February 1, 2011
TO:
PARTIES INTERESTED IN STRUCTURAL CAST STEEL
CONNECTORS
SUBJECT:
Proposed Acceptance Criteria for Structural Cast Steel Connectors for
Use as Bracing Connections in Accordance with AISC 341 Sections
13.3 and 14.4, Subject AC427-0211-R1 (BG/DZ)
Dear Colleague:
We are seeking your comments on the enclosed proposal for a new acceptance
criteria, which is being posted for 30 days of public comment on the ICC-ES web site.
Public comments will be considered in preparing a revised draft of the criteria, which
we hope to present at a future Evaluation Committee hearing. The proposed new
criteria provides conditions of acceptance for structural cast steel connectors. The
connectors are intended to be used with concentric braced frames as bracing
connections to connect the brace elements to other portions of the structure. The
applicable references are Sections 13.3 and 14.4 of AISC 341-05, Seismic Provisions
for Structural Steel Buildings.
An evaluation report applicant has developed a series of connector elements cast
from steel represented as complying with ASTM A 958. ASTM A 958 is not currently
referenced in either AISC 341 or AISC 360-05, Specification for Steel Buildings. The
enclosed public review primer from the report applicant provides information on the
connectors and their suitability for use bracing connections for special or ordinary
concentric braced frames. Neither AISC 341 nor AISC 360 is clear with respect to
acceptance of other, nonreferenced steels such as ASTM A 958. In Chapter 9 and
Appendix A of AISC 358-05s1-09, Supplement No. 1 to ANSI/AISC 358-05,
Prequalified Connections for Special and Intermediate Steel Moment Frames for
Seismic Applications, a specific grade and class of steel within ASTM A 958 has been
accepted for producing the Kaiser Bolted Bracket Moment Connection. Appendix A to
AISC 358-05s1-09 contains supplemental test and quality control provisions. The
evaluation report applicant suggests that the existence of Appendix A would resolve
the need for supplemental requirements acknowledged in AISC 360 Section C-A3.1a
for use within a seismic load–resisting system. There are some differences to note as
a prelude to this interpretation. First, Section 9.1 of AISC 358-05s1-09 states that
“yielding and plastic hinge formation is intended to occur primarily in the beam, at the
end of the bracket away from the column face.” This conclusion was based on 21 fullscale tests according to the accompanying commentary. We note that the Kaiser
Bolted Brackets are connected to other members using either bolts or fillet welds.
The report applicant’s cast steel connector is attached to the brace using complete
AC427-0211-R1
2
joint penetration welds, which may affect whether the supplemental quality provisions
in Appendix A of AISC 358 Supplement No. 1 are extensive enough.
For special concentric braced frames, AISC 341 Section 13.3b indicates the plastic
hinge may occur within the cast steel connectors, a possibility particularly when
buckling of the brace assembly is in-plane. Therefore, the cast steel connector may
be the most critical component of the braced frame assembly, as it could be the locus
of a plastic hinging limit state; whereas the Kaiser Bolted Bracket is not the
component of the moment frame that sustains plastic deformation, since plastic
hinging occurs in the beam, not the bracket or column. AISC 341 and AISC 358 are
relatively clear with respect to acceptance of alternative moment frame connection
systems and their expected performance. It may not be prudent to rely on
precedence established in AISC 358-05s1-09 for a moment frame connection due to
differences in configurations, expected performance of member connections, failure
mechanisms, and possibly qualification methods. For special moment frames, it is
clear that their seismic resistance will be consistent with the performance
requirements expected by the 2009 International Building Code® (IBC) and ASCE 705, Minimum Design Loads for Buildings and Other Structures, provided the beam-tocolumn connections comply with Sections 9.2 and 9.3 of AISC 341 and the
assemblies are designed and constructed in accordance with the IBC and AISC 341.
However, the demand requirements on the bracing connections, such as ability to
sustain plastic deformations, are not as explicitly identified in AISC 341 and are not
well correlated to the overall seismic performance of the special concentric braced
frames. For example, AISC 341 Section 13.3b permits two methods for determining
adequacy of bracing connections subject to flexure. Section 13.3b requires the
bracing connection to develop 110 percent of the required flexural strength of the
brace about its critical buckling axis (1.1RyMp), for which inelastic rotation will occur
within brace. As an alternative, bracing connections that develop the required tensile
strength of the brace (RyFyAg) and can accommodate inelastic rotation resulting from
post buckling rotations of the brace, are permitted. While Section 13.3b is not specific
as to how inelastic rotations can be accommodated, the AISC 341 commentary
explains that detailing a single gusset plate according to Figure C-I-13.2 should be
satisfactory to permit the exception. Neither AISC 341 nor the commentary is clear as
to what other conditions need to be observed in order to apply the exception to
provide for adequate strength, stiffness, and ductility. For example, no information is
given on allowing the connectors to be a separate component from the brace and
gusset of a concentrically braced frame. Typically, tubular braces are extended to a
gusset and welded, and may need to be reinforced; while the applicant’s connector
may be either welded or bolted to the gusset plate. Other possible conditions include
the configuration (round vs. rectangular) and slenderness of the braces and the
welding of the gusset plate to the beams and columns. For the report applicant’s
connection, a complete joint penetration weld will attach the connector to the brace.
Therefore, the connector and the complete joint penetration weld may be subjected to
flexure if inelastic rotation is to occur in this region due to the relative fixity of the
gusset plate, brace, and connector. The proposed content of AC427 is not clear as to
what is needed to establish flexural behavior of the connector under seismic motions.
AC427-0211-R1
3
As a result, the structural designer would need to detail assembly for expected
performance without complete guidelines in either AISC 341 or the proposed AC427.
The report applicant indicates the connector complies with the code except for the
material. The scope of AC427 as proposed will encompass verification of connector
configuration as complying with AISC 360 and AISC 341, and verification of cast steel
properties and quality control as complying with Appendix A of AISC 35805s1-09.
Our comments are:
1. Is the proposed criteria adequate for a unique connector within a seismic load–
resisting system in that it specifies only material-related properties and quality
control? There may need to be a global approach to assess deformation
performance, since it is unclear whether the specific participation of each potential
contributing hinge can be identified. AISC 341 is not clear as to how to qualify the
concentrically braced systems where situations like this occur. We note that AISC
341 does stipulate full-scale testing for other lateral force–resisting systems such
as moment frames and buckling restrained braced frames. Full-scale cyclic testing
of the concentric braced frame may be needed to adequately support the design
model of the AISC 341, due to differences in connector configuration and
materials from the connections documented previously in the code. If there is
agreement on this level of testing, the scope of testing needs to be explored to
establish the critical variables such as number of replicates per prototype; testing
protocol (cyclic excursion levels and quantity of cycles); intended brace
configuration (diagonal, X, V or inverted V); brace size (slenderness ratio) and
type; connection between connector and gusset plate (welded or bolted); gusset
plate configuration; and permissible steel and welding materials. The extent to
which the tested assemblies can be extrapolated to other assemblies also needs
to be addressed. Also, input is needed on measures to confirm acceptable
behavior of test assemblies. It is unclear what the minimum drift should be in
creating a model to yield the assemblage in tension and assess the residual
compression capacity after compression buckling has occurred in the assembly.
In addition, potentially undesirable sources of inelastic deformations, such as
connector yielding or weld fracture, should be determined and utilized to establish
criteria for acceptable behavior. AISC 341 Commentary to Section 13.1 indicates
the bracing members and their connections could be expected to undergo
inelastic post-buckling deformations of 10 to 20 times the deformation at yield.
2. The evaluation report applicant seeks an evaluation report on an alternative
connector that can used in any special or ordinary concentric braced frame
permitted by AISC 341. The structural design of the entire bracing system,
including the connectors, would also comply with AISC 341 without modification.
In order to confirm whether a special or ordinary concentric braced frame
incorporating the proprietary cast steel connectors performs adequately when
designed in accordance with the IBC and AISC 341, we ask whether methods to
confirm a rational analysis with validation testing needs to be incorporated within
AC427-0211-R1
4
AC427. This approach would require a detailed structural analysis of selected
special concentric braced frame configurations, and full-scale seismic tests of
these configurations. The test results would be evaluated to confirm whether the
structural design adequately predicts performance including expected or desired
limit states. Parameters to be considered in selecting configurations have been
identified in comment 1, above, such as brace type, size, steel grade, and
orientation; connector type, size, and steel grade; and weldment size and process.
Should AC427 incorporate full-scale seismic validation testing, what applicable
parameters need to be observed in construction the specimens? Also, what
conditions of acceptance need to be applied to verify reliable seismic performance
of the proposed analysis methods?
3. Is the proposed criteria sufficient to permit a registered design professional to
apply the IBC in determining performance of the connector due to tension,
compression, and flexural loadings through the connector, welds, and bolting? It is
understood that certain aspects, such as flexural loadings on the connectors, are
addressed in other references, such as the AISC commentary, which would
require specific approval by the registered design professional and the building
official for each instance of application.
4. The design methodology should be clearly presented in the evaluation report, and
should conform to AISC 341. While inelastic rotation out-of-plane of the brace line
in the gusset plates or in the HSS or pipe brace would likely minimize combined
axial compression and flexural stresses, the proposed AC427 does not provide for
proof that this limit state can be achieved. Design details may need to clearly note
this is needed to prevent to in-plane rotations of the assemblage.
5. Should welding of the cast steel connector to the brace element be limited to
approved fabricators as defined in IBC Section 1704.4? The codes are not clear
as to whether fabrication and special inspection at the jobsite is permitted, though
certain inspection requirements (such as magnetic particle testing and ultrasonic
testing) may be difficult to adequately implement outside the shop environment.
If it is of interest, please review the draft criteria and send us your comments at the
earliest opportunity. At the end of the 30-day comment period, we will post on our
web site the correspondence we have received.
To submit your comments, please use the form on the web site and attach any letters
or other materials. If you would like an explanation of the “alternate criteria process,”
under which we are soliciting comments, this too is available on the ICC-ES web site.
Please do not try to communicate directly with any Evaluation Committee member
about a criteria under consideration, as committee members cannot accept such
communications.
AC427-0211-R1
5
Thank you for your interest and your contributions. If you have any questions, please
contact me at (800) 423-6587, extension 3260, or David Zhao, at extension 3721.
You may also reach us by e-mail at es@icc-es.org.
Yours very truly,
Brian Gerber
Principal Structural Engineer
BG/md
Enclosures
cc: Evaluation Committee
ICC-ES AC427 Public Review Primer
Cast ConneX® High-Strength Connectors™
General Description
Cast ConneX® High-Strength Connectors™ (Figure 1) were
developed at the University of Toronto by Professors Jeffrey
A. Packer and Constantin Christopoulos for use in the
construction of Ordinary Concentrically Braced Frames
(OCBF) and Special Concentrically Braced Frames (SCBF)
designed according to AISC 341.
The off-the-shelf connectors accommodate bolted (or welded)
connection to a gusset plate on one end and complete joint
penetration (CJP) welded connection to a round Hollow
Structural Section (HSS) or Pipe brace member on the other.
Thus, in practice, the cast connectors can be welded to the
hollow section braces in the shop, with the brace-connector
assembly being bolted (or welded) to the gussets in the field
(Figures 2 and 3).
Each Cast ConneX High-Strength Connector is standardized
to accommodate all round HSS or Pipe members of a given
outer diameter, regardless of their wall thickness or grade of
steel (Figure 3). Typically, the connectors are used in conjunction with round HSS produced to ASTM
A500, ASTM A501, CAN/CSA G40.20/21, EN 10210, EN 10219, ASTM A53 pipe, and API 5L line pipe.
®
Figure 1 Cast ConneX High-Strength Connectors™
Figure 2 Shop welding of brace-connector assembly (top left), connector-brace assemblies (bottom left), connector-brace assembly
installed in a braced frame (right)
1
Cast ConneX®
High-Strength Connector™
Gusset
connecting
end
H
ipe
or P
S
S
El e
ce
Bra
me
nt
Complete Joint
Penetration groove weld
Plastic hinge region
during out-of-plane buckling
Figure 3 High-Strength Connector shown in field-bolted configuration (left); CJP weld between connector and HSS (right)
Code Compliancy Issues Involved
Strength of the Connectors
The requirements for bracing connections in SCBF and OCBF are outlined in AISC 341-05 Sections 13.3
and 14.4, respectively. Using the code provisions in AISC 360-05, one can readily demonstrate that the
connectors, which are produced to ASTM A958 Grade SC8620 Class 80/50, a weldable, ductile, notch
tough ASTM cast steel grade having a specified minimum yield strength of 50 ksi and a specified
minimum tensile strength of 80 ksi, meet these requirements as follows:
ƒ
On one end, the connectors are joined via complete joint penetration groove weld to the hollow
section brace [in accordance with IBC Section 2204.1] – a joint that is inherently as strong as the
connected brace, thereby meeting the strength requirements of AISC 341-05 Sections 13.3 and
14.4;
ƒ
On their other end, the connectors are joined to a gusset plate via double-shear bolted
connection [in accordance with IBC Section 2204.2] or fillet welded connection [in accordance
with IBC Section 2204.1] – connections which can be detailed (by the Engineer of Record) using
provisions in AISC 360-05 to meet the strength requirements of AISC 341-05 Sections 13.3 or
14.4. Further, as outlined in AISC 341-05 Section 13.3b, the “2tp rule” can be used to
accommodate the requisite out-of-plane end rotation of the brace in SCBF assemblages (the free
length of gusset plate is to be left beyond the end of the connector);
ƒ
In between, the connector’s solid steel “body” is analogous to a cap plate that transitions well
within the conservative distribution slope of 2.5:1 described in AISC 360-05 Section K1.6 (refer to
AISC Design Guide 24 page 83 for the cap-plate-to-round HSS case), thereby eliminating shearlag in the connection to the hollow section brace.
2
Steel Material and Quality Control
Given that these connectors can be shown to meet the AISC 341-05 strength requirements for SCBF and
OCBF brace connections, the only element of these connectors that is not specifically code
compliant is the steel grade to which they are produced, as ASTM A958 Grade SC8620 Class 80/50
is not explicitly listed in AISC 360-05 or AISC 341-05. Additionally, it would be prudent to set
requirements for quality control to ensure the soundness of the components in production, hence Cast
Connex Corporation’s decision to approach ICC-ES for the development of a suitable Acceptance Criteria
and ultimately for the creation of an ICC-ES Evaluation Report on Cast ConneX High-Strength
Connectors.
Recently, AISC TC-9, with the support of the Steel Founders’ Society of America, set casting and
examination requirements in Appendix A of Supplement No. 1 to AISC 358-05 for similar seismic-resistant
cast steel components produced to precisely the same ASTM cast steel grade as Cast ConneX HighStrength Connectors. Kaiser Bolted Brackets are similar to High-Strength Connectors in that they are a
“capacity designed” element of a seismic load resisting system (SLRS). For clarity, this means that both
the Kaiser Bolted Brackets and High-Strength Connectors are to remain elastic while transmitting force
between other elements of the SLRS. Because of this similarity, ICC-ES has developed AC427 based on
the casting and non-destructive examination requirements set out in Appendix A of Supplement No. 1 to
AISC 358-05.
In regards to the cast steel grade itself, we believe that the approval by AISC TC-9 for the use of ASTM
A958 Grade SC8620 Class 80/50 material in a seismic application (Kaiser Bolted Brackets) is highly
persuasive evidence that the material is suitable for similar seismic uses (i.e. as capacity designed
elements in other seismic applications). Further, ASTM A958 is listed as a reference standard cast steel
grade suitable for structural use in the Canadian equivalent to AISC 360, CAN/CSA S16-09.
Additional Reference documents and Materials
Please visit the publications section of Cast Connex Corporation’s website, www.castconnex.com, to
access a number of related Journal and Conference papers published by researchers at the University of
Toronto on these unique, seismic-resistant connectors.
Please also feel free to view the following videos showing some of the full-scale tests that have been
conducted on braces equipped with these connectors:
Full-scale brace assembly test
Full-scale braced frame test
http://www.youtube.com/user/CastConneX#p/u/2/YD4o6ItXVAU
http://www.youtube.com/user/CastConneX#p/u/1/_AOSYakbGBo
Closing comments
With our general position on the code compliancy of Cast ConneX High-Strength Connectors having been
briefly discussed above, we would much appreciate it if you could carefully review AC427 and provide
your comments to ICC-ES so that we can ultimately ensure the successful use of our connectors, which
we believe enhance the safety and simplify the design and construction of steel braced frames.
Sincerely,
Cast ConneX Corporation
3
www.icc-es.org | (800) 423-6587 | (562) 699-0543
A Subsidiary of the International Code Council ®
PROPOSED ACCEPTANCE CRITERIA FOR
STRUCTURAL CAST STEEL CONNECTORS FOR USE AS
BRACING CONNECTIONS IN ACCORDANCE WITH AISC 341-05
SECTIONS 13.3 AND 14.4
AC427
Proposed February 2011
PREFACE
Evaluation reports issued by ICC Evaluation Service, LLC (ICC-ES), are based upon performance features of
the International family of codes and other widely adopted code families, including the Uniform Codes, the BOCA
National Codes, and the SBCCI Standard Codes. Section 104.11 of the International Building Code® reads as
follows:
The provisions of this code are not intended to prevent the installation of any materials or to
prohibit any design or method of construction not specifically prescribed by this code,
provided that any such alternative has been approved. An alternative material, design or
method of construction shall be approved where the building official finds that the proposed
design is satisfactory and complies with the intent of the provisions of this code, and that the
material, method or work offered is, for the purpose intended, at least the equivalent of that
prescribed in this code in quality, strength, effectiveness, fire resistance, durability and safety.
Similar provisions are contained in the Uniform Codes, the National Codes, and the Standard Codes.
ICC-ES may consider alternate criteria, provided the report applicant submits valid data demonstrating that the
alternate criteria are at least equivalent to the criteria proposed in this document, and otherwise meet the
applicable performance requirements of the codes. Notwithstanding that a product, material, or type or method
of construction meets the requirements of the criteria proposed in this document, or that it can be demonstrated
that valid alternate criteria are equivalent to the criteria in this document and otherwise meet the applicable
performance requirements of the codes, ICC-ES retains the right to refuse to issue or renew an evaluation report,
if the product, material, or type or method of construction is such that either unusual care with its installation or
use shall be exercised for satisfactory performance, or malfunctioning is apt to cause unreasonable property
damage or personal injury or sickness relative to the benefits to be achieved by the use of the product, material,
or type or method of construction.
Acceptance criteria are developed for use solely by ICC-ES for purposes of issuing ICC-ES evaluation reports.
AC427-0211-R1
Page 2
February 2011
PROPOSED ACCEPTANCE CRITERIA FOR STRUCTURAL
CAST STEEL CONNECTORS FOR USE AS BRACING
CONNECTIONS IN ACCORDANCE WITH AISC 341
SECTIONS 13.3 AND 14.4
1.0
INTRODUCTION
1.1
Purpose: The purpose of this acceptance criteria is to establish
casting and nondestructive examination requirements for structural cast steel
connectors for use as bracing connections in accordance with AISC 341Sections
13.3 and 14.4 to be recognized in ICC Evaluation Service, LLC (ICC-ES),
evaluation reports under the 2009 International Building Code® (IBC). The basis
of recognition is IBC Section 104.11.
The reason for the development of these criteria is to allow for the
recognition of structural cast steel connectors that comply as bracing connections
with AISC 341 Sections 13.3 and 14.4 except are produced from a cast steel
grade that is beyond the scope of the IBC and referenced standards.
1.2
Scope: This criteria establishes procedures for casting and quality
control including nondestructive examination of cast steel connectors that comply
with AISC 341 Sections 13.3 and 14.4 as permitted by Section 2205 of the IBC.
This criteria addresses material requirements relating to strength, weldability,
ductility, notch toughness, and soundness.
1.3
Referenced Standards:
1.3.1
Council.
2009 International Building Code® (IBC), International Code
PROPOSED ACCEPTANCE CRITERIA FOR STRUCTURAL
CAST STEEL CONNECTORS FOR
USE AS BRACING CONNECTIONS IN
ACCORDANCE WITH AISC 341 SECTIONS 13.3 AND 14.4
1.3.2
AC427-0211-R1
Page 3
February 2011
AISC 303-05, Code of Standard Practice for Steel Buildings
and Bridges, American Institute of Steel Construction.
1.3.3
AISC 341-05, Seismic Provisions for Structural Steel
Buildings, American Institute of Steel Construction.
1.3.4
AISC 358-05s1-09, Supplement No. 1 to AISC 358-05,
Prequalified Connections for Special and Intermediate Steel Moment Frames for
Seismic Applications, American Institute of Steel Construction.
1.3.5
AISC 360-05, Specification for Structural Steel Buildings,
American Institute of Steel Construction.
1.3.6
ANSI/AWS D1.1-2004, Structural Welding Code – Steel,
American Welding Society.
1.3.7
ANSI/AWS D1.8-2005, Structural Welding Code – Seismic
Supplement, American Welding Society.
1.3.8
ASTM A 958/A 958M-09, Standard Specification for Steel
Castings, Carbon and Alloy, with Tensile Requirements, Chemical Requirements
Similar to Standard Wrought Grades, ASTM International.
1.4
Definitions: Definitions in the IBC, AISC 303, AISC 341, AISC 358-
05s1-09, and AISC 360 apply to these criteria. Additionally:
1.4.1
Connector: A device incorporating two joints, one at each
end, to transmit forces between attached structural steel elements.
2.0 BASIC INFORMATION
2.1
General: The following information shall be submitted:
PROPOSED ACCEPTANCE CRITERIA FOR STRUCTURAL
CAST STEEL CONNECTORS FOR
USE AS BRACING CONNECTIONS IN
ACCORDANCE WITH AISC 341 SECTIONS 13.3 AND 14.4
2.1.1
AC427-0211-R1
Page 4
February 2011
Product Description: Complete information concerning the
connectors including: intended use(s), dimensions, available strength, material
specifications, manufacturing process, and non-destructive examination
requirements. In addition, statements concerning restrictions or limitations on use
shall be submitted. Calculations deriving the critical gross section properties and
supplemental gross section properties at bolting locations shall be submitted.
Information establishing compatible connected elements, such as braces and
gusset plates shall be submitted, subject to applicable code requirements.
2.1.2
Installation Instructions: Instructions shall include the
following items:
a. Description of how the product will be used or installed at the fabricator’s shop
and the project site.
b. Procedures establishing quality control at the fabricator’s shop.
c.
Procedures establishing quality control at project sites during installation.
d. Requirements for product handling and storage.
e. Requirements for welding or bolting the connectors to other structural elements.
f. Special inspection shall be provided in accordance with Chapter 17 of the IBC
and in accordance with this criteria. For each type of connector system, the
manufacturer shall submit inspection procedures to verify proper usage.
2.1.3
Packaging and Identification: A description of the method
of packaging and field identification of the connectors. Identification provisions
shall include the evaluation report number and the name or logo of the inspection
agency.
PROPOSED ACCEPTANCE CRITERIA FOR STRUCTURAL
CAST STEEL CONNECTORS FOR
USE AS BRACING CONNECTIONS IN
ACCORDANCE WITH AISC 341 SECTIONS 13.3 AND 14.4
2.1.4
AC427-0211-R1
Page 5
February 2011
Documentation: The following documents shall be
submitted to the building official and the registered design professional:
2.1.4.1.
Production inspection and non-destructive testing reports
for each heat.
2.2
2.1.4.2.
Tensile and Charpy V-Notch test reports for each heat.
2.1.4.3.
Weld repair reports for each connector.
Testing Laboratories: Testing laboratories shall comply with the
ICC-ES Acceptance Criteria for Test Reports (AC85) and Section 4.2 of the ICCES Rules of Procedure for Evaluation Reports.
2.3
Test Reports: Test reports shall comply with AC85. The test reports
shall include information described in the referenced standard, and visual records
of the test specimens before, during, and after testing.
2.4
Product Sampling: Sampling of the connectors for tests under this
criteria shall comply with Section 3.1 of AC85.
2.5
Structural Design:
2.5.1
General: The connector shall be designed to transmit forces
between the attached structural steel elements, and the connector’s configuration
shall be such that its available strength shall be determined in accordance with
the provisions of AISC 341 and AISC 360. The connector shall demonstrate
compliance with Sections 13.3a, 13.3b, 13.3c, and 14.4 of AISC 341 as a bracing
connection capable developing the specified strengths of the connected braces.
The registered design professional specifying the use of a
connector complying with this criteria shall design the welded or bolted joints at
PROPOSED ACCEPTANCE CRITERIA FOR STRUCTURAL
CAST STEEL CONNECTORS FOR
USE AS BRACING CONNECTIONS IN
ACCORDANCE WITH AISC 341 SECTIONS 13.3 AND 14.4
AC427-0211-R1
Page 6
February 2011
either end of the connector to provide the required strength as outlined below.
The required strength shall not exceed the available strength of the connector.
The connector shall be considered within a protected zone and subject to
provisions of Sections 7.4 and 13.6 of AISC 341.
2.5.2
Required Strength of Joints for Connectors Used as a
Brace Member End Connection in a Seismic-Resistant Concentrically
Braced Frame: Design and detailing shall comply with Section 13.3 of AISC
341for connectors used in Special Concentrically Braced Frames or Section 14.4
of AISC 341 for connectors used in Ordinary Concentrically Braced Frames.
2.5.3
Design Procedures: Details and examples of how the
connector is designed, analyzed and detailed shall be submitted, including
equations, with procedures and properties for design analysis.
2.5.4
Construction Documents: Structural design drawings and
specifications, shop drawings and erection drawings shall comply with Section 5
of AISC 341.
2.6
Welding:
2.6.1
General: Where heat treatment of connectors complying
with this criteria include quenching and tempering (QT), documentation
establishing welding practices for QT materials shall be developed and
submitted. A Welding Procedure Specification (WPS), prepared in accordance
with Section 6.1 of AWS D1.8, and Section 1704.3.1, Table 1704.3 and Section
1708 of IBC, shall be developed for each welding position, welding process,
electrode manufacturer, filler metal trade name for the electrode type selected;
PROPOSED ACCEPTANCE CRITERIA FOR STRUCTURAL
CAST STEEL CONNECTORS FOR
USE AS BRACING CONNECTIONS IN
ACCORDANCE WITH AISC 341 SECTIONS 13.3 AND 14.4
AC427-0211-R1
Page 7
February 2011
and for all essential variable changes in the Procedure Qualification Record
(PQR) that exceed allowable tolerances. Each WPS shall be qualified by a
documented PQR in accordance with Section 4 of AWS D1.1.
2.6.2
Welding the Cast Steel Connector to a Brace Element for
Use as a Brace Member End Connection in Seismic-Resistant
Concentrically Braced Frames: The welding shall comply with the
requirements set forth for demand critical welds in AISC 341, AISC 360,
ANSI/AWS D1.1, and ANSI/AWS D1.8 for welded connections in seismicresistant applications.
3.0
CAST STEEL GRADE
3.1
Cast steel grade shall comply with ASTM A 958 Grade SC 8620
Class 80/50, including Appendix A of AISC 358-05s1-09.
4.0
QUALITY CONTROL
4.1
The products shall be manufactured under an approved quality
control program with inspections by an inspection agency complying with Section
1.3.1 of the ICC-ES Acceptance Criteria for Quality Documentation (AC10).
Quality control shall comply with Section A.2 of AISC 358-05s1-09 for Cast Steel
Connectors.
4.2
Quality documentation complying with the ICC-ES Acceptance
Criteria for Quality Documentation (AC10) shall be submitted.
4.3
Fabrication and assembly work requiring special inspection is permitted to
be done on the premises of approved fabricators. The quality assurance program for
PROPOSED ACCEPTANCE CRITERIA FOR STRUCTURAL
CAST STEEL CONNECTORS FOR
USE AS BRACING CONNECTIONS IN
ACCORDANCE WITH AISC 341 SECTIONS 13.3 AND 14.4
AC427-0211-R1
Page 8
February 2011
fabrication practices shall be documented and comply with the IAS Accreditation Criteria
for Fabricator Inspection Programs for Structural Steel (AC172).
4.4
Jobsite quality assurance shall conform to Sections 1705, 1706 and 1708.4
of the IBC, Section 18 and Appendix Q of AISC 341, and applicable portions of AISC
303.
4.5
Special inspection shall be provided in accordance with Sections
1704.3 and 1707.2 of the IBC, Section 18 and Appendix Q of AISC 341, and
Section 7 of AWS D1.8.
5.0
EVALUATION REPORT RECOGNITION
The evaluation report shall include the following information:
5.1
Information described in Section 2.1, 2.5, and 2.6 of this criteria.
5.2
Illustrations of the connectors showing a typical installation and load
direction.
5.3
Limitations on design, fabrication, and erection as determined in
accordance with this criteria.
5.4
Fabrication program as described in Section 4.3 of this criteria.
5.5
Provisions for quality assurance and special inspection as described
in Sections 4.4 and 4.5 of this criteria. ■