X5.20, and Table
scheme.
X5.3;
6.2.10 The dead load of the specimen is to be included in the
P = ultimate mean shear strength from Eq 1 or the mean of
e
ultimate load calculation when specified by the producer.
any depth in accordance with 6.2.12.2;
6.2.11 The mean ultimate shear values shall show logical
v = coefficient of variation of combined data from Eq 3 or,
progression of strength as a function of depth. A linear
in accordance with 6.2.12.2, from Eq 2 when any depth
regression analysis of the mean values shall have a coefficient
is evaluated alone;
of determination (r ) of at least 0.9, or the specified tests of
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D5055 − 19
(2) Nonstandard Grades; Standard Lengths—Flanges uti-
C = product of any appropriate special use reduction factors
lizing nominal 8-ft (2.44-m) and longer structural composite or
from Appendix X7; and
sawn lumber, but not meeting the standard grade criteria of
P = shear capacity.
s
6.4.1.2 (1). Qualification testing and analysis shall be in
6.2.12.5 When data are combined, the factor K is based on
accordance with 6.4.1.3 and 6.4.1.4. End joints, when used,
a sample size N = ∑n − J. When the criteria of 6.2.11 are not
i
shall be qualified in accordance with 6.5. Alternatively, a single
met and for depths excluded from the regression analysis, then
end joint, when used, shall be permitted to be included within
the allowable shear capacity is computed separately for each
the gauge length of each flange specimen when tested in
such depth and is:
accordance with 6.4.1.3. To use this alternative method, the
¯ ¯
~ ! minimum end-joint spacing permitted in application and used
P 5 C P 2 Kv P /2.37 (5)
s i i i
to determine L in 6.4.1.5 shall be the tested gauge length.
and the factor K is for a sample size of n . A discussion of the
i
(3) Any Grades; Short Lengths—Flanges utilizing struc-
reduction factor (2.37) is given in Appendix X7.
tural composite lumber or sawn lumber in lengths shorter than
6.3 Reaction Capacity Qualification—Reaction capacity
8 ft (2.44 m) before end jointing. Qualification testing and
shall be determined in accordance with Annex A1. analysis shall be in accordance with 6.4.1.3 and 6.4.1.4.
Qualification specimens shall be used to establish a character-
6.4 Moment Capacity Qualification—Moment capacity
istic (that is, average) joint spacing as noted in Eq 7. Average
shall be determined either analytically from the characteristics
joint spacing in individual flanges in the qualification sample
of flange material (6.4.1) or empirically from the results of
shall not be less than 75 % of the established characteristic
I-joist bending tests (6.4.3).
joint spacing. The characteristic joint spacing established
6.4.1 Analytical Method:
during qualification shall be maintained in subsequent produc-
6.4.1.1 In this method, the I-joist moment capacity is
tion.
determined as follows:
L 5 L/N (7)
J
M 5 K F A y (6)
a L a net
where:
where:
L = characteristic joint spacing,
J
K = length adjustment factor, computed in accordance
L
L = total length of flange in the gage length for the
with 6.4.1.5. The factor adjusts flange material F as
a
qualification sample, and
a function of joist span and stress. Joist depth, tension
N = total number of joints in the gage length for the
test gage length, finger joint spacing, and material or
qualification sample.
joint variability are utilized in determining K ;
L
6.4.1.3 Tension Tests—For flange material conforming to
A = net area of one flange (excluding areas of all web
net
6.4.1.2 (2) or (3), tension tests parallel to grain shall be
material and rout);
y = distance between flange centroids (with the rout conducted on a gage length (distance between grips) of not less
removed); and than 8 ft (2.44 m) for sawn lumber and 3 ft (0.91 m) for
F = design flange axial stress, taken as the lower of flange
structural composite lumber. When flanges utilize sawn lumber
a
tensile stress adjusted to the reference gage length or or structural composite lumber less than 8 ft long, the charac-
end joint tensile stress computed in accordance with
teristic end joint spacing for the qualification sample shall
6.4.1.4, or flange compressive stress computed in comply with the provisions of 6.4.1.2 (3). Testing speed shall
accordance with 6.4.1.6.
be in accordance with 9.5.4 of Test Methods D4761. The
NOTE 6—The assessment of axial stress on the basis of average stress minimum sample size shall be 53. The flange material vari-
at a given cross section matches committee judgment and experimental
ability (coefficient of variation) and tension gage length shall
evidence based on joists in which the thickness of an individual flange is
be reported.
less than approximately one sixth of the overall joist depth. For joists not
meeting this criterion, additional consideration of extreme fiber stresses
NOTE 8—SPS-4 provides alternative methods which comply with the
may be needed.
intent of characteristic joint spacing and minimum gage length provisions
NOTE 7—The information in this specification is not intended to be
of 6.4.
limited to the allowable stress design (ASD) format. Provided that
6.4.1.4 Capacity—The tensile capacity shall be the lower 5
appropriate scaling of design values is completed (from ASD to the limit
states design (LSD) or load and resistance factor design (LRFD) format)
% tolerance limit with 75 % confidence, divided by 2.1. The
in accordance with applicable standards.
lower 5 % tolerance limit shall be established with 75 %
confidence using either parametric or nonparametric proce-
6.4.1.2 Flange Material Types—Flange materials fall into
dures; however, if parametric procedures are adopted, an
one of the following three categories:
appropriate analysis used to confirm the type of distribution
(1) Standard Lumber Grades; Standard Lengths—Flanges
must be presented. Minimal evidence that a distribution fits the
utilizing nominal 8-ft (2.44-m) and longer sawn lumber of a
data shall consist of a cumulative plot of the data with the
standard grade permitted by the governing code and graded
chosen distribution superimposed on the data. The latter shall
under standards recognized by American Lumber Standards
be either a curve as shown in Fig. X5.1 or a linearized plot as
Committee (ALSC) or Canadian Lumber Standards Accredita-
shown in Fig. X5.5.
tion Board (CLSAB). The tabulated allowable tension value,
F , is assumed to be based on a 12-ft (3.66-m) gage length. End 6.4.1.5 The length adjustment factor K is the lesser of 1.0
t L
joints, when used, shall be qualified in accordance with 6.5. or the value computed as follows:
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D5055 − 19
Z
K 5 K L /L # 1.0 (8) mm) on center. In addition, the maximum permitted web hole
~ !
L S 1
specified in 6.4.3.2 is optional.
where:
6.4.2.3 Any specimen failing at a calculated maximum
K = length adjustment factor;
L
moment of less than 2.1 times the calculated capacity indicates
K = stress distribution adjustment factor (adjusts design
S
the possibility of errors in manufacturing, material selection, or
flange axial stress (F ) from full-length constant stress
a
calculation. The reason for such failures shall be carefully
(such as a tension test) to the reference stress condition
evaluated and probable cause determined. Further testing shall
= 1.15;
be conducted as indicated in 6.4.2.4 and 6.4.2.5.
L = gage length, (in.). For 6.4.1.2 (1) utilizing flange stress,
6.4.2.4 If the determined probable cause identified in 6.4.2.3
L = 144 in. (3658 mm). For 6.4.1.2 (2) utilizing flange
results in manufacturing or design changes of the product,
stress, L = distance between tension tester grips. For
retesting shall be conducted in accordance with 6.4.2.1.
6.4.1.2 (3) utilizing flange stress, L = distance be-
6.4.2.5 If a probable cause is not found and the low result
tween tension tester grips. For 6.4.1.2 (1) and (2)
cannot be attributed to errors that can be corrected, further
utilizing end joint stress, L = minimum end joint
testing shall be conducted. A minimum of 10 additional
spacing allowed in the I-joist;
samples for parametric analysis or 43 additional samples for
L = joist span = 18 times the joist depth (in.); and
nonparametric statistics shall be tested. The tested moment
Z = exponent for Eq 8 in accordance with Table 1.
A capacity shall be the lower 5 % tolerance limit with 75 %
TABLE 1 Exponent (Z) for Eq 8
B,C confidence divided by 2.1. To confirm the analytical method,
COV , % Z
the tested moment capacity shall be greater than or equal to the
#10 0.06
15 0.09
calculated moment capacity determined in 6.4.1.1.
20 0.12
25 0.15
NOTE 10—Although it is unlikely that in a ten-specimen confirming test
$30 0.19
of a controlled manufacturing process, a result below 2.1 times the
A
calculated capacity will be encountered, it is statistically possible that such
Interpolation between tabular values is permitted.
B
Cefficient of variation of the full data set based on a normal distribution, taken as a specimen could appear. Increasing the sample size and applying
not less than the higher COV attained from the tensile strength of flange material
parametric or nonparametric procedures to analyze the data will determine
or end joints.
if changes to the analytical moment capacity are needed. (See commentary
C
Cefficient of variation for 6.4.1.2 (1) material shall be 20 % for machine-graded
in X2.5.3.)
lumber (including SPS-4 material) and 25 % for visually graded lumber.
6.4.3 Empirical Method:
NOTE 9—K is not intended for use as an adjustment factor for specific
L
6.4.3.1 Test Procedure—Bending tests are to be conducted
application lengths. It is a modifier for assigning design I-Joist moment
on a span of 17 to 21 times the joist depth. Two point loads are
capacity by depth. (See Eq 6.)
to be placed symmetrically about the center and the spacing
6.4.1.6 Values for compression shall be established by
between such load points shall be a minimum of one third of
testing the material in tension and assigning a value in
the span. Joists shall be reinforced under the load points when
compression such that:
necessary to prevent local failure. Load rate shall be adjusted to
produce failure in not less than 1 min. Maximum moment in
F 5 F ~F /F ! (9)
ci ti c t
the specimen and the location of failure shall be recorded.
where:
NOTE 11—A span to depth ratio of 18 is a frequent international
F = closest assigned code value in tension for same species
t
practice.
and size as tested pieces;
6.4.3.2 Specimens Tested—Specimens shall be typical of
F = code assigned value in compression for same grade,
c
intended production. Each flange material, grade, dimension,
species, and size as F visual grades;
t
species and supplier, combined with each web type, thickness
F = tensile value as determined in 6.4.1.3; and
ti
and grade, shall be tested. Procedures for evaluating materials
F = allowable stress in compression.
ci
from each supplier shall be addressed in the manufacturing
If F is larger than the highest value given in tables of visual
ti
standard. One method of evaluation is shown in X2.1.1.8.
grade lumber for the species, then the ratio of tension to
When flanges contain end joints, such joints shall have been
compression shall be from tables for the nearest machine stress
qualified in accordance with 6.5.1, and all bending test speci-
rated (MSR) lumber grade.
mens shall include at least one joint in the tension flange
6.4.2 Analytical Method Confirming Tests:
located between the load points. When holes are allowed in the
6.4.2.1 It is required that a minimum of ten I-joist speci- web in accordance with 6.7, the maximum permitted hole shall
be located approximately at the center of the span. Sufficient
mens be tested at each of the extremes of flange size, allowable
stress, and joist depth. This testing is not intended to substan- bearing length or reinforcement, or both, shall be provided at
supports to prevent bearing failures.
tiate the moment capacity determined in 6.4.1, but is consid-
6.4.3.3 Remanufactured Solid Sawn Flanges—When
ered necessary for any new product to generally confirm the
overall performance of the assembled components. This testing flanges utilize remanufactured lumber, the specimens tested
shall be typical of the specifications in the manufacturing
is also necessary to satisfy the requirements of 6.6.
standard in accordance with 9.1.1.1.
6.4.2.2 Test setup and procedures shall conform to the
requirements of 6.4.3, except that loading may simulate uni-
NOTE 12—It is strongly recommended that plant personnel performing
form load with load points spaced no greater than 24 in. (610 regrading activities be trained by an agency under an accreditation
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D5055 − 19
program such as the ALSC.
moment capacity in accordance with 6.4.1; or (2) when
moment capacity is determined in accordance with 6.4.3, the
6.4.3.4 Sample Size and Analysis—For qualification, a mini-
flange MOE shall be obtained from tables of recognized values
mum of 28 specimens are required in each tested depth. Testing
or tests of the flange material. (3) Elastic properties of the web
shall be at joist depth intervals no greater than 3 in. (76 mm),
material shall be obtained from the appropriate standard.
with a minimum of four depths tested, including the minimum
6.6.3 Creep—Two of the I-joist specimens shall be loaded to
and maximum joist depths. The mean ultimate moment capaci-
20 % of their moment capacity and center-span deflection
ties shall show logical progression as a function of the depth
readings taken. For purposes of this test, 20 % is assumed to be
squared. A linear regression analysis of the mean values shall
typical basic dead load (BDL). The specimen shall then be
have a coefficient of determination (r ) of at least 0.9. If the
loaded to 1 ⁄2 times the moment capacity for 1 h and deflection
manufacturer produces less than 4 depths, 53 specimens of
readings taken. The specimen shall be unloaded to BDL and
each depth shall be tested, but the requirement for a coefficient
deflection readings shall be taken after 15 min. The specimens
of determination shall not apply. Moment capacity shall be
must recover an average of 90 % of the total deflection from
based on the lower 5 % tolerance limit with 75 % confidence,
BDL to the end of the 1-h load period.
divided by 2.1. Nonparametric statistics shall be used to
determine the tolerance limit and confidence unless justifica-
6.7 Details of End Use:
tion is presented for using parametric procedures. Joist depths
6.7.1 The intent of this section is to define common appli-
not tested shall be assigned capacities based on a logical
cation details. In addition to the following minimum
progression of the depth squared between values assigned at
considerations, other details which affect application perfor-
the nearest depths tested to either side.
mance shall be investigated (for example, minimum nail
spacing to avoid splitting).
6.5 End Joint Qualification:
6.7.2 Web Openings:
6.5.1 Standards—Adhesives used in joints shall conform to
the requirements of 5.4.
6.7.2.1 Holes which remove a significant portion of the web
6.5.2 Testing—Tension tests parallel to grain, on full-section will reduce shear strength at that section of the I-joist. Tests are
joints, shall be conducted on a gage length (distance between to define such reductions for varying size and shape openings
grips) of not less than 2 ft (0.61 m). Testing speed shall be in so that in application, openings can be located at sections
subjected to appropriate shear levels. A minimum of five
accordance with 9.5.4 of Test Methods D4761. The minimum
sample size shall be 53. The design stress shall be determined specimens of at least three depths encompassing the product
range shall be tested for each depth/opening combination. Test
from 6.4.1.4. End joint variability (coefficient of variation)
shall be reported. specimens and setup are permitted to be the same as specified
in 6.2 with an opening located between support and load points
6.5.3 Requirements—Joints in any flange material shall
and centered on a web joint, when web joints exist in the
conform to this specification, with particular reference to
product.
Section 10 when applicable.
6.7.2.2 Maximum size hole which can be located anywhere
6.6 Stiffness Capacity and Creep:
in the web, shall be specified by the manufacturer and
6.6.1 Tests—The tests of 6.4.2 or the first ten tests at the
supported by data.
extremes of depth in accordance with 6.4.3 shall be used to
6.7.2.3 Spacing of allowed multiple holes must be verified
confirm stiffness capacity and evaluate creep characteristics.
by test.
Center span deflection measurements shall be recorded at a
1 6.7.3 Special Details—Depending on joist configuration,
minimum of four increments to 1 ⁄2 times expected moment
concentrated loads require local reinforcement. Loads sup-
capacity at time of qualification.
ported by connection to the web or applied to the bottom flange
6.6.2 Stiffness Capacity—Any formula which accurately
require special consideration and appropriate details. These
predicts the effects of both bending and shear deformation is
and other special conditions of application require appropriate
permitted to be used. The equation must be adjusted when the
evaluation and testing to ensure the safety provisions of this
mean of the ratios of test deflections at moment capacity load
specification are maintained.
(determined from a least square line fitted through the data
points), to predicted deflection is more than 1.01S/=N, where
7. Design Values
S is the standard deviation of the ratios of test to predicted
deflections and N is the total number of deflection tests 7.1 Design Value Limited—Design values are determined
conducted. from the analysis and capacities as specified in this specifica-
NOTE 13—Usually, a required adjustment will be applied only to the tion. In no case shall a design value exceed the capacity
flange modulus of elasticity (MOE) used in the equation. For stiffness-
determined in Sections 6 or 11. (See definitions of capacity and
limited applications of I-joists, the largest percentage of deflection is
design value in 3.1.1.)
typically attributed to bending, and because of the section geometry, the
principle elastic modulus is that of the flange material. Therefore, here and
7.2 Design Value—It is the responsibility of the I-joist
in Sections 9 and 11, emphasis is placed on the flange MOE.
producer to determine design values. Judgment is required
6.6.2.1 Elastic Properties—Mean values are to be used in particularly when assessing design values from qualification
the deflection equation (1) when flange modulus of elasticity tests. Design values shall consider potential low-line lot
cannot be obtained from tables of recognized values, it shall be capacities to avoid marginal application performance or uneco-
obtained from tests of the flange material used to establish nomical reject rates in the quality assurance program.
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D5055 − 19
8. Independent Inspection 9.3.1 All inspection reports and records of test equipment
calibration whether accomplished by in-house or qualified
8.1 A qualified agency shall be employed by the manufac-
agency personnel,
turer to audit the quality assurance program and inspect the
9.3.2 All test data, including retests and data associated with
production process of the plant without prior notification or
rejected production, and
with minimal prior notification. The audit and inspection shall
9.3.3 Details of any corrective actions taken and the dispo-
include review and approval of the plant’s quality assurance
sition of any rejected production, resulting from tests or
program and inspection of randomly selected products and QC
inspections.
data. When production is sporadic, the qualified agency shall
communicate with the manufacturer to schedule inspections to
9.4 Testing Equipment—Testing equipment is to be properly
coincide with production.
maintained, calibrated, and evaluated for accuracy and ad-
8.2 A qualified agency is defined as one that: equacy in accordance with 6.1.1.3, at a frequency satisfactory
to the qualified agency.
8.2.1 Has been accredited by an International Accreditation
Forum (IAF) accreditor as meeting ISO/IEC 17020 require-
9.5 I-Joist Quality Control Testing:
ments;
9.5.1 Objectives—The following objectives are to be met
8.2.2 Has trained technical personnel to verify that the
simultaneously with the quality-control testing program:
grading, measurement, species, construction, shaping,
9.5.1.1 Provide test data for use in maintaining and updating
bonding, workmanship, and other characteristics of the prod-
design values, and
ucts as determined by inspection, sampling, and testing comply
9.5.1.2 Verify production process and material quality on a
with all applicable requirements specified herein;
daily basis.
8.2.3 Has procedures to be followed by its personnel in
9.5.2 Initial Quality Control—When qualification is based
performance of the inspection and testing; and
on no more than the minimum testing required in this
8.2.4 Has no financial interest in, or is not financially
specification, the producer shall initiate higher test frequencies
dependent upon, any single company manufacturing the prod-
and retest levels. All new producers are advised to intensify
uct being inspected or tested;
quality control in early production.
8.2.5 Is not owned, operated, or controlled by any such
9.5.3 Required Tests—The following shall be the scope of a
company.
minimum testing program:
9. In-House Quality Assurance 9.5.3.1 Test methods shall be identical to those of Section 6.
9.5.3.2 The shear strength test described in 6.2 shall be used
9.1 Manufacturing Standard:
for quality control of shear strength. This test is required even
9.1.1 A manufacturing standard shall be written and main-
if qualification is by calculation.
tained for each product and each production facility and shall
9.5.3.3 If flanges contain end joints qualified in accordance
be the basis for the qualified agency’s specific inspection at that
with 6.5, daily tension tests of full-section joints shall be
location. As a minimum, it shall include the following:
conducted and failure loads recorded. The manufacturing
9.1.1.1 Material specifications, including incoming inspec-
standard must include the characteristic joint spacing that will
tion and acceptance requirements, and specifications for re-
be maintained in production. Durability tests of such joints are
grading flange stock when applicable,
required only at such frequency as required to verify adhesive
9.1.1.2 Process controls for each operation in production of
performance in accordance with 5.4.
the product,
9.5.3.4 When flange material is qualified by test in accor-
9.1.1.3 Quality control, inspection and testing procedures,
dance with 6.4.1.2 (2) or 6.4.1.2 (3), the testing of that section
and frequencies, and
shall be included in daily quality control tests. In all cases, QA
9.1.1.4 Finished product identification, handling, protection,
pr
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