AISI S100-16/S1-18

AISI STANDARD

Supplement 1 to the 2016 Edition

of the North American Specification

for the Design of Cold-Formed Steel

Structural Members

2018 Edition
 DISCLAIMER

The material contained herein has been developed by a joint effort of the American Iron and
Steel Institute (AISI) Committee on Specifications, CSA Group Technical Committee on Cold
Formed Steel Structural Members (S136), and Camara Nacional de la Industria del Hierro y del
Acero (CANACERO) in Mexico. The organizations and the Committees have made a diligent
effort to present accurate, reliable, and useful information on cold-formed steel design. The
Committees acknowledge and are grateful for the contributions of the numerous researchers,
engineers, and others who have contributed to the body of knowledge on the subject. Specific
references are included in the Commentary on the Specification.
With anticipated improvements in understanding of the behavior of cold-formed steel and
the continuing development of new technology, this material may eventually become dated. It
is anticipated that future editions of this Specification will update this material as new
information becomes available, but this cannot be guaranteed.
The materials set forth herein are for general information only. They are not a substitute for
competent professional advice. Application of this information to a specific project should be
reviewed by a registered professional engineer. Indeed, in most jurisdictions, such review is
required by law. Anyone making use of the information set forth herein does so at their own
risk and assumes any and all resulting liability arising therefrom.

First Printing – December 2018

Copyright American Iron and Steel Institute 2018

AISI S100-16/S1-18, Supplement 1 to the 2016 Edition of the North American Specification for the Design of
Cold-Formed Steel Structural Members

AISI Committee on Specifications for the Design

of Cold-Formed Steel Structural Members and Its Subcommittees
R. B. Haws, Chairman S. R. Fox, Vice-Chairman H. H. Chen, Secretary D. Allen
P. Bodwell R. L. Brockenbrough J. Buckholt S. Call
J. K. Crews R. S. Douglas W. S. Easterling P. Ford
R. S. Glauz P. S. Green W. B. Hall G. J. Hancock
A. J. Harrold L. Kruth R. L. Madsen J. A. Mattingly
W. McRoy C. Melcher C. Moen J. R. U. Mujagic
J. J. Pote N. A. Rahman G. Ralph V. E. Sagan
T. Samiappan A. Sarawit B. W. Schafer K. Schroeder
T. Sputo S. Torabian C. Yu R. Zadeh
R. Ziemian

Emeritus Membership
J. M. Fisher R. A. LaBoube D. L. Johnson T. M. Murray
J. N. Nunnery T. B. Pekoz R. M. Schuster T. W. J. Trestain
W. W. Yu

Subcommittee 3 – Connections and Joints

P. S. Green, Chairman R. Bogh B. Cameron L. Chen
R. S. Douglas W. S. Easterling D. Fox B. Gerber
C. Gill W. Gould W. B. Hall G. J. Hancock
A. J. Harrold D. L. Johnson J. A. Mattingly C. Melcher
C. Moen S. Morton J. R. U. Mujagic T. M. Murray
J. N. Nunnery K. Peterman N. A. Rahman G. Ralph
V. E. Sagan T. Samiappan K. Schroeder W. E. Schultz
F. Sesma T. Sputo S. Torabian C. Yu

Subcommittee 4 – Assemblies and Systems

V. E. Sagan, Chairman D. Allen V. D. Azzi B. Cameron
M. Detwiler R. S. Douglas B. Gerber W. Gould
W. B. Hall A. J. Harrold J. M. Klaiman R. L. Madsen
C. Melcher C. Moen J. R. U. Mujagic K. Peterman
J. J. Pote N. A. Rahman G. Ralph B. W. Schafer
M. Schmeida K. Schroeder R. M. Schuster M. Seek
F. Sesma D. D. Tobler C. Yu

Subcommittee 6 – Test-Based Design

S. R. Fox, Chairman R. S. Douglas D. Fox W. Gould
P. S. Green W. B. Hall R. B. Haws R. L. Madsen
J. R. Martin C. Melcher C. Moen J. R. U. Mujagic
T. M. Murray K. Peterman N. A. Rahman G. Ralph
V. E. Sagan T. Samiappan B. W. Schafer M. Schmeida
R. M. Schuster F. Sesma M. Speicher T. Sputo
S. Torabian C. Yu

Subcommittee 22 – Stability and Combined Actions

J. K. Crews, Chairman R. L. Brockenbrough J. Buckholt B. Cameron
R. S. Douglas R. S. Glauz P. S. Green G. J. Hancock
AISI S100-16/S1-18, Supplement 1 to the 2016 Edition of the North American Specification for the Design of
Cold-Formed Steel Structural Members

A. J. Harrold R. B. Haws D. L. Johnson R. L. Madsen

C. Melcher C. Moen J. R. U. Mujagic K. Peterman
G. Ralph V. E. Sagan T. Samiappan A. Sarawit
B. W. Schafer K. Schroeder M. Seek J. Thompson
S. Torabian L. Xu C. Yu R. Ziemian

Subcommittee 24 – Member Design

R. S. Glauz, Chairman D Allen R. L. Brockenbrough J. Buckholt
D. Camotim J. K. Crews R. S. Douglas P. S. Green
G. J. Hancock A. J. Harrold R. B. Haws D. L. Johnson
Z. Li R. L. Madsen C. Melcher C. Moen
K. Peterman J. J. Pote G. Ralph V. E. Sagan
T. Samiappan B. W. Schafer K. Schroeder R. M. Schuster
M. Seek T. Sputo J. Thompson D. D. Tobler
C. Yu

Subcommittee 31 – General Provisions

A. J. Harrold, Chairman D. Allen R. L. Brockenbrough J. K. Crews
M. Detwiler R. S. Douglas J. M. Fisher W. Gould
W. B. Hall R. B. Haws D. L. Johnson J. M. Klaiman
R. L. Madsen C. Melcher C. Moen G. Ralph
B. W. Schafer M. Schmeida R. M. Schuster F. Sesma

Subcommittee 33 – Diaphragm Design

T. Sputo, Chairman P. Bodwell S. Call K. Cullum
R. S. Douglas W. S. Easterling C. Gill W. Gould
J. A. Mattingly C. Moen J. R. U. Mujagic K. Peterman
G. Ralph V. E. Sagan B. W. Schafer W. E. Schultz
S. Torabian K. Voigt C. Yu

CSA Group Technical Committee on Cold Formed Steel Structural Members

R. M. Schuster, Chairman S. R. Fox, Vice Chairman A. Ahmad D. Bak
J. J. R. Cheng D. G. Delaney D. Fox J. B. Grace
B. Mandelzys S. S. McCavour M. Mir C. Rogers
K. S. Sivakumaran M. Sommerstein M. Tancredi P. Versavel
L. Xu
AISI S100-16/S1-18, Supplement 1 to the 2016 Edition of the North American Specification for the Design of
Cold-Formed Steel Structural Members

Personnel

A. Ahmad Bailey Metal Products Ltd.

D. Allen Super Stud Building Products
V. D. Azzi Rack Manufacturers Institute
D. Bak Steelway Building Systems
P. Bodwell Verco Decking, Inc.
B. Bough Verco Decking, Inc.
R. L. Brockenbrough R. L. Brockenbrough and Associates
J. Buckholt Computerized Structural Design
S. Call Call Engineering
H. H. Chen American Iron and Steel Institute
L. Chen Baltimore Aircoil Company
J. J. R. Cheng University of Alberta
J. K. Crews Unarco Material Handling, Inc.
K. Cullum Simpson Strong-Tie
D. G. Delaney Flynn Canada Ltd.
M. Detwiler NCI Group, Inc.
R. S. Douglas National Council of Structural Engineers Association
W. S. Easterling Virginia Polytechnic Institute and State University
J. M. Fisher Consultant
P Ford Steel Framing Industry Association
D. Fox TOTAL JOIST By iSPAN Systems
S. R. Fox Canadian Sheet Steel Building Institute
B. Gerber IAPMO Uniform Evaluation Service
C. Gill Hilti, Inc.
R. S. Glauz RSG Software, Inc.
W. Gould ICC Evaluation Service, Inc.
J. B. Grace Robertson Building Systems
P. S. Green Bechtel Power Corporation
W. B. Hall University of Illinois
G. J. Hancock University of Sydney
A. J. Harrold BlueScope Buildings North America
R. B. Haws Nucor Buildings Group
J. M. Klaiman ADTEK Engineers
L Kruth American Institute of Steel Construction
R. A. LaBoube Wei-Wen Yu Center for Cold-Formed Steel Structures
Z. Li SUNY Polytechnic Institute
R. L. Madsen Supreme Steel Framing System Association
B. Mandelzys Steelrite
J. R. Martin Verco Decking, Inc.
J. A. Mattingly Consultant
W. McRoy ICC Evaluation Service, Inc.
C. Melcher Simpson Strong-Tie
M. Mir Vicwest
C. Moen NBM Technologies, Inc.
J. R. U. Mujagic Consultant
T. M. Murray Consultant
R. V. Nunna S. B. Barnes Associates
AISI S100-16/S1-18, Supplement 1 to the 2016 Edition of the North American Specification for the Design of
Cold-Formed Steel Structural Members

J. N. Nunnery Consultant
T. B. Pekoz Consultant
K. Peterman University of Massachusetts Amherst
J. J. Pote Steel Joist Institute
N. A. Rahman The Steel Network, Inc.
G. Ralph ClarkDietrich Building Systems
C. Rogers McGill University
V. E. Sagan Metal Building Manufacturers Association
T. Samiappan OMG, Inc.
A. Sarawit Simpson Gumpetz & Heger
B. W. Schafer Johns Hopkins University
M Schmeida Gypsum Association
K. Schroeder Devco Engineering Inc.
W. E. Schultz Nucor Vulcraft
R. M. Schuster Consultant
M. Seek Old Dominion University
F. Sesma California Expanded Metal Products
K. S. Sivakumaran McMaster University
M. Sommerstein M&H Engineering
T. Sputo Steel Deck Institute
M. Tancredi Ferroeng Group Inc.
J. Thompson TrusSteel
D. D. Tobler American Buildings Company
S. Torabian Cold-Formed Steel Research Consortium
T. W. J. Trestain Consultant
P. Versavel Behlen Industries LP
K. Voigt New Millennium Building Systems, LLC
L. Xu University of Waterloo
C. Yu University of North Texas
R. Zadeh RAZ Tech, Inc.
R. Ziemian Structural Stability Research Council
AISI S100-16/S1-18, Supplement 1 to the 2016 Edition of the North American Specification for the Design of
Cold-Formed Steel Structural Members

Supplement 1 to AISI S100-16:

1. Revise AISI S100-16 Section A3.3.2 first paragraph as shown below:

A3.3.2 Strength Increase From Cold Work of Forming

(Revise the first paragraph as shown below.)
Strength increase from cold work of forming is permitted by substituting Fya for Fy,
where Fya is the average yield stress of the full section. Such increase shall be limited to
Chapters D, E, and F (excluding Section F2.4); Sections H1, I4 and I6.2 and; to sections not
subject to strength reduction from local or distortional buckling at stress level Fy: specifically,
for columns, Pn = Pne from Section E3 and Pnd = Py from Section E4, and for beams, Mn =
Mne from Section F3 and Mnd = My from Section F4. The limits and methods for
determining Fya shall be in accordance with (a), (b) and (c).

2. Revise AISI S100-16 Section E2.2 last paragraph as shown below:

E2.2 Doubly- or Singly-Symmetric Sections Subject to Torsional or Flexural-
Torsional Buckling
(Revise the last paragraph as shown below.)
For singly-symmetric unstiffened angle sections for which the effective area (Ae) not subject
to local buckling at stress Fy is equal to the full unreduced cross-sectional area (A) for effective width
method, or Pn = Pne from Section E3 for Direct Strength Method, Fcre shall be computed using
Eq. E2.1-1, where r is the least radius of gyration.

3. Revise AISI S100-16 Section H1.2 second paragraph of the section as shown below:
H1.2 Combined Compressive Axial Load and Bending
(Revise the second paragraph as shown below.)
For singly-symmetric unstiffened angle sections with unreduced effective area or Pn = Pne
not subject to local buckling at stress Fy, M y is permitted to be taken as the required flexural
strength [moment due to factored loads] only. For other angle sections or singly-symmetric
unstiffened angles subject to local buckling at stress level Fy for which the effective area (Ae) at
stress Fy is less than the full unreduced cross-sectional area (A), or Pn < Pne, M y shall be taken
either as the required flexural strength [moment due to factored loads] or the required flexural
strength [moment due to factored loads] plus ( P )L/1000, whichever results in a lower
permissible value of P .
AISI S100-16/S1-18, Supplement 1 to the 2016 Edition of the North American Specification for the Design of
Cold-Formed Steel Structural Members

4. Revise Section J7 as shown below:

J7 Connections to Other Materials
In bolted, screw, and power-actuated fastener connections, the available strength
[factored resistance] of the connection to other materials shall be determined in
accordance with Section J7.1. For power-actuated fasteners embedded in concrete,
Section J7.2 is permitted to be used as an alternative.

5. Delete entire Section J7.2 as shown below:

J7.2 Power-Actuated Fasteners (PAFs) in Concrete
J7.2.1 Minimum Spacing, Edge and End Distances
The minimum center-to-center spacing of the PAFs and the minimum distance from
center of the fastener to any edge of the connected part, regardless of the direction of the
force, shall be as provided by Table J7.2.1-1.
Table J7.2.1-1
Minimum Required Edge and Spacing Distances in Concrete
PAF Shank Diameter, ds, in. Minimum PAF Spacing Minimum Edge Distance
(mm) in. (mm) in. (mm)

0.106 (2.69) ≤ ds< 0.158 (4.01) 4.00 (102) 3.20 (81.3)

0.158 (4.01) ≤ ds< 0.197 (5.00) 5.00 (127) 3.50 (88.9)

0.197 (5.00) ≤ ds< 0.206 (5.23) 6.00 (152) 4.00 (102)

J7.2.2 Pull-Out Strength in Shear

For PAFs, as depicted in Figure J5-1(a), used to cold-formed steel framing track-to-
concrete connections, the nominal pull-out strength [resistance] in shear is permitted to be
taken as Pnos = 1,450 lbs (6,450 N), and the following safety factor and resistance factors shall
be applied to determine the available strength [factored resistance] in accordance with Section
B3.2.1, B3.2.2, or B3.2.3:
Ω = 3.25 (ASD)
φ = 0.50 (LRFD)
= 0.40 (LSD)
In addition, the following limit conditions shall apply:
(a) ds ≥ 0.118 in. (3.00 mm),
(b) Normal weight concrete as defined in ACI 318 for the United States and Mexico
and CAN/CSA A23.3 for Canada with minimum specified compressive strength, f’c, of 2.5
ksi (17.2 MPa),
(c) dc ≥ 3 (hET),
(d) hET ≥ 1.0 in. (25.4 mm), and
(e) Minimum required edge and spacing distances as shown in Table J7.2.1-1.
where
AISI S100-16/S1-18, Supplement 1 to the 2016 Edition of the North American Specification for the Design of
Cold-Formed Steel Structural Members

ds = Nominal shank diameter

dc = Thickness of supporting concrete
hET = Embedment depth of PAF in concrete
AISI S100-16/S1-18, Supplement 1 to the 2016 Edition of the North American Specification for the Design of
Cold-Formed Steel Structural Members

Supplement 1 to AISI S100-16-C:

1. Revise the 10th paragraph of Section A3.3.2 as follows:

A3.3.2 Strength Increase From Cold Work of Forming

(Revise the 10th paragraph as follows.)
Prior to 2016, the requirements for applying the provisions of strength increase from cold
work of forming were written for using the Effective Width Method. The requirements were
revised in 2016 to make the provisions also applicable to the Direct Strength Method. The
strength increase from cold work of forming is applicable to sections that are not subject to
strength reduction from local and distortional buckling at a stress level of Fy for compression
members or when the extreme compression fiber reaches Fy for flexural members. In some
cases, when evaluating the effective width of the web using the Effective Width Method, the
reduction factor ρ according to Specification Section 1.1.2 may be less than unity but the sum
of b1 and b2 of Figure 1.1.2-1 of the Specification may be such that the web is fully effective,
and cold work of forming may be used. This situation only arises when the web width to
flange width ratio, ho/bo, is less than or equal to 4. This requires the cross-section to be fully
effective when using the Effective Width Method, or λ ≤ 0.776 in Specification Section E3.2 or
F3.2 when using the Direct Strength Method.

2. Revise Section J7 as shown below:

J7 Connections to Other Materials

When a cold-formed steel structural member is connected to other materials, such as hot-rolled
steel, aluminum, concrete, masonry or wood, the connection strength should be the smallest of
the strength of the fastener, the strength of the fastener attachment to the cold-formed steel
structural member, or the strength of the fastener attachment to the other material.
In 2016, provisions were added to Specification Section J7.2 for power-actuated fasteners
(PAFs) connecting cold-formed steel framing track-to-concrete base materials. These provisions
were based on an experimental study where cold-formed steel wall tracks were attached to
concrete base materials and subjected to monotonic and cyclic/seismic test loads (AISI, 2013h).
In 2018, these provisions were removed to avoid unconservative designs of track and other
cold-formed steel structural member attachments to concrete and to avoid unintended
interpretation of the validity of these provisions in different applications.

3. Delete the entire Section J7.2:

J7.2 Power-Actuated Fasteners (PAFs) in Concrete
In 2016, provisions were added to Specification Section J7.2 for power-actuated fasteners
(PAFs) connecting cold-formed steel framing track-to-concrete base materials. These
provisions are based on an experimental study where cold-formed steel wall tracks were
attached to concrete base materials and subjected to monotonic and cyclic/seismic test loads
AISI S100-16/S1-18, Supplement 1 to the 2016 Edition of the North American Specification for the Design of
Cold-Formed Steel Structural Members

(AISI, 2013h). The experimental data demonstrated that residual monotonic shear strength of
power-actuated fastener connections after cyclic/seismic loading closely matched the reference
monotonic shear strength.
The experimental data further demonstrated that ductile steel failure modes limit the
capacity of the connection with thinner cold-formed steel track. Where this failure mode is
dominant, the use of Specification Section J5.3.2 to determine the strength of cold-formed steel
track connection is appropriate. For thicker track, the limit state was pull-out of the fastener in
shear. Figure C-J7.2-1 illustrates the connection failure of the power-actuated fastener pull-out
(pry-out) in shear. The nominal value of Pnos = 1,450 lbs (6,450 N) is given by Specification
Section J7.2.2. This nominal value is based on tests with normalweight concrete as specified in
ACI 318 for the United States and Mexico and in CAN/CSA A23.3 for Canada with the
minimum specified concrete strength of 2.5 ksi (17.2 MPa). The nominal value is considered
as a lower bound strength based on the concrete strength used in the test program. Where
justified in manufacturers’ evaluation reports or test data that the shear strength of PAF in
lightweight concrete is equivalent to normalweight concrete, this nominal value may be
extended to the following applications:
(a) For the United States and Mexico: Sand-lightweight concrete, as specified in ACI 318,
with a minimum specified concrete strength of 3.0 ksi (20.7 MPa) and a minimum
embedment at 1 in. (25.4 mm); and
(b) For Canada: Structural low-density concrete, as specified in CAN/CSA A23.3, with a
minimum specified concrete strength of 20 MPa and a minimum embedment at 25 mm.
Industry installation guidelines recommend that the thickness of the concrete base
material, dc, should be greater than or equal to three times the PAF embedment, hET.

Figure C-J7.2-1 PAF Pull-Out (Pry-Out) in Shear

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S100-16/S1-18E