1. No category

IAPMO ES
Cover Sheet
Evaluation Criteria of
COLD-FORMED STEEL or WOOD FRAMED / STEEL-SHEATHED SHEAR WALLS
Posted for public commenting on 12/11/08 thru 1/14/09
Comments currently under review
Ph: 1‐877‐4IESRPT • Fax: 909.472.4171 • Web: www.iapmoes.org • 5001 East Philadelphia Street • Ontario, California 91761‐2816 – USA International Association of Plumbing and Mechanical Officials
Evaluation Criteria of
COLD-FORMED STEEL or WOOD FRAMED / STEEL-SHEATHED SHEAR WALLS
EC 003-XXXX
1.0 INTRODUCTION
in a seismic or wind force-resisting system of cold1.1 Purpose: The purpose of this evaluation criteria is
formed steel or wood light-framed walls as an
to establish requirements for steel-sheathed shear
alternative to all other sheathing panels on cold-
walls with cold-formed steel and wood framing to be
formed steel or wood framed light-frame shear walls
recognized in an IAPMO-ES, evaluation report under
described in Section 2210.5 and Chapter 23 of the
®
the 2006 International Building Code (IBC), the 2006
International Residential Code
California Building Code®
®
(IRC), the 2007
(CBC).
Bases of
recognition are IBC Section 104.11, IRC Section
R104.11 and CBC Section 108.7.
The reason for the development of this criteria is to
provide guidelines for the testing and assignment of
design loads and deflections, where the codes do not
provide the necessary requirements for the products
described in this criteria. The criteria also provides a
means to categorize the products for use in a seismic
force-resisting system for the purpose of assigning
seismic and wind design coefficients and factors.
1.2 Scope: This criteria provides a basis for testing
and evaluating steel-sheathed light frame shear walls
consisting of steel-sheathing that is attached directly
IBC, Section R603 and R602 of the IRC and Section
2210 of the CBC. The steel-sheathing shall consist of
a sheet steel panel and a non-structural sheathing
that are applied to the interior or exterior of the
engineered shear walls. The steel sheets may be
applied on single sided and double sided shear walls
for lateral control on cold-formed steel or wood
framing.
1.3 Codes and Referenced Standards:
1.3.1
2006 International
Building Code
®
(IBC),
International Code Council (ICC).
1.3.2
2006 International Residential Code® (IRC),
International Code Council (ICC).
1.3.3 2007 California Building Code® (CBC)
to cold-formed steel or wood framing complying with
1.3.4 2001 (with 2004 supplement) AISI Standard for
Section 2210.5 and Chapter 23 of the IBC, Section
Cold-Formed
R603 or R602 of the IRC, and Section 108.7 of the
Steel
Framing
–
Lateral
Design,
American Iron and Steel Institute.
CBC. The steel-sheathing panels are intended for use
Ph: 1‐877‐4IESRPT • Fax: 909.472.4171 • Web: www.iapmoes.org • 5001 East Philadelphia Street • Ontario, California 91761‐2816 – USA 1.3.5 ASCE/SEI 7-05, Minimum Design Loads for
comply with the standards specified for the steel or
Building and Other Structures, American Society of
wood for which recognition is sought. The use of
Civil Engineers.
timber-strand bottom plate may be recognized for
wood framed assemblies.
1.3.6 ASTM E 2126-07a, Standard Test Methods of
Cyclic (Reversed) Load Test of Shear Resistance of
2.1.1.2.2 Fasteners: The standards and
specifications applicable to the fasteners shall be
Vertical Elements of the Lateral Force Resisting
disclosed, and the minimum structural quality of the
Systems for Buildings, Method A in Section 8.3,
fasteners shall be specified. Fasteners shall be
ASTM International.
properly described, including fastener type, size,
length, location and edge distance. Wall assemblies
1.3.7 2001 AISI North American Specification for the
shall be constructed with fasteners having approved
Design of Cold-Formed Steel Structural Members
values. Where no values are recognized by the
(AISI-NAS), with Appendix A and 2004 Addendum,
applicable code, the fasteners shall be recognized in
American Iron and Steel Institute
a current evaluation report or a national product
standard, or shall otherwise be justified to the
1.3.8 2005 National Design Specification(with the
2005
supplements)
satisfaction of IAPMO-ES.
for Wood
Construction, American Forest & Paper Association.
2.1.1.2.3 Steel Sheets: The sheet steel shall comply
with the standard specified for the product for which
2.0 BASIC INFORMATION
recognition is sought.
2.1 General: The following information shall be
submitted:
Non-structural
Sheathing:
The
non-
structural sheathing shall comply with the standard
specified for the product for which recognition is
2.1.1 Shear Wall Assembly:
sought.
2.1.1.1 General: The wall assembly shall use
sheathing,
2.1.1.2.4
fasteners,
connectors,
and
framing
consistent with those intended for recognition in the
2.1.1.2.5 Steel-Sheathing: A sheathing assembly
consisting of steel sheets and non-structural
sheathing.
evaluation report.
2.1.2 Packaging and Identification: A description of
2.1.1.2 Material Requirements:
the method of packaging and field identification of the
steel-sheathing
2.1.1.2.1 Framing Members: The cold formed steel-
shall
be
provided.
Identification
provisions shall include the evaluation report number.
framing members used in the tests shall comply with
Chapter 2210.5 of the 2006 IBC. The wood framing
2.2 Testing Laboratories: Testing laboratories shall
members used in the tests shall comply with Chapter
meet the requirements for compliance with the
23 of the 2006 IBC. All framing members shall
ISO/IEC Standards 17025 or accredited independent
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(envelope) curve. The actual design capacities shall
Accreditation
be determined as outlined in Section 3.3.4 .
Cooperation
Mutual
Recognition
Arrangement or ANSI. Testing at a non-accredited
laboratory may be permitted by IAPMO ES, provided
3.3.3 The seismic design coefficients and factors
the testing is conducted under the supervision of an
listed in ASCE/SEI 7, Table 12.2-1 for light-frame
accredited laboratory and the supervising laboratory
walls sheathed with wood structural panels, steel
issues the test report.
sheets or steel-sheathing rated for shear resistance
shall apply to the use of design loads under the 2006
2.3 Test Reports: Test reports shall be submitted to
IBC.
IAPMO-ES for generation of evaluation reports.
3.3.4 2006 IBC Design Loads
2.4 Product Sampling: Sampling of the shear wall
components for tests under this criteria shall be
3.3.4.1 Allowable Stress Design (ASD): The ASD
approved by IAPMO ES.
resistance load shall be taken as the lesser of the
allowable loads based on drift and the peak strength
3.0 TEST AND PERFORMANCE REQUIREMENTS
of the wall assembly as follows:
3.1 Wall Size: The tested wall assemblies shall have
3.3.4.1.1 Drift: The ASD seismic and wind resistance
aspect
and
load shall be determined on the basis of the
dimensions consistent with the intended use and such
ratios
(wall
height-to-width
ratios)
requirements of ASCE/SEI 7, Sections 12.12.1 and
aspect ratios shall be the maximum recognized in the
12.8.6, as referenced in IBC Section 1613.1 as well
evaluation report.
as the wind code of the CBC in Section 1609.1.
Tests shall be performed, at a
maximum, with aspect ratio of 2¼:1 and, at a
minimum, with an aspect ratio of 1:1. Testing in the
3.3.4.1.1.1
The
maximum
inelastic
response
criteria does not allow for penetrations in test panels.
displacement δx shall be taken as the lesser of the
code-specified allowable story drift Δa in Table 12.12-
3.2 Test Procedures: Tests shall be conducted in
accordance with Section 4.0 of this criteria.
3.3 Data Analysis:
3.3.1 Shear design values for the wall assemblies
may be based on the average of the test values if
variation limits set forth in Section 4.3 are satisfied.
Otherwise, the lowest of the test values shall be used.
3.3.2 Load values for both Allowable Stress Design
(ASD) and Load and Resistance Factor Design
(LRFD) shall be based on the first cycle backbone
1 of ASCE/SEI 7 and the drift ΔSL corresponding to
the peak strength from a test.
3.3.4.1.1.2 Using δx, the Cd value in accordance with
Section 3.3.3 of this criteria, and an importance factor
I equal to 1.0, the LRFD (Strength Design) level
response displacement, δxe, shall be calculated as δxe
= δxI/Cd.
3.3.4.1.1.3 From the first-cycle backbone curve
defined in Section 3.3.2, the load Fs corresponding to
δxe shall be determined. Fs defines the LRFD
Ph: 1‐877‐4IESRPT • Fax: 909.472.4171 • Web: www.iapmoes.org • 5001 East Philadelphia Street • Ontario, California 91761‐2816 – USA assembly times a resistance factor φ = 0.55 for
resistance load of the wall assembly.
seismic load and φ = 0.55 for wind load. The drift
3.3.4.1.1.4 In accordance with ASCE/SEI 7, Section
corresponding to the LRFD resistance load shall be
2.4.1, the ASD resistance load shall be computed as
derived from the first-cycle backbone curve and the
0.7 times the LRFD resistance load.
value shall be included in the evaluation report.
3.3.4.1.1.5 The drift corresponding to the ASD
4.0 TEST METHODS
resistance load (Section 3.3.4.1.1.4) shall be derived
from the first-cycle backbone curve and the value
4.1 Steel Sheet: The base-steel thickness (uncoated)
shall be included in the evaluation report. Testing for
of the sheet steel used in the sheet steel panels shall
foundations on grade, raised floor foundations and
be measured and reported. Base-steel thickness is
any upper level applications are beyond the scope of
the thickness of the steel exclusive of any coating,
this criteria.
such as galvanization.
The yield strength and
ultimate tensile strength of the sheet steel shall be
first-cycle
measured. The measured strengths shall meet the
backbone curve defined in Section 3.3.2, the ASD
minimum specified strengths for the particular steel
resistance load shall be taken as the peak strength of
grade when tested in accordance with ASTM A370.
3.3.4.1.2
Peak
Strength:
From
the
the wall assembly divided by a factor of safety of 2.5
for seismic forces and 2.0 for wind forces. The drift
4.2 Test Setup:
corresponding to the ASD resistance load shall be
derived from the first-cycle backbone curve and the
4.2.1 The bottom track/plate of the wall assembly
shall be attached to a fixed base in such a manner
value shall be included in the evaluation report.
that in-plane displacement of the sheathing is not
restricted.
3.3.4.2 Load and Resistance Factor Design
(LRFD): The LRFD (Strength Design) resistance load
4.2.2 The bottom track/plate of the wall assembly
shall be taken as the lesser of the strength loads
shall be adequately connected to the fixed base so as
based on drift and the peak strength of the wall
to exceed the expected shear transfer requirements.
assembly as follows:
3.3.4.2.1
Drift:
The
LRFD
seismic
and
wind
resistance load shall be determined as the resistance
load Fs defined in Section 3.3.4.1.1.3.
The drift
corresponding to the LRFD resistance load shall be
derived from the first-cycle backbone curve and the
value shall be included in the evaluation report.
3.3.4.2.2 Peak Strength: The LRFD resistance load
shall be taken as the peak strength of the wall
4.2.3 Hold-downs shall be installed at each end of the
wall assembly. The capacity of the hold-downs shall
exceed the anticipated peak strength of the wall
assembly.
4.2.4 A loading plate connected to the wall assembly
top plate shall be used to distribute the applied load
along the top of the wall. The loading plate shall be
attached to the wall assembly in such a manner that
in-plane displacement of the sheathing is not
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with this criteria, in-plane cyclic shear tests in
accordance with Section 1.3.6 are required.
4.2.5 Each test assembly shall be instrumented to
measure the following displacements at the locations
4.4.2 Termination of Loading History: The loading
indicated:
history defined in Section 4.4.1 of this criteria shall be
continued until the resistance of the wall assembly
4.2.5.1 Lateral in-plane displacement at the top of
decreases to 50 percent of the peak assembly
wall.
strength.
4.2.5.2 Uplift and compression displacement at each
5.0 QUALITY CONTROL
end of wall.
4.2.5.3 Base slip.
4.2.6 Applied racking loads shall be measured. Holddown load measurement is optional.
4.2.7 Test equipment shall be capable of recording
racking loads and displacements at a minimum rate of
50 readings per cycle.
4.3 Test Procedure:
5.1 IAPMO-ES approved inspections of
manufacturing facilities in accordance with ISO 17025
are required for this product.
5.2 Quality documentation complying with the IAPMOES Minimum Requirements for Listee’s Quality
Assurance System (IAPMO ES-010) shall be
submitted.
6.0 EVALUATION REPORT RECOGNITION
4.3.1 A minimum of three identical wall assemblies of
6.1 The product identification label shall include the
a given construction shall be tested. The average of
manufacturer’s name and address, the evaluation
the three test results may be used if each of the three
report number, as required by IAPMO. The product
values is within 15 percent of the average, otherwise,
identification label shall be visible on the product.
the lowest of the three test values shall be used.
Alternatively, the average of five or more identical
6.2 The evaluation report shall clearly indicate that the
tests may be used.
product application is limited to use in light-framed
wood and cold-formed steel construction complying
4.3.2 Racking shear loads shall be applied to the top
with the code.
of the wall assembly, displacing the top of the wall in
accordance with the displacement schedule described
6.3 The approved products shall be limited to use
in Section 4.4.
within height limits and seismic categories (IBC)
permitted for the equivalent seismic performance
4.4 Cyclic Load Test Protocol
coefficients and factors systems listed in ASCE / SEI
7 Table 12.12-1 (IBC) for light frame shear walls.
4.4.1 In-plane Cyclic Shear Load Tests: To comply
When the approved product is installed in jurisdictions
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accordance with the code requirements for the
applicable type (wood or cold-formed steel) of lightframed construction. Include in the evaluation report
restrictions and limitations of use.
6.4 When used to resist seismic loads within the lightframed system of a structure, the approved product
shall not be combined with other types of lateral forceresisting products in a given story and particular load
direction, unless justification of such a combination is
provided by the building design professional.
6.5 The allowable load tables in the evaluation report
will not include a 1.33 increase intended for transient
loading.
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