CEBC · California Existing Building Code

Seismic retrofit and evaluation (Appendix A and seismic provisions/sections for evaluation and retrofit)

This hub summarizes CEBC seismic evaluation and retrofit requirements (Appendix A and Sections 317, 319–321), including applicability, Method A/B choices, performance levels, and peer‑review expectations.

Last reviewed: July 6, 2026

Overview

This area of the California Existing Building Code (CEBC) governs earthquake evaluation and retrofit of existing buildings — who must be evaluated, the minimum seismic performance objectives, and when structural retrofit is required. The scope and applicability are set out in Section 317 (§317), which establishes when an evaluation is required and when retrofit must follow; Appendix A supplies prescriptive guidelines for common building types (for example, unreinforced masonry and light-frame wood) to support retrofit design.

The CEBC offers two principal design approaches: Method A (prescriptive/ASCE 41 linear procedures) in Section 320 (§320) and Method B (performance-based evaluation) in Section 321 (§321), with peer review and acceptance requirements where Method B is used. The code also ties required performance levels to Table 317.5 and to ASCE 41 procedures and tiers, so retrofit design is framed by prescribed hazard levels and structural/nonstructural performance objectives.

Key decision points appear in Section 319 (§319) (selection of seismic criteria and when particular procedures are mandatory), the specific allowances for state‑owned buildings in Section 319.1.1 (use of Appendix A procedures without peer review for certain types), and the voluntary modification/repair rules in Section 317.11 (§317.11). These sections together direct data collection, method selection, analysis level, and required documentation for retrofit projects.

In this section

Code references

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

  • CEBC § 317.2 High relevance — show source text

    317.2 Scope. All alterations, structurally connected additions and/or repairs to existing structures or portions thereof shall, at a minimum, be designed and constructed to resist the effects of seismic ground motions as provided in this section. The structural system shall be evaluated by a registered design professional and, if not meeting or exceeding the minimum seismic design performance requirements of this section, shall be retrofitted in compliance with these requirements.

    Exception: Those structures for which Section 317.3 determines that assessment is not required, or for which Section 317.4 determines that retrofit is not needed, then only the requirements of Section 317.11 apply.

    317.3 Applicability.

    317.3.1 Existing state-owned buildings. [BSC, DSA-SS] For existing state-owned structures including all buildings owned by the University of California and the California State University, the requirements of Section 317 apply whenever the structure is to be retrofitted, repaired or modified and any of the following apply: 1. Total construction cost, not including cost of furnishings, fixtures and equipment, or normal maintenance, for the building exceeds 25 percent of the construction cost for the replacement of the existing building. The changes are cumulative for past modifications to the building that occurred after adoption of the 1995 California Building Code and did not require seismic retrofit.

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    PROVISIONS FOR ALL COMPLIANCE METHODS

    2. There are changes in risk category. 3. The modification to the structural components increases the seismic forces in or strength requirements of any structural component of the existing structure by more than 10 percent cumulative since the original construction, unless the component has the capacity to resist the increased forces determined in accordance with Section 319. If the building’s seismic base shear capacity has been increased since the original construction, the percent change in base shear may be calculated relative to the increased value.

    4. Structural elements need repair where the damage has reduced the lateral-load-resisting capacity of the structural system by more than 10 percent. 5. Changes in live or dead load increase story shear by more than 10 percent.

    317.3.2 Public school buildings. [DSA-SS] For public schools, the provisions of Section 317 apply when required in accordance with Sections 4-307 and 4-309(c) of the California Administrative Code.

    317.3.3 Community college buildings. [DSA-SS/CC] For community colleges, the provisions of Section 317 apply when required in accordance with Sections 4-307 and 4-309(c) of the California Administrative Code.

    317.4 Evaluation required. If the criteria in Section 317.3 apply to the project under consideration, the design professional of record shall provide an evaluation in accordance with Section 317 to determine the seismic performance of the building in its current configuration and condition. If the structure's seismic performance as required by Section 317.5 is evaluated as satisfactory and the peer reviewer(s), when Method B of Section 321 is used, concur, then no structural retrofit is required.

    _**317.5 Minimum seismic design performance levels for structural and nonstructural components.

  • CEBC § 319.8. High relevance — show source text

    unless it can be demonstrated that_ reduced capacity meets the requirements of Section 319.8. 2. The lateral loading to or strength requirement of existing structural components is not increased beyond their capacity. 3. New structural components are detailed and connected to the existing structural components as required by the California Building Code. 4. New or relocated nonstructural components are detailed and connected to existing or new structural components as required by the California Building Code. 5. A dangerous condition is not created.

    Use of ASCE 41 Tier 1 and Tier 2 deficiency only retrofit procedures are pre-approved for use where Section 317.3 does not require an

    assessment.

    319.12.1 State-owned buildings. [BSC] Voluntary modifications to lateral force-resisting systems conducted in accordance with Appendix A of this code and the referenced standards of the California Building Code shall be permitted.

    319.12.1.1 Design documents. [BSC] When Section 319.12 is the basis for structural modifications, the approved design documents must clearly state the scope of the seismic modifications and the accepted criteria for the design. The approved design documents must clearly have the phrase “The seismic requirements of the California Existing Building Code have not been checked to determine if these structural modifications meet the full seismic evaluation and strengthening requirements of Sections 317-322: the modifications proposed are to a different seismic performance standard than would be required in Section 319 if they were not voluntary as allowed in Section 319.12.”

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    319.12.2 Public schools and community colleges. [DSA-SS, DSA-SS/CC] When Section 319.12 is the basis for structural modifications, the approved design documents must clearly indicate the scope of modifications and the acceptance criteria for the design.

    SECTION 320 [BSC, DSA-SS & DSA-SS/CC]—METHOD A

    320.1 General. The retrofit design shall employ the Linear Static or Linear Dynamic Procedures of ASCE 41, Section 7.4.1 or 7.4.2, and comply with the applicable general requirements of ASCE 41, Chapters 6 and 7. The earthquake hazard level and performance level given specified in Section 317.5 for the building’s risk category shall be used. Structures shall be designed for seismic forces coming from any horizontal direction.

    SECTION 321 [BSC, DSA-SS & DSA-SS/CC]—METHOD B

    321.1 The existing or retrofitted structure shall be demonstrated to have the capability to sustain the deformation response due to the specified earthquake ground motions and meet the seismic performance requirements of Section 317. The registered design professional shall provide an evaluation of the response of the existing structure in its modified configuration and condition to the ground motions specified. If the building’s seismic performance is evaluated as satisfactory and the peer reviewer(s) and the enforcement agency concurs, then no further structural retrofit and/or repair of the lateral load-resisting system is required.

  • CEBC § 319.1 High relevance — show source text

    Buildings complying with the requirements of the exception in Section 319.1 are deemed to meet the seismic performance requirements of this section._
    4. State-owned and state-leased essential services buildings are subject to the regulatory authority of DSA-SS per Section 1.9.2.1.|

    317.6 Retrofit required. Where the evaluation indicates the building does not meet the required performance objectives of this section, the owner shall take appropriate steps to ensure that the building’s structural system is retrofitted in accordance with the provisions of Section 317. Appropriate steps are either: 1) undertake the seismic retrofit as part of the additions, alterations and/or repairs of the structure; or 2) provide a plan, acceptable to the building official, to complete the seismic retrofit in a timely manner. The relocation or moving of an existing building is considered to be an alteration requiring filing of the plans and specifications approved by the building official.

    317.7 The additions, alteration or repair to any existing building are permitted to be prepared in accordance with the structural and nonstructural requirements for a new building as given in the California Building Code, applied to the entire building.

    317.8 The requirements of ASCE 41 Chapters 14 and 15 are to apply to the use of seismic isolation and passive energy systems, respectively, for the repair, voluntary lateral-force-resisting system modification or retrofit of an existing structure. When seismic isolation or passive energy dissipation is used, the project must have project peer review as prescribed in Section 322.

    317.9 Any construction required by this chapter shall include structural observation by the registered design professional who is responsible for the structural design in accordance with Section 319.10.

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    317.10 Where Method B of Section 321 is used or is required by Section 319.7, the proposed method of building evaluation and design procedures must be accepted by the building official prior to the commencement of the work.

    317.11 Voluntary lateral-force-resisting system modifications. Where the exception of Section 317.2 applies, modifications of existing structural components and additions of new structural components that are initiated for the purpose of improving the seismic performance of an existing structure and that are not required by other portions of this chapter are permitted under the requirements of Section 319.12.

    SECTION 318 [BSC, DSA-SS & DSA-SS/CC]—DEFINITIONS

    318.1 In addition to the definitions given in Section 202, for the purposes of Sections 317 through 323, certain terms are defined as follows:

    [DSA-SS & DSA-SS/CC] For the purposes of Section 317 through 323, definitions of terms given in Section 4-207 or 4-314 of the California Administrative Code govern over those in Section 202.

    ADDITION [BSC] means any work that increases the floor or roof area or the volume of enclosed space of an existing building, and is structurally attached to the existing building by connections that are required for transmitting vertical or horizontal loads between the addition and the existing structure.

  • CEBC § 1.10.1 High relevance — show source text
    CHAPTER TOPICS Col2
    CHAPTER SUBJECTS
    1, 2 Administrative Requirements and Definitions
    3 Provisions for all Compliance Methods
    4 Repairs
    5 Prescriptive Compliance Method for Existing Buildings
    6–11 Work Area Compliance Method for Existing Buildings
    13 Performance Compliance Method for Existing Buildings
    14 Relocated Buildings
    15 Construction Safeguards
    16 Referenced Standards
    Appendix A Guidelines for Seismic Retrofit of Existing Buildings
    Appendix B Supplementary Accessibility Requirements for Existing Buildings
    Appendix C Guidelines for Wind Retrofit of Existing Buildings
    Appendix D Board of Appeals
    Appendix E Temporary Emergency Uses
    Resource A Guidelines on Fire Ratings of Archaic Materials and Assemblies

    CALIFORNIA BUILDING CODE CORRELATED TOPICS

    The CEBC requirements for construction safeguards are directly correlated to the requirements of the CBC. The following table shows chapters of the CBC that are correlated with the CEBC:

    CEBC/CBC CORRELATED TOPICS Col2 Col3
    CEBC CHAPTER/SECTION CBC CHAPTER/SECTION SUBJECT
    Chapter 15 Chapter 33 Construction safeguards

    Chapter 1 Scope and Administration.

    Chapter 1 establishes the limits of applicability of the code and describes how the code is to be applied and enforced. The provisions of Chapter 1 establish the authority and duties of the code official appointed by the authority having jurisdiction and also establish the rights and privileges of the design professional, contractor and property owner.

    Chapter 2 Definitions.

    Chapter 2 is the repository of the definitions of terms used in the body of the code. The user of the code should be familiar with and consult this chapter because the definitions are essential to the correct interpretation of the code and because the user may not be aware that a term is defined.

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    Chapter 3 Provisions for All Compliance Methods.

    Chapter 3 guides the use of the three compliance methods of the CEBC and provides requirements that apply globally. The globally applicable requirement include general requirements related to buildings materials and other applicable codes, storm shelters, structural loads, in-situ load tests, accessibility, smoke alarms, carbon monoxide detection and exterior wall coverings.

    Chapter 3A Provisions for All Compliance Methods.

    Chapter 3A controls the compliance options for alteration, repair, addition, evaluation and change of occupancy of existing structures regulated by the Department of Health Care Access and Information/Office of Statewide Hospital Planning and Development, which include hospitals and correctional treatment centers (applications listed in Sections 1.10.1 (OSHPD 1).

    Chapter 4 Repairs.

    Chapter 4, a chapter independent of the three compliance methods, governs the repair of existing buildings. The provisions define conditions under which repairs may be made using materials and methods like those of the original construction or the extent to which repairs must comply with requirements for new buildings.

    Chapter 4A Repairs.

    Chapter 4A governs the repair of existing buildings regulated by the Department of Health Care Access and Information/Office of State- wide Hospital Planning and Development, which include hospitals and correctional treatment centers (applications listed in Sections 1.10.1 (OSHPD 1).

  • CEBC § 102.4 High relevance — show source text

    Chapter 14 is applicable to any building that is moved or relocated. This chapter is independent of any of the three compliance methods and focuses on the structural loads where the building is being relocated.

    Chapter 15 Construction Safeguards.

    Chapter 15 establishes specific regulations in order to minimize the risk to the public and adjacent property during construction. Additionally, this chapter addresses fire and life safety and means of egress during the construction process. This includes requirements for a site safety plan. This chapter is also consistent with Chapter 33 of the CBC and Chapter 33 of the California Fire Code (CFC).

    Chapter 16 Referenced Standards.

    Chapter 16 lists all of the product and installation standards and codes that are referenced throughout Chapters 1 through 15 and includes identification of the promulgators and the section numbers in which the standards and codes are referenced. As stated in Section 102.4, these standards and codes become an enforceable part of the code (to the prescribed extent of the reference) as if printed in the body of the code.

    Appendix A Guidelines for the Seismic Retrofit of Existing Buildings.

    Appendix A provides guidelines for upgrading the seismic resistance capacity of different types of existing buildings. It is organized into separate chapters which deal with buildings of different types, including unreinforced masonry buildings, reinforced concrete and reinforced masonry wall buildings, and lightframe wood buildings. This appendix includes its own referenced standards.

    Appendix B Supplementary Accessibility Requirements for Existing Buildings and Facilities.

    Chapters 11A and 11B of the CBC contain provisions that set forth requirements for accessibility to buildings and their associated sites and facilities for people with physical disabilities. Appendix B was added to address accessibility in construction for items that are not typically enforceable through the traditional building code enforcement process.

    Appendix C Guidelines for the Wind Retrofit of Existing Buildings.

    The purpose of Appendix C is to provide voluntary prescriptive alternatives for addressing the retrofit of buildings in high-wind areas. Currently, there are two chapters which deal with the retrofit of gable ends and the fastening of roof decks, Appendix Chapters C1 and C2, respectively. This appendix includes its own referenced standards.

    Appendix D Board of Appeals.

    Appendix D contains the provisions for appeal and the establishment of a board of appeals. The provisions include the application for an appeal, the makeup of the board of appeals and the conduct of the appeal process.

    Appendix E Temporary Emergency Uses.

    Appendix E is intended to provide guidance for designers, engineers, architects and fire and building officials on allowing temporary emergency uses of existing buildings with respect to the minimum code requirements. This appendix is a template or checklist that references the relevant code requirement of concerns.

    Resource A Guidelines on Fire Ratings of Archaic Materials and Assemblies.

    In the process of repair and alteration of existing buildings, based on the nature and the extent of the work, the CEBC might require certain upgrades in the fire-resistance rating of building elements, at which time it becomes critical for the designers and the code

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    officials to be able to determine the fire-resistance rating of the existing building elements as part of the overall evaluation for the assessment of the need for improvements. These guidelines are based upon the Guideline on Fire Ratings of Archaic Materials published by the National Institute of Building Sciences (NIBS).

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  • CEBC § 1.5. High relevance — show source text

    Exception: Components required for life-safety purposes after an earthquake, including emergency and standby power systems, mechanical smoke removal systems, fire protection sprinkler systems, fire alarm control panels and egress stairways shall have a component importance factor (I p ) of 1.5.

    304A.3.1.2 Major structural alteration, additions or repairs. Major structural alterations, additions or repairs shall be in accor- dance with Section 304A.3.4.1 or 304A.3.4.3 as applicable.

    304A.3.2 Seismic evaluation and retrofit of general acute care hospitals for compliance with the California Administrative Code, Chapter 6. Notwithstanding any other requirements of this code, existing general acute care hospitals shall comply with the seismic evaluation requirements specified in Chapter 6, of the California Administrative Code, when applicable. Seismic retrofit to comply with requirements specified in Chapter 6 of the California Administrative Code shall be permitted to be in accordance with these provisions. When load combinations which do not include seismic forces are required, the new building provisions of this code shall be applicable.

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    304A.3.3 SPC-4D. Nonconforming hospital buildings satisfying the following requirements and one of Sections 501A.3.1, 501A.3.2 or 304A.3.4.5, but not a combination thereof, shall be considered to satisfy the requirements of SPC-4D. 1. Approval of construction documents based on building characterization in accordance with the California Administrative Code (CAC) Chapter 6 Section 2.1.2.1, material properties in accordance with the CAC Chapter 6 Section 2.1.2.2 and Section 304A.5.3 of this code, and a complete rational structural analysis shall be required. 2. Where the SPC-4D upgrade involves construction, a building permit prior to construction shall be required. 3. Where multiple building permits are used to upgrade a building to SPC-4D, a complete rational structural analysis to justify compliance with SPC-4D, for the building in its final configuration, shall be submitted as part of the construction documents submittal to the Office for the last project. 4. Where the SPC-4D upgrade involves construction, buildings shall be assigned to SPC-4D after all projects required for SPC- 4D are closed in compliance.

    304A.3.4 Performance objectives of performance-based methods. Except for the modifications as set forth in Sections 304A.3.4, 304A.3.5 (for ASCE 41-13), and 304A.3.6 (for ASCE 41-23) of this code, all additions, alterations, repairs and seismic retrofit to existing structures or portions thereof shall be permitted to be designed in accordance with the provisions of ASCE 41-23.

    Use of ASCE 41-13 shall be limited to SPC-2 and SPC-4D buildings only.

  • CEBC § 8-706 High relevance — show source text

    SECTION 8-706 LATERAL LOAD REGULATIONS

    8-706.1 Seismic forces. Strength-level seismic forces used to evaluate the structure for resistance to seismic loads shall be based on the R -values tabulated in the regular code for similar lateral-force-resisting systems including consideration of the structural detailing of the members where such R -values exist. Where such R -values do not exist, an appropriate R -value shall be rationally assigned considering the structural detailing of the members.

    Exceptions:

    1. The forces need not exceed 0.75 times the seismic forces prescribed by the regular code requirements.
    2. For Risk Category I, II or III structures, near-fault increases in ground motion (maximum considered earthquake ground motion of 0.2 second spectral response greater than 150 percent at 5 percent damping) need not be considered when the fundamental period of the building is 0.5 seconds in the direction under consideration.
    3. For Risk Category I or II structures, the seismic base shear need not exceed 0.30W.
    4. For Risk Category III or IV structures, the seismic base shear need not exceed 0.40W.

    8-706.1.1 When a building is to be strengthened with the addition of a new lateral force resisting system, the R -value of the new system can be used when the new lateral force resisting system resists at least 75 percent of the building’s base shear regardless of its relative rigidity.

    8-706.1.2 Evaluation and seismic improvement of unreinforced masonry bearing wall buildings shall comply with the California Existing Building Code (CEBC), Appendix Chapter A1 2013 Edition, and as modified by the CHBC.

    Exceptions:

    1. Alternative standards may be used on a case-by-case basis when approved by the authority having jurisdiction. It shall be permitted to exceed the strength limitation of 100 psi in Section A108.2 of the CEBC when test data and building configuration supports higher values subject to the approval of the authority having jurisdiction.
    2. CEBC Section A102.2 shall not apply to Qualified Historical Buildings in Risk Category III buildings and other structures whose primary occupancies are public assembly with an occupancy load greater than 300.

    8-706.1.3 All deviations from the detailing provisions of the lateral-force-resisting systems shall be evaluated for stability and the ability to maintain load-carrying capacity at the expected inelastic deformations.

    8-706.2 Existing building performance. The seismic resistance may be based upon the ultimate capacity of the structure to perform, giving due consideration to ductility and reserve strength of the lateral-force-resisting system and materials while maintaining a reasonable factor of safety. Broad judgment may be exercised regarding the strength and performance of materials not recognized by regular code requirements. (See Chapter 8-8, Archaic Materials and Methods of Construction.)

    8-706.2.1 All structural materials or members that do not comply with detailing and proportioning requirements of the regular code shall be evaluated for potential seismic performance and the consequence of non-compliance. All members that would be reasonably expected to fail and lead to collapse or life threatening injury when subjected to seismic demands shall be judged unacceptable, and appropriate structural strengthening shall be developed.

    8-706.3 Load path. A complete and continuous load path, including connections, from every part or portion of the structure to the ground shall be provided for the required forces. It shall be verified that the structure is adequately tied together to perform as a unit when subjected to earthquake forces.

  • CEBC § 3.3. High relevance — show source text

    BSE-C RESPONSE ACCELERATION PARAMETERS [BSC] are the parameters (S XS and S X1 ) taken from 5-percent/50-year maximum direction spectral response acceleration curves or by a Site Specific Response Spectrum developed in accordance with ASCE 41, Section 2.3.3.

    BSE-R RESPONSE ACCELERATION PARAMETERS [BSC] are the parameters (S XS and S X1 ) taken from 20-percent /50-year maximum direction spectral response acceleration curves or by a Site Specific Response Spectrum developed in accordance with ASCE 41, Section 2.3.3.

    SECTION 319 [BSC, DSA-SS & DSA-SS/CC]—SEISMIC CRITERIA SELECTION FOR EXISTING BUILDINGS

    319.1 Basis for evaluation and design. This section determines what technical approach is to be used for the seismic evaluation and design for existing buildings. For those buildings or portions of buildings for which Section 317 requires action, the procedures and limitations for the evaluation of existing buildings and design of retrofit systems and/or repair thereof shall be implemented in accordance with this section.

    One of the following approaches must be used: 1. Method A of Section 320;

    2. Method B of Section 321, with independent review of a peer reviewer as required in Section 322; or 3. For state-owned buildings only, the use of one of the specific procedures listed in Section 319.1.1.

    When Method B is chosen it must be approved by the building official, and, where applicable, by the peer reviewer. All referenced standards in ASCE 41 shall be replaced by referenced standards listed in Chapter 35 of the California Building Code.

    Exceptions: 1. [BSC] For buildings constructed to the requirements of California Building Code, 2019 or later edition, as adopted by the governing jurisdiction, that code is permitted to be used in place of those specified in Section 319.1. 2. [DSA-SS & DSA-SS/CC] For the conversion of nonconforming buildings to conforming school buildings in accordance with Section 4-307 of the California Administrative Code, nonconforming buildings constructed to the requirements of California Building Code, 2019 or later edition, that code as it was adopted by the governing jurisdiction is permitted to be used in place of those specified in Section 319.1 provided the building complies with Seismic Design Category D or higher.

    319.1.1 Specific procedures. [BSC] For state-owned buildings, the following specific procedures located in Appendix A may be used, without peer review, for their respective types of construction to comply with the seismic performance requirements for Risk Category I, II or III buildings: 1. Seismic Strengthening Provisions for Unreinforced Masonry Bearing Wall Buildings (Chapter A1). 2. Earthquake Hazard Reduction in Existing Reinforced Concrete and Reinforced Masonry Wall Buildings with Flexible Diaphragms (Chapter A2).

    319.1.2 When a design project is begun under Method B the selection of the peer reviewer is subject to the approval of the building official. Following approval by the peer reviewer, the seismic criteria for the project and the planned evaluation provisions must be approved by the building official. The approved seismic criteria and evaluation provisions shall apply. Upon approval of the building official these are permitted to be modified.

  • CEBC § 9.1 High relevance — show source text

    Exception: Where the existing vertical elements of the seismic force-resisting system are shown to comply with this chapter, diaphragms need not be evaluated.

    [BS] A403.9 Wood-framed shear walls. Wood-framed shear walls shall have strength and stiffness sufficient to resist the seismic loads and shall conform to the requirements of this section. Where new sheathing is applied to existing studs to create new wood

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    APPENDIX A—GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING BUILDINGS

    framed shear walls, the new wall elements shall be considered bearing wall systems for purposes of determining seismic design parameters.

    [BS] A403.9.1 Gypsum or cement plaster products. Gypsum or cement plaster products shall not be used to provide the strength required by Section A403.3 or the stiffness required by Section A403.4.

    [BS] A403.9.2 Wood structural panels.

    [BS] A403.9.2.1 Drift limit. Wood structural panel shear walls shall meet the story drift limitation of Section A403.4. Conformance to the story drift limitation shall be determined by approved testing or calculation. Individual shear panels shall be permitted to exceed the maximum aspect ratio, provided that the allowable story drift and allowable shear capacities are not exceeded.

    [BS] A403.9.2.2 Openings. Shear walls are permitted to be designed for continuity around openings in accordance with the building code. Blocking and steel strapping shall be provided at corners of the openings to transfer forces from discontinuous boundary elements into adjoining panel elements. Alternatively, perforated shear wall provisions of the building code are permitted to be used.

    [BS] A403.9.3 Hold-down connectors.

    [BS] A403.9.3.1 Expansion anchors in tension. Expansion anchors that provide tension strength by friction resistance shall not be used to connect hold-down devices to existing concrete or masonry elements.

    [BS] A403.9.3.2 Required depth of embedment. The required depth of embedment or edge distance for the anchor used in the hold-down connector shall be provided in the concrete or masonry below any plain concrete slab unless satisfactory evidence is submitted to the code official that shows that the concrete slab and footings are of monolithic construction.

    A403.10 Steel retrofit systems. Steel retrofit systems shall have strength and stiffness sufficient to resist the seismic loads and shall conform to the requirements of this section.

    A403.10.1 Special moment frames. Steel special moment frames shall comply with all applicable provisions of AISC 341, except that Section E3.4a addressing strong-column/weak-beams of AISC 341, is not required for columns that carry no gravity load.

    A403.10.2 Inverted moment frame systems. Cantilevered column systems shall be permitted to be designed as inverted special, intermediate or ordinary moment frames, with corresponding moment frame seismic design coefficients, where the system satisfies the following conditions:

    1. The columns carry no gravity load.
    2. The columns are configured in pairs or larger groups connected by a continuous reinforced concrete foundation or grade beam.
  • CEBC § 317.1.2.1 High relevance — show source text

    The provisions of Section 317 through 323 also establish minimum standards for earthquake evaluation and design for rehabilitation of existing public buildings currently under the jurisdiction of DSA-SS.

    317.1.2.1 Reference to other chapters. For public schools, where reference within this chapter is made to sections in Chapters 16, 17, 18, 19, 21 or 22 of the California Building Code, the provisions in Chapters 16A, 17A, 18A, 19A, 21A and 22A of the California Building Code, respectively, shall apply instead.

    317.1.3 Community college buildings. [DSA-SS/CC] The provisions of Sections 317 through 323 establish minimum standards for earthquake evaluation and design for the rehabilitation of existing buildings for use as community college buildings under the jurisdiction of the Division of the State Architect—Structural Safety/Community Colleges [DSA-SS/CC], refer to Section 1.9.2.2.

    The provisions of Section 317 through 323 also establish minimum standards for earthquake evaluation and design for rehabilitation of existing community college buildings currently under the jurisdiction of DSA-SS/CC.

    317.1.3.1 Reference to other chapters. For community colleges, where reference within this chapter is made to sections in Chapters 17 or 18 of the California Building Code, the provisions in Chapters 17A and 18A of the California Building Code, respectively, shall apply instead.

    317.2 Scope. All alterations, structurally connected additions and/or repairs to existing structures or portions thereof shall, at a minimum, be designed and constructed to resist the effects of seismic ground motions as provided in this section. The structural system shall be evaluated by a registered design professional and, if not meeting or exceeding the minimum seismic design performance requirements of this section, shall be retrofitted in compliance with these requirements.

    Exception: Those structures for which Section 317.3 determines that assessment is not required, or for which Section 317.4 determines that retrofit is not needed, then only the requirements of Section 317.11 apply.

    317.3 Applicability.

    317.3.1 Existing state-owned buildings. [BSC, DSA-SS] For existing state-owned structures including all buildings owned by the University of California and the California State University, the requirements of Section 317 apply whenever the structure is to be retrofitted, repaired or modified and any of the following apply: 1. Total construction cost, not including cost of furnishings, fixtures and equipment, or normal maintenance, for the building exceeds 25 percent of the construction cost for the replacement of the existing building. The changes are cumulative for past modifications to the building that occurred after adoption of the 1995 California Building Code and did not require seismic retrofit.

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  • CEBC § 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 1in 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.

  • CEBC § 319.3 High relevance — show source text

    Where original building plans and specifications are not available, “as-built” plans shall be prepared that depict the existing vertical and lateral structural systems, exterior elements, foundations and nonstructural systems in sufficient detail to complete the design.

    Data collection shall be directed and observed by the project structural engineer or design professional in charge of the design.

    319.3 Site geology and soil characteristics. Soil profile shall be assigned in accordance with the requirements of Chapter 18 of the California Building Code.

    319.4 Risk categories. Each structure shall be placed in one of the Risk Categories in accordance with the requirements of the California Building Code.

    319.5 Configuration requirements. Each structure shall be designated structurally regular or irregular. If the evaluation and retrofit is in accordance with Table 317.5, Footnote 2 or 3, the building shall be classified by application of ASCE 7, Section 12.3.2. If the evaluation and retrofit is in accordance with ASCE 41, the building shall be classified as irregular when an irregularity defined in ASCE 41, Sections 7.3.1.1.1 through 7.3.1.1.4 exists.

    319.6 General selection of the design method. The requirements of Method B (Section 321) may be used for any existing building.

    319.7 Prescriptive selection of the design method. The requirements of Method A per Section 320 or the specific procedures for applicable building types given in Section 319.1.1 are permitted to be used except if the building has one or more characteristics described in Sections 319.7.1 through 319.7.7, in which case Method B shall be used.

    319.7.1 A building with prestressed or post- tensioned structural components (beams, columns, walls or slabs) or precast structural components (beams, columns, walls or flooring systems).

    319.7.2 A building classified as irregular per Section 319.5.

    Exceptions: 1. The retrofit design removes the configurational attributes that caused the building to be classified as irregular. 2. The irregularity is demonstrated not to affect the seismic performance of the building.

    319.7.3 A building assigned to Risk Category IV per Section 319.4.

    319.7.4 A building with an undefined or hybrid structural system.

    2025 CALIFORNIA EXISTING BUILDING CODE 3-19

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    PROVISIONS FOR ALL COMPLIANCE METHODS

    319.7.5 A building with a seismic isolation or energy dissipation system, either as part of the existing structure or as part of the retrofit.

    319.7.6 A building greater than 240 feet (73 m) in height.

    319.7.7 A building evaluated per ASCE 41 and its application requires the use of a nonlinear analysis procedure.

Frequently asked questions

When is a seismic evaluation required?

An evaluation is required whenever the triggers in Section 317.3 apply (for example, significant alteration cost, changes in risk category, increased seismic demand, or damage); the design professional must perform the evaluation per Section 317.4 and, if performance is inadequate, the building must be retrofitted per Section 317.6.

Which design methods can I use for retrofit?

You may use Method A (Section 320) or Method B (Section 321). Method A follows linear ASCE 41 procedures; Method B is a performance-based evaluation that typically requires building‑official approval and peer review. Specific prescriptive procedures in Appendix A are permitted for some building types and state‑owned buildings per Section 319.1.1.

Does Appendix A replace ASCE 41?

No — Appendix A provides prescriptive, type‑specific retrofit guidelines that can be used where allowed, but the CEBC generally references ASCE 41 performance procedures (tiers and chapters) for systematic evaluation and retrofit; Table 317.5 and the ASCE 41 tiers remain the basis for required performance levels unless the code explicitly permits an Appendix A procedure.

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