CBC · California Building Code

What are the seismic design and detailing requirements for steel seismic force‑resisting systems?

If your building is in higher seismic zones (SDC D, E, F), the California Building Code requires steel seismic force‑resisting systems be designed and detailed to AISC 341, with beam‑to‑column connections prequalified or tested and Chapter 17 special inspections and NDT applied; lower categories may allow AISC 360 only in a specific ASCE 7–designated case.

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Last reviewed: July 5, 2026

What the code requires — 2-4 sentences

The California Building Code requires that seismic design, detailing, fabrication and erection of structural steel seismic force‑resisting systems follow the referenced AISC standards specified by seismic design category: use the provisions in Section 2202.2.1, which direct SDC B/C work per § 2202.2.1.1 and SDC D/E/F work per § 2202.2.1.2. In short, structures in Seismic Design Categories D, E or F must be designed and detailed in accordance with AISC 341; SDC B or C structures must follow § 2202.2.1.1 (AISC 341 where an R from ASCE 7 Table 12.2‑1 is used) with a limited exception allowing AISC 360 under the specific ASCE 7 R designation. See § 2202.2, § 2202.2.1 and § 2202.2.1.2 in the CBC for the controlling language .

Requirements in detail

Which standard applies (high level)

  • Seismic design of steel seismic force‑resisting systems is governed by Section 2202.2 and the subsections that follow; the CBC delegates the detailed design and detailing to AISC 341 for the higher seismic categories and to AISC 341 (or, in narrow cases, AISC 360 per ASCE 7 allowance) for lower categories. See § 2202.2, § 2202.2.1, § 2202.2.1.1 and § 2202.2.1.2 for the baseline requirements .

Moment‑connection prequalification

  • Beam‑to‑column moment connections used in special or intermediate moment frames must be prequalified in accordance with AISC 341 Section K1, or qualified by testing per AISC 341 Section K2, or prequalified per AISC 358 — the CBC repeats these connection requirements in both § 2202.2.1.1 and § 2202.2.1.2 .

Special inspection and nondestructive testing

  • Special inspection and nondestructive testing requirements for structural steel in seismic force‑resisting systems reference the quality assurance requirements of AISC 341; the CBC requires special inspections and NDT per Chapter 17 where AISC 341 applies (exceptions are noted where the code allows AISC 360 under ASCE 7 tables). See § 1705.13.1 and § 1705.14.1.1 for the special inspection and testing cross references in the CBC .

Decision‑relevant summary table

Decision factor Required provision / value Code Reference
Seismic Design Category D, E or F Design and detailing in accordance with AISC 341 (all structural steel seismic FR systems) § 2202.2.1.2
Seismic Design Category B or C (when ASCE 7 R table value used) Design and detailing in accordance with AISC 341; beam‑to‑column connections prequalified per AISC 341 K1/K2 or AISC 358 § 2202.2.1.1
Seismic Design Category B or C (alternative permitted case) Where ASCE 7 designates the R for “Steel systems not specifically detailed for seismic resistance…”, AISC 360 is permitted instead of AISC 341 Exception to § 2202.2.1.1
Connection prequalification Beam‑to‑column moment connections must be prequalified per AISC 341 Sec K1, or tested per K2, or prequalified per AISC 358 § 2202.2.1.1 and § 2202.2.1.2
Special inspection / NDT Structural steel in SFRS must meet AISC 341 quality assurance requirements for special inspections and NDT (Chapter 17 references) §§ 1705.13.1 and 1705.14.1.1

(Note: the CBC text delegates many numeric seismic parameters, response modification coefficients (R), and specific detailing measures to ASCE 7 and the referenced AISC standards; those numerics and test procedures are in the referenced standards rather than in the CBC text excerpts we retrieved. The CBC language telling you which standard to use is in § 2202.2 and § 2202.2.1.x .)

Exceptions & special cases

  • The CBC explicitly allows one exception for SDC B/C where the ASCE 7 Table 12.2‑1 R value for “Steel systems not specifically detailed for seismic resistance, excluding cantilever column systems” is used: such systems may be designed and detailed per AISC 360 instead of AISC 341 (see the exception to § 2202.2.1.1) .
  • The CBC also notes that ASCE 7 Table 15.4‑1 can permit design and detailing other than AISC 341 for some systems in SDC D/E/F; however, the primary requirement for SDC D/E/F in the CBC is AISC 341 unless ASCE 7 specifically allows otherwise (§ 2202.2.1.2) .
  • The OSHPD/DSA administrative margins and California‑specific appendices modify some AISC provisions for regulated facilities — those are called out in the code extracts and must be checked where applicable (the CBC text includes bracketed OSHPD/DSA notes) .

If a given detail (e.g., protected‑zone marking, weld/NDT scope) is required by AISC 341 or by a California modification, follow that standard and state‑specific modification — the CBC points you to the standard and to local modifications in adjacent CBC appendices .

Common mistakes

  • Assuming AISC 360 is acceptable in SDC D/E/F. The CBC requires AISC 341 for those categories unless ASCE 7 Table 15.4‑1 specifically permits otherwise — check § 2202.2.1.2 rather than defaulting to AISC 360 .
  • Failing to prequalify or test beam‑to‑column moment connections per AISC 341 K1/K2 or AISC 358 as required by § 2202.2.1.1 and § 2202.2.1.2 .
  • Overlooking the CBC referral to special inspections and NDT: if your system falls under AISC 341 requirements, Chapter 17 special inspection and testing rules apply (many jurisdictions require continuous or periodic inspection as specified) — see §§ 1705.13.1 and 1705.14.1.1 .
  • Not checking ASCE 7 tables that determine whether the CBC requires AISC 341 or allows AISC 360 — the CBC statements reference ASCE 7 (e.g., Table 12.2‑1 and Table 15.4‑1) rather than restating those tables in the Code text .

Worked example — applying the rule

Scenario: A new commercial building is assigned to Seismic Design Category D by the site and occupancy analysis.

  1. CBC step: Identify controlling CBC section. Because the building is in SDC D, follow § 2202.2.1.2, which requires design and detailing in accordance with AISC 341 for structural steel seismic force‑resisting systems .
  2. Connection requirement: All beam‑to‑column moment connections intended as part of special or intermediate moment frames must be prequalified under AISC 341 Section K1, or qualified by testing per K2, or be an AISC‑358 prequalified connection — document the chosen path on the construction documents per § 2202.2.1.2 .
  3. Inspection and testing: Because AISC 341 applies, arrange special inspection and NDT in accordance with the AISC 341 quality assurance provisions and Chapter 17 of the CBC; specify inspection frequency and tests on the submittal (see §§ 1705.13.1 and 1705.14.1.1) .
  4. Documentation: On the structural drawings and specifications, explicitly state that AISC 341 is the governing standard, identify the connection prequalification method, and include references to the special inspection procedures required by Chapter 17; this mirrors the CBC direction in § 2202.2.1.2 and related special inspection sections .

Note: to compute seismic forces, select response modification coefficient R and other parameters from ASCE 7 (the CBC delegates the R values/selection to ASCE 7 tables referenced by the CBC) — the CBC text refers you to ASCE 7 but does not restate those numeric values in §§ 2202.2.1.x .

Related provisions

  • § 2202.2 — Seismic design (frames the use of §§ 2202.2.1 / 2202.2.2)
  • § 2202.2.1 — Structural steel seismic force‑resisting systems: delegation to AISC 341 or AISC 360 per ASCE 7 references
  • § 2202.2.1.1 — SDC B or C requirements (and the AISC 360 exception when the ASCE 7 R value is the “not specifically detailed” row)
  • § 2202.2.1.2 — SDC D, E or F requirements (AISC 341 required; prequalification/testing rules for connections)
  • § 2202.1 — General requirement that structural steel design/fabrication/erection follow AISC 360 unless otherwise stated
  • § 1705.13.1 — Special inspections for structural steel seismic force‑resisting systems (AISC 341 QA)
  • § 1705.14.1.1 — Nondestructive testing for seismic force‑resisting systems (AISC 341 QA)
  • § 2202.2.2 — Steel elements of seismic systems (AISC 341 required for elements when criteria met)

Code references

Grounded in the retrieved California Building Code — click a citation to read the verbatim passage:

  • CBC § 2202.2 High relevance — show source text

    2202.2 Seismic design. Where required, the seismic design, fabrication and erection of buildings, structures and portions thereof shall be in accordance with Section 2202.2.1 or 2202.2.2, as applicable.

    2202.2.1 Structural steel seismic force-resisting systems and composite structural steel and concrete seismic force-resist- ing systems. The design, detailing, fabrication and erection of structural steel seismic force-resisting systems and composite structural steel and concrete seismic force-resisting systems shall be in accordance with the provisions of Section 2202.2.1.1 or 2202.2.1.2, as applicable.

    [ OSHPD 1R, 2 & 5 ] Seismic requirements for composite structural steel and concrete construction shall be considered as an alter- native system, except as permitted by Section 2202.4.1.

    2202.2.1.1 Seismic Design Category B or C. Structures assigned to Seismic Design Category B or C shall be of any construction permitted in Section 2202. Where a response modification coefficient, R, in accordance with ASCE 7, Table 12.2-1, is used for the design of structures assigned to Seismic Design Category B or C, the structures shall be designed and detailed in accordance with the requirements of AISC 341. Beam-to-column moment connections in structural steel special moment frames and intermediate moment frames shall be prequalified in accordance with AISC 341, Section K1, qualified by testing in accordance with AISC 341, Section K2, or shall be prequalified in accordance with AISC 358.

    Exception: The response modification coefficient, R, designated for “Steel systems not specifically detailed for seismic resistance, excluding cantilever column systems” in ASCE 7, Table 12.2-1, shall be permitted for structural steel systems designed and detailed in accordance with AISC 360, and need not be designed and detailed in accordance with AISC 341.

    2202.2.1.2 Seismic Design Category D, E or F. Structures assigned to Seismic Design Category D, E or F shall be designed and detailed in accordance with AISC 341, except as permitted in ASCE 7, Table 15.4-1. Beam-to-column moment connections in structural steel special moment frames and intermediate moment frames shall be prequalified in accordance with AISC 341, Section K1, qualified by testing in accordance with AISC 341, Section K2, or shall be prequalified in accordance with AISC 358.

    [OSHPD 1R, 2 & 5] All structural steel seismic force-resisting systems in ASCE 7 Table 15.4-1 shall be designed in accordance with AISC 341.

    2202.2.2 Structural steel elements. The design, detailing, fabrication and erection of structural steel elements in seismic forceresisting systems other than those covered in Section 2202.2.1, including struts, collectors, chords and foundation elements, shall be in accordance with AISC 341 where either of the following applies:

    1. The structure is assigned to Seismic Design Category D, E or F, except as permitted in ASCE 7, Table 15.4-1.
    2. A response modification coefficient, R, greater than 3 in accordance with ASCE 7, Table 12.2-1, is used for the design of the structure assigned to Seismic Design Category B or C.
  • CBC § 2.1 High relevance — show source text

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    1. For members designed based on tension, the slenderness ratio (L/r) shall not exceed 300, except for the design of hangers and bracing in accordance with NFPA 13 and for rod hangers in tension. 2. For members designed based on compression, the slenderness ratio (KL/r) shall not exceed 200, except for the design of hangers and bracing in accordance with NFPA 13.

    2202 A .2 Seismic design. Where required, the seismic design, fabrication and erection of buildings, structures and portions thereof shall be in accordance with Section 2202 A .2.1 or 2202 A .2.2, as applicable.

    2202 A .2.1 Structural steel seismic force-resisting systems and composite structural steel and concrete seismic force- resisting systems. The design, detailing, fabrication and erection of structural steel seismic force-resisting systems and composite structural steel and concrete seismic force-resisting systems shall be in accordance with the provisions of Section 2202 A .2.1.1 or 2202 A .2.1.2, as applicable. Seismic force-resisting systems of structural steel acting compositely with reinforced concrete shall be considered as an alternative system, except as permitted by:

    [DSA-SS] Section 2202A.6.1.

    [OSHPD 1 & 4] Section 2202A.4.1.

    2202 A .2.1.1 Seismic Design Category B or C. Not permitted by DSA-SS and OSHPD.

    2202 A .2.1.2 Seismic Design Category D, E or F. Structures assigned to Seismic Design Category D, E or F shall be designed and detailed in accordance with AISC 341. Beam-to-column moment connections in structural steel special moment frames and intermediate moment frames shall be prequalified in accordance with AISC 341, Section K1, qualified by testing in accordance with AISC 341, Section K2, or shall be prequalified in accordance with AISC 358.

    2202 A .2.2 Structural steel elements. The design, detailing, fabrication and erection of structural steel elements in seismic forceresisting systems, including struts, collectors, chords and foundation elements, shall be in accordance with AISC 341.

    2202A.3 Modifications to AISC 341. [OSHPD 1 and 4]

    2202A.3.1 Section A4. Modify Section A4.1 Item (c) by adding the following:

    (c) Locations and dimensions of protected zones. The fabricator shall permanently mark protected zones of structural elements in the seismic force-resisting system in the building that are designated on the construction documents. If these markings are obscured during construction, such as after the application of fire protection, the owner’s designated representative shall re-mark the protected zones as they are designated on the construction documents. [OSHPD 1 & 4] Primers or paints used to mark protected zones on steel surfaces, which are to receive sprayed fire-resistance material, shall comply with California Building Code Section 704.13.3.2.

  • CBC § 3114.8.4.2 High relevance — show source text

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    3114.8.4.2 Seismic design parameters. The seismic force-resisting system shall be designed and detailed in accordance with ASCE 7 and one of the following:

    1. Where all or portions of the profiled steel panel elements are considered to be the seismic force-resisting system, design and detailing shall be in accordance with the AISI S100 and ASCE 7, Table 12.2-1 requirements for steel systems not specifically detailed for seismic resistance, excluding cantilever column systems. [DSA-SS & DSA-SS/CC] Not permitted by DSA.

    2. Where all or portions of the profiled steel panel elements are not considered to be part of the seismic force-resisting system, an independent seismic force-resisting system shall be selected and detailed in accordance with ASCE 7, Table 12.2-1.

    3. Where all or portions of the profiled steel panel elements are retained and integrated into a seismic force-resisting system other than as permitted by Item 1, seismic design parameters shall be developed from testing and analysis in accordance with Section 104.2.3 and ASCE 7, Section 12.2.1.1 or 12.2.1.2.

    3114.8.4.3 Allowable shear value. The allowable shear values for the profiled steel panel side walls and end walls shall be determined in accordance with the design approach selected in Section 3114.8.4.2. Where penetrations are made in the side walls or end walls designated as part of the lateral force-resisting system, the penetrations shall be substantiated by rational analysis.

    3114.8.5 Simplified structural design procedure of single-unit containers. Single-unit intermodal shipping containers conforming to the limitations of Section 3114.8.5.1 shall be permitted to be designed in accordance with Sections 3114.8.5.2 and 3114.8.5.3. [DSA-SS & DSA-SS/CC] Not permitted by DSA.

    3114.8.5.1 Limitations. The use of Section 3114.8.5 is subject to the following limitations:

    1. The intermodal shipping container shall be a single-unit, stand-alone unit supported on a foundation and shall not be in contact with or supporting any other shipping container or other structure.

    2. The intermodal shipping container top and bottom rails, corner castings, and columns or any portion thereof shall not be notched, cut, or removed in any manner.

    3. The intermodal shipping container shall be erected in a level and horizontal position with the floor located at the bottom.

    4. The intermodal shipping container shall be located in Seismic Design Category A, B, C or D.

    3114.8.5.2 Structural design assumptions. Where permitted by Section 3114.8.5.1, single-unit, stand-alone intermodal shipping containers shall be designed using the following assumptions for the profile steel panel lateral-force resisting system:

    1. The appropriate detailing requirements contained in Chapters 16 through 23.
    2. Response modification coefficient, R = 2.
    3. Overstrength factor, Ω 0 = 2.5.
    4. Deflection amplification factor, C d = 2.
    5. Limits on structural height, h n = 9.5 feet (2900 mm).

    **3114.8.5.3 Allowable shear.

  • CBC § 2201.5 High relevance — show source text

    2201.5 Anchor rods. Anchor rods shall be set in accordance with the approved construction documents. The protrusion of the threaded ends through the connected material shall fully engage the threads of the nuts, but shall not be greater than the length of the threaded portion of the bolts.

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    2201.5.1 Shear transfer at column base plate. [OSHPD 1R, 2 & 5] Where the holes in column base plates are more than [1] / 8 inch (3 mm) larger than the anchor rods, as permitted by AISC 360, the anchor rods shall be designed for the induced bending stresses in combination with axial and shear stresses. Alternatively, shear lugs designed in accordance with ACI 318 Section 17.11 shall be permitted to transfer shear forces between column base plates and the supporting structure.

    SECTION 2202—STRUCTURAL STEEL AND COMPOSITE STRUCTURAL STEEL AND CONCRETE

    2202.1 General. The design, fabrication and erection of structural steel elements and composite structural steel and concrete elements in buildings, structures and portions thereof shall be in accordance with AISC 360.

    Exceptions : [OSHPD 1R, 2 & 5] 1. For members designed based on tension, the slenderness ratio (L/r) shall not exceed 300, except for the design of hangers and bracing in accordance with NFPA 13 and for rod hangers in tension. 2. For members designed based on compression, the slenderness ratio (KL/r) shall not exceed 200, except for the design of hangers and bracing in accordance with NFPA 13.

    2202.2 Seismic design. Where required, the seismic design, fabrication and erection of buildings, structures and portions thereof shall be in accordance with Section 2202.2.1 or 2202.2.2, as applicable.

    2202.2.1 Structural steel seismic force-resisting systems and composite structural steel and concrete seismic force-resist- ing systems. The design, detailing, fabrication and erection of structural steel seismic force-resisting systems and composite structural steel and concrete seismic force-resisting systems shall be in accordance with the provisions of Section 2202.2.1.1 or 2202.2.1.2, as applicable.

    [ OSHPD 1R, 2 & 5 ] Seismic requirements for composite structural steel and concrete construction shall be considered as an alter- native system, except as permitted by Section 2202.4.1.

    2202.2.1.1 Seismic Design Category B or C. Structures assigned to Seismic Design Category B or C shall be of any construction permitted in Section 2202. Where a response modification coefficient, R, in accordance with ASCE 7, Table 12.2-1, is used for the design of structures assigned to Seismic Design Category B or C, the structures shall be designed and detailed in accordance with the requirements of AISC 341. Beam-to-column moment connections in structural steel special moment frames and intermediate moment frames shall be prequalified in accordance with AISC 341, Section K1, qualified by testing in accordance with AISC 341, Section K2, or shall be prequalified in accordance with AISC 358.

  • CBC § 2.1.2 High relevance — show source text

    2202 A .2.1.2 Seismic Design Category D, E or F. Structures assigned to Seismic Design Category D, E or F shall be designed and detailed in accordance with AISC 341. Beam-to-column moment connections in structural steel special moment frames and intermediate moment frames shall be prequalified in accordance with AISC 341, Section K1, qualified by testing in accordance with AISC 341, Section K2, or shall be prequalified in accordance with AISC 358.

    2202 A .2.2 Structural steel elements. The design, detailing, fabrication and erection of structural steel elements in seismic forceresisting systems, including struts, collectors, chords and foundation elements, shall be in accordance with AISC 341.

    2202A.3 Modifications to AISC 341. [OSHPD 1 and 4]

    2202A.3.1 Section A4. Modify Section A4.1 Item (c) by adding the following:

    (c) Locations and dimensions of protected zones. The fabricator shall permanently mark protected zones of structural elements in the seismic force-resisting system in the building that are designated on the construction documents. If these markings are obscured during construction, such as after the application of fire protection, the owner’s designated representative shall re-mark the protected zones as they are designated on the construction documents. [OSHPD 1 & 4] Primers or paints used to mark protected zones on steel surfaces, which are to receive sprayed fire-resistance material, shall comply with California Building Code Section 704.13.3.2.

    2202A.3.2 Section I2. [OSHPD 1 & 4] Replace Section I2.1 Item (d) as follows:

    (d) Decking attachments that penetrate the beam flange shall not be placed on beam flanges within the protected zone, except power-actuated fasteners up to 0.18 inch in diameter are permitted, provided that the penetration is less than 85 percent of beam flange thickness.

    2202A.4 Modifications to AISC 358. [OSHPD 1 and 4]

    2202A.4.1 Modifications to AISC 358 Chapter 10. [OSHPD 1 and 4] Steel and concrete ConXtech ConXL composite special moment frame connections shall be permitted, provided: 1. Beams are provided with reduced beam sections (RBS); 2. Web extension to beam web two-sided fillet welds are sized to develop expected strength of the beam web and shall not be less than a [1] / 4 inch fillet weld; and 3. The built-up box column wall thickness shall not be less than 1.25 inches and the HSS column wall thickness shall not be less than [1] / 2 inch.

    2202A.4.2 Modifications to AISC 358 Chapter 11 Welded Moment Connection. The welded side plate steel moment connection shall be permitted, provided: 1. The beams shall consist of either rolled or built-up wide flange sections. 2. The biaxial dual-strong axis and column minor axis configurations of the moment connection shall be considered as an alternative system. 3. For SMF and IMF systems, U-shaped cover plates shall be used and the hinge-to-hinge span to beam depth, L h _/d,

  • CBC § 3114.8.1.1 High relevance — show source text

    3114.8.1.1 Anchorage. Intermodal shipping containers shall be anchored to foundations or other supporting structures as necessary to provide a continuous load path for all applicable design and environmental loads in accordance with Chapter 16.

    3114.8.1.2 Stacking. Intermodal shipping containers used to support stacked units shall comply with Section 3114.8.4.

    3114.8.2 Welds. The strength of new welds and connections shall be of not less than the strength provided by the original connections. All new welds and connections shall be designed and constructed in accordance with Chapters 16, 17 and 22.

    3114.8.3 Structural design. The structural design for the intermodal shipping containers repurposed for use as a building or structure, or as part of a building or structure, shall comply with Section 3114.8.4 or 3114.8.5.

    3114.8.4 Detailed design procedure. A structural analysis meeting the requirements of this section shall be provided to the building official to demonstrate the structural adequacy of the intermodal shipping containers.

    Exception: Structures using an intermodal shipping container designed in accordance with Section 3114 8.5.

    3114.8.4.1 Material properties. Structural material properties for existing intermodal shipping container steel components shall be established by Section 2202.

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    3114.8.4.2 Seismic design parameters. The seismic force-resisting system shall be designed and detailed in accordance with ASCE 7 and one of the following:

    1. Where all or portions of the profiled steel panel elements are considered to be the seismic force-resisting system, design and detailing shall be in accordance with the AISI S100 and ASCE 7, Table 12.2-1 requirements for steel systems not specifically detailed for seismic resistance, excluding cantilever column systems. [DSA-SS & DSA-SS/CC] Not permitted by DSA.

    2. Where all or portions of the profiled steel panel elements are not considered to be part of the seismic force-resisting system, an independent seismic force-resisting system shall be selected and detailed in accordance with ASCE 7, Table 12.2-1.

    3. Where all or portions of the profiled steel panel elements are retained and integrated into a seismic force-resisting system other than as permitted by Item 1, seismic design parameters shall be developed from testing and analysis in accordance with Section 104.2.3 and ASCE 7, Section 12.2.1.1 or 12.2.1.2.

    3114.8.4.3 Allowable shear value. The allowable shear values for the profiled steel panel side walls and end walls shall be determined in accordance with the design approach selected in Section 3114.8.4.2. Where penetrations are made in the side walls or end walls designated as part of the lateral force-resisting system, the penetrations shall be substantiated by rational analysis.

  • CBC § 2201A.5.1 High relevance — show source text

    2201 A .5 Anchor rods. Anchor rods shall be set in accordance with the approved construction documents. The protrusion of the threaded ends through the connected material shall fully engage the threads of the nuts, but shall not be greater than the length of the threaded portion of the bolts. 2201A.5.1 Shear transfer at column base plate. Where the holes in column base plates are more than [1] / 8 inch (3 mm) larger than the anchor rods, as permitted by AISC 360, the anchor rods shall be designed for the induced bending stresses in combination with axial and shear stresses. Alternatively, shear lugs designed in accordance with ACI 318 Section 17.11 shall be permitted to transfer shear forces between column base plates and the supporting structure.

    SECTION 2202 A —STRUCTURAL STEEL AND COMPOSITE STRUCTURAL STEEL AND CONCRETE

    2202 A .1 General. The design, fabrication and erection of structural steel elements and composite structural steel and concrete elements in buildings, structures and portions thereof shall be in accordance with AISC 360.

    Exceptions : [OSHPD 1 & 4]

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    1. For members designed based on tension, the slenderness ratio (L/r) shall not exceed 300, except for the design of hangers and bracing in accordance with NFPA 13 and for rod hangers in tension. 2. For members designed based on compression, the slenderness ratio (KL/r) shall not exceed 200, except for the design of hangers and bracing in accordance with NFPA 13.

    2202 A .2 Seismic design. Where required, the seismic design, fabrication and erection of buildings, structures and portions thereof shall be in accordance with Section 2202 A .2.1 or 2202 A .2.2, as applicable.

    2202 A .2.1 Structural steel seismic force-resisting systems and composite structural steel and concrete seismic force- resisting systems. The design, detailing, fabrication and erection of structural steel seismic force-resisting systems and composite structural steel and concrete seismic force-resisting systems shall be in accordance with the provisions of Section 2202 A .2.1.1 or 2202 A .2.1.2, as applicable. Seismic force-resisting systems of structural steel acting compositely with reinforced concrete shall be considered as an alternative system, except as permitted by:

    [DSA-SS] Section 2202A.6.1.

    [OSHPD 1 & 4] Section 2202A.4.1.

    2202 A .2.1.1 Seismic Design Category B or C. Not permitted by DSA-SS and OSHPD.

  • CBC § 501A.3 High relevance — show source text

    501 A .2 Fire-resistance ratings. Fire-resistance ratings shall comply with the California Building Standards Code.

    501A.3 Prescriptive compliance provisions. Alterations, additions and changes of occupancy to the following categories of existing buildings and structures shall comply with the provisions of this section.

    501A.3.1 Prescriptive compliance provisions for SPC-4D using the California Building Code, 1980 (CBC 1980). Nonconforming buildings shall satisfy the following requirements: 1. The California Building Code, 1980 (CBC 1980), as used in this chapter, consists of the Uniform Building Code, 1979 (UBC 1979) along with requirements contained in: a) California Code of Regulations, Title 24- Building Standards, dated February 2, 1980 (Revision record for Register 80, No. 5). b) California Code of Regulations, Title 22 – Social Security, dated October 13, 1979 (Revision Record for Register 79, No 41). c) California Code of Regulations, Title 17 – Public Health, dated October 13, 1979 (Revision Record for Register 79, No 41-B). 2. All existing structural elements of Seismic Force Resisting System (SFRS) shall satisfy the detailing requirements in the CBC 1980 or demonstrate that the level of seismic performance is equivalent to that given in the CBC 1980, as determined by the building official. 3. A continuous load path or paths with adequate strength and stiffness to transfer all the forces from the point of origin to final point of resistance shall be justified by analysis. 4. Site data report in accordance with the CBC 1980 shall establish that seismically induced differential settlement does not exceed 1 ″ in 40 ′ .

    5. Adjacent buildings shall satisfy the SPC building separation requirements in accordance with the California Administrative Code, Chapter 6 Section 3.4. 6. The addition of new structural elements or strengthening of existing structural elements for retrofit of nonconforming build- ings to SPC-4D shall comply with the following: a) The seismic demand (forces or displacements) shall be in accordance with the CBC 1980; b) Capacity, detailing and connections for new structural elements shall satisfy the requirements in the CBC 2025 for new construction; and c) The strengthening of existing structural elements shall use capacities determined in accordance with the CBC 2025 for new construction consistent with the detailing and connections used in the strengthened member. 7. All construction, quality assurance and quality control shall be in accordance with the new construction provisions of CBC 2025.

    8. Elements not part of the Seismic Force-Resisting System (SFRS), including those identified in the California Administrative Code Chapter 6, Article 10, shall be evaluated using seismic forces and the requirements of the CBC 1980. 9. Any column or wall that forms part of two or more intersecting SFRS and is subjected to axial load due to seismic forces acting along either principal plan axis equaling or exceeding 20 percent of the axial design strength of the column or wall shall be _evaluated for the most critical load effect due to application of seismic force in any direction.

  • CBC § 2210.1.1.1 High relevance — show source text

    2210.1.1.1 Structural steel. The design, fabrication and erection of structural steel shall be in accordance with Section 2202.

    2210.1.1.2 Cold-formed steel. The design of cold-formed carbon and low-alloy steel structural members shall be in accordance with Section 2204.

    2210.1.1.3 Steel joists. The design of steel joists shall be in accordance with Section 2207.

    2210.1.1.4 Steel cable. The design, fabrication and erection of steel cables, including related connections, shall be in accordance with Section 2214.

    2210.2 Seismic design. Where required, the seismic design, fabrication and erection of the structural steel seismic force-resisting system shall be in accordance with Section 2202.2.1 or 2202.2.2, as applicable.

    SECTION 2211—INDUSTRIAL BOLTLESS STEEL SHELVING

    2211.1 General. The design, testing and utilization of industrial boltless steel shelving shall be in accordance with MHI ANSI/MH 28.2. Where required by ASCE 7, the seismic design of industrial boltless steel shelving shall be in accordance with Chapter 15 of ASCE 7.

    SECTION 2212—INDUSTRIAL STEEL WORK PLATFORMS

    2212.1 General. The design, testing and utilization of industrial steel work platforms shall be in accordance with MHI ANSI/MH 28.3. Where required by ASCE 7, the seismic design of industrial steel work platforms shall be in accordance with Chapter 15 of ASCE 7.

    SECTION 2213—STAIRS, LADDERS AND GUARDING FOR STEEL STORAGE RACKS AND INDUSTRIAL STEEL WORK PLATFORMS

    2213.1 General. The design and installation of stairs, ladders and guarding serving steel storage racks and industrial steel work platforms shall be in accordance with MHI ANSI/MH 32.1.

    SECTION 2214—STEEL CABLE STRUCTURES

    2214.1 General. The design, fabrication and erection including related connections, and protective coatings of steel cables for buildings shall be in accordance with ASCE 19.

    [OSHPD 1R, 2 & 5] Steel cables with glass or polymer fabric material acting as a tensile membrane structure shall be considered as an alternative system.

    SECTION 2215 — ADDITIONAL REQUIREMENTS FOR COMMUNITY COLLEGES [DSA-SS/CC]

    2215.1 General.

    2215.1.1 Shear transfer at column base plate. Where the holes in column base plates are more than [1] / 8 inch (3 mm) larger than the anchor rods, as permitted by AISC 360, the anchor rods shall be designed for the induced bending stresses in combination with axial and shear stresses. Alternatively, shear lugs designed in accordance with ACI 318 Section 17.11 shall be permitted to transfer shear forces between column base plates and the supporting structure.

    2215.2 Modifications to AISC 341.

    2215.2.1 Section B5. Modify exception of Section B5.2(a) as follows:

  • CBC § 1613.2.4 High relevance — show source text

    The structure consists of light-frame construction; the design spectral response acceleration at short periods, S DS, as determined in Section 1613.2.4, does not exceed 0.5; and the building height of the structure does not exceed 35 feet (10 668 mm). 2. The seismic force-resisting system of the structure consists of reinforced masonry or reinforced concrete; the design spectral response acceleration at short periods, S DS, as determined in Section 1613.2.4, does not exceed 0.5; and the building height of the structure does not exceed 25 feet (7620 mm). 3. The structure is a detached one- or two-family dwelling not exceeding two stories above grade plane and does not have any of the following horizontal or vertical irregularities in accordance with Section 12.3 of ASCE 7: 3.1. Torsional or extreme torsional irregularity. 3.2. Nonparallel systems irregularity. 3.3. Stiffness-soft story or stiffness-extreme soft story irregularity. 3.4. Discontinuity in lateral strength-weak story irregularity.

    1705.13.1 Structural steel. Special inspections for seismic resistance shall be in accordance with Section 1705.13.1.1 or 1705.13.1.2, as applicable.

    1705.13.1.1 Seismic force-resisting systems. Special inspections of structural steel in the seismic force-resisting systems in buildings and structures assigned to Seismic Design Category B, C, D, E or F shall be performed in accordance with the quality assurance requirements of AISC 341. [OSHPD 1R, 2 & 5] and this code.

    Exceptions: [OSHPD 1R, 2 & 5] Not permitted by OSHPD.

    1. In buildings and structures assigned to Seismic Design Category B or C, special inspections are not required for structural steel seismic force-resisting systems where the response modification coefficient, R, designated for “Steel systems not specifically detailed for seismic resistance, excluding cantilever column systems” in ASCE 7, Table 12.2-1, has been used for design and detailing.

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    1. In structures assigned to Seismic Design Category D, E, or F, special inspections are not required for structural steel seismic force-resisting systems where design and detailing in accordance with AISC 360 is permitted by ASCE 7, Table 15.4-1.

    1705.13.1.2 Structural steel elements. Special inspections of structural steel elements in the seismic force-resisting systems of buildings and structures assigned to Seismic Design Category B, C, D, E or F other than those covered in Section 1705.13.1.1, including struts, collectors, chords and foundation elements, shall be performed in accordance with the quality assurance requirements of AISC 341. [OSHPD 1R, 2 & 5] and this code.

  • CBC § 12.2 High relevance — show source text

    Exceptions: [OSHPD 1R, 2 & 5] Not permitted by OSHPD.

    1. In buildings and structures assigned to Seismic Design Category B or C, special inspections are not required for structural steel seismic force-resisting systems where the response modification coefficient, R, designated for “Steel systems not specifically detailed for seismic resistance, excluding cantilever column systems” in ASCE 7, Table 12.2-1, has been used for design and detailing.

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    1. In structures assigned to Seismic Design Category D, E, or F, special inspections are not required for structural steel seismic force-resisting systems where design and detailing in accordance with AISC 360 is permitted by ASCE 7, Table 15.4-1.

    1705.13.1.2 Structural steel elements. Special inspections of structural steel elements in the seismic force-resisting systems of buildings and structures assigned to Seismic Design Category B, C, D, E or F other than those covered in Section 1705.13.1.1, including struts, collectors, chords and foundation elements, shall be performed in accordance with the quality assurance requirements of AISC 341. [OSHPD 1R, 2 & 5] and this code.

    Exceptions: [OSHPD 1R, 2 & 5] Not permitted by OSHPD.

    1. In buildings and structures assigned to Seismic Design Category B or C, special inspections of structural steel elements are not required for seismic force-resisting systems with a response modification coefficient, R, of 3 or less.
    2. In structures assigned to Seismic Design Category D, E, or F, special inspections of structural steel elements are not required for seismic force-resisting systems where design and detailing other than AISC 341 is permitted by ASCE 7, Table 15.4-1. Special inspection shall be in accordance with the applicable referenced standard listed in ASCE 7, Table 15.4-1.

    1705.13.2 Structural wood. For the seismic force-resisting systems of structures assigned to Seismic Design Category C, D, E or F:

    1. Continuous special inspection shall be required during field gluing operations of elements of the seismic force-resisting system.
    2. Periodic special inspection shall be required for nailing, bolting, anchoring and other fastening of elements of the seismic force-resisting system, including wood shear walls, wood diaphragms, drag struts, braces, shear panels and hold-downs.

    Exception: Special inspections are not required for wood shear walls, shear panels and diaphragms, including nailing, bolting, anchoring and other fastening to other elements of the seismic force-resisting system, where the lateral resistance is provided by structural sheathing, and the specified fastener spacing at the panel edges is more than 4 inches (102 mm) on center.

    1705.13.3 Cold-formed steel light-frame construction. For the seismic force-resisting systems of structures assigned to Seismic Design Category C, D, E or F, periodic special inspection shall be required for both:

    1. Welding operations of elements of the seismic force-resisting system.
    2. Screw attachment, bolting, anchoring and other fastening of elements of the seismic force-resisting system, including shear walls, braces, diaphragms, collectors (drag struts) and hold-downs.
  • CBC § 1705.14 High relevance — show source text

    1705.14 Testing for seismic resistance. Testing for seismic resistance shall be required as specified in Sections 1705.14.1 through 1705.14.4, unless exempted from special inspections by the exceptions of Section 1704.2.

    1705.14.1 Structural steel. Nondestructive testing for seismic resistance shall be in accordance with Section 1705.14.1.1 or 1705.14.1.2, as applicable.

    1705.14.1.1 Seismic force-resisting systems. Nondestructive testing of structural steel in the seismic force-resisting systems in buildings and structures assigned to Seismic Design Category B, C, D, E or F shall be performed in accordance with the quality assurance requirements of AISC 341. [OSHPD 1R, 2 & 5] and this code.

    Exceptions: [OSHPD 1R, 2 & 5] Not permitted by OSHPD.

    1. In buildings and structures assigned to Seismic Design Category B or C, nondestructive testing is not required for structural steel seismic force-resisting systems where the response modification coefficient, R, designated for “Steel systems not specifically detailed for seismic resistance, excluding cantilever column systems” in ASCE 7, Table 12.2-1, has been used for design and detailing.
    2. In structures assigned to Seismic Design Category D, E, or F, nondestructive testing is not required for structural steel seismic force-resisting systems where design and detailing in accordance with AISC 360 is permitted by ASCE 7, Table 15.4-1.

    1705.14.1.2 Structural steel elements. Nondestructive testing of structural steel elements in the seismic force-resisting systems of buildings and structures assigned to Seismic Design Category B, C, D, E or F other than those covered in Section 1705.14.1.1, including struts, collectors, chords and foundation elements, shall be performed in accordance with the quality assurance requirements of AISC 341. [OSHPD 1R, 2 & 5] and this code.

    Exceptions: [OSHPD 1R, 2 & 5] Not permitted by OSHPD.

    1. In buildings and structures assigned to Seismic Design Category B or C, nondestructive testing of structural steel elements is not required for seismic force-resisting systems with a response modification coefficient, R, of 3 or less.
    2. In structures assigned to Seismic Design Category D, E or F, nondestructive testing of structural steel elements is not required for seismic force-resisting systems where design and detailing other than AISC 341 is permitted by ASCE 7, Table 15.4-1. Nondestructive testing of structural steel elements shall be in accordance with the applicable referenced standard listed in ASCE 7, Table 15.4-1.

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Frequently asked questions

Must I always use AISC 341 for steel seismic systems in California?

Not always — the CBC requires AISC 341 for structures in Seismic Design Categories D, E or F (see § 2202.2.1.2) and for many SDC B/C cases where ASCE 7 R values are used; an exception in § 2202.2.1.1 permits AISC 360 when ASCE 7’s specific R row for “steel systems not specifically detailed for seismic resistance” is used .

Are beam‑to‑column moment connections subject to special qualification?

Yes. Beam‑to‑column moment connections in special and intermediate moment frames must be prequalified per AISC 341 Section K1, qualified by testing per AISC 341 Section K2, or prequalified per AISC 358 as required in §§ 2202.2.1.1 and 2202.2.1.2 .

Do I need special inspection and NDT if AISC 341 governs my design?

Yes. Where the CBC requires AISC 341 for the seismic force‑resisting system, Chapter 17 requires special inspection and nondestructive testing in accordance with the AISC 341 quality assurance provisions (see §§ 1705.13.1 and 1705.14.1.1) .

Where do I find the numeric R, Ω0 or Cd values referenced by the CBC?

The CBC points you to ASCE 7 for numerical seismic parameters (e.g., response modification coefficient R). The CBC text does not list those numeric values in §§ 2202.2.1.x; consult ASCE 7 (and the AISC standards for detailing rules) to obtain the actual coefficients and amplification factors .

What should I put on the drawings to satisfy the CBC?

Explicitly identify the governing standard (AISC 341 or AISC 360 as permitted), state the moment‑connection prequalification path, and include the special inspection and NDT requirements consistent with Chapter 17 and AISC 341 quality assurance language as directed by § 2202.2.1.x and the Chapter 17 references .

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