Section 319

SEISMIC CRITERIA SELECTION

FOR EXISTING BUILDINGS

319.1 Basis for evaluation and design. This section deter-¶

mines what technical approach is to be used for the seismic evaluation and design for existing buildings. For those build- ings 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 require- ments of California Building Code, 2013 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 public schools and community colleges constructed to the require- ments of California Building Code, 2013 or later edition, that code 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 Rein- forced 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 evalu- ation provisions shall apply. Upon approval of the build- ing official these are permitted to be modified.

319.1.3 For state-owned and community college build- ings, where unreinforced masonry is not bearing, it may be used only to resist applied lateral loads. Where unrein- forced masonry walls are part of the structure they must be assessed for stability under the applicable nonstruc- tural evaluation procedure.

319.1.4 Public schools. [DSA-SS, DSA-SS/CC] For pub- lic schools, unreinforced masonry shall not be used to resist in-plane or out-of-plane seismic forces or superim- posed gravity loads.

319.1.5 Public schools. [DSA-SS, DSA-SS/CC] For pub- lic schools of light-frame construction, horizontal dia- phragms and vertical shear walls shall consist of either diagonal lumber sheathing or structural panel sheathing. Braced horizontal diaphragms may be acceptable when approved by DSA. Straight lumber sheathing may be used in combination with diagonal or structural panel sheath-

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ing as diaphragms or shear walls. Let-in bracing, plaster (stucco), hollow clay tile, gypsum wallboard and particle- board sheathing shall not be assumed to resist seismic forces.

319.2 Existing conditions. The existing condition and prop-¶

erties of the entire structure must be determined and docu- mented by thorough inspection of the structure and site, review of all available related construction documents, review of geotechnical and engineering geologic reports, and performance of necessary testing and investigation. Where samples from the existing structure are taken or in situ tests are performed, they shall be selected and interpreted in a sta- tistically appropriate manner to ensure that the properties determined and used in the evaluation or design are repre- sentative of the conditions and structural circumstances likely to be encountered in the structure as a whole. Adjacent structures or site features that may affect the retrofit design shall be identified.

The entire load path of the seismic-force-resisting system shall be determined, documented and evaluated. The load path includes all the horizontal and vertical elements partici- pating in the structural response: such as diaphragms, dia- phragm chords, diaphragm collectors, vertical elements such as walls frames, braces; foundations and the connections between the components and elements of the load path. Repaired or retrofitted elements and the standards under which the work was constructed shall be identified.

Data collection in accordance with ASCE 41 Section 6.2 shall meet the following minimum levels:

1. [BSC] For state-owned buildings, the requirements shall be met following the data collection requirements of ASCE 41, Section 6.2.

2. [DSA-SS, DSA-SS/CC] For public schools and com- munity college buildings constructed in conformance with the Field Act, the “Usual” level as defined in ASCE 41, Section 6.2.2.

3. [DSA-SS, DSA-SS/CC] For public schools and com- munity college buildings not constructed in confor- mance with the Field Act, the “Comprehensive” level as defined in ASCE 41, Section 6.2.3.

Concrete material requirements and testing for public school and community college buildings shall also comply with Sections 1911A and 1909.5 of the California Building Code, respectively.

Qualified test data from the original construction may be accepted, in part or in whole, by the enforcement agency to fulfill the data collection requirements.

Exceptions:

1. The number of samples for data collection may be adjusted with approval of the enforcement agency when it has been determined that adequate informa- tion has been obtained or additional information is required.

2. Welded steel moment frame connections of buildings that may have experienced potentially damaging ground motions shall be inspected in accordance

PROVISIONS FOR ALL COMPLIANCE METHODS

with Chapters 3 and 4, FEMA 352, Recommended Post Earthquake Evaluation and Repair Criteria for Welded Moment-Frame Construction for Seismic Applications (July 2000).

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 ele- ments, foundations and nonstructural systems in sufficient detail to complete the design.

Data collection shall be directed and observed by the proj- ect 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. For purposes of earthquake-resistant¶

design, each structure shall be placed in one of the risk cate- gories in accordance with the requirements of the California Building Code.

319.5 Configuration requirements. Each structure shall be¶

designated structurally regular or irregular in accordance with the requirements of ASCE 41, Sections 7.3.1.1.1 to 7.3.1.1.4.

319.6 General selection of the design method. The require-¶

ments 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 (Section 320) or the specific pro- cedures for applicable building types given in Section 319.1.1 are permitted to be used except under the following condi- tions, where the requirements of Method B (Section 321) must be used.

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

319.7.2 When the building is classified as irregular in ver- tical or horizontal plan by application of ASCE 7, Section 12.3 and/or ASCE 41, Sections 7.3.1.1.1 to 7.3.1.1.4, unless the irregularity is demonstrated not to affect the seismic performance of the building.

Exception: If the retrofit design removes the configura- tional attributes that caused the building to be classi- fied as irregular, then Section 319.7.2 does not apply and Method A may be used.

319.7.3 For any building that is assigned to Risk Category IV.

319.7.4 For any building using undefined or hybrid struc- tural systems.

319.7.5 When seismic isolation or energy dissipation sys- tems are used in the retrofit or repair, either as part of the existing structure or as part of the modifications.

319.7.6 When the height of the structure exceeds 240 feet (73 152 mm).

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PROVISIONS FOR ALL COMPLIANCE METHODS

319.7.7 When ASCE 41 is the evaluation standard and its application requires the use of nonlinear procedures.

319.8 Strength requirements. All components of the lateral-¶

force-resisting system must have the strength to meet the acceptance criteria prescribed in ASCE 41, Chapter 7 or as prescribed in the applicable Appendix A chapter of this code if a specific procedure in Section 319.1.1 is used. Any compo- nent not having this strength shall have its capacity increased by modifying or supplementing its strength so that it exceeds the demand, or the demand is reduced to less than the exist- ing strength by making other modifications to the structural system.

Exception: A component’s strength is permitted to be less than that required by the specified seismic load combina- tions if it can be demonstrated that the associated reduc- tion 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 perfor- mance 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. Struc-¶

tural, geotechnical and construction 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 correspond- ing to seismic design category (SDC) D. At a minimum the project site will be visited by the responsible design profes- sional to observe existing conditions and to review the con- struction work for general compliance with approved plans, specifications and applicable structural regulations. Such visits shall occur at significant construction stages and at the completion of the structural retrofit. Structural observation shall be provided for all structures. The plan for testing and inspection shall be submitted to the building official for review and approval with the application for permit.

Additional requirements: For public schools and commu- nity colleges, construction material testing, inspection and observation during construction shall also comply with Section 4-333 of the California Administrative Code.

319.10.1 The registered design professional, or their des- ignee, responsible for the structural design shall be retained to perform structural observation and inde- pendently report to the owner of observations and findings as they relate to adherence to the permitted plans and good workmanship.

319.10.2 At the conclusion of construction, the structural observer shall submit to the enforcement agency and the owner a final written statement that the required site visits have been made, that the work, to the best of the structural observers knowledge and belief, is or is not in general conformity to the approved plans and that the observed structural deficiencies have been resolved and/or listing those that, to the best of the structural observers knowl- edge and belief, have not been satisfactorily corrected.

319.10.2.1 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.

319.10.2.2 Preconstruction meeting. A preconstruc- tion meeting is mandatory for all projects which require structural observation. The meeting shall include, but is not limited to, the registered design pro- fessional, 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 compo- nents and connections that affect the lateral and verti- cal load systems and to review scheduling of the required observations for the project’s structural sys- tem retrofit.

319.11 Temporary actions. When compatible with the build-¶

ing 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 Exception 1 in Section 319.12 that allows inade- quate capability in some existing components, as long as the required performance levels given in Section 317 can be pro- vided 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 compo- nents and additions of new structural components are initi- ated 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 permit- ted 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 reduced capacity meets the require- ments of Section 319.8.

2. The lateral loading to or strength requirement of exist- ing 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.

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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 modifi- cations to lateral force-resisting systems conducted in accordance with Appendix A of this code and the refer- enced 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 cri- teria for the design. The approved design documents must clearly have the phrase “The seismic require- ments of the California Existing Building Code have not been checked to determine if these structural modi- fications meet the full seismic evaluation and strength- ening requirements of Sections 317-322: the modifications proposed are to a different seismic per- formance standard than would be required in Section 319 if they were not voluntary as allowed in Section 319.12.”

nts of the California Existing Building Code have_ not been checked to determine if these structural modi- fications meet the full seismic evaluation and strength- ening requirements of Sections 317-322: the modifications proposed are to a different seismic per- formance standard than would be required in Section 319 if they were not voluntary as allowed in Section 319.12.”

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.