San Francisco County Municipal Code Part D Application of Asce 41-06 to Evaluation and Retrofit Design

DISCUSSION : Further development of this section is expected as needed to address issues specific to Chapter 5E. The sections outlined below cover broad issues consistent with Chapter 5E. Otherwise, use of this standard is subject to existing Department procedures for implementation of SFBC 104A.2.8, Alternate materials, design, and methods of construction. D1. Required scope of work

1. No nonstructural evaluation or retrofit is required.
2. Retrofit strength need not exceed 1.3 times the strength of the story above. Wherever the strength of two stories is being compared, an adequate load path must be assumed for all walls and partitions in the upper story.

Commentary: This requirement prevents underestimating the upper story strength. It will apply for calculations of weak story or soft story ratio in ASCE 31/41, CEBC Appendix A - Chapter A4, and other code-based procedures; application of the 1.3 cap on retrofit strength for ASCE 41 and CEBC Appendix A

• Chapter A4 retrofits; and calculation of spectral capacity with FEMA P-807. Part E. APPLICATION OF ASCE 31-03 TO EVALUATION

DISCUSSION : Further development of this section is expected as needed to address issues specific to Chapter 5E. The sections outlined below cover broad issues consistent with Chapter 5E. Otherwise, use of this standard is subject to existing Department procedures for implementation of SFBC 104A.2.8, Alternate materials, design, and methods of construction. E1. Required scope of work

1. No nonstructural evaluation is required.
2. Wherever the strength of two stories is being compared, an adequate load path must be assumed for all walls and partitions in the upper story.

Commentary: This requirement prevents underestimating the upper story strength. It will apply for calculations of weak story or soft story ratio in ASCE 31/41, CEBC Appendix A - Chapter A4, and other code-based procedures; application of the 1.3 cap on retrofit strength for ASCE 41 and CEBC Chapter Appendix A - Chapter A4 retrofits; and calculation of spectral capacity with FEMA P-807. Part F. APPLICATION OF THE CURRENT EDITION OF CEBC APPENDIX A - CHAPTER A4 TO RETROFIT DESIGN F1. Modifications and interpretations of CEBC Appendix A - Chapter A4. Compliance with SFEBC Chapter 5E using CEBC Appendix A - Chapter A4 shall require compliance with that code chapter and its reference codes and standards except as otherwise modified, waived, or interpreted in this section and Bulletin Part A. The following modifications and interpretations refer to Appendix A - Chapter A4 section numbers. A401.1 Purpose

Commentary: This provision refers to “minimum standards.” In the context of Appendix A - Chapter A4, this means minimum standards for policy equivalence with other criteria when retrofit is triggered elsewhere in the CEBC. In the context of SFEBC Chapter 5E, the provisions of Appendix A - Chapter A4 might or might not require the same scope of retrofit as other criteria allowed by SFEBC Section 506E.2. The other criteria are acceptable even if they require less retrofit scope or produce retrofit designs with lower capacity than Appendix A - Chapter A4. A401.2 Scope. Omit.

Commentary: When used for compliance with SFEBC Chapter5E, the scope and applicability of Appendix A - Chapter A4 is established by Ordinance 66-13. The absence of any condition listed by Section A401.2 has no bearing on compliance with Chapter 5E. A402 Definitions. Add, omit, or revise the following definitions as follows: BUILDING CODE. The current San Francisco Building Code. GROUND FLOOR. A target story, generally a basement story that extends above grade or the first story above grade plane. Alternately, depending on context, GROUND FLOOR might mean the floor level at the base of a target story. A403.1. Omit the exception and revise the first sentence as follows: A403.1 General. All modifications required ... the building code provisions for new construction, except as modified by this chapter and applicable Administrative Bulletins.

Commentary: The exception is not necessary because Section A404 is omitted. See below. A403.2. Omit the exception and revise the provision as follows: A403.2 Scope of analysis. This chapter requires the alteration, repair, replacement or addition of structural elements and their connections to meet the strength and stiffness requirements herein. The lateral-load-path analysis shall include the resisting elements and connections from the wood diaphragm immediately above any target story to the foundation soil interface. Stories above the uppermost target story shall be considered in the analysis but need not be modified. The lateral-load-path analysis for added structural elements shall also include evaluation of the allowable soil- bearing and lateral pressures in accordance with the building code. Where any portion of a building within the scope of this chapter is constructed on or into a slope, the lateral force-resisting system at and below the first story above grade plane shall be analyzed for the effects of concentrated lateral forces caused by this hillside condition. A403.3. Correct Δ0 to Ω0 in multiple places. Also, add the following sentences at the end of the section: A403.3 Design base shear and design parameters. ... Despite any other requirement of Section A403.3 or A403.4, the total expected strength of retrofit elements added to any target story need not exceed 1.3 times the expected strength of the story immediately above, as long as the retrofit elements are located symmetrically about the center of mass of the story above or so as to minimize torsion in the target story.

Commentary: The added sentence implements the SEAONC recommendation to cap the required strength, consistent with FEMA P-807. Exception 4: For retrofit systems involving different seismic force-resisting systems in the same direction within the same story, resisting elements are permitted to be designed using the least value of R for the different structural systems found in each independent line of resistance if the following conditions are met: (1) Risk Category I or II building, (2) four stories or less above grade plane, and (3) the seismic force-resisting systems are composed of WSP shear walls, steel moment-resisting frames, steel cantilever columns, and steel braced frames. Values for Cd and Ω0 shall be consistent with the R value used. Add the following subsection: A403.3.1 Story strength. Calculation of story strength and identification of irregularities in Section A403.3 shall be based on the expected strength of all wall lines, even if sheathed with nonconforming materials. The strength of a wall line may be reduced to account for inadequate load path or overturning resistance.

Commentary: The expected strength of the story above may be calculated using the FEMA P-807 criteria given in Bulletin Section B5.1. The requirement to assume an adequate load path prevents underestimating the upper story strength. It will apply for calculations of weak story or soft story ratio in ASCE 31/41, CEBC Appendix A - Chapter A4, and other code-based procedures; application of the 1.3 cap on retrofit strength for ASCE 41 and IEBC Appendix A - Chapter A4 retrofits; and calculation of spectral capacity with FEMA P-807. A403.5. Revise the subsection heading and the provision as follows: A403.5. Deformation Compatibility and PΔ effects. The requirements of the building code shall apply, except as modified herein. All structural framing elements and their connections not required by design to be part of the lateral force-resisting system shall be designed and/or detailed to be adequate to maintain support of expected gravity loads when subjected to the expected deformations caused by seismic forces. Increased demand due to PΔ effects and story side sway stability shall be considered in retrofit stories that rely on the strength and stiffness of cantilever columns for lateral resistance.

Commentary: This revision is consistent with a change approved for the latest edition of IEBC. A403.8. Revise the provision as follows: A403.8 Horizontal diaphragms. The diaphragm immediately above the target story shall be evaluated and/or strengthened as required by Bulletin Section A1.1. Rotational effects shall be accounted for when asymmetric wall stiffness increases shear demands.

Commentary: This revision is consistent with a change approved for the latest edition of IEBC. A403.9.1 Revise the provision as follows: A403.9.1 Gypsum or cement plaster products. Gypsum or cement plaster products shall not be used to provide lateral resistance in a target story. A404. Omit Section A404 entirely.

Commentary: Section A404 applies to two-story buildings only. Two-story buildings are exempt from SFEBC Chapter 5E. A405.1. Revise the provision as follows: A405.1 New materials. New materials shall meet the requirements of the building code, except where allowed by this chapter or applicable Administrative Bulletins. A407 Quality Control. Omit Section A407 entirely.

Commentary: Bulletin Sections A4 and A5, as well as AB 106, apply instead. Part G. GUIDELINES FOR ALTERNATIVE RATIONAL DESIGN BASES

DISCUSSION : Further development of this section is expected as needed to address issues specific to Chapter 5E. Sections to be outlined below will cover broad issues consistent with Chapter 5E. Otherwise, use of this standard is subject to existing Department procedures for implementation of SFBC 104A.2.8, Alternate materials, design, and methods of construction.

Revision signed by: Tom C. Hui, S.E., C.B.O. June 27, 2017 Director Department of Building Inspection Originally approved by Building Inspection Commission on November 20, 2013 Revisions approved November 19, 2014; December 16, 2015; May 19, 2016; May 17, 2017 AB-108 Application of California Existing Building Code, Appendix Chapter A3

NO. AB-108 :

DATE : April 16, 2014 (Updated 01/01/2023 for code references) SUBJECT : Permit Processing and Issuance TITLE : Application of California Existing Building Code, Appendix Chapter A3 PURPOSE : The purpose of this Bulletin is to detail procedures for the application of California Existing Building Code (CEBC), Appendix Chapter A3, Prescriptive Provisions for Seismic Strengthening of Cripple Walls and Sill Plate Anchorage of Light, Wood- Frame Residential Buildings. This Bulletin also provides guidance for property owners which to take advantage of the incentive programs being offered by the California Residential Mitigation Program. REFERENCE : Current edition of the California Existing Building Code (CEBC), Appendix Chapter A3 California Residential Mitigation Program’s Earthquake Brace and Bolt website: http://www.earthquakebracebolt.com/ DISCUSSION : CEBC, Appendix Chapter A3 has been adopted as part of the California Code of Regulations, Title 24, Part 10. This code supplements the California Building Code, Title 24, Part 2. It provides prescriptive provisions for voluntary seismic strengthening of foundations, cripple walls and sill plate anchorage of certain wood-frame residential buildings.

Due to restrictions on cripple wall height, the prescriptive provisions of CEBC, Appendix Chapter A3 apply to a limited number of buildings in San Francisco. Where the prescriptive limits for height of cripple walls are exceeded, buildings may be considered to meet CEBC, Appendix Chapter A3 when approved by the Department. The voluntary implementation of the strengthening provisions of CEBC, Appendix Chapter A3 can be expected to reduce earthquake damage in residential buildings; however such provisions are not intended to meet any specific seismic performance goal. The strengthening of individual buildings will result in an improvement in the resilience of citywide building stock and will aid the City in meeting its earthquake resilience goals such as residential shelter-in-place. The use of these prescriptive provisions will assist San Francisco building owners in strengthening buildings by providing a clear set of construction requirements and by allowing building owners to qualify for assistance from various seismic improvement programs. Building owners using the prescriptive provisions will not need to engage the services of a registered design professional and will generally find that seismic improvement design and construction costs are reduced compared to engineered retrofits.

SCOPE It is the intent of the Department of Building Inspection to allow the application of the provisions of CEBC, Appendix Chapter A3 to residential buildings of Occupancy Classifications R-3 and R-3.1. IMPLEMENTATION Permits seeking to comply with this Administrative Bulletin shall be in accordance with CEBC, Appendix Chapter A3. PLAN REVIEW AND PERMIT ISSUANCE On-line, over-the-counter and other expedited forms of permit issuance shall be allowed for work that fully complies with CEBC, Appendix Chapter A3. If proposed work does not conform to all prescriptive requirements or exceeds the scope of CEBC, Appendix Chapter A3, either over-the-counter plan review or submittal of permit application shall be required. Submitted applications will be processed in accordance with standard Department procedures. PERMIT SUBMITTAL DOCUMENTS Each building permit application that is submitted to comply with CEBC, Appendix Chapter A3 must clearly state in the “Project Description” portion of the application, “This Permit is for work to be performed in general conformance with California Existing Building Code, Appendix Chapter A3.” For Permits that Conform to all Prescriptive Requirements of CEBC, Appendix Chapter A3 A simplified plan shall be prepared for work that meets all of the requirements of CEBC, Appendix Chapter A3 and this bulletin. Such plan shall include: 1. approximate length and height along each wall line. 2. number of stories above each wall line or portion of wall line. 3. approximate percentage of each wall line or portion of wall line proposed to be braced. This plan need not be prepared by a licensed design professional provided the proposed design does not exceed the limitations under state law requiring a licensed design professional. Permits that fully comply with A3 shall be issued over-the-counter. Field inspection by Department staff shall verify that work is done in conformance with prescriptive requirements. For Permits that Do Not Conform to all Prescriptive Requirements of CEBC, Appendix Chapter A3 Submittal documents prepared by a licensed design professional must accompany a permit application for work that does not conform to all of the prescriptive requirements of CEBC, Appendix Chapter A3. Such submittal documents must show: 1. A plan of the floor(s) or level(s) to be reinforced showing a. approximate length and height along each wall line. b. number of stories above each wall line or portion of wall line. c. approximate location of proposed bracing. 2. For cripple walls that are proposed to be braced that are over 4 feet in height in buildings up to two stories, or over 14 inches in height for three story buildings, a stamped and signed analysis by a registered design professional or other submittal documentation determined acceptable by the Department shall be submitted showing that the proposed alternatives are equivalent to CEBC, Appendix Chapter A3 in strength, deflection and capacity. 3. For new or partial foundation construction to be undertaken as part of the CEBC, Appendix A3 upgrade work, engineered foundation plans meeting the requirements of the San Francisco Building Code prepared by a registered design professional shall be submitted. PLAN REVIEW BY OTHER CITY AGENCIES Review by agencies other than the Department of Building Inspection shall be in accordance with standard plan review guidelines. Specific conditions of permit approval may be required by other City agencies. Project sponsors should carefully review all comments and notes on plans and permits regarding such conditions of approval. FEES Fees for plan review and permit issuance by all agencies shall be as detailed in San Francisco codes and regulations. TRIGGERED CODE REQUIREMENTS Water heater bracing is required to be part of all CEBC, Appendix Chapter A3 seismic strengthening work. Smoke detectors and carbon monoxide detectors are required to be installed at the time of this work, unless already in place. Water conservation devices for toilets and showers may be required to be installed at the time of this work. For more information on these requirements, please see Chapter 13A of the San Francisco Building Code for Commercial Water Conservation or Chapter 12A of the San Francisco Housing Code for Residential Water Conservation Other code requirements may be triggered by this voluntary seismic upgrade work. Department of Building Inspection staff, including field inspection staff, can provide further information on such requirements.

INSPECTION AND SPECIAL INSPECTION The following requirements apply to all construction work undertaken to comply with CEBC, Appendix Chapter A3. A copy of building permit(s) and all approved construction documents issued for the work shall be available on the job site for reference by Department inspection staff. When approved by the Department, special Inspection is not required for adhesive, expansion, or other foundation anchor elements or for other related construction when work is strictly in accordance with the prescriptive requirements of CEBC, Appendix Chapter A3. Special inspection may be required for other elements as designated by the Department in accordance with the requirements of San Francisco Building Code, Chapter 17. Approved construction documents should be carefully reviewed for any such special inspection requirements. Final inspection shall be made by Department inspection staff confirming completion of all work necessary to conform to CEBC, Appendix Chapter A3, including proper installation of wall bracing elements. COMPLETION OF WORK Upon completion of permit work, including final inspection, submittal and approval of any Special Inspection documents and verification of compliance with all conditions of approval, documents confirming completion of work will become part of the permanent record at the Department of Building Inspection. RECORDKEEPING AND REPORTING A list of buildings by street address and by block and lot number for which work has been completed to strengthen according to CEBC, Appendix Chapter A3 will be maintained. Originally signed by: Tom C. Hui, S.E., C.B.O. April 16, 2014 Director Department of Building Inspection Approved by Building Inspection Commission on April 16, 2014 AB-109 Application of Engineering Criteria in SFEBC Section 329 NO. AB-109 :

DATE : August 21, 2014 (Updated 01/01/2023 for code references) SUBJECT : Seismic Evaluation of Private School Facilities TITLE : Application of Engineering Criteria in SFEBC Section 329 PURPOSE : The purpose of this Bulletin is to establish acceptable evaluation criteria and reporting standards for complying with Section 329 of the 2019 San Francisco Existing Building Code, as amended by Ordinance No. 202-14. REFERENCE : Chapter 4, 2019 San Francisco Existing Building Code ASCE 41-13, Seismic Evaluation and Retrofit of Existing Buildings DISCUSSION : SFEBC Section 329, created with Ordinance 202-14, mandates the seismic evaluation of certain existing buildings and non-building structures used by schools that are not under the jurisdiction of the Division of the State Architect’s Structural Safety section. SCOPE : Part A of this Bulletin provides regulations to implement the general requirements of SFEBC Section 329, as well as background commentary. Part B of this Bulletin provides interpretation and additional guidance regarding the application of technical provisions in ASCE 41-13, referenced by SFEBC Section 329.

Part A. Regulations and Commentary for SFEBC Section 329 Part A of this Bulletin restates the provisions of Section 329 and provides corresponding interpretations and background commentary. Commentary is shown in italic font. Section numbers refer to SFEBC Section 329. Submittal schedule SFEBC Sections 329.3 and 329.4 provide two submittal deadlines: The Evaluation Scope document for each school is to be submitted within one year of the effective date of Section 329. The Evaluation Report for each school building and non-building structure is to be submitted within three years of the effective date of Section 329. Report templates for each submittal are provided as attachments to this Bulletin. 329.1 General. The intent of Section 329.1 is to cover certain E-occupancy buildings that are not under the jurisdiction of the Division of State Architect’s

Structural safety section and non-building structures accessory to those buildings. The intent of Section 329.1 is to cover all the buildings and non-building structures on the school campus that are used primarily for school purposes, including cafeterias, gyms and multipurpose rooms. Schools will have the opportunity to use the Scoping Document to state buildings they intend to evaluate. For purposes of Section 329, a “non-building structure” is defined in SFBC Chapter 2 as a structure that does not support or shelter any use or occupancy and is also defined in ASCE 7-16 Chapter 15. The intent of Section 329.1 is to include non-building structures such as retaining walls, covered walkways, patio covers, and other structures that are prone to earthquake damage, but only when these non-building structures serve buildings subject to Section 329. It is not the intent of Section 329.1 to include lightweight structures with no history of poor earthquake performance, such as well-anchored playground equipment or light wood or metal fences. Some Department judgment is expected to apply during review of the Evaluation Scope document. It is not the intent of Section 329.1 to cover: • Buildings off of the school’s campus, even if used by students or faculty. • Buildings on the school’s campus that are used primarily for non-school purposes, such as churches or convents, including such buildings occupied by 25 or more persons for less than 12 hours per week or four hours in any given day. SFBC Section 305.1.1 applies to spaces associated with the functions of the place of religious worship to which they are accessory. It is the intent of SFEBC Section 329.1 that classrooms in buildings used for religious worship are within the scope of Section 329.1 if they are used for educational purposes for an amount of time that exceeds the time restrictions listed in 329.1 Exception 1. • Buildings occupied by 25 or more persons for less than 12 hours per week or four hours in any given day. • Schools where the average enrollment of the past three years is 25 or fewer students. In accordance with SFBC Section 303.1.3, school gyms, auditoriums, and other spaces or structures used for assembly purposes that are nevertheless assigned an E occupancy and are thus within the scope of Section 329.1. Evaluations shall be conducted under the supervision of a licensed design professional. 329.2 Scope and Criteria For purposes of Section 329, previous versions of ASCE 41, specifically ASCE 31-03 and ASCE 41-06, are not acceptable as alternatives to ASCE 41-13. See Part B of this Bulletin for modifications and interpretations of ASCE 41-13 criteria.

Commentary: The intent of the evaluation is to identify hazards known to be associated with earthquake- related severe injury or death. In addition to the tabulated scope, voluntary mitigation of contents hazards is encouraged. Such mitigation could include bracing, restraint, or removal of supplies, stored items, or furnishings prone to hazardous tipping or sliding. It might also include nonstructural mitigation that is not required by Section 329. References regarding contents bracing have been developed by FEMA, the Division of the State Architect, and others. For example, see “Guide and Checklist for Nonstructural Earthquake Hazards in California Schools,” available at https://mitigation.eeri.org/wp- content/uploads/guide-and-checklist-for-cal-schools.pdf. 329.5 Voluntary Minimum Life-Safety Retrofit

Commentary: Section 329 requires evaluation only. Section 329.5, however, anticipates that some schools will perform voluntary mitigation or retrofit either before or after completing their evaluation. To encourage this work and to relieve these schools from unknown future requirements, Section 329.5 provides, for a period of 20 years after the effective date of Section 329, that any building or non-building structure within the scope of Section 329 for which voluntary seismic strengthening is performed to meet or exceed the criteria of ASCE 41-13, S-3 N-C with the BSE-1E hazard shall not be identified as a seismic hazard pursuant to any local building standards adopted after the effective date of Section 329 unless the building incurred disproportionate damage, or otherwise has been damaged or altered so that it no longer meets the engineering criteria under which it was retrofitted. Part B. APPLICATION OF ASCE 41-13 TO EVALUATION Part B of this Bulletin makes modifications to and interpretations of ASCE 41-13 as they relate to compliance with SFEBC Section 329. The section numbers refer to section numbers in ASCE 41-13.

Omit. Retrofit is beyond the scope of SFEBC Section 329.

Omit. Evaluation objectives are given in SFEBC Section 329.2.

The level of seismicity shall be taken as High for all schools subject to SFEBC Section 329.

The Site Class designation should be made following the current edition of the applicable code and standard (e.g., ASCE 7, SFBC). The Site Class definitions should be based on Vs30 and presence of soft clay or liquefiable soils. According to the code-based Site Class designation, Vs30 is defined in the free field from the ground surface to the depth of 30 m (100 ft). However, Site Class may be defined below the bottom of the mat foundation (see Section 10.2.2 Ground Motion Characterization Commentary), if deemed appropriate.

The effects of sea level rise during the design life of structures should be evaluated based on NRC 2012; CCSF 2014; CCSF 2016; Plane et al. 2019; Yasuhara, et al. 2007; and others. Effects considered should include, but are not limited to, the potential for increased flooding and the effect of rising groundwater on increasing hydrostatic pressure, increasing liquefaction potential, saltwater intrusion, and decreasing bearing capacity.

Basement walls should be designed against the more critical of the following conditions: (1) At-rest soil pressure and (2) active soil pressure plus dynamic increment. In addition, effects of surcharge loads (traffic and adjacent building foundation, if not underpinned) should be considered. When calculating hydrostatic pressure, the design groundwater table with consideration of sea level rise and seasonal fluctuation of groundwater table should be identified and used. If a drainage system is not installed behind the basement walls above the design groundwater table, the basement walls should be waterproofed beginning at the ground surface. In this case, the basement walls should be designed per code requirements and checked for the groundwater table being at the ground surface, but using a load factor of 1.0 as opposed to 1.6 for this check.

Commentary: According to the load combination in current building code, a factor of 1.6 is applied to hydrostatic pressure. The resulting pressure in most cases accounts for effects of sea level rise, fluctuation in groundwater table, or effects of a temporary buildup of water behind the basement walls due to a possible breakage in a water conveying pipe adjacent to the site. Care should be exercised to avoid undue conservatism in design against hydrostatic pressure.

Resistance to lateral loads could be calculated by considering frictional resistance on basement walls and beneath the foundation (if not pile- supported) and passive pressure against the basement walls, pile caps, grade beams, and foundation edge extending below the basement walls. In calculating frictional resistance, the effects of the presence of a waterproofing membrane (if used) on allowable frictional resistance should be accounted for. A load-deflection curve for passive resistance should be developed by the GEOR and used by the SEOR to account for displacement compatibility within various components contributing to lateral resistance. For basement walls in contact with slopping ground conditions, the effects of unbalanced soil pressure on basement walls should be considered. 11. FOUNDATION SUPPORT Shallow or deep foundation systems may be appropriate for support of tall buildings depending on the ground conditions, structural loads, and performance criteria. Unless it could be demonstrated through comprehensive geotechnical and structural studies that the computed total and differential settlement will not compromise the safety and functionality of the structure and its components, foundation systems should be designed to meet the following criteria using the best estimate soil properties: (1) the total short-term and long-term computed settlement of the foundation under gravity and seismic loads should not exceed 4 inches, and (2) its differential settlement under gravity and seismic loads should not exceed an angular distortion of 1/500. Nonstructural components such as cladding or partition walls may control the acceptable threshold of differential settlement. The amount of dishing of the site under building load should be communicated to the SEOR in the geotechnical report, so that the appropriate building camber could be provided.

Commentary: The inherent variability of natural soil deposits often causes tilting of the foundation (rigid body rotation), which would add to differential settlement (dishing) caused by the applied structural loads. The magnitude of foundation tilting is directly related to the extent of total settlement. Some tilting can be compensated for during construction; however, some tilting may occur after construction is completed. If settlement of more than 4 inches is calculated, GEOR and SEOR should work together and carefully evaluate the impact of settlement larger than 4 inches on the structural system and nonstructural components. Factors to be considered include the amount of settlement occurring after placement of the mat and before the lowest floor is constructed, the timing of placement of cladding and ability to correct foundation tilting before cladding is installed, and of course, the tolerance of cladding to differential settlement caused by tilting and/or by dishing of the mat foundation. Settlement analyses are often made using the approximation that the foundation soil deposits are uniform, homogeneous layers. If this simplification is adopted, it is recommended that the GEOR perform analyses to evaluate the sensitivity of the computed settlement on the input soil parameters.

For shallow foundations, the factor of safety against bearing failure (both global failure mechanism and punching shear failure mechanism) should be evaluated. A minimum factor of safety of 2.0 should be maintained under anticipated gravity loads considering the above bearing failure mechanisms. If ground improvement is used to mitigate the effects of compressible, weak, liquefiable, or other problematic soil conditions, the GEOR should review design calculations by the design-build (DB) contractor to check that the integrity of ground improvement elements is maintained during both static and seismic loading conditions; that is to say, the replacement ratio and geometry of grid pattern should be such that the ground improvement system maintains its integrity under structural gravity loads, seismic loads (base shear and overturning moment applied by the structure), and seismic loads due to vertical propagation of seismic waves.

Commentary: Recent research indicates that individual columns of deep soil mix (DSM) would bend during design-level ground shaking, thereby limiting the effectiveness of DSM columns for prevention of soil liquefaction. In addition to lateral movement, individual unreinforced DSM columns could crack in bending and with excessive repeated loading and extensive cracking, could have the effect of losing the cohesive strength associated with cementation, with a residual strength related to contact through friction only. Unreinforced individual columns of DSM are brittle and could fail to transfer gravity loads to more competent soils at depth.

If deep foundations are used to bypass compressible, soft, or liquefiable soils, the following construction design issues should be addressed:

The geotechnical report should address axial and lateral pile capacity, driving criteria, noise and vibration effects, corrosion protection, indicator- pile driving program, and pile load testing.

The geotechnical report should address axial and lateral pile capacity, integrity testing requirements (especially in case of loose to medium dense saturated sandy soils and soft clayey soils) using, for example, cross hole sonic logging, cross hole Gamma-Gamma logging, thermal testing, or a combination of these methods, as appropriate, pile load testing, and requirements for an automated data-acquisition system.

The geotechnical report should address axial and lateral pile capacity, axial pile load test for drilled shafts with reaction piles or bidirectional load cells, integrity testing using cross-hole sonic logging, cross-hole Gamma-Gamma logging, thermal testing, or a combination of these methods, as appropriate. End bearing for shafts is normally ignored unless pile capacity can be verified by top-down or by using bidirectional load tests. For end bearing in dense sand or bedrock, the bottom of a shaft should be cleaned out thoroughly and tested using Mini SID (Shaft Identification Device) or similar tools for evaluating proper clean out. 12. SHORING, DEWATERING, EXCAVATION AND UNDERPINNING The geotechnical report should address shoring, dewatering, and underpinning. Design of the shoring, dewatering, and underpinning system is usually provided by specialty contractors, with design parameters (soil and groundwater pressure) provided by the GEOR. If shoring is used to support an adjacent building, the design soil pressure should correspond to the at-rest pressure and account for building surcharge. The GEOR and the EDRT should review the contractor’s analysis and design to evaluate that the design has used appropriate soil and groundwater pressures. The GEOR and the EDRT should also review the contractor’s Plan of Action for trigger levels (e.g., Warning Level or Design Limit) of lateral and vertical movement of the shoring and underpinning system before the start of construction. Because of the potential presence of confined aquifers within or below the BM and OBC, nested piezometers should be installed outside of the excavation for monitoring of drop in groundwater table and water head within various sand layers, as appropriate. Bottom of excavation should be evaluated for expected conditions for stability. If cohesionless soil is exposed at the bottom of the excavation, the factor of safety against bottom instability should be calculated to check that piping (quick sand condition) is prevented. If cohesive soil is exposed at bottom of excavation, the factor of safety against basal heave should be calculated. Finally, if a cohesionless soil layer at depth is overlain by a layer of cohesive soil at the bottom of excavation, the blowout condition should be carefully analyzed and, if necessary, the cohesionless soil layer should be depressurized to prevent a bottom blowout condition. 13. INSTRUMENTATION AND CONSTRUCTION MONITORING The GEOR should provide recommendation for geotechnical instrumentation and construction monitoring at locations where ground conditions, type of loading, or proximity of existing structures could be adversely affected by planned construction.

The type, location, and requirements for instrumentation should be determined by the GEOR based on the impact of construction related to excavation, shoring, dewatering, foundation installation including noise and vibration, and implementation of ground improvement on groundwater conditions and performance of adjacent structures, roadways, utilities, and other improvements. The geotechnical report should provide the rationale for selection of instrumentation type and number, installation method, and the frequency of monitoring for each type of instrumentation. The frequency of monitoring should be defined based on the type of loading and construction activities. Monitoring should be initiated before the construction work starts to obtain ambient or baseline conditions. As appropriate, monitoring rates may be adjusted after initial period of monitoring, if data from instrumentations indicate that the rate of change is diminishing with time. The instrumentation used for monitoring during construction should be sufficient to meet accuracy and reliability requirements needed for the duration of monitoring.

The GEOR should develop a plan for preconstruction monitoring of adjacent buildings and improvements. The GEOR should request that the shoring and dewatering contractor(s) evaluate the effects of lowering of the groundwater on adjacent structures and improvements, and define the allowable drop in groundwater level outside of the excavation. The allowable lowering of the groundwater elevation should account for the duration of the anticipated construction-related change in the groundwater level. The GEOR should request that the dewatering contractor prepare for review and approval a plan of action in case the groundwater table drop below the contractor’s specified limit.

The baseline and data collected during construction from piezometers and inclinometers, and field warnings (see section 9 for discussion on warning level or design limit) should be reported to the design and construction team in a timely manner. If in response to a field warning any changes are made to the original design, the revised design should be presented to the GEOR and the geotechnical members of EDRT for further review. 14. OTHER CONSTRUCTION CONSIDERATIONS The geotechnical report should address the following construction considerations: • The effects of construction on adjacent buildings, notably where ground improvements or new foundations extend below the foundation of the adjacent buildings; • The potential of loss of ground and displacements due to construction of large-diameter drilled shafts installed deeper than the foundation of an adjacent buildings; • Impact of installation of deep foundations on previously installed foundations; • The potential impact of ground-surface heave or vibrations on adjacent structures and improvements; • The effect of construction on the groundwater level inside and outside of the construction area. 15. SETTLEMENT MONITORING REQUIREMENTS Prior to completion of all new tall building projects where the building is planned to be supported on a shallow foundation underlain by soil (i.e.

the foundation is not bearing directly on bedrock) or on a deep foundation system not gaining axial support within bedrock or not driven to bedrock / bedrock-type material, the project Sponsor shall secure a contract with qualified Monitoring Surveyors and Instrumentation Engineers (MSIEs) to monitor the settlement of the buildings for a period of 10 years after the issuance of CFC/TCO. A notarized legal document, completed by the Project Sponsor and recorded against the property title, with the MSIE’s contact details, shall be submitted to DBI prior to issuance of the CFC/TCO and shall be retained with the project’s permanent records and readily retrievable within DBI’s inspection records on this project. Settlement monitoring data are to be submitted annually to DBI’s Building Inspection Division each year of this 10-year period. Should the settlement monitoring data exceed the project sponsor’s geotechnical engineer’s estimated time rate of settlement in any annual data reporting period, the project sponsor/owner is required to immediately notify the DBI’s Deputy Director for Inspection Services and bring this condition to his/her attention for immediate additional investigation. Originally signed by: Patrick O’Riordan June 24, 2020 Interim Director Department of Building Inspection Daniel Lowrey June 24, 2020 Permit Services Deputy Director Department of Building Inspection Gary Ho June 24, 2020 Plan Review Services Manager Department of Building Inspection Approved by the Building Inspection Commission on June 17, 2020 AB-112 Implementation of Regulations for All Electric New Construction and Major Renovations

NO. AB-112 :

DATE : Effective June 1, 2026 (Supersedes AB-112 issued June 1, 2021) SUBJECT : Administration and General Design TITLE : Implementation of Regulations for All Electric New Construction and Major Renovations PURPOSE : The purpose of this Administrative Bulletin is to detail standards and procedures for the implementation of the all-electric new construction requirements of the San Francisco Building Code. REFERENCE : San Francisco Building Code; San Francisco Green Building Code; San Francisco Administrative Bulletin 005: Procedures for Approval of Local Equivalencies; California Building Standards Code; San Francisco Environment Code, Chapter 7.

CONTENTS

1. Discussion
2. Criteria for Exception Allowing a Mixed-Fuel Building System or Area
3. Review for Determination of Infeasibility
4. Project Completion Attachment 1: Design Guideline for Public Safety and Electric Ready Construction Attachment 2: Final Compliance Verification - Form Attachment 3: Commercial Food Service Exception - Form Attachment 4: Review of Pre-Existing Agreement - Form Attachment 5: Gas-Fueled Appliance Meeting a Federal Efficiency Standard - Form Attachment 6: Summary of Investor-Owned Utility Options for Proposed Electric Load Exceeding Capacity of Utility Infrastructure

7/1/2026 (S-2) Page 112-1

AB-112 2025 SAN FRANCISCO BUILDING CODE

1. DISCUSSION San Francisco Building Code 106A.1.17 requires newly constructed buildings and major renovations to existing buildings to be designed and constructed such that all space conditioning, water heating, cooking, and clothes drying systems are all-electric, as defined. San Francisco Building Code 106A.1.17 prohibits installation of infrastructure, piping systems, or piping for distribution of natural gas or propane to such uses, and allows limited exceptions. APPLICABILITY San Francisco Building Code Section 106A.1.17 applies to all permit applications submitted on or after June 1, 2021 proposing to construct one or more new buildings, and to all permit applications submitted on or after July 1, 2026 proposing a major renovation to an existing building in San Francisco. In the case of Site Permits, the effective date is the date the Site Permit application (not an addendum) is filed with the Department of Building Inspection. Addenda to site permits and revisions to permit applications received before the dates above are not required to meet the requirements of San Francisco Building Code Section 106A.1.17, unless the addenda or revisions change the scope of the project such that current codes are generally applicable, or such that an exception is no longer warranted. WHAT IS AN ALL-ELECTRIC BUILDING An All-Electric Building or Project as defined by San Francisco Building Code Section 202 relies on electricity as the source of energy for space heating, space cooling, water heating, cooking, and clothes drying. In addition, building permits are prohibited for projects proposing to install gas piping systems, fixtures, or infrastructure for decorative uses and lighting or onsite generation of electricity. Steam generated off-site may be used for space conditioning, water heating, or laundry equipment. MAJOR RENOVATIONS TO EXISTING BUILDINGS A ‘Major Renovation’ is an extensive alteration or addition that proposes replacing mechanical systems. Specifically, a Major Renovation is defined by San Francisco Building Code: Major Renovation: In addition to substantial upgrade to mechanical systems, the project fits one or more of the following categories: (1) a Non-structural Alteration that is substantial pursuant to ... Section 304.51 of the San Francisco Existing Building Code;

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1 As of January 2026, the section of San Francisco Existing Building Code (2025 edition) describing a non-structural alteration was relocated to Section 304.5. Section 503.11.1 is no longer applicable.

(2) a Substantial Structural Alteration as defined by Section 202 of the San Francisco Existing Building Code; (3) an addition that is a Substantial Improvement as defined by Section 202 of the San Francisco Existing Building Code. Substantial Upgrade to Mechanical Systems: The proposed project: (1) “Replaces space heating and hot water heating system for the entire building; or (2) Installs space heating and water heating systems that will serve 80% or more of the total conditioned floor area of the building; or (3) Installs space conditioning or water heating systems serving the area of addition.”

EXCEPTIONS In the following circumstances natural gas or propane piping systems, fixtures, or infrastructure may be installed to the minimum extent necessary for the operation of equipment installed as part of the proposed project. All buildings or projects covered by San Francisco Building Code 106A.1.17 shall comply with the Design Guidelines and for Public Safety and Electric Ready Construction (Attachment 1). Exceptions (A) through (G) below describe exceptions that apply prescriptively to circumstances specified in the San Francisco Building Code. Exception (H) allows flexibility if it is not physically or technically feasible to build all-electric. A. USES NOT SPECIFICALLY REGULATED Gas piping systems, fixtures, or infrastructure may be installed strictly to serve areas and systems outside the scope of the definitions of All- Electric Buildings and Mixed-Fuel Buildings. For example, industrial processes are not specifically addressed by either definition. In an industrial project, natural gas piping systems, infrastructure, and fixtures may be installed as needed for a proposed industrial process - but space heating, space cooling, water heating, cooking, and clothes drying must be all-electric. B. APPLIANCES CERTIFIED BY THE MANUFACTURER AS MEETING FEDERAL ENERGY STANDARDS The federal Energy Policy and Conservation Act (EPCA) empowers the US Department of Energy (US DOE) to set standards for energy

efficiency of appliances sold in the United States. US DOE adopts standards by issuing regulations that specify the specific characteristics of appliances that a standard applies to, minimum energy efficiency, and testing procedures. US DOE maintains public records of which appliances have been certified by the manufacturer to meet a given standard. If a specific gas-fueled appliance has been certified to meet a given EPCA energy efficiency standard, the appliance may be installed in an ‘all-electric’ project. In a project where a gas-fueled appliance is installed, natural gas piping and infrastructure associated with this exception shall be limited to the operation of appliances specified and installed in the project. Gas piping systems, fixtures, and infrastructure shall not be installed to serve the location of any appliance that does not require natural gas to operate, nor any appliance not certified as meeting an EPCA efficiency standard. To propose installation of gas-fueled appliances complete the form in Attachment 5: “Application to Install Gas-Fueled Appliance Meeting a Federal Efficiency Standard.” C. COMMERCIAL COOKING AREAS – NEW CONSTRUCTION For new construction projects which submit an initial application for permit: • On or after June 1, 2021 and before January 1, 2022: Areas specifically designated for commercial food service may provide gas piping systems, fixtures, and infrastructure exclusively for cooking equipment within the area designated for commercial food service. • January 1, 2022 or thereafter: Permission may be granted to install gas piping systems, fixtures, and infrastructure exclusively to serve cooking equipment within an area designated for a specific commercial food service establishment, such as a specific restaurant. Proposed gas infrastructure and piping shall be documented by completing Attachment 3: Application for Gas in Commercial Food Service. Include the name of the food service establishment, proposed gas cooking appliances, and fuel consumption rating for each device. D. COMMERCIAL COOKING AREAS – MAJOR RENOVATIONS TO EXISTING BUILDINGS In Major Renovation projects where an initial application for permit is submitted on or after July 1, 2026, gas piping systems, fixtures, and/or infrastructure shall be limited to areas designated for installation of gas-fueled cooking equipment for a food facility. Gas piping may be installed to serve a food facility that is part of the proposed project or a future food facility. Proposed gas infrastructure and piping shall be documented by completing Attachment 3: Application for Gas in Commercial Food Service. For food facility water heating systems, see also Physical or Technical Infeasibility below. E. AFFORDABLE HOUSING All-electric requirements apply to construction of new buildings, including affordable housing, where an initial application for permit is submitted on or after June 1, 2021. For projects which submit an initial application for permit for a major renovation to an existing building which will create or preserve 100% affordable housing: • Prior to July 1, 2027: The project is exempt from all-electric requirements including Design Guidelines and for Public Safety and Electric Ready Construction. Other regulations may continue to apply, such as electric-ready provisions of Title 24 Part 6 (2025) and Bay Area Air District Regulation 9 Rule 6: Nitrogen Oxide Emissions from Water Heaters. • From July 1, 2027 to January 1, 2031: If the cost of converting to All-Electric would conflict with a project’s ability to meet project Affordable Housing Goals, Mayor’s Office of Housing and Community Development (MOHCD) shall submit a waiver request to the Environment Department, documenting: ° The project’s affordable housing goals as defined by MOHCD, ° The issue facing the project, ° The specific gas piping systems, infrastructure, and fixtures requested, and ° Proposed modified compliance with Design Guidelines for Public Safety and Electric Ready Construction, if necessary to the project’s Affordable Housing Goals. The waiver request shall be submitted via email to: greenbuilding@sfgov.org. The Environment Department shall review the waiver request via the procedures described in Environment Code Section 705. • January 1, 2031 and thereafter: Shall be all-electric. F. NON-RESIDENTIAL TO RESIDENTIAL CONVERSION Projects proposing to convert an existing building from primarily non-residential use to primarily multifamily residential use (R-2 occupancy) prior to January 1, 2031 are exempt from all-electric requirements of San Francisco Building Code 106A.1.17.3. Note that this exemption does not apply to relevant state and regional regulations, such as Bay Area Air District Rule 9-4 limiting nitrous oxide (NOx) emissions from water heaters and boilers, and Rule 9-6 limiting nitrous oxide emissions from furnaces. G. EXISTING DEVELOPMENT AGREEMENT OR CONTRACT Some development agreement projects or other multiphase projects may entail separate applications for permits to construct infrastructure serving an area versus buildings constructed after infrastructure is developed. San Francisco Building Code Section 106A.1.17 applies to any application to construct a building submitted to the Department of Building Inspection on or after June 1, 2021, or an application to construct a major renovation to an existing building submitted on or after June 1, 2026. If a project sponsor believes that application of San Francisco Building Code Section 106A.1.17 to a phase of development or to an individual building would violate the terms of a development or other agreement with the City, the project sponsor may seek a determination using Attachment 4: Application for Review of an Existing Agreement. Department of Building Inspection staff will refer the matter to the City Attorney’s Office to analyze the request fo

ncisco Building Code Section 106A.1.17 to a phase of development or to an individual building would violate the terms of a development or other agreement with the City, the project sponsor may seek a determination using Attachment 4: Application for Review of an Existing Agreement. Department of Building Inspection staff will refer the matter to the City Attorney’s Office to analyze the request for exception and the extent to which all or part of San Francisco Building Code Section 106A.1.17 will apply. An exception shall only apply to the extent required under the development agreement or other contract.

H. PHYSICAL OR TECHNICAL INFEASIBILITY A case-by-case exception for mixed-fuel construction may be granted when all-electric design is not feasible due to physical or technical constraints specific to the site and occupancy, and the same project is feasible if gas-fueled equipment is allowed to serve a specific system or area. Installation of natural gas piping systems, fixtures, or infrastructure shall be allowed only to the extent necessary to resolve the demonstrated infeasibility. Section 2 of this bulletin describes the criteria for a situation to be physically or technically infeasible. Section 3 describes the process to determine whether an issue of physical or technical infeasibility applies. 2) DETERMINATION OF PHYSICAL OR TECHNICAL INFEASIBILITY Physical or technical infeasibility is understood to refer to an exceptional situation where: A project proposal cannot be accomplished due to physical or technical constraints specific to the site and occupancy that prohibit elements, spaces or features necessary to comply with all requirements that apply to the proposed project; AND The project proposal is feasible and able to fully comply with all applicable requirements if gas piping systems, fixtures and infrastructure are allowed to serve a specific system or area. Table 1 below describes criteria to identify situations that may result in physical or technical infeasibility.

Table 1: Criteria for physical or technical infeasibility: Category Criteria A) Energy Standards Compliance with Title 24 Part 6 Energy Standards for all-electric design may be infeasible only if there is no prescriptive option for compliance with the Energy Standards, nor an option for compliance under the performance method for any system or technology serving the specific use. Proposal to install a technology, system, or design not allowed under the Energy Standards does not demonstrate infeasibility where available all-electric technologies, systems, or designs would comply with the Energy Standards. All new construction and most renovations entail installation or modification of electric utility infrastructure. All-electric construction is infeasible only if all-electric design would impose substantially greater delay to construct electric utility infrastructure than an equivalent mixed-fuel design. “Substantially greater” refers to a delay that adversely impacts viability of the project. Recent California laws (SB410 & AB50, 2023) require PG&E to improve customer service for new and modified electric service. The CPUC has set the following targets:

B) Electric Utility Infrastructure Delay - General Utility Activity Average Target (calendar days) CPUC Maximum Timeline (calendar days) Increase in CPUC Maximum Timeline Review Application 10 45 – Energize Line Extension

• Either from secondary transformer to meter, from substation to secondary transformer, or both combined 182 357 – New Distribution Circuit (12 kV or greater) – 684 92% Substation Upgrade – 1,021 49% New Substation – 3,242 218% More info: cpuc.ca.gov/industries-and-topics/electrical-energy/infrastructure/energization To determine whether electric infrastructure is physically or technically infeasible: • Prepare electric load calculations for both mixed-fuel and all-electric design, with equivalent occupancies, functions, and floor area; and • Submit an application for service to the electric utility serving the project. New Construction The all-electric option shall be deemed infeasible if: • The time required to construct the utility infrastructure for the all-electric design option is substantially greater than for mixed-fuel, and • The utility-estimated delivery date for such electric infrastructure improvements is significantly later than the proposed date for completion of construction. Major Renovation The all-electric option shall be deemed infeasible if the project qualifies for the new construction exception above, OR the CPUC’s Maximum Target timeline for improvements associated with the all-electric project (see table above) is 45% longer than for mixed fuel. Example: Mixed fuel requires a line extension (Maximum: 357 days). All-electric requires a new distribution circuit (Maximum: 684 days). 684 days is 92% longer than 357 days: all-electric is infeasible. See Section 3, Review for Determination of Feasibility for streamlined process determination of feasibility due to electric utility infrastructure for small infill sites and major renovations producing housing. C) Electric Utility Infrastructure: Delay - New Construction Served by SFPUC For a new construction project where electric service is being provided to a customer by the San Francisco Public Utilities Commission (“SFPUC”), and SFPUC confirms the peak electric demand requested for the all-electric design option would directly or indirectly require SFPUC to do any of the following: (i) Revise a previously submitted application for service to Pacific Gas and Electric Company (“PG&E”) that is currently under review by PG&E; (ii) Submit a new application for service to PG&E to serve a load for which there is an existing service agreement with PG&E; (iii) Alter plans for electric infrastructure that have been approved or alter infrastructure under construction; or (iv) Make changes to existing infrastructure that would impair or limit a contract right that exists as of the effective date of this ordinance. Situations (i) to (iv) above do not represent a basis for a finding of infeasibility if the same issue applies to a mixed-fuel design constructed at the same site with equivalent occupancies, functions, and floor area. Situations (i) to (iv) will only apply to developments where an application for wholesale electric service relating to the parcel has been submitted to and deemed complete by PG&E as of the effective date of the ordinance (June 1, 2021), and the project sponsor demonstrates it is physically or technically infeasible to build all-electric within the electrical capacity constraints documented in existing applications for service to PG&E for the purpose of serving buildings that were planned but not yet permitted as of the effective date of the ordinance. An over-estimation of ampacity requirements for all-electric design compared to mixed fuel is not a basis for exception. Under California Public Utilities Commission Rule 2.C, utilities are obligated to provide service. Request by the utility for the customer’s proposal to comply with applicable tariff, easement, safety, and reliability requirements, or for reasonable time to construct improvements, is not a basis for infeasibility.

D) Physical Constraint in Small Infill Sites All-electric design may be infeasible if based on the rules published by the electric utility serving the site:

1. Mixed-fuel design does not require the installation of an electric service transformer; and
2. All-electric design with the same features would require the installation of an electric transformer; and Either New Construction: • The site has a linear footage of street frontage of 75 feet or less;2 and • The Planning Department confirms there is no feasible option to locate an electrical transformer on the premises. OR Major Renovation: • The site has a linear footage of street frontage of 75 feet or less; and • The existing utility service capacity serving the site (and the sum of capacity of service transformers if applicable) are: • insufficient for the proposed all-electric design, and • sufficient for mixed fuel. This exception does not apply if the proposed mixed-fuel design will install a new transformer on the premises or a sub-surface vault in the public right of way, including replacement with a transformer of greater capacity than was previously installed. E) Food Service Water Heating - Existing Buildings In addition to meeting San Francisco Plumbing Code, water heating systems for commercial food facilities must be approved by the San Francisco Department of Public Health as complying with California Retail Food Code §114192(a), which requires hot water to be supplied at 120°F minimum. The California Conference of Directors of Environmental Health (CCDEH) Guidelines for Sizing Water Heaters (2020) provide a clear and repeatable standard for minimum sizing. The Heat Pump Plan Review for Food Facilities technical bulletin published by the Environment Department and Department of Public Health explains that tank-type hybrid heat pump water heaters with built-in electric resistance coils can satisfy 2020 CCDEH sizing guidelines. However, hybrid heat pump water heaters and electric resistance water heaters may be infeasible for large food facilities or facilities that utilize dish machines to clean eating and drinking utensils for public use. An exception applies if: • If dish machines are proposed: Each machine is a heat-recovery with cold water input only • The minimum input for an electric water heater (including heat pump water heaters) per CCDEH Guidelines (2020) Section VI. Sizing Requirements for Storage Water Heaters is 12 kW or greater. As of March 2026, CCDEH and California utilities are collecting field performance data to revise the CCDEH guidelines to better address all types of water heaters, including additional heat pump-based designs suitable for large food facilities. It is recommended that the Environment Department, Department of Public Health, and Department of Building Inspection review and revise this exception when CCDEH Guidelines are updated. F) Exceptional Circumstance All-electric design may be infeasible if • It is demonstrated physical or technical constraints specific to site and occupancy prohibit elements, spaces or features necessary for full and strict compliance with all-electric construction; and • If gas piping systems and fixtures are substituted for electrical equipment serving a specific system or area, the project can attain full and strict compliance with all- electric construction. Proposal to install a technology, system, or design that is inconsistent with, or not allowed by the discretionary determination by a City agency shall not be a basis for demonstration of infeasibility.

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2 The linear footage of street frontage is calculated by adding the lengths of all property lines directly adjacent to the right of way.

3. REVIEW FOR DETERMINATION OF INFEASIBILITY Compliance with San Francisco Building Code Section 106A.1.17 and all other requirements for new construction have been determined to be practical and feasible in general. San Francisco Building Code Section 106A.1.17 allows for approval of exception allowing gas infrastructure and piping systems to be installed on a case-by-case basis where All-Electric construction is demonstrated to be infeasible.

The conditions of infeasibility depend substantially on design details, and design development provides the opportunity to address physical and technical conditions. An application for design review for exception due to infeasibility will not be approved in the absence of substantial architectural detail, including the architectural addendum and Title 24 compliance documentation. Prior to DBI review of an application for exception due to infeasibility, a Review of All-Electric Infeasibility must be completed by engineers with specialized understanding of electrical engineering, mechanical design, energy efficiency including compliance with Title 24 Energy Standards, and experience with the design of all-electric systems for space conditioning and water heating. In all cases, it is the responsibility of the Design Professional of Record, with the support of the entire project team, to apply all available energy efficiency and electric load minimization practices. Review of All-Electric Infeasibility A Review of All-Electric Infeasibility answers two core questions: • What specific physical or technical constraint makes an all-electric design infeasible, but does not affect a mixed-fuel design? • Can the constraint be solved through reasonable design changes? To address these questions, the review shall include the following steps:

1. Identify the Constraint • Clearly describe the physical or technical issue that prevents All-Electric construction. Provide enough detail to show why the issue does not apply to a mixed fuel design.
2. Identify Alternatives A Review of All-Electric Infeasibility shall • Be prepared by professionals experienced with successful all-electric construction, as described in Qualifications for All-Electric Infeasibility Reviewers, below. The project sponsor is responsible for all costs related to All Electric Infeasibility Review, including hiring reviewers. • Review plans, calculations, and supporting documentation to determine whether the constraint can be resolved. For projects utilizing commissioning, the Owners Project Requirements and Basis of Design shall be shared with reviewers. (CalGreen 5.410 requires commissioning for non-residential projects of 10,000 square feet or larger. Residential projects that apply the LEED BD+C rating system will also undergo commissioning.) Consider alternatives in three areas: Efficiency Options: • Confirm all applicable energy efficiency design and construction practices have been applied, and the design meets or is more efficient

than Title 24 Energy Standards, including each applicable compliance metric. • Verify all equipment is no less efficient than the prescriptive baseline specified by Title 24 Energy Standards. • Confirm all feasible design and construction practices have been applied in order to reduce peak electrical load and electrical capacity required for the project. Mechanical Options • Determine whether alternative mechanical equipment size and type, piping and ducting layout, or envelope design can reduce peak heating and cooling loads in order to reduce peak electrical demand. • Determine whether mechanical system output can be reduced while maintaining Basis of Design consistent with Owners Project Requirements. Right-sizing heat pumps can significantly reduce the cost of mechanical and electric construction. Electrical Options: • Review electrical panel schedule and load calculations for the all-electric design. Confirm connected electrical load and demand electric load are calculated in accord with California Electrical Code, and consistent with the design used in Title 24 Energy Standards compliance calculations. • Make a specific recommendation as to whether proposed utility electric service capacity can be reduced in order to eliminate the constraint and enable all-electric construction. Comparable Examples • Document examples of all-electric construction in similar circumstances and identify the design and construction approaches that differ from the proposed design. Document Available Solutions: • Identify the specific area and system proposed as mixed fuel. • Document the options considered. • Demonstrate that a mixed-fuel exception is the only option that will resolve the constraint. • Confirm gas piping, fixtures or systems are strictly limited to the area where all-electric compliance is infeasible. 3. Apply Electric-Ready and Safety Requirements.

If mixed fuel is allowed, the affected area must be built electric-ready, which means the design includes sufficient space, safety features, and capacity for both safe operation and future installation of electric equipment. A complete All-Electric Infeasibility Review shall: • Comply with Design Guidelines for Public Safety and Electric Ready Construction (Attachment 1). If complete adherence to the Design Guidelines conflicts with the basis for an exception, staff shall approve modified compliance to the extent necessary to the viability of the project. • Review construction methods, equipment, and features proposed for the mixed-fuel area and recommend any additional measures needed to ensure health, safety, and fire protection equivalent to an all-electric design. 4. Submit a Review of All-Electric Infeasibility for approval Submit a Local Equivalency Request (Administrative Bulletin 005), with two copies of the following: • Project plans specifying the area and system proposed for mixed-fuel construction • Complete All Electric Infeasibility Review document, including design alternatives considered and comparable examples, and signatures of reviewers for electrical, mechanical, and architectural/Title 24 and stamp by the Design Professional of Record. • Proposed plans and specifications consistent Design Guidelines for Public Safety and Electric-Ready Construction. If any aspects of Design Guidelines cannot be met, indicate the specific issue and proposed modification. Pay plan review fees as noted in Administrative Bulletin 005. 5. Project Review Meeting The Department of Building Inspection will lead a review meeting with participation of the Environment Department, Design Professional of Record, Project Mechanical Engineer, and All-Electric Infeasibility Reviewers. The participants shall: • Review plans, calculations, Title 24 compliance documents, the Basis of Design where applicable, and supporting documentation described in “2. Identify Alternatives” above, in order to confirm: ° All possible energy-efficiency measures and design alternatives were considered. ° Gas piping systems, fixtures, and infrastructure are proposed only to the extent necessary for project feasibility. ° The proposed design meets the Design Guidelines for Public Safety and Electric-Ready Construction, in order to provide equivalent fire protection and health and safety to all-electric design. DBI will issue one of the following decisions • Approved with conditions determined by Department of Building Inspection with concurrence by Department of Environment, • Placed on “hold” pending submittal of additional information, or • Disapproved. Determinations may be appealed to the Board of Examiners, as established under Section 105.1 of the San Francisco Building Code. See https://sfdbi.org/board-examiners for details. Upon approval, a copy of the signed Request for Approval of Local Equivalency (AB-005) approving the indicating all conditions of approval will be part of the permanent record of the project, and a copy will be sent to the project sponsor. The project sponsor shall include all specified conditions in plans, specifications, and addenda. QUALIFICATIONS FOR ALL-ELECTRIC INFEASIBILITY REVIEWERS All-Electric Infeasibility Reviewers must apply specialized knowledge and experience in the application of energy efficiency design and construction; compliance of all-electric systems with Title 24 Energy Standards, and experience with the design of all-electric systems for space conditioning and water heating. The review team must include each of the following:

Item Qualification Minimum Experience 1 Licensed Professional Engineer with Mechanical Specialty Design and demonstration of compliance for at least one all- electric project which is: • Either multifamily (3 or more housing units), or commercial (minimum of 10,000 square feet floor area); AND • Either

• Construction of a new building, OR
• Alteration where scope included replacement of space conditioning and water heating systems. 2 Licensed Professional Engineer with Electrical Specialty 3 California Association of Building Energy Consultants – Certified Energy Analyst Title 24 documentation accepted for compliance for at least one all-electric new construction project of the same or similar occupancy to the project under review. Each discipline above must be represented by a third party, i.e. individuals not employed by a company responsible for the design or construction of the project. Due to the qualifications required, review is expected to be performed by a team, but individuals holding multiple qualifications may serve more than one role.

Simplified Process for Small Infill Sites: For projects seeking exception on the basis of physical constraint for small infill sites:

1. Persons responsible for the design of the project may be responsible for preparation of the review.
2. Reviewer(s) must include: • Licensed Professional Engineer with Electrical Specialty, AND • Either Licensed Professional Engineer with Mechanical Specialty, or CABEC Certified Energy Analyst.
3. Prepare a Review for Determination of All-Electric Infeasibility as described above. Simplified Process for Electric Utility Infrastructure Delay: Where delay to construct electric utility infrastructure for all-electric construction would result in substantially greater delay compared to a mixed- fuel alternative (Table 1, item B), the process for Review for All-Electric Infeasibility shall be limited to:
4. Persons responsible for the design of the project may be responsible for preparation of the review.
5. Reviewer(s) must include: • Licensed Professional Engineer with Electrical Specialty, AND • Either Licensed Professional Engineer with Mechanical Specialty, or CABEC Certified Energy Analyst.
6. Prepare a Review for Determination of All-Electric Infeasibility as described above. As detailed in Table 1, Criteria B, document the projected date of utility electric service connection for both the all-electric and mixed-fuel options, projected date to complete the construction of the project, and the reason the resulting delay in utility electric service would adversely impact viability of the project.

4. PROJECT COMPLETION Final compliance verification documentation (Attachment 2) is required prior to final inspection. No final Certificate of Completion may be issued until All-Electric Ordinance: Final Compliance Verification has been received, reviewed, and accepted by the Department of Building Inspection. Failure to ensure the project is designed and constructed in a manner consistent with an exception and conditions approved will subject the project to the enforcement and abatement remedies detailed in the San Francisco Building Code.
5. LIST OF ALL-ELECTRIC INFEASIBILITY REVIEWERS The Department of Building Inspection with the assistance of Department of Environment shall conduct an Open Call for Interest and Qualification to Review All Electric Infeasibility to identify professionals with specialized knowledge and experience in the design and construction of all-electric systems Title 24 Energy Standards. Department of Building Inspection shall provide upon request a list of individuals who have provided evidence of holding such qualifications. Review of All-Electric Infeasibility will only be considered when prepared by individuals holding the appropriate qualifications. A project sponsor may use reviewers not on the list, provided the proposed reviewer submits the same information required to establish qualifications of listed reviewers. Submittal of substantially inadequate or incorrect analysis shall be grounds for removal from the list of qualified reviewers. Signed by:

David Kane, S.E. May 29, 2026 Interim Director Department of Building Inspection Approved by the Building Inspection Commission on January 20, 2021 Revision approved April 15, 2026 Attachment 1: Design Guideline for Public Safety and Electric Ready Construction Attachment 2: Final Compliance Verification - Form Attachment 3: Commercial Food Service Exception - Form Attachment 4: Review of Pre-Existing Agreement - Form Attachment 5: Gas-Fueled Appliance Meeting a Federal Efficiency Standard - Form Attachment 6: Summary of Investor-Owned Utility Options for Proposed Electric Load Exceeding Capacity of Utility Infrastructure AB-113 Application of Engineering Criteria in SFEBC Appendix A, Chapter A6

NO. AB-113 :

DATE : 11 July 2025 SUBJECT : Seismic Retrofit Provisions for Concrete Buildings TITLE : Application of Engineering Criteria in SFEBC Appendix A, Chapter A6 PURPOSE : The purpose of this Administrative Bulletin is to provide technical details and commentary on the application of engineering criteria in SFEBC Appendix A, Chapter A6, which addresses the seismic evaluation and retrofitting of concrete buildings. REFERENCE : 2022 San Francisco Existing Building Code (SFEBC) ASCE 7-16 Minimum Design Loads for Buildings and Other Structures ASCE 41-17 Seismic Evaluation and Retrofit of Existing Buildings ACI 318-19 Building Code Requirements for Structural Concrete DISCUSSION : San Francisco Existing Building Code (SFEBC) Chapter A6 outlines seismic retrofit provisions to reduce the collapse risk of vulnerable concrete buildings, as defined in Chapter 5G. This includes certain types of concrete buildings and their construction dates as well as buildings with rigid walls and flexible diaphragms. If a building owner elects to carry out seismic evaluation or retrofitting to have their building removed from the inventory established per Chapter 5G, they may do so by satisfying the structural engineering criteria in Chapter A6. A key focus is on addressing common seismic deficiencies, detailed in Table A6.4-2, which include weak stories, irregularities in lateral-force-resisting elements, non-ductile moment frames, shear- governed concrete columns or wall piers, punching shear in concrete slabs, weak connections of concrete walls to flexible diaphragms, and inadequate bearing connection lengths. This bulletin provides further clarification by offering commentary on selected sections of Appendix A, Chapter A6 of the SFEBC. In addition to commentary, this bulletin provides the specific technical requirements to identify, evaluate, and retrofit the seismic deficiencies of Table A6.4-2 when using Engineering Criteria Option (a).

SFEBC Chapter A6 technical details and commentary: I. A6.2 Definitions Commentary: Chapter A6 includes a definition of the term “wall pier,” used to specify buildings exempt from the requirements of the Chapter and to specify seismic deficiencies required to be addressed by Engineering Criteria Option (a). The definition of wall pier is per Section 2.3 of ACI 318-19. II. A6.3 Design professionals Commentary: Chapter A6 requires that evaluations and design be performed by or under the supervision of “appropriately licensed individuals.” The State of California governs the registration of professional engineers and requires that engineers practice only in areas where they have demonstrated competence. The registration status of any licensed professional engineer can be checked at: http://www.bpelsg.ca.gov/consumers/lic_lookup.shtml. The successful execution of a seismic retrofit project and the building’s performance in an earthquake rely heavily on the analysis and design by the building owner’s engineer. Building owners are encouraged to check references for the engineer they plan to engage, and to understand the engineer’s experience and qualifications as they relate to the building’s type, size, and other characteristics. Questions an owner may ask a structural or civil engineer before selecting them include: • Do you have experience with seismic retrofitting of concrete buildings? • Do you have experience using the seismic evaluation and retrofit standard ASCE 41? • Can you describe structures that you have evaluated or retrofitted that are most similar to my building? III. A6.4 Structural engineering criteria A. A6.4.1 Engineering criteria Commentary: Table A6.4-1 provides two options for engineering criteria that engineers may use for seismic evaluation or retrofit of Concrete Buildings. Option (a) specifies lower seismic forces, and also requires addressing the seismic deficiencies listed in Table A6.4-2. Option (b) specifies greater seismic forces. i. Criteria Option (a) For Engineering Criteria Option (a), addressing the seismic deficiencies in Table A6.4-2 is required, even if analysis indicates the building satisfies Collapse Prevention for the BSE-1E earthquake level without addressing a listed deficiency. Addressing the seismic deficiencies in Table A6.4-2 is intended to enable gravity-load-resisting elements to withstand severe earthquake movements, greater than BSE-1E, while maintaining their capacity to support gravity loads. These seismic deficiencies can be critical contributors to the collapse vulnerability of concrete buildings. They do not include all possible seismic deficiencies. ii. Criteria Option (b) Engineering Criteria Option (b) equates to the requirements of ASCE 41 for the Basic Performance Objective for Existing Buildings (BPOE)

except: • Non-structural evaluation and retrofitting is limited to elements of unreinforced masonry. • Evaluation of the Life Safety structural performance level for the BSE-1E earthquake level is not required. Addressing the seismic deficiencies specified in Table A6.4-2 is not necessarily required in meeting Engineering Criteria Option (b) if seismic evaluation at the BSE-2E earthquake level demonstrates acceptable performance. For buildings assigned to Risk Category I or II, the criteria for Engineering Criteria Option (b) will typically also provide compliance with triggered retrofit requirements for Substantial Alteration (Section 304.3.2 of the SFEBC). For Engineering Criteria Option (b), the Life Safety performance check for the BSE-1E earthquake level is omitted because, under San Francisco’s seismic hazard parameters, it does not govern over the Collapse Prevention check for the BSE-2E level. This is because the typical ratio between the two ground motion levels is approximately 1.8, while the ratio between the Collapse Prevention and Life Safety acceptance limits in ASCE 41 does not exceed 1.33. iii. “75% of code” criteria not permitted in Appendix A6 The approach (in Section 304.3.2) of using 75 percent of the prescribed forces of the new building code is intentionally not included in Chapter A6, and thus not permitted for use in Chapter A6 because this approach does not clearly address (a) the design of gravity framing for imposed deformations and (b) structural detailing that does not conform to any concrete seismic-force-resisting system that is permitted in high seismic design categories. iv. Buildings assigned to Risk Category III or IV Chapter A6 provides retrofit criteria intended to achieve basic safety for Risk Category II buildings. The criteria can be applied to Risk Category III or IV buildings if the goal is only to achieve this basic safety criteria (i.e., Structural Collapse Prevention (S-5) for the BSE-2E earthquake hazard level). It is not in the scope of Chapter A6 to provide retrofit criteria to achieve the higher performance related to safety or recovery associated with new structures assigned to Risk Category III and IV. v. Elements of unreinforced masonry Both engineering criteria options in Table A6.4-1 require removing or retrofitting any unreinforced masonry elements. This requirement addresses the safety risk from elements such as unreinforced masonry chimneys, hollow clay tile partitions, and brick masonry walls falling out of plane. Except for these elements, Chapter A6 does not require seismic retrofitting of nonstructural components. B. Flexible floor- or roof-diaphragms Requirements: For buildings with one or more flexible diaphragms, compliance with Appendix A, Chapter A2 is sufficient to comply with the portions of Chapter A6 related to the wall anchorage system and collectors. In addition, for buildings satisfying all of the following, compliance with Chapter A2 is sufficient to meet the structural requirements of Chapter A6: (a) The building has no more than two stories above grade plane, excluding mezzanines. (b) The building does not include concrete columns nor wall piers, as defined in Chapter A6. (c) The building’s floor and roof diaphragms are both flexible in-plane, i.e. sheathed with plywood, wood decking (e.g., 1x or 2x), or metal deck without concrete topping slab. Commentary: Rigid-wall-flexible-diaphragm (RWFD) buildings are addressed by Chapter A2. Chapter A6 is not expected to be invoked for one-story buildings. For Concrete Buildings taller than one story, where Chapter A6 is invoked and the structure satisfies all of (a), (b), and (c) above, the wall-to-roof diaphragm and wall-to-floor diaphragm anchorage system, and collectors are the only structural aspects of such buildings required to be addressed per Chapter A6. C. Combinations of seismic-force-resisting systems Requirements: For buildings having structural systems that are partially concrete and partially other structural materials, the building shall comply with Chapter A6 as a combined system, except: (a) Vertical combinations of seismic-force-resisting systems: For vertical combinations of seismic-force-resisting systems (i.e. different seismic-force-resisting system in upper stories compared to lower stories) where only the lower system is concrete, if the existing upper system (including the lateral-force-resisting system and gravity system) is not of concrete construction, the existing upper system is not required to comply with Chapter A6. (b) Combinations of seismic-force-resisting systems in different directions: For combinations of seismic-force-resisting systems where different seismic-force-resisting systems are used along each of the two orthogonal axes of the structure, if the gravity system is not of concrete construction, the existing non-concrete lateral-force-resisting system need not comply with Chapter A6. D. Technical requirements for addressing the seismic deficiencies of Table A6.4-2 when using Engineering Criteria Option (a). Requirements: The following requirements apply to identifying, evaluating, and retrofitting the seismic deficiencies listed in Table A6.4-2. Potential deficiency Requirements Commentary Potential deficiency Requirements Commentary

Weak story: The structure includes one or more stories having lateral strength less than the story above. The structure shall not have vertical structural irregularity of Type 5a nor Type 5b in Table 12.3-2 of ASCE 7. If the structure has a weak story or extreme weak story, to meet Engineering Criteria Option (a) the weak story deficiency must be eliminated by retrofitting. Otherwise the structure must meet Engineering Criteria Option (b). Lateral-force-resisting-element irregularity: The lateral-force- resisting system includes one or more concrete walls or frames that are not continuous to the foundation. The building shall not have a horizontal structural irregularity Type 4 of Table 12.3-1 or vertical structural irregularity Type 4 of Table 12.3-2 of ASCE 7. If the structure has either of the specified irregularities—in-plane or out-of-plane offset or discontinuity—to meet Engineering Criteria Option (a), the irregularity must be corrected by retrofitting. Otherwise the structure must meet Engineering Criteria Option (b). Non-ductile moment frame: The main lateral-force-resisting- system includes concrete moment frames that do not satisfy strong- column-weak-beam requirements or that have shear-governed columns or beams. Comply with all of the following:

1. Moment frame columns shall satisfy Section 18.7.3 of ACI 318 and Section 18.7.6.1 of ACI 318.
2. Moment frame beams shall satisfy Section 18.6.5.1 of ACI

Section 18.7.3 requires strong- column weak-beam strength proportions. Section 18.6.6.1 requires columns to be flexure governed. Section 18.6.5.1 requires beams to be flexure governed. Such requirements are essential for ductile behavior of concrete moment frames. Shear-governed concrete column or wall pier: The structure includes one or more concrete columns or wall piers that are shear-governed and susceptible to failure resulting in loss of gravity load support. For each column or wall pier, comply with one or more of the following:

1. Columns and wall piers shall have design shear strength satisfying Section 18.7.6.1 of ACI 318 or greater than the maximum shear that can be delivered to the column or wall pier based on a capacity design approach. For wall piers, joint faces shall be taken as the top and bottom of the clear height of the wall pier.
2. Provide or demonstrate an alternate load path to support design gravity load assuming the column or wall pier fails and cannot support gravity load.
3. For wall piers in buildings that do not have an Extreme Torsional Irregularity per ASCE 7 Table 12.3-1 Type 1b, demonstrate compliance with the Tier 1 Quick Check for shear stress in concrete walls in that story in each plan direction per Section 4.4.3.3 of ASCE 41. Pseudo seismic force V shall be 2 times the pseudo seismic force at the BSE-1E earthquake level, but need not exceed that at BSE-2E. System modification factor Ms shall be for Collapse Prevention performance.
4. Shear governed columns or wall piers can be a serious deficiency that leads to building collapse. Retrofitting columns or wall piers by jacketing, such as with fiber reinforced polymer (FRP), can be used to make the elements flexure-governed.
5. If failure of columns or wall piers can be shown to not cause collapse because of an alternate load path for gravity load, the shear-governed behavior is permitted. An example of an acceptable alternate load path is a beam that can span over a failed column or wall pier to supports not susceptible to failure, or an added column adjacent to the susceptible column or wall pier. The alternate load path is to be a complete load path, i.e. to the foundation and supporting soil, that does not rely on non- compliant elements.
6. If the building meets the quick- check for shear at the specified level and does not have an Extreme Torsional Irregularity, the consequences of shear failure of wall piers will likely be limited. Option 3 is not permitted for structures with high plan- torsion irregularity because, in such cases, columns or wall piers on one side of the building plan are more vulnerable to concentrated damage.

Punching shear in concrete slab: One or more concrete floor or roof slabs are supported by columns without beams framing into the column and susceptible to loss of gravity load support following punching shear failure. Comply with one or more of the following in each principal plan direction at each column:

1. Demonstrate compliance with Section 18.14.5 of ACI 318 with earthquake force E and design story driftΔ x taken as 2 times the earthquake force and story drift at the BSE-1E earthquake level, but need not exceed that at BSE- 2E, determined in accordance with Section 7.4 of ASCE 41. Also comply with Section 8.7.4.2.2 of ACI 318. The slab bottom bars must be continuous through the column or spliced using mechanical or welded splices.

2. Demonstrate the existence of continuity reinforcement in accordance with ASCE 41 Table 10-15 footnote d.

3. For post-tensioned slabs, demonstrate compliance with Section 8.7.5.6 of ACI 318.

4. Provide an alternate load path to support design gravity load, assuming the slab-column interface fails and cannot support gravity load.

5. Section 18.14.5 addresses acceptable punching shear stress from gravity load as a function of story drift, a key indicator of susceptibility to punching shear of slab-column connections. Section 8.7.4.2.2 requires two slab bottom bars to pass between the column cage longitudinal bars in each plan direction.

6. ASCE 41 Table 10-15 footnote d requires one post-tensioning tendon to pass through the column cage in each plan direction, or slab bottom bars with steel area based on the gravity shear demand on the slab critical section.

7. Section 8.7.5.6 requires two prestressing tendons to pass through the column cage in each plan direction, or slab bottom bars with steel area based on the column and slab geometry. The tendons or bottom bars help prevent collapse of the slab if punching shear initiates.

8. If the existing condition is susceptible to punching shear, a possible retrofit solution is to provide a path of support such as a collar at the top of a column that supports the bottom of the slab beyond the expected punching shear failure plane. Weak connection of concrete wall to flexible diaphragm: The structure includes one or more concrete walls supporting one or more flexible diaphragms, where the wall is not adequately anchored into the diaphragm. For each flexible floor or roof diaphragm, comply with Chapter A2, or ASCE 41 with a performance objective of Structural Collapse Prevention with the BSE-2E earthquake level. The objective of this item is to reduce the likelihood that a concrete wall will separate from a flexible floor or roof diaphragm in a way that could lead to floor or roof collapse. For floor or roof diaphragms that have timber framing in combination with a complete grid of concrete floor beams, Chapter A2 may be used to demonstrate that existing concrete floor beams are connected to the walls in such a way that they resist out-of- plane forces on the walls at least equal to the forces prescribed in Chapter A2. Inadequate length of bearing connection: One or more beams or slabs are supported by a bearing connection with short bearing length. Provide bearing length to support gravity load, such that the bearing length satisfies all of the following:

9. Section 18.14.4.1(d) of ACI

11. Two times the displacement demand at the BSE-1E earthquake level, determined in accordance with Section 7.4 of ASCE 41, but need not exceed that at BSE-2E. In some cases, including at building expansion joints, concrete floor structures, either cast-in-place or precast, have bearing supports. In older structures such bearing supports may not have adequate bearing length compared to earthquake displacement demands.

12. Section 18.14.4.1(d) requires a bearing length of 5 inches for beams, or 2 inches + L/180 for slabs.

    E. A6.4.2 Building separation Commentary. Building separation issues are not addressed in Chapter A6 because of the likely impracticalities of addressing property-line separations in San Francisco. Engineers are encouraged to inform the building owner if there is a risk of pounding damage at building separations. F. A6.4.3 Liquefaction and landslide risk.

Commentary. Similarly, seismic evaluation and retrofit per Chapter A6 is not required to address soil liquefaction or landslide risk. Engineers are required to notify the owner if their building is in a zone of high or very high risk of liquefaction or landslide. The exemption from considering the geotechnical hazards of liquefaction and landslide does not apply to lateral earth pressure. Forces from static and dynamic earth pressure on walls (absent liquefaction or landslide) shall be considered in the seismic evaluation in combination with other forces on the structure. For properties subject to the Slope and Seismic Hazard Zone Protection Act (San Francisco Building Code Section 106A.4.1.4), retrofitting per Chapter A6 does not necessarily trigger the requirements of the act if the project does not include work of the type and quantity specified in the Scope (Section 106A.4.1.4.3) of the act, and further detailed in Information Sheet S-19. However, if the project does include such triggering work, even if the work is done to comply with Chapter A6, then the project must comply with the requirements of the act. G. A6.4.4 Other retrofit triggers Commentary. Section A6.4.4 clarifies that meeting the requirements of Chapter A6 does not replace the need to meet Section 304.4 (minimum lateral force for existing buildings) when a project is subject to a Substantial Structural Alteration (Section 503.11) or a Non-structural Alteration (Section 503.11.1). Triggered retrofits must comply with Section 304.4. In most cases, owners may also choose to meet the requirements of Chapter A6 so the building can be removed from the inventory established under Chapter 5G. However, if the owner does not pursue removal from the inventory, then Chapter A6 does not apply to the retrofit requirements subject to Section 304.4. H. A6.4.5 Masonry infill Commentary. If the infill is unreinforced masonry, its attachment to the main structure must be addressed as shown in Table A6.4-1. In addition, for both reinforced and unreinforced masonry infill, the effect of the infill on the building’s seismic response must be addressed as required by this subsection. /signed/ July 21, 2025 Patrick O’Riordan, C.B.O. Date Director Department of Building Inspection Approved by the Building Inspection Commission on July 16, 2025.