When is a seismic evaluation required for an existing building?

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.

  3-16 2025 CALIFORNIA EXISTING BUILDING CODE

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

  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 § 317.3.2 High relevance — show source text

  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. Following the notations of ASCE 41, the seismic requirements for design and assessment are based upon a prescribed Seismic Hazard Level (BSE-1N, BSE-2N, BSE-1E, BSE-R or BSE-C), a specified structural performance level (S-1 through S-5) and a nonstructural performance level (N-A through N-E). The minimum seismic performance criteria are given in Table 317.5 according to the Building Regulatory Authority and the Risk Category as determined in Chapter 16 of the California Building Code or by the regulatory authority. The building shall be evaluated in accordance with a Tier 3 Systematic Evaluation and Retrofit per ASCE 41 Chapter 6 for both the Level 1 and Level 2 performance levels, and the more restrictive requirements shall apply.

  Exception: If the floor area of an addition is greater than the larger of 50 percent of the floor area of the original building or 1,000 square feet (93 m [2] ), then the Table 317.5 entries for BSE-R (or BSE-1E) and BSE-C are replaced by BSE-1N and BSE-2N, respectively.

  |TABLE 317.5—SEISMIC PERFORMANCE REQUIREMENTS2,

• 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 § 303.3 High relevance — show source text

  Exceptions:

  1. Where an addition is being added on an existing Group E site, and where the addition is not of sufficient size to accommodate the required occupant capacity of the storm shelter for all of the buildings on-site, the storm shelter shall at a minimum accommodate the required capacity for the addition.
  2. Where approved by the code official, the required design occupant capacity of the shelter shall be permitted to be reduced by the design occupant capacity of any existing storm shelters on the site.

  303.3 Occupancy classification. The occupancy classification for storm shelters shall be determined in accordance with Section 423.3 of the California Building Code .

  SECTION 304—STRUCTURAL DESIGN LOADS AND EVALUATION AND DESIGN PROCEDURES

  [BS] 304.1 Live loads. Where an addition or alteration does not result in increased design live load, existing gravity load-carrying structural elements shall be permitted to be evaluated and designed for live loads approved prior to the addition or alteration. If the approved live load is less than that required by Section 1607 of the California Building Code, the area designated for the nonconforming live load shall be posted with placards of approved design indicating the approved live load. Where the addition or alteration results in increased design live load, the live load required by Section 1607 of the California Building Code shall be used.

  [BS] 304.2 Snow loads on adjacent buildings. Where an alteration or addition changes the potential snow drift effects on an adjacent building, the code official is authorized to enforce Section 7.12 of ASCE 7.

  [BS] 304.3 Seismic evaluation and design procedures. Where required, seismic evaluation or design shall comply with the procedures and criteria in this section, regardless of which compliance method is used. The scope of the required evaluation or design shall be as indicated in applicable provisions of Chapters 4 through 11 .

  [BS] 304.3.1 Full seismic criteria. Where required, seismic evaluation or design shall comply with one of the following methodologies, which shall not be applied in combination with each other:

  1. Section 1613 of the California Building Code . Where the existing seismic force-resisting system is a type that can be designated as “Ordinary,” values of R, Ω 0 and C d used for analysis in accordance with Chapter 16 of the California Building Code shall be those specified for structural systems classified as “Ordinary” in accordance with Table 12.2-1 of ASCE 7, unless it can be demonstrated that the structural system will provide performance equivalent to that of a “Detailed,” “Intermediate” or “Special” system.
  2. ASCE 41, using a Tier 3 procedure and both levels of the two-level performance objective in Table 304.3.1 for the applicable risk category.
• CEBC § 304.2 High relevance — show source text

  [BS] 304.2 Snow loads on adjacent buildings. Where an alteration or addition changes the potential snow drift effects on an adjacent building, the code official is authorized to enforce Section 7.12 of ASCE 7.

  [BS] 304.3 Seismic evaluation and design procedures. Where required, seismic evaluation or design shall comply with the procedures and criteria in this section, regardless of which compliance method is used. The scope of the required evaluation or design shall be as indicated in applicable provisions of Chapters 4 through 11 .

  [BS] 304.3.1 Full seismic criteria. Where required, seismic evaluation or design shall comply with one of the following methodologies, which shall not be applied in combination with each other:

  1. Section 1613 of the California Building Code . Where the existing seismic force-resisting system is a type that can be designated as “Ordinary,” values of R, Ω 0 and C d used for analysis in accordance with Chapter 16 of the California Building Code shall be those specified for structural systems classified as “Ordinary” in accordance with Table 12.2-1 of ASCE 7, unless it can be demonstrated that the structural system will provide performance equivalent to that of a “Detailed,” “Intermediate” or “Special” system.
  2. ASCE 41, using a Tier 3 procedure and both levels of the two-level performance objective in Table 304.3.1 for the applicable risk category.

  [BS] TABLE 304.3.1—PERFORMANCE OBJECTIVES FOR USE IN ASCE 41 FOR COMPLIANCE WITH FULL SEISMIC CRITERIA	Col2	Col3
  RISK CATEGORY (Based on IBC Table 1604.5)	STRUCTURAL PERFORMANCE LEVEL FOR USE WITH BSE-1N EARTHQUAKE HAZARD LEVEL	STRUCTURAL PERFORMANCE LEVEL FOR USE WITH BSE-2N EARTHQUAKE HAZARD LEVEL
  I	Life Safety (S-3)	Collapse Prevention (S-5)
  II	Life Safety (S-3)	Collapse Prevention (S-5)
  III	Damage Control (S-2)	Limited Safety (S-4)
  IV	Immediate Occupancy (S-1)	Life Safety (S-3)

  [BS] 304.3.2 Reduced seismic criteria. Where required, seismic evaluation or design shall comply with one of the following methodologies, which shall not be applied in combination with each other:

  1. Section 1613 of the California Building Code using 75 percent of the prescribed forces. Values of R, Ω 0 and C d used for analysis shall be as specified in Section 304.3.1 of this code.

  2025 CALIFORNIA EXISTING BUILDING CODE 3-5

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

  PROVISIONS FOR ALL COMPLIANCE METHODS

  2. Applicable chapters of Appendix A of this code, for structures or portions of structures specified in Items 2.1 through 2.4 subject to the limitations of the respective chapter. 2.1. Chapter A1 for unreinforced masonry bearing wall buildings assigned to Risk Category I or II. 2.2. Chapter A2 for the wall anchorage system in reinforced concrete and reinforced masonry wall buildings with flexible diaphragms assigned to Risk Category I or II.
• CEBC § 317.1.2.1 Medium 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.

  3-16 2025 CALIFORNIA EXISTING BUILDING CODE

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

  PROVISIONS FOR ALL COMPLIANCE METHODS

• CEBC § 3-20 Medium relevance — show source text

  3-20 2025 CALIFORNIA EXISTING BUILDING CODE

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

  PROVISIONS FOR ALL COMPLIANCE METHODS

  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.

  When the evaluation indicates the building does not meet the required performance levels given in Table 317.5 for the risk category, then a retrofit and/or repair design shall be prepared that provides a structure that meets these performance objectives and reflects the appropriate consideration of existing conditions. Any approach to analysis and design is permitted to be used, provided that the approach shall be rational, shall be consistent with the established principals of mechanics and shall use the known performance characteristics of materials and assemblages under reversing loads typical of severe earthquake ground motions.

  Exception: Further consideration of the structure’s seismic performance may be waived by the enforcement agency if both the registered design professional and peer reviewer(s) conclude that the structural system can be expected to perform at least as well as required by the provisions of this section without completing an analysis of the structure’s compliance with these requirements. A detailed report shall be submitted to the responsible building official that presents the reasons and basis for this conclusion. This report shall be prepared by the registered design professional. The peer reviewer(s) shall concur in this conclusion and affirm to it in writing. The building official shall either approve this decision or require completion of the indicated work specified in this section prior to approval.

  321.2 The approach, models, analysis procedures, assumptions on material and system behavior and conclusions shall be peer reviewed in accordance with the requirements of Section 322 and accepted by the peer reviewer(s).

  Exceptions: 1. The enforcement agency may perform the work of peer review when qualified staff is available within the jurisdiction. 2. The enforcement agency may modify or waive the requirements for peer review when appropriate.

• CEBC § 7.12 Medium relevance — show source text

  SECTION 303 A — RESERVED

  SECTION 304 A —STRUCTURAL DESIGN LOADS AND EVALUATION AND DESIGN PROCEDURES

  304 A .1 Live loads. Where an addition or alteration does not result in increased design live load, existing gravity load-carrying structural elements shall be permitted to be evaluated and designed for live loads approved prior to the addition or alteration. If the approved live load is less than that required by Section 1607 A of the California Building Code, the area designated for the nonconforming live load shall be posted with placards of approved design indicating the approved live load. Where the addition or alteration results in increased design live load, the live load required by Section 1607 A of the California Building Code shall be used.

  304 A .2 Snow loads on adjacent buildings. Where an alteration or addition changes the potential snow drift effects on an adjacent building, the code official is authorized to enforce Section 7.12 of ASCE 7.

  304 A .3 Additions, alterations, repairs and seismic retrofit to existing buildings or structures.

  304 A .3.1 Structures designed in accordance with pre-1973 building code. Provisions of this section shall apply to hospital build- ings which were originally designed to pre-1973 building codes and not designated as SPC 3 or higher in accordance with Chapter 6 of the California Administrative Code.

  304A.3.1.1 Incidental and minor structural alteration, additions, or repairs. Incidental and minor structural additions shall be permitted, provided the additions meet the California Building Code for new construction using importance factor, I e , equal to or greater than 1.0. Alterations or repair to existing gravity and lateral force-resisting systems shall be made to conform to the requirements of Section 503A or Chapter 4A, respectively, using importance factor, I e , equal to or greater than 1.0. 1. Nonstructural components. Component importance factor, I p , shall be permitted to be 1.0.

  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.

• CEBC § 503.7 Medium relevance — show source text

  [BS] 503.7 Anchorage for concrete and reinforced masonry walls. Where the work area exceeds 50 percent of the building area, the building is assigned to Seismic Design Category C, D, E or F and the building’s structural system includes concrete or reinforced masonry walls with a flexible roof diaphragm, the alteration shall comply with Section 304.3.2 by evaluation of the existing condition or by installation of wall anchors at the roof line.

  [BS] 503.8 Anchorage for unreinforced masonry walls in major alterations. Where the work area exceeds 50 percent of the building area, the building is assigned to Seismic Design Category C, D, E or F and the building’s structural system includes unreinforced masonry bearing walls, the alteration shall comply with Section 304.3.2 by evaluation of the existing condition or by installation of wall anchors at the floor and roof lines.

  [BS] 503.9 Bracing for unreinforced masonry parapets in major alterations. Where the work area exceeds 50 percent of the building area, and where the building is assigned to Seismic Design Category C, D, E or F, and the building has parapets constructed of unreinforced masonry, the alteration shall comply with Section 304.3.2 by evaluation of the existing condition or by installation of parapet bracing to resist out-of-plane seismic forces.

  [BS] 503.10 Anchorage of unreinforced masonry partitions in major alterations. Where the work area exceeds 50 percent of the building area, or where the building is assigned to Seismic Design Category C, D, E or F, and the building has unreinforced masonry partitions and nonstructural walls, the alteration work shall include evaluation of the existing condition or removal, anchoring or alteration of any such partitions or walls within the work area and adjacent to egress paths from the work area, to comply with Section 304.3.2.

  [BS] 503.11 Substantial structural alteration. Where the work area exceeds 50 percent of the building area and where work involves a substantial structural alteration, the lateral load-resisting system of the altered building shall satisfy the requirements of Section 1609 of the California Building Code and Section 304.3.2 of this code. Where the building is assigned to Seismic Design Category D or F, supports and attachments for nonstructural components required to serve any portion of the building with a use included in Risk Category IV shall comply with Section 1613 of the California Building Code or shall comply with ASCE 41 using an objective of Position Retention nonstructural performance with the BSE-1E earthquake hazard level.

  Exceptions:

  1. Buildings of Group R occupancy with not more than five dwelling or sleeping units used solely for residential purposes that are altered based on the conventional light-frame construction methods of the California Building Code or in compliance with the provisions of the California Residential Code .
  2. Where the intended alteration involves structural components of the lowest story of a building, only the lateral loadresisting system above that story need not comply with this section.

  [BS] 503.12 Roof diaphragms resisting wind loads in high-wind regions. Where the intended alteration requires a permit for reroofing and involves removal of roofing materials from more than 50 percent of the roof diaphragm of a building or section of a building located where the basic wind speed, V, is greater than 130 mph (58 m/s) in accordance with Figure 1609.3(2) of the California

• CEBC § 309.2.1 Medium relevance — show source text

  2||||X|X|||||||||||||||||||| |309.2.1|||X|||||||||||||||||||||| |310 – 311|||||||||||X|X|||X|||||||||| |312|||||||||||X|||||||||||||| |313 – 316|||X|||||||||||||||||||||| |317 – 322|X|||||||X|X|||||||||||||||| |323||||||||X|X||||||||||||||||

  The state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.

  2025 CALIFORNIA EXISTING BUILDING CODE 3-1

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

  3-2 2025 CALIFORNIA EXISTING BUILDING CODE

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

  3 PROVISIONS FOR ALL COMPLIANCE METHODS

  User notes:

  About this chapter: Chapter 3 explains the three compliance options for alterations and additions available in the code. In addition, this chapter also lays out the methods to be used for seismic design and evaluation throughout this code. Finally, this chapter clarifies that provisions in other I-Codes related to repairs, alterations, additions, relocation and changes of occupancy must also be addressed unless they conflict with this code. In that case, this code takes precedence.

  SECTION 301—ADMINISTRATION

  301.1 Applicability. The repair, alteration, change of occupancy, addition or relocation of all existing buildings shall comply with Section 301.2, 301.3 or 301.4. The provisions of Sections 302 through 309 shall apply to all alterations, repairs, additions, relocation of structures and changes of occupancy regardless of compliance method. [OSHPD 1R, 2, 4 and 5] Section 301.4 not permitted by OSHPD.

  Exceptions: 1. Existing state-owned structures. [BSC] The repair, alteration, change of occupancy, addition or relocation of all existing buildings shall comply with the provisions of Sections 317 through 322 as the minimum standards for earthquake evaluation and design for retrofit of existing state-owned structures, including buildings owned by the University of California, the California State University or the Judicial Council. The provisions of Sections 317 through 322 may be adopted by a local jurisdiction for earthquake evaluation and design for retrofit of existing buildings. 2. Public school buildings [DSA-SS] The provisions of Sections 317 through 323 establish minimum standards for earthquake evaluation and design for the rehabilitation of existing buildings for use as public school buildings under the jurisdiction of the Division of the State Architect—Structural Safety (DSA-SS, refer to Section 1.9.2.1) where required by Sections 4-307 and 4-309(c) of the California Administrative Code. The provisions of Sections 317 through 323 also establish minimum standards for earthquake evaluation and design for rehabilitation of existing public school buildings currently under the jurisdiction of DSA-SS. 3. _**Community college buildings.

• CEBC § 3-17 Medium relevance — show source text

  2025 CALIFORNIA EXISTING BUILDING CODE 3-17

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

  PROVISIONS FOR ALL COMPLIANCE METHODS

  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.

  ALTERATION [BSC] means any change within or to an existing building, which does not increase and may decrease the floor or roof area or the volume of enclosed space.

  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.

• CEBC § 8-706 Medium 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.