CEBC · California Existing Building Code
When must a seismic evaluation or retrofit be performed (Section 317 triggers)?
If your project is a state‑owned building alteration, addition, or repair and it exceeds **25%** of replacement cost, changes risk category, increases seismic demand by **>10%**, or causes >**10%** loss of lateral capacity (or increases story shear >**10%**), the CEBC requires a seismic evaluation by a registered design professional—and if the building fails the required **§ 317.5** performance levels it must be retrofitted.
Last reviewed: July 6, 2026
What the code requires — 2–4 sentences
Under § 317, the structural system of an existing building subject to alterations, structurally connected additions, or repairs must be evaluated for seismic performance and, if it fails to meet the minimum performance levels in § 317.5, must be retrofitted to comply with Section 317.
If the specific applicability tests in § 317.3 do not require assessment or if § 317.4 shows retrofit is not needed, then only the limited requirements of § 317.11 apply.
The single most important rule: if your project triggers any of the tests in § 317.3, a registered design professional must evaluate the building per § 317.4, and if the building does not meet the performance objective in § 317.5, the owner must complete a retrofit under § 317.6.
Requirements in detail
Scope and who this applies to
- The Chapter 3 provisions in Sections 317–323 establish minimum standards for earthquake evaluation and retrofit of existing state-owned buildings, and may be adopted by local jurisdictions for other buildings; see § 317.1.
- For public school and community college buildings there are parallel triggers tied to the California Administrative Code (see § 317.1.2, § 317.3.2, § 317.3.3).
Applicability — the decision dimensions that trigger an evaluation or retrofit
The primary decision tests that require an evaluation or retrofit are in § 317.3 (state-owned buildings) and related subsections for schools/colleges. Key numeric thresholds and decision dimensions are shown below.
| Decision dimension (what to check) | Trigger (when action is required) | Code Reference |
|---|---|---|
| Total construction cost of the project (state‑owned buildings) | Project cost exceeds 25 percent of the replacement cost of the existing building (cumulative since 1995 for past mods that didn’t already require retrofit) → assessment required | § 317.3.1(1) |
| Change in Risk Category | Any change in risk category for the building → assessment required | § 317.3.1(2) |
| Increase in seismic force demand on a component | Modification increases seismic forces or strength requirements of any structural component by more than 10 percent cumulative since original construction (unless component already has capacity per § 319) → assessment required | § 317.3.1(3) |
| Damage to lateral system | Repair needed because damage reduced lateral-load-resisting capacity by more than 10 percent → assessment required | § 317.3.1(4) |
| Change in gravity loads | Changes in live or dead load that increase story shear by more than 10 percent → assessment required | § 317.3.1(5) |
| Public schools / community colleges | Applicability tied to CA Admin Code Sections 4-307 and 4-309(c) (see referenced subsections) → assessment required when those provisions require it | § 317.3.2 / § 317.3.3 |
Notes:
- The defined term ADDITION (any work increasing floor/roof area and structurally attached to existing building) matters because additions are explicitly included in scope; see § 318.1 (ADDITION).
What the evaluation must achieve (and when retrofit is required)
- If the criteria in § 317.3 apply, the registered design professional of record must provide a seismic evaluation in accordance with Section 317 to determine the building’s current seismic performance. If after evaluation the building satisfies the performance requirements in § 317.5, and peer reviewers concur when required, no retrofit is required. Otherwise retrofit is required. This is the requirement of § 317.4 and § 317.6.
- § 317.5 establishes the minimum seismic design performance levels (structural S‑levels S‑1 to S‑5; nonstructural N‑levels N‑A to N‑E) tied to prescribed seismic hazard levels (BSE‑1N, BSE‑2N, BSE‑1E, BSE‑R, BSE‑C) and requires evaluation per ASCE 41 Tier 3 (Systematic Evaluation and Retrofit) for the specified performance levels. The evaluation must meet the more restrictive of Level 1 and Level 2 requirements.
- Exception in § 317.5: if an addition’s floor area is greater than the larger of 50 percent of the original building area or 1,000 square feet, certain BSE entries in Table 317.5 are replaced by more demanding BSE levels—so additions can change which hazard level applies.
Methods and review
- For buildings where Section 317 requires action, the seismic evaluation and retrofit design must follow the technical approaches in § 319 (selection of criteria) and then one of: Method A (Section 320 — Linear procedures per ASCE 41), Method B (Section 321 — performance-based evaluation with peer review), or the state-specific alternatives in § 319.1. If Method B is used, peer review and approval are required per § 321 and § 322.
Exceptions & special cases
- If § 317.3 determines assessment is not required, or § 317.4 determines retrofit is not needed, then only § 317.11 (voluntary lateral‑force modifications) applies instead of full Section 317 retrofit provisions.
- Additions larger than the larger of 50 percent of the original floor area or 1,000 sq ft replace certain seismic hazard entries in Table 317.5 with the more demanding BSE‑1N/BSE‑2N entries (see § 317.5 Exception). That can increase retrofit/design requirements.
- For public schools and community colleges, additional or alternate triggers and procedural references reside in the California Administrative Code (see § 317.3.2 and § 317.3.3).
- Voluntary seismic improvements that are not required by Section 317 can follow the voluntary procedures in § 319.12 (including pre‑approved ASCE 41 Tier 1 & Tier 2 deficiency‑only procedures where an assessment is not required).
Common mistakes
- Treating the 25 percent cost threshold as applying to all buildings — that threshold is explicitly stated for existing state‑owned buildings in § 317.3.1(1); other building types may be governed by local adoption or by school/college rules.
- Forgetting the cumulative nature of the 10 percent seismic force/strength increase test — past modifications since the 1995 CBC that didn’t require retrofit are counted. See § 317.3.1(3).
- Failing to involve a registered design professional for the required evaluation under § 317.4, or omitting required peer review when using Method B per § 321.
- Misapplying the addition area exception in § 317.5 — the relevant comparison is the larger of 50 percent of the original floor area or 1,000 sq ft.
- Assuming ASCE 41 Tier 1 or 2 procedures always suffice — where § 317.3 requires an assessment, § 317.5 generally requires Tier 3 Systematic Evaluation and Retrofit per ASCE 41 Chapter 6.
Worked example — concrete scenario
Scenario: A state university owns a building with a replacement cost of $2,000,000. The planned alteration will cost $600,000 (construction only). The project will also add new mechanical equipment that increases story shear by 5%, and will not change the building’s risk category.
Step 1 — cost trigger: Project cost $600,000 is 30% of $2,000,000 (600k / 2,000k = 0.30), which exceeds 25 percent, so the project triggers an assessment per § 317.3.1(1).
Step 2 — required evaluation: A registered design professional must perform the seismic evaluation under § 317.4 to determine whether the building meets the performance objectives in § 317.5. Because the cost trigger applied, Tier 3 evaluation procedures per ASCE 41 Chapter 6 will be used as required by § 317.5.
Step 3 — retrofit decision: If the evaluation shows the building does not meet required performance levels (for example Life Safety), the owner must either perform the required retrofit as part of the current work or submit an acceptable plan to complete retrofit in a timely manner as required by § 317.6.
(If instead the project cost had been $300,000 (15%), and no other § 317.3 triggers applied, an assessment would not be required under the cost test — but verify whether other triggers apply and whether local adoption changes applicability.)
Related provisions
- § 317.2 — Scope: baseline requirement that alterations/additions/repairs be designed to resist seismic ground motions; evaluation and retrofit if performance levels aren’t met.
- § 317.3 — Applicability: the detailed list of triggers (cost %, risk category change, >10% force increases, >10% damage, >10% story shear).
- § 317.4 — Evaluation required: who must perform the evaluation and the consequence (no retrofit if performance met).
- § 317.5 — Minimum seismic performance levels: ASCE 41 hazard levels, S/N performance levels, Tier 3 requirement and Table 317.5 details.
- § 317.6 — Retrofit required: owner’s obligations when evaluation indicates retrofit is needed.
- § 319 — Seismic criteria selection and permitted methods (Method A, Method B, and state-specific options).
- § 320 — Method A: retrofit design linear procedures (ASCE 41).
- § 321 — Method B: performance evaluation with peer review; acceptance criteria and when used.
- § 322 — Peer review requirements (applies when Method B or other peer-review triggers are used).
- § 318.1 (ADDITION) — definition of ADDITION, relevant to the scope and 50%/1,000 sq ft test in § 317.5.
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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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 § 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 § 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 § 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 § 2.2 High relevance — show source text
405 A .2.2 Disproportionate earthquake damage. A building assigned to Seismic Design Category D, E or F that has sustained disproportionate earthquake damage shall be subject to the requirements for buildings with substantial structural damage to vertical elements of the lateral force-resisting system.
405 A .2.3 Substantial structural damage to vertical elements of the lateral force-resisting system. A building that has sustained substantial structural damage to the vertical elements of its lateral force-resisting system shall be evaluated in accordance with Section 405 A .2.3.1, and either repaired in accordance with Section 405 A .2.3.2 or repaired and retrofitted in accordance with Section 405 A .2.3.3, depending on the results of the evaluation.
405 A .2.3.1 Evaluation. The building shall be evaluated by a registered design professional, and the evaluation findings shall be submitted to the building official. The evaluation shall establish whether the lateral force-resisting system of the damaged building, including its foundation, if repaired to its predamage state, would comply with the provisions of the California Build- ing Code for load combinations that include wind and earthquake effects. Earthquake loads for this evaluation, if required, shall
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REPAIRS
be permitted to be 75 percent of those prescribed in California Building Code Section 1613A. Alternatively, where the earthquake damage has not resulted in disproportionate earthquake damage or did not result in collapse, the earthquake load evaluation shall be permitted to be performed in accordance with Section 304A.3.4.4 for SPC-2 buildings and Section 304A.3.4.5 for buildings rated SPC-3, SPC-4D and SPC-4. SPC-5 buildings shall be permitted to be evaluated in accordance with Section 304A.3.4.6, except that the seismic hazard shall be permitted to be reduced to BSE-1E and BSE-2E.
405 A .2.3.2 Extent of repair for compliant buildings. If the evaluation establishes that the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the damaged elements shall be permitted to be restored to their predamage condition.
405 A .2.3.3 Extent of repair for noncompliant buildings. If the evaluation does not establish that the lateral force-resisting system of the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the lateral forceresisting system, and its foundation, shall be retrofitted to comply with the provisions of this section. The wind loads for the repair and retrofit shall be those required by the building code in effect at the time of original construction, unless the damage was caused by wind, in which case the wind loads shall be in accordance with the California Building Code . The earthquake loads shall not be less than those required by the building code in effect at the time of original construction but not less than 75 _percent of those prescribed in California Building Code Section 1613A.
CEBC § 0.91 High relevance — show source text
Fourth, fifth_
and sixth floors and the second and third basement floor level quantity shall be reduced to 75 percent of this table. The seventh through 10th floor and below the third basement
floor level quantity shall be reduced to 50 percent of this table.
2. Permitted only when stored or used in approved exhausted gas cabinets, exhausted enclosures or fume hoods. Quantities of high toxics in use in open systems need not be reduced
above the third floor or below the first basement floor level. Individual container size shall be limited to 2 pounds (0.91 kg) for solids and1/4 gallon (0.95 L) for liquids.|SECTION 317 [BSC, DSA-SS & DSA-SS/CC]—EARTHQUAKE EVALUATION AND DESIGN FOR RETROFIT OF EXISTING BUILDINGS
317.1 Purpose.
317.1.1 Existing state-owned structures. [BSC] The provisions of Sections 317 through 322 establish minimum standards for earthquake evaluation and design for retrofit of existing state-owned structures, including buildings owned by the University of California and the California State University.
The provisions of Sections 317 through 323 may be adopted by a local jurisdiction for earthquake evaluation and design for retrofit of existing buildings.
317.1.2 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.
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.
CEBC § 1.9.2.1. High relevance — show source text
State-owned and state-leased essential services buildings are subject to the regulatory authority of DSA-SS per Section 1.9.2.1._|1. ASCE 41 provides acceptance criteria (e.g., m-factor, rotation) for Immediate Occupancy (S1), Life Safety (S3) and Collapse Prevention (S5), and specifies in Table 2-1 the method
to interpolate values for S-2 and S-4. When evaluating for the Hazards Reduced Nonstructural Performance Level, the requirements need not be greater than what would be
required by ASCE 7 nonstructural provisions for new construction.
2. Buildings evaluated and retrofitted to meet the structural and nonstructural requirements for a new building as given in the California Building Code as adopted by DSA or BSC, as
applicable, are deemed to meet the seismic performance requirements of this section.
3. 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.|1. ASCE 41 provides acceptance criteria (e.g., m-factor, rotation) for Immediate Occupancy (S1), Life Safety (S3) and Collapse Prevention (S5), and specifies in Table 2-1 the method
to interpolate values for S-2 and S-4. When evaluating for the Hazards Reduced Nonstructural Performance Level, the requirements need not be greater than what would be
required by ASCE 7 nonstructural provisions for new construction.
2. Buildings evaluated and retrofitted to meet the structural and nonstructural requirements for a new building as given in the California Building Code as adopted by DSA or BSC, as
applicable, are deemed to meet the seismic performance requirements of this section.
3. 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.
CEBC § 319.9 High relevance — show source text
Exception: A component’s strength is permitted to be less than that required by the specified seismic load combinations if it can be demonstrated that the associated reduction in seismic performance of the component or its removal due to the failure does not result in a structural system that does not comply with the required performance objectives of Section 317. If this exception is taken for a component, then it cannot be considered part of the primary lateral-load-resisting system.
319.9 Nonstructural component requirements. Where the nonstructural performance levels required by Section 317, Table 317.5 are N-D or higher, mechanical, electrical and plumbing components shall comply with the provisions of ASCE 41, Chapter 13, Section 13.2.
Exception: Modifications to the procedures and criteria may be made subject to approval by the building official, and concurrence of the peer reviewer if applicable. All reports and correspondence shall also be forwarded to the building official.
319.10 Structural observation, testing and inspection. Structural observation, testing and inspection as used in this section shall mean meeting the requirements of Chapter 17 of the California Building Code, with a minimum allowable level of investigation corresponding to seismic design category (SDC) D. Structural observation visits shall occur at significant construction stages and at the completion of the structural retrofit. Structural observation shall be provided for all structures.
Additional requirements: [DSA-SS, DSA-SS/CC] For public schools and community colleges, construction material testing, inspection and observation during construction shall also comply with the California Administrative Code.
319.10.1 The requirement for structural observation shall be noted and prominently displayed on the front sheet of the approved plans and incorporated into the general notes on the approved plans.
319.10.2 Preconstruction meeting. A preconstruction meeting is mandatory for all projects which require structural observation. The meeting shall include, but is not limited to, the registered design professional, structural observer, general constructor, affected subcontractors, the project inspector and a representative of the enforcement agency (designated alternates may attend if approved by the structural observer). The structural observer shall schedule and coordinate this meeting. The purpose of the meeting is to identify and clarify all essential structural components and connections that affect the lateral and vertical load systems and to review scheduling of the required observations for the project’s structural system retrofit.
319.11 Temporary actions. When compatible with the building use, and the time phasing for both use and the retrofit program, temporary shoring or other structural support is permitted to be considered. Temporary bracing, shoring and prevention of falling hazards are permitted to be used to qualify for Item 1 in Section 319.12 that allows inadequate capability in some existing components, as long as the required performance levels given in Section 317 can be provided by the permanent structure. The consideration for such temporary actions shall be noted in the design documents.
319.12 Voluntary modifications to the lateral-force resisting system. Where modifications of existing structural components and additions of new structural components are initiated for the purpose of improving the lateral-force resisting strength or stiffness of an existing structure and they are not required by other sections of this code, then they are permitted to be designed to meet an approved seismic performance criteria provided that an engineering analysis is submitted that follows: 1. The capacity of existing structural components required to resist forces is not reduced, unless it can be demonstrated that
CEBC § 309.2.1 High 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.
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3-2 2025 CALIFORNIA EXISTING BUILDING CODE
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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 § 3.6 High relevance — show source text
2, 6, 9,
18, 20, 21|21/2| |W-8-M-43|85/8″|Core: clay or shale structural tile; facings: exposed
side only; see Note 17.|See
notes|1 hr
30 min||1||1, 2, 6, 9,
19, 20, 21|11/2| |W-8-M-44|85/8″|Core: clay or shale structural tile; facings: side 1, see
Note 17; side 2, none.|See
notes|3 hrs||1||1, 2, 6, 10,
18, 20, 21|3| |W-8-M-45|85/8″|Core: clay or shale structural tile; facings: fire side
only; see Note 17.|See
notes|1 hr
30 min||1||1, 2, 6, 10,
19, 20, 21|11/2| |W-8-M-46|85/8″|Core: clay or shale structural tile; facings: side 1, see
Note 17; side 2, none.|See
notes|3 hrs
30 min||1||1, 2, 6, 12,
18, 20, 21|31/2| |W-8-M-47|85/8″|Core: clay or shale structural tile; facings: exposed
side only; see Note 17.|See
notes|1 hr
45 min||1||1, 2, 6, 12,
19, 20, 21|13/4| |W-8-M-48|85/8″|Core: clay or shale structural tile; facings: side 1, see
Note 17; side 2, none.|See
notes|4 hrs||1||1, 2, 6, 16,
18, 20, 21|4| |W-8-M-49|85/8″|Core: clay or shale structural tile; facings: fire side
only; see Note 17.|See
notes|2 hrs||1||1, 2, 6, 16,
19, 20, 21|2| |W-8-M-50|85/8″|Core: 4″, 40% solid clay or shale clay structural tile;
4″ brick plus5/8″ of 1:3 sanded gypsum plaster
facings on one side.|See
notes|4 hrs||1||1, 20|4| |W-8-M-51|83/4″|83/4″ × 21/2″ and 4″ × 21/2″ cellular fletton (1873 psi)
single and triple cell hollow brick set in1/2″ sand
mortar in alternate courses.|3.6
tons/ft|6 hrs|||7|23, 29|6| |W-8-M-52|83/4″|83/4″ thick cement brick (2527 psi) with Portland
cement and sand mortar.|3.6
tons/ft|6 hrs|||7|23,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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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.
Frequently asked questions
When exactly does the 25% cost test apply?
The 25 percent cost threshold is stated for existing state‑owned buildings in § 317.3.1(1): when total construction cost for the building (excluding furnishings, fixtures, equipment, and normal maintenance) exceeds 25% of replacement cost, the Section 317 requirements apply.
Is the 10% seismic‑force increase test cumulative?
Yes. § 317.3.1(3) treats increases in seismic forces or strength requirements cumulatively since original construction (with special treatment if the component already has capacity per § 319).
Who must perform the seismic evaluation?
A registered design professional of record must perform the evaluation required by § 317.4; when Method B is used, the peer reviewer(s) must concur as required by § 321 and § 322.
Do voluntary retrofits have to follow Section 317?
Voluntary lateral‑force‑resisting modifications that are not required by Section 317 may follow the voluntary procedures in § 319.12, including certain Appendix A procedures for state buildings — but those voluntary procedures are distinct from required Section 317 retrofits.
How do additions affect the seismic hazard level used?
If an addition’s floor area is greater than the larger of 50 percent of the original floor area or 1,000 sq ft, the Table 317.5 entries for certain BSE designations are replaced by more demanding BSE levels (see § 317.5 Exception). This can raise the seismic design/performance demands.
More in California Existing Building Code
- Administration and Definitions (Scope, enforcement, code official duties, definitions)
- Provisions for All Compliance Methods (general requirements that apply to all compliance options; Chapter 3 / 3A)
- Seismic retrofit and evaluation (Appendix A and seismic provisions/sections for evaluation and retrofit)
- Referenced Standards and Appendices (Chapter 16 and Appendices A–E, Resource A)
- Repairs (Chapter 4 — repair-specific rules for materials, means of egress, structural, MEP, etc.)
- Alterations — Level 1, Level 2, Level 3 (technical requirements for each alteration level; Chapters 7–9)
- Change of Occupancy and Additions (requirements for occupancy changes and additions; Chapters 10–11)
- Compliance Methods — Prescriptive, Work Area, Performance (Chapters 5, 6–11, 13)
- Relocated Buildings (requirements for buildings moved or relocated; Chapter 14)
- Construction Safeguards (site safety, means of egress and life-safety during construction; Chapter 15)
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California Existing Building Code