K1.1 Scope
This section contains minimum requirements for prequalification of beam-to-column moment connections in special moment frames (SMF), intermediate moment frames (IMF), composite special moment frames (C-SMF), composite intermediate moment frames (C-IMF), and link-to-column connections in eccentrically braced frames (EBF). Prequalified connections are permitted to be used, within the applicable limits of prequalification, without the need for further qualifying cyclic tests. When the limits of prequalification or design requirements for prequalified connections conflict with the requirements of these Provisions, the limits of prequalification and design requirements for prequalified connections shall govern.
K1.2 General Requirements
K1.2a Basis for Prequalification
Connections shall be prequalified based on test data satisfying Section K1.3, supported by analytical studies and design models. The combined body of evidence for prequalification must be sufficient to ensure that the connection is able to supply the required story drift angle for SMF, IMF, C-SMF, and C-IMF systems, or the required link rotation angle for EBF, on a consistent and reliable basis within the specified limits of prequalification. All applicable limit states for the connection that affect the stiffness, strength, and deformation capacity of the connection and the seismic force-resisting system must be identified. The effect of design variables listed in Section K1.4 shall be addressed for connection prequalification.
K1.2b Authority for Prequalification
Prequalification of a connection and the associated limits of prequalification shall be established by a connection prequalification review panel (CPRP) approved by the authority having jurisdiction.
K1.3 Testing Requirements
Data used to support connection prequalification shall be based on tests conducted in accordance with Section K2. The CPRP shall determine the number of tests and the variables considered by the tests for connection prequalification. The CPRP shall also provide the same information when limits are to be changed for a previously prequalified connection. A sufficient number of tests shall be performed on a sufficient number of nonidentical specimens to demonstrate that the connection has the ability and reliability to undergo the required story drift angle for SMF, IMF, C-SMF, and C-IMF, and the required link rotation angle for EBF, where the link is adjacent to columns. The limits on member sizes for prequalification shall not exceed the limits specified in Section K2.3b.
K1.4 Prequalification Variables
In order to be prequalified, the effect of the following variables on connection performance shall be considered. Limits on the permissible values for each variable shall be established by the CPRP for the prequalified connection.
K1.4a Beam and Column Parameters for SMF and IMF, Link and Column Parameters for EBF
- (a) Cross-section shape: wide-flange, box, or other
- (b) Cross-section fabrication method: rolled shape, welded shape, or other
- (c) Depth
- (d) Weight per foot
- (e) Flange thickness
- (f) Material specification
- (g) Beam span-to-depth ratio (for SMF or IMF), or link length (for EBF)
- (h) Width-to-thickness ratio of cross-section elements
- (i) Lateral bracing
- (j) Column orientation with respect to beam or link: beam or link is connected to column flange, beam or link is connected to column web, beams or links are connected to both the column flange and web, or other
- (k) Other parameters pertinent to the specific connection under consideration
K1.4b Beam and Column Parameters for C-SMF and C-IMF
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(a) For structural steel members that are part of a composite beam or column: specify parameters required in Section K1.4a
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(b) Overall depth of composite beam and column
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(c) Composite beam span-to-depth ratio
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(d) Reinforcing bar diameter
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(e) Reinforcement material specification
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(f) Reinforcement development and splice requirements
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(g) Transverse reinforcement requirements
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(h) Concrete compressive strength and density
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(i) Steel anchor dimensions and material specification
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(j) Other parameters pertinent to the specific connection under consideration
K1.4c Beam-to-Column or Link-to-Column Relations
- (a) Panel-zone strength for SMF, IMF, and EBF
- (b) Joint shear strength for C-SMF and C-IMF
- (c) Doubler plate attachment details for SMF, IMF, and EBF
- (d) Joint reinforcement details for C-SMF and C-IMF
- (e) Column-to-beam (or column-to-link) moment ratio
K1.4d Continuity and Diaphragm Plates
- (a) Identification of conditions under which continuity plates or diaphragm plates are required
- (b) Thickness, width, and depth
- (c) Attachment details
K1.4e Welds
- (a) Location, extent (including returns), type (CJP, PJP, fillet, etc.), and any reinforcement or contouring required
- (b) Filler metal classification strength and notch toughness
- Details and treatment of weld backing and weld tabs
- (c) Details and treatment of weld backing and we (d) Weld access holes: size, geometry, and finish (e) Welding quality control and quality assurance
- (e) Welding quality control and quality assurance beyond that described in Chapter J, including nondestructive testing (NDT) method, inspection frequency, acceptance criteria, and documentation requirements
K1.4f Bolts
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(a) Bolt diameter
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(b) Bolt grade: ASTM F3125/F3125M Grades A325, A325M, A490, A490M, F1852, F2280, or other
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Installation requirements: pretensioned, snug-tight, or other
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(d) Hole type: standard, oversized, short slot, long slot, or other
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(e) Hole fabrication method: drilling, punching, sub-punching and reaming, or other
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(f) Other parameters pertinent to the specific connection under consideration
K1.4g Reinforcement in C-SMF and C-IMF
- (a) Location of longitudinal and transverse reinforcement
- (b) Cover requirements
- (c) Hook configurations and other pertinent reinforcement details
K1.4h Quality Control and Quality Assurance
Requirements that exceed or supplement requirements specified in Chapter J, if any.
K1.4i Additional Connection Details
All variables and workmanship parameters that exceed AISc, RCSC, and AWS requirements pertinent to the specific connection under consideration, as established by the CPRP.
K1.5 Design Procedure
A comprehensive design procedure must be available for a prequalified connection. The design procedure must address all applicable limit states within the limits of prequalification.
K1.6 Prequalification Record
A prequalified connection shall be provided with a written prequalification record with the following information:
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(a) General description of the prequalified connection and documents that clearly identify key features and components of the connection
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(b) Description of the expected behavior of the connection in the elastic and inelastic ranges of behavior, intended location(s) of inelastic action, and a description of limit states controlling the strength and deformation capacity of the connection
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(c) Listing of systems for which connection is prequalified: SMF, IMF, EBF, C-SMF, or C-IMF
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(d) Listing of limits for all applicable prequalification variables listed in Section K1.4
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(e) Listing of demand critical welds
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(f) Definition of the region of the connection that comprises the protected zone
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(g) Detailed description of the design procedure for the connection, as required in Section K1.5
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(h) List of references of test reports, research reports, and other publications that provided the basis for prequalification
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(i) Summary of quality control and quality assurance procedures