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Home My WebLink AboutStaff Report 2505-4746CITY OF PALO ALTO Policy & Services Committee Special Meeting Tuesday, February 10, 2026 6:00 PM Agenda Item 1.Update and Feedback to Staff Regarding Progress and Direction for the Seismic Hazards Identification and Risk Mitigation Ordinance Update. CEQA Determination: Not a Project. Presentation Policy & Services Committee Staff Report From: City Manager Report Type: ACTION ITEMS Lead Department: Planning and Development Services Meeting Date: February 10, 2026 Report #:2505-4746 TITLE Update and Feedback to Staff Regarding Progress and Direction for the Seismic Hazards Identification and Risk Mitigation Ordinance Update. CEQA Determination: Not a Project. RECOMMENDATION Review progress and initial recommendations to develop an updated Seismic Hazards Identification and Risk Mitigation Ordinance; provide feedback to staff for additional refinement and analysis. EXECUTIVE SUMMARY The City is updating its Seismic Hazards Identification and Risk Mitigation ordinance set forth in Palo Alto Municipal Code (PAMC) Chapter 16.42. The purpose of this effort is to more effectively reduce seismic vulnerability in buildings, enhance life safety protections, and support business and service continuity following a seismic event. Last comprehensively updated in 1986, the current program requires mandatory evaluations of a select number of vulnerable buildings (89) and includes outdated references to the 1973 Uniform Building Code. Voluntary compliance is incentivized but not required. To align with current best practices, the program would need to include additional vulnerable building types, explore mandatory retrofit requirements, and incorporate modern retrofit seismic standards. Staff seeks feedback from the Policy and Services Committee on anticipated aspects of an updated program based on extensive analysis prepared by industry experts and diverse representation from a community advisory group. This effort recommends the City expand its list of vulnerable building types, update its evaluation screening methodology, establish retrofit compliance options and timelines, and consideration of limited residential compliance exemptions. This report also introduces key considerations related to financial and policy incentives, public disclosure practices, and tenant rights. BACKGROUND 1 These efforts resulted in a comprehensive Seismic Risk Assessment Study completed by Rutherford & Chekene in April 2017.2 In October 2017, the City Council directed staff to refine the seismic inventory, assess community impacts, and explore program options, disclosures, and incentives.3 However, this project was later deprioritized to address other critical City initiatives, including the City’s pandemic response.4 5 6 In February 2025, Council approved a contract with Rutherford & Chekene to provide these services.7 In May 2025, staff issued the consultant a notice to proceed and the team began work, including forming an advisory group of both community members and development, design, housing policy, seismic safety and finance experts. A list of advisory group members is included in Attachment F. 1 https://portal.laserfiche.com/Portal/DocView.aspx?id=50804&repo=r-704298fc&searchid=40cbf59c-d0a1-4c36- b16f-7681f1f06744 2 https://portal.laserfiche.com/Portal/DocView.aspx?id=136329&repo=r-704298fc&searchid=40cbf59c-d0a1-4c36- b16f-7681f1f06744 3 https://www.cityofpaloalto.org/files/assets/public/v/1/agendas-minutes-reports/reports/city-manager-reports- cmrs/year-archive/2017/id-8207-seismic.pdf 4 https://portal.laserfiche.com/Portal/DocView.aspx?id=136329&repo=r-704298fc&searchid=40cbf59c-d0a1-4c36- b16f-7681f1f06744 5 https://cityofpaloalto.primegov.com/Portal/viewer?id=2677&type=0 6 https://procurement.opengov.com/portal/palo-alto-ca/projects/94858/document 7 https://portal.laserfiche.com/Portal/DocView.aspx?id=155404&repo=r-704298fc&searchid=9be649d9-7fee-4ce6- 926f-089d174a5d37 updated ordinance. The remaining 1,224 buildings that were surveyed were found to be unlikely to fall into one of these categories and are considered to pose less of a threat to life safety in a major earthquake. ANALYSIS Existing Building Categories While the existing ordinance is outdated, it was the result of a robust policy development process many years ago and was forward-thinking for its time. Category I: Buildings constructed of unreinforced masonry (except for those smaller than 1,900 square feet with six or fewer occupants) Category II: Buildings constructed prior to January 1, 1935, containing 100 or more occupants Category III: Buildings constructed prior to August 1, 1976, containing 300 or more occupants. 15 In addition, the CAG, consultant team and staff support adding new categories based on construction types to address new structural systems that have been found less resilient during a seismic event. Staff seeks Policy and Services Committee feedback and any concerns with this recommendation. 15 More information about the original policy-making process for this ordinance is available on the City’s seismic program update webpage: https://www.paloalto.gov/Departments/Planning-Development- Services/Development-Services/Seismic-Hazards-Identification-Program-Update. Additional Vulnerable Building Types Staff, consultant team and the CAG recommend the updated ordinance include the following additional key categories to address seismically vulnerable buildings in Palo Alto: Weak-Story Wood Frame Buildings Built Before 1977 (324 buildings) Older weak-story wood-frame buildings are at risk of partial or total collapse during seismic events. These buildings generally accommodate parking on the ground floor, which results in fewer shear walls at this level and poorly distributed walls. They can be soft (too flexible), weak (lacking in shear strength), and have open fronts (for parking) that lead to twisting during seismic events from the poor layout of walls. These buildings have performed poorly in past earthquakes, including collapses in the Marina district in San Francisco in the 1989 Loma Prieta Earthquake and in the San Fernando Valley in the 1994 Northridge Earthquake. The year 1977 is used as the milestone date to help distinguish when certain statewide building code changes came into effect, leading to better performance. This category includes buildings with mostly residential uses. Note: These buildings are commonly called “soft-story” buildings and represent the most common category of building included in local seismic safety ordinances in California, including those in San Jose, San Francisco, Oakland and Berkeley. Rigid-Wall Flexible Diaphragm Buildings Built Before 1998 (474 buildings) The primary deficiencies in these buildings are poor out-of-plane tension connections between the roof and walls in one-story buildings and between the roof and floors and the walls in multi-story buildings. The perimeter walls can fall outward, leading to partial collapse. These building have performed poorly during seismic events in the past, including the 1971 San Fernando and 1994 Northridge Earthquakes. In 1998, statewide building code changes were made to address damage that occurred in the 1994 Northridge Earthquake from various seismic deficiencies in these types of buildings. This category includes buildings with mostly non-residential (retail, industrial, office) uses. Nonductile Concrete Buildings Built before 1977 (313 buildings) Older concrete buildings can have many different seismic deficiencies, including weak and/or soft ground stories, that may result in partial or total collapse during a seismic event. This can be exacerbated by older nonductile detailing which can lead to premature, brittle cracking of elements such as walls and columns. These buildings have performed poorly during seismic events in the past, including the 1971 San Fernando and 1994 Northridge Earthquakes. The year 1977 is used as a benchmark to mark when statewide building code requirements became more stringent and resulted in improved building performance. This category includes buildings with both residential and non- residential uses. Steel Moment Frame Buildings Built Before 1998 (64 buildings) Steel moment frame buildings are also at risk of partial or total collapse during a seismic event, but less so than the other categories described here. In older buildings of this type, the connection detailing and construction techniques used can lead to premature, brittle failure such as weld cracking, beam buckling, or fracture at column flanges during seismic events. Code updates were made in 1998 to address these issues following the 1994 Northridge Earthquake. This category includes both residential and non-residential buildings. Residential Exemptions Based on Unit Count Staff and the consultant team recommend exempting one- and two-unit residential properties from the Seismic Hazards Identification and Risk Mitigation Program. Under this approach, only residential properties with three or more units would be subject to the program. This threshold aligns with the City’s definition of multi-family properties (PAMC Section 18.04.030, Definitions).17 It also reflects a public policy approach that prioritizes buildings housing multiple households, where life-safety risks are higher and occupants often have limited control or resources to address seismic hazards, while recognizing that owners of one- and two-unit homes generally have greater autonomy to manage their own risk. The CAG was also supportive of this approach overall, though some members thought duplexes should not be exempted. Staff seeks Policy and Services Committee feedback and any concerns with this recommendation. Structures proposed for exemption typically fall into the weak-story, wood-frame building category. The table below summarizes unit thresholds for similar programs in a selection of jurisdictions across California. Table 1: Summary of Soft-Story, Wood-Frame Program Unit Thresholds in California Jurisdiction Unit Threshold West Hollywood 1 or more units Albany, San Jose 3 or more units Los Angeles 4 or more units San Francisco, Berkeley, Oakland, Alameda 5 or more units Reducing the threshold to include two-unit residential structures would require review of approximately 260 additional properties for potential seismic vulnerabilities and result in 17 https://codelibrary.amlegal.com/codes/paloalto/latest/paloalto_ca/0-0-0-76370 additional project expense. Raising the threshold to five or more units would decrease the number of residential buildings in the inventory from approximately 400 to 290 units. Retrofit and Performance Standards Seismic Evaluation and Retrofit of Existing Buildings, is the nationally recognized standard for earthquake safety upgrades to existing buildings. The current version, ASCE 41-23, covers all building types being considered for the City’s expanded seismic safety ordinance. ASCE 41-23 uses a performance-based approach, meaning buildings are evaluated based on how they would perform during actual earthquakes rather than applying one-size-fits-all requirements. Table 2: BPOE Earthquake Scenarios Earthquake Scenario Probability Required Performance Meaning Moderate earthquake Major earthquake Table 3: Recommended Evaluation and Retrofit Standards by Building Category I Unreinforced Masonry ASCE 41-23 or California Existing Building Code Appendix Chapter A1 II Built before 1/1/35 with 100 or more occupants ASCE 41-23 III Built before 8/1/76 with 300 or more occupants ASCE 41-23 IV Pre-1977 weak-story wood frame ASCE 41-23 or California Existing Building Code Appendix Chapter A4 or FEMA P-807 V Pre-1998 rigid wall – flexible diaphragm ASCE 41-23 or California Existing Building Code Appendix Chapter A2 VI Pre-1977 nonductile concrete ASCE 41-23 or a new local standard similar to San Francisco’s Administrative Bulletin entitled “Application of Engineering Criteria in SFEBC Appendix A, Chapter A6” (see Attachment G) VII Pre-1998 steel moment frame ASCE 41-23 The following steps are anticipated as part of the program implementation and compliance process: Notification: Using the City’s recently updated building inventory, written notices will be issued to all potentially vulnerable buildings in the identified categories informing them of program requirements. Mandatory Screening: Following written notice of program requirements, all buildings on the City’s “List of Seismically Vulnerable Buildings”, will be required to hire a licensed design or engineering professional to complete an initial screening to verify whether the building fits into one or more of the vulnerable building categories included in the updated ordinance. If a building’s screening determines it does not fall within any of the vulnerable building categories, then the building will be removed from the “List of Seismically Vulnerable Buildings” maintained by the City. Mandatory Evaluations: If a building’s screening determines that the building falls into one or more of the vulnerable building categories included in the updated ordinance, the property owner must hire a licensed civil or structural engineer to prepare an investigation and engineering report. This report will identify the building’s structural deficiencies, if any, and be submitted to the City. If a building’s seismic evaluation determines that the building already meets the Basic Performance Objective for Existing Buildings (BPOE) outlined in ASCE 41-23, or one of the acceptable alternative standards listed in Table 3, then the building will be considered compliant with the program and removed from the City’s List of Seismically Vulnerable Buildings. If not, the building may be required to complete a mandatory retrofit to bring the building up to these standards. Plan Submissions: If the evaluation confirms that a building is required to complete a retrofit, then the evaluation submissions to the City must also include retrofit plans and structural calculations demonstrating how the building will be brought up to the approved seismic standards. Once the plan review is approved, a building permit will be issued. Retrofit Completion: Construction may begin once the building permit is issued. After the building passes its final inspection for the required retrofit work, it will be considered compliant with the program and removed from the City’s “List of Seismically Vulnerable Buildings”. As previously noted, the passage of AB 130, which limits changes to the residential building code through 2031, requires further analysis to determine the extent to which certain standards may still be enacted. Compliance Types and Timelines As detailed in the proposed implementation process above, staff recommend mandatory screenings for all potentially vulnerable buildings in the listed categories. Staff also recommend mandatory seismic evaluations for any buildings in which the screenings identify structural deficiencies that may pose life safety risks. These evaluations would serve to educate building owners about the specific risks associated with their building and potential retrofits needed. Staff envisions a combination of mandatory and voluntary retrofits to address structural deficiencies by building type. If a mandatory retrofit is required, the ordinance could establish a clear deadline for retrofit completion as well as interim deadlines for plan submissions and building permit applications and receipt. Once all work has been completed, the building would be removed from the City’s “List of Seismically Vulnerable Buildings.” If a mandatory retrofit is not required for a specific building category, staff recommend setting clear standards for the level of voluntary retrofit required to remove a building from the City’s “List of Seismically Vulnerable Buildings”. This would ensure that buildings would remain on the City’s List of Seismically Vulnerable Buildings if incomplete or insufficient voluntary retrofits were completed. Table 4: Potential Retrofit Requirements and Timelines by Building Category Building Type Potential Retrofit Compliance Type Screening Deadline Evaluation Deadline* Retrofit Plan Submission Building Permit Receipt Retrofit Completion Same as evaluation Same as evaluation Same as evaluation Same as evaluation N/A for voluntary retrofits N/A for voluntary retrofits N/A for voluntary retrofits Pre-1977 Nonductile Concrete Buildings Mandatory 1.5-3 years 3-10 years Same as evaluation 5-15 years 10-25 years Pre-1998 Steel Moment Frame Buildings Voluntary 1.5-10 years 3-15 years N/A for voluntary retrofits N/A for voluntary retrofits N/A for voluntary retrofits ^ Retrofit compliance type for this category may vary based on occupancy type (ie. residential vs. non-residential) ^^ Retrofit compliance deadlines for this category may vary based on total unit count Local Policy and/or Financial Incentives Mandatory screening and evaluation requirements are not expected to burden building owners with significant costs. However, mandatory retrofit requirements could be quite costly depending on the type of building and the scope of the work needed. Some buildings may qualify for loans or similar incentives through State programs.19 However, the City may also need to offer local incentive packages to make mandatory retrofits feasible for building owners. Staff seeks initial input from the Policy and Services Committee on which types of incentives best align with the Council’s priorities currently. Options include: Procedural: Technical support for building owners and/or expedited permit processing Development: Density or height increases and/or reductions in parking or similar requirements Fee Waivers or Reductions: Waived or reduced building permit fees, demolition fees, and/or development impact fees (as applicable) Financial Incentives: City-issued, low-interest loans or grants for building owners and/or local tax incentives These options would each require further work and analysis by staff, but staff seeks the Committee’s feedback on which, if any, to prioritize. Public Disclosure Consistent with past discussions on this topic, staff recommend that the City maintain a searchable online inventory/list of all potentially vulnerable buildings subject to compliance 19 See section 3.3 “Funding Sources” in “Summarize Relevant State Laws – Memorandum” for more information: https://www.paloalto.gov/files/assets/public/v/1/development- services/palo-alto-seismic-memo-on-relevant-state-laws.pdf with the updated seismic ordinance. Removal from the list would be dependent upon completion of mandatory or voluntary retrofits to the required life safety standards. The Policy and Services Committee may also provide feedback to staff to consider additional public disclosure measures, such as exterior building placards and/or tenant notification at time of leasing. Note: California law already requires buyer notification of potential seismic vulnerabilities at the time of building sale. Tenant Considerations Habitability standards and/or plans; Temporary relocation assistance (property owner or City funded); and/or Rent increase caps and/or limits to cost pass throughs. FISCAL/RESOURCE IMPACT STAKEHOLDER ENGAGEMENT August 20, 2025: Project History & Scope October 14, 2025: Policy Context & Precedent Programs January 6, 2026: Program Applicability & Compliance Staff plans to host three more community advisory group meetings later this year. These will focus on policy and financial incentives, public disclosure requirements, tenant rights and draft ordinance development and review. ENVIRONMENTAL REVIEW ATTACHMENTS APPROVED BY: Summary of Relevant State Laws “Summarize Relevant State Laws – Memorandum 1” is available for review on the City of Palo Alto’s Seismic Program Update webpage 2. 1 https://www.paloalto.gov/ﬁles/assets/public/v/1/development-services/palo-alto-seismic-memo-on- relevant-state-laws.pdf 2 https://www.paloalto.gov/Departments/Planning-Development-Services/Development-Services/Seismic- Hazards-Identiﬁcation-Program-Update Summary of Precedent Programs at the Local Level “Summary of Relevant Progress at the Local Level - Memorandum 1” is available for review on the City of Palo Alto’s Seismic Program Update webpage 2. 1 https://www.paloalto.gov/ﬁles/assets/public/v/1/development-services/palo-alto-seismic-task-a.2-memo-psc- draft.pdf 2 https://www.paloalto.gov/Departments/Planning-Development-Services/Development-Services/Seismic- Hazards-Identiﬁcation-Program-Update Summary of Retroﬁt Techniques “Summary of Applicable Retroﬁt Techniques - Memorandum 1” is available for review on the City of Palo Alto’s Seismic Program Update webpage 2. 1 https://www.paloalto.gov/ﬁles/assets/public/v/1/development-services/palo-alto-seismic-memo-on- retroﬁt-standards-and-techniques.pdf 2 https://www.paloalto.gov/Departments/Planning-Development-Services/Development-Services/Seismic- Hazards-Identiﬁcation-Program-Update Summary of Field Survey Findings and Process “Field Survey Report - Memorandum 1” is available for review on the City of Palo Alto’s Seismic Program Update webpage 2. 1 https://www.paloalto.gov/ﬁles/assets/public/v/1/development-services/seismic/palo-alto-seismic-task-a.4- memo-rc-2026-01-25.pdf 2 https://www.paloalto.gov/Departments/Planning-Development-Services/Development-Services/Seismic-Hazards- Identiﬁcation-Program-Update Summary of Vulnerable Building Categories “Building Types Subject to the Updated Ordinance - Memorandum 1” is available for review on the City of Palo Alto’s Seismic Program Update webpage. 2 1 https://www.paloalto.gov/ﬁles/assets/public/v/1/development-services/palo-alto-seismic-memo-on- vulnerable-building-categories.pdf 2 https://www.paloalto.gov/Departments/Planning-Development-Services/Development-Services/Seismic- Hazards-Identiﬁcation-Program-Update January 2026 2025-2026 Community Advisory Group Members City of Palo Alto Seismic Risk Mitigation Program Update Subject Matter Experts 1. Abha Nehru, Carrasco & Associates 2. Anil Babbar, California Apartment Association 3. Christopher Rojahn, Applied Technology Council 4. Doug Hohbach, Hohbach-Lewin, Inc. 5. Emily Ann Ramos, Silicon Valley at Home 6. Janiele Maﬀei, California Earthquake Authority 7. John Shenk, Thoits Bros., Inc. 8. Jon Goldman, Premier Properties 9. Ken Hayes, Hayes Group Architects 10. Laurel Mathews, City and County of San Francisco 11. Luke Farley, Heritage Bank of Commerce 12. Michael Germeraad, Association of Bay Area Governments 13. Rich Cody, CVG Builders 14. Roxy Rapp, Rapp Development 15. Sarah Atkinson, SPUR 16. Tim Steele, The Sobrato Organization 17. Tom Holzer, USGS City of Palo Alto Staﬀ 1. Alex Andrade, Economic Development Manager 2. Andres Orozco, Oﬃce of Emergency Services Coordinator 3. David Chung, Assistant Chief Building Oﬃcial 4. George Hoyt, Chief Building Oﬃcial 5. Julia Knight, Special Projects and Innovation Manager 6. Maddie Salah, Deputy City Attorney 7. Nathaniel Rainey, Oﬃce of Emergency Services Coordinator 8. Steven Switzer, Senior Historic Planner Consultant Team 1. Bret Lizundia, structural engineer and lead consultant, Rutherford + Chekene, 2. Zahraa Saiyed, public policy and engagement specialist, Scyma Consulting 2022 San Francisco Building Code AB-XXX Draft by ATC. 6/5/2025 8:26:00 AM Page 1 of 6 ADMINISTRATIVE BULLETIN NO. AB-XXX : DATE : DRAFT by ATC 6 May 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 covers the seismic evaluation and retrofitting of concrete buildings. REFERENCES : 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 the seismic retrofit provisions aimed at reducing the collapse risk of vulnerable Concrete Buildings (CB), as defined in Chapter 5G. This includes certain types of concrete buildings and their associated vintage as well as buildings with rigid- walls and flexible diaphragms. Chapter A6 establishes structural engineering criteria, including Engineering Criteria Options (per Table A6.4-1) that a Concrete Building must satisfy through seismic evaluation or retrofit. The document also specifies other retrofit triggers, such as substantial structural or non-structural alterations, which necessitate adherence to these provisions. 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 this commentary, this bulletin provides the specific technical requirements for how to identify, evaluate, and retrofit the seismic deficiencies of Table A6.4-2 when using Engineering Criteria Option (a). SFEBC Chapter A6 Commentary: I. A6.2 Definitions Commentary: This subsection of Chapter A6 includes a definition of the term “wall pier,” which is used in the chapter to specify buildings that are exempt from the requirements of the chapter and to specify seismic deficiencies that are 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 2022 San Francisco Building Code AB-XXX Draft by ATC. 6/5/2025 8:26:00 AM Page 2 of 6 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 resulting building performance in an earthquake rely heavily on the analysis and design work done by the Owner’s Engineer. Building owners are encouraged to seek references for the engineer that they plan to engage, and to understand the engineer’s experience and qualifications applicable to the building type, size, and other characteristics. Questions that an owner may want to 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 (b) specifies greater seismic forces. Option (a) specifies lower seismic forces, but it requires also addressing the seismic deficiencies that are listed in Table A6.4-2. i. Criteria Option (a) For Engineering Criteria Option (a), addressing the seismic deficiencies in Table A6.4-2 is required, even if analysis indicates that 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 undergo 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) uses the BSE-2E earthquake hazard level for Collapse Prevention and equates to the requirements of ASCE 41 for the Basic Performance Objective for Existing Buildings (BPOE) except that non-structural evaluation and retrofitting is limited to elements of unreinforced masonry, and evaluation of the Life Safety 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). 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), evaluation of the Life Safety performance level for the BSE- 1E earthquake level need not be evaluated, because for San Francisco earthquake hazard parameters, it will not govern over Collapse Prevention for the BSE-2E level. This is because the ratio between these earthquake ground motion levels is typically around 1.8, while the ratio between the Collapse Prevention and Life Safety acceptability limits in ASCE-41 does not exceed 1.33. iii. “75% of code” criteria not permitted in Appendix A6 The option (in Section 304.3.2) to use 75 percent of the prescribed forces of the new building code is intentionally not included in Chapter A6, and thus is not permitted for use in Chapter A6 because this option does not make clear how to address (a) the design of gravity framing for 2022 San Francisco Building Code AB-XXX Draft by ATC. 6/5/2025 8:26:00 AM Page 3 of 6 imposed deformations and (b) structural detailing that does not conform to that of 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 (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 that is 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 unreinforced masonry elements (if any). 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, meaning 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 that are 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 (meaning different seismic-force-resisting system in upper story(s) compared to lower story(s)) where only the lower system is of concrete, if the existing upper system (including the lateral-force-resisting system and gravity system) is not of concrete construction, the existing upper system need not 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. 2022 San Francisco Building Code AB-XXX Draft by ATC. 6/5/2025 8:26:00 AM Page 4 of 6 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 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 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 eliminated 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 318. 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 are susceptible to failure resulting in loss of gravity load support. For each column or wall pier, comply with at least one 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 a failure of the column or wall pier such that it cannot support gravity load. 3. For wall piers in buildings that do not have an Extreme Torsional Irregularity per 1. 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. 2. If failure of columns or wall piers can be shown not to 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. 2022 San Francisco Building Code AB-XXX Draft by ATC. 6/5/2025 8:26:00 AM Page 5 of 6 Potential deficiency Requirements Commentary 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. check for shear at the specified level and does not have an Extreme Torsional Irregularity, it is judged that there is enough wall that the consequences of shear failure of wall piers will be limited. Option 3 is not permitted for structures with high plan-torsion irregularity because of a concern that columns or wall pier on one side of the building plan could suffer undo damage in such a case. 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 drift ∆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 a failure at the slab-column interface such that the slab-column interface cannot support gravity load. 1. 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. 2. 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. 3. 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. 4. 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 to 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 make it unlikely 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 2022 San Francisco Building Code AB-XXX Draft by ATC. 6/5/2025 8:26:00 AM Page 6 of 6 Potential deficiency Requirements Commentary 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: 1. Section 18.14.4.1(d) of ACI 318. 2. 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. 1. 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 required to be considered 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. 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. G. A6.4.5 Masonry infill Commentary. If the infill is of unreinforced masonry, its attachment to the main structure is to be addressed as shown in Table A6.4-1. Additionally, for either reinforced or unreinforced masonry infill, the effect of the infill on building response is to be addressed per this subsection. _________________________________________________ Patrick O’Riordan, C.B.O. Date Director Department of Building Inspection Approved by the Building Inspection Commission on (date) FEBRUARY 10, 2026 SEISMIC ORDINANCE UPDATE Policy & Services Committee Discussion Julia Knight, Senior Program Manager PaloAlto.gov PRESENTATION OVERVIEW Recommendation Review progress and initial recommendations to develop an updated Seismic Hazards Identification and Risk Mitigation Ordinance; provide feedback to staff for additional refinement and analysis. Key Content •Project Background & Timeline •Potential Policy Changes •Additional Policy Considerations 2 Project Background & Timeline 3 EXISTING ORDINANCE OVERVIEW & IMPACT Now Out-of-Date •Adopted in 1986; references old standards Limited Scope from the Start •Mandatory evaluations; voluntary retrofits •Regulated 89 buildings in 3 vulnerable building categories •Includes some policy incentives, like FAR bonuses for retrofit projects Overall Positive Impact •approx. 67 buildings demolished or retrofit to-date •approx. 28 vulnerable buildings remaining across the 3 categories* * 6 additional buildings subject to the 1986 ordinance were recently identified 4 1986 PAST POLICYMAKING & PROGRESS 2014 Northridge Earthquake (magnitude 6.7) 1994 Napa Valley Earthquake (magnitude 6.0) Note: Timeline not to scale 2015-2016 2017 2023 2025 5 Loma Prieta Earthquake (magnitude 6.9) 1989 February March April May June August SeptemberJuly 2026 LOOK-AHEAD October 6 UPCOMING ADVISORY GROUP MEETINGS •Advisory Group Meeting #4 | Support & Implementation •Policy Discussion: Public Disclosure, Tenant Displacement & Incentives •Technical Discussion: Fiscal Impact Analysis & Financing Tools •Advisory Group Meeting #5 | Draft Ordinance Discussion •Policy Discussion: First Draft Ordinance Discussion •Technical Discussion: Inventory update •Advisory Group Meeting #6 | Ordinance Refinement •Policy Discussion: Second Draft Ordinance Review •Technical Discussion: Trial evaluation & Retrofit FEB 24 JUN 2 APR 14 7 Potential Policy Changes 8 SEISMIC ORDINANCE UPDATE PURPOSE Update Palo Alto Municipal Code Chapter 16.42: Seismic Hazards Identification Program to more effectively reduce seismic vulnerability in buildings, enhance life safety protections, and support business and service continuity following a seismic event . 9 ORDINANCE UPDATE OVERVIEW To align with current best practices, the ordinance could: •make minor amendments to existing building categories •regulate retrofit requirements for additional vulnerable building categories •introduce mandatory retrofit requirements and strict compliance timelines •incorporate modern seismic retrofit standards and procedures •provide a wider variety of policy and/or other incentives 10 POLICYMAKING FLOWCHART 1. Identify vulnerable building categories 2. Set building age thresholds (if any) 3. Set building size thresholds (if any) 4. Establish screening and retrofit standard 5. Set screening deadline Determine if voluntary or mandatory retrofit is required For each building category… Benchmark years are based on when building code updates were made Can exempt buildings of certain sizes, occupancy levels, or unit counts Screening confirms what, if any, building category a building falls into 11 MANDATORY COMPLIANCE FLOWCHART 6. Establish notification timeline and procedures 7. Set evaluation deadline (if any) 9. Develop evaluation forms 8. Set retrofit plan submission deadline (if any) If mandatory, then… 10. Set final retrofit completion deadline Option to skip evaluation for buildings also required to submit plans Evaluation identifies a building’s specific seismic deficiencies 12 MINOR AMENDMENTS TO EXISTING CATEGORIES 13 Existing Category #Existing Description Possible Modifications Estimated # of Buildings^ Category I Buildings constructed of unreinforced masonry (URM), except for those smaller than 1,900 square feet with six or fewer occupants -Apply to all buildings regardless of size or occupancy level -Reduce scope to just URM bearing wall buildings (not recommended by consultant team) 3-12 buildings (no residential units) Category II Buildings constructed prior to January 1, 1935, containing 100 or more occupants None 3 buildings (no residential units) Category III Buildings constructed prior to August 1, 1976, containing 300 or more occupants None 13 buildings (215 residential units) ^ Some buildings are represented in more than one category Existing Building Category Details Ordinance will provide specific compliance procedures for buildings that fall into multiple categories ADDITIONAL BUILDING CATEGORIES 14 Category Description Notes Estimated # of Buildings^ Estimated # of Residential Units^^ Category IV Weak-Story Wood Frame Buildings Built Before 1977 -Lack of well-distributed shear walls at ground level -Risk of partial or total collapse -Most common category included in peer programs, after URMs 270 buildings 2,134 units Category V Rigid-Wall Flexible Diaphragm Buildings Built Before 1998 -Poor connections between roof, floors and walls -Risk of partial or full collapse 479 buildings 1,058 units Category VI Nonductile Concrete Buildings Built before 1977 -May contain weak and/or soft stories as well as structural elements prone to premature and/or brittle cracking -Risk of partial or total collapse 458 buildings 2,474 units Category VII Steel Moment Frame Buildings Built Before 1998 -Weak beam-to-column welded joints -Risk of partial or total collapse 60 buildings 248 ^ Some buildings are represented in more than one category; numbers updated from staff report ^^ Some units are represented in more than one category Vulnerable Building Type Details VII. Steel Moment FrameVI. Nonductile Concrete I.Unreinforced Masonry Buildings II. Before 1/1/35 and Over 100 Occupants III. Before 8/1/76 and Over 300 Occupants IV. Weak-Story Wood-Frame V. Concrete and Masonry Buildings with Wood Floors and Roofs VULNERABLE BUILDING TYPE EXAMPLES Image sources available upon request. MANDATORY RETROFIT REQUIREMENTS 16 Staff and the consultant team engaged the CAG in a preliminary discussion on retrofit requirement types. The group assumed incentives would be offered. •Categories I, II & III: CAG, consultant team & staff support for mandatory retrofits with short-term compliance deadlines •Nearly all have had access to incentives to comply voluntarily for 40 years •Could consider voluntary retrofit requirement for non-residential buildings in Category II (i.e. Palo Alto Woman’s Club and MacArthur Park, but not Cardinal Hotel) •Category IV: CAG, consultant team & staff support for mandatory retrofits with mid-term compliance deadlines •Category VI: CAG, consultant team & staff support for mandatory retrofits for with long-term compliance deadlines •Categories V & VII: continued discussion needed with CAG, staff and consultant team MODERN SEISMIC RETROFIT STANDARDS 17 American Society of Civil Engineers Standard for Seismic Evaluation and Retrofits of Existing Buildings (ASCE 41-23) is the seismic retrofit standard proposed by the consultant team and reviewed by the CAG and staff. It provides methods to assess and strengthen structures in order to reduce the risk of building collapse and protect lives during earthquakes. Alternative standards, such as the California Existing Building Code or California Historical Building Code standards, could also be used. INCENTIVE PACKAGES Offering a package of incentive options to property owners will support compliance. Incentives may include: •Procedural: Technical support for building owners and/or expedited permit processing •Development: Density or height increases and/or reductions in parking or similar requirements •Fee Waivers or Reductions: Waived or reduced building permit fees, demolition fees, and/or development impact fees (as applicable) •Financial Incentives: City-issued, low-interest loans or grants for building owners and/or local transfer tax incentives 18 Additional Policy Considerations 19 ASSEMBLY BILL 130 Assembly Bill (AB) 130 (2025) limits the City's authority to adopt new building standards that apply to residential units until 2031. Interpretations of this new law are still evolving, and staff are evaluating how it may affect the proposed updates to the City’s Seismic Hazards Identification and Risk Mitigation Program. 20 TENANT PROTECTIONS Retrofits of both residential and non-residential buildings may impact tenants in one of several ways. •Temporary construction disruptions (reduced parking, noise etc.) •Temporary displacement (if building is not occupiable during retrofit) •Increased costs (if building owner adjust rents to recover retrofit costs) Further research and policy development is needed to identify implementable tenant support systems and resources. •Guidelines to minimize tenant disruption and/or displacement •Relocation support services •Retrofit cost pass-through limits 21 PUBLIC DISCLOSURE The City may wish to increase community awareness for buildings that pose seismic safety risks. One or more of the following tools could be considered: •Publicly available list of noncompliant vulnerable buildings •Physical Placards (not recommended by consultant team) •Written notification requirements for existing and/or new tenants Note: Buyer notification of a building’s seismic deficiencies at time of sale is already regulated by State law 22 RESIDENTIAL EXEMPTIONS Staff, the consultant team, and many of the CAG members recommend applying the updated ordinance to residential buildings with 3 or more units , therefore exempting 1- and 2-unit residential buildings.^ Similarly, the City could consider varying compliance deadlines for residential buildings by unit count. For example, buildings with fewer units could be required to comply sooner than others, or vice versa. ^Some members of the CAG suggested only exempting 1-unit residential buildings. Consultant team also open to exempting 3 - and 4-unit buildings. 23 POLICY & SERVICES FEEDBACK P&S may provide feedback on any of the covered content, including: •Building categories to be regulated •Proposed mandatory and voluntary retrofit requirements •City incentives to minimize costs for property owners •Residential exemptions under three units 24 GEORGE HOYT Chief Building Official george.hoyt@paloalto.gov (650) 329-2368 JULIA KNIGHT Senior Program Manager julia.knight@paloalto.gov 650-838-2839 Thank you! 26 27 Category Description Retrofit Compliance Type Retrofit Timeline^ Category I Unreinforced Masonry Buildings Mandatory 2-4 years Category II Buildings constructed prior to January 1, 1935, containing 100 or more occupants Mandatory 4-8 years Category III Buildings constructed prior to August 1, 1976, containing 300 or more occupants Mandatory 4-8 years Category IV Weak-Story Wood Frame Buildings Built Before 1977 Mandatory 6-10 years Category V Rigid-Wall Flexible Diaphragm Buildings Built Before 1998 Voluntary (or Mandatory) TBD Category VI Nonductile Concrete Buildings Built before 1977 Mandatory 10-25 years Category VII Steel Moment Frame Buildings Built Before 1998 Voluntary (or Mandatory) TBD ^ approximate timelines based on similar programs in peer cities; years from adoption date to complete retrofit Retrofit Compliance Types and Timelines by Building Category 28 Category Description Evaluation and Retrofit Standards ^^ Category I Unreinforced Masonry Buildings ASCE^ 41-23 or California Existing Building Code Appendix Chapter A1 Category II Buildings constructed prior to January 1, 1935, containing 100 or more occupants ASCE 41-23 Category III Buildings constructed prior to August 1, 1976, containing 300 or more occupants ASCE 41-23 Category IV Weak-Story Wood Frame Buildings Built Before 1977 ASCE 41-23 or California Existing Building Code Appendix Chapter A4 or FEMA P-807 Category V Rigid-Wall Flexible Diaphragm Buildings Built Before 1998 ASCE 41-23 or California Existing Building Code Appendix Chapter A2 Category VI Nonductile Concrete Buildings Built before 1977 ASCE 41-23 or a new local standard like that used in San Francisco Category VII Steel Moment Frame Buildings Built Before 1998 ASCE 41-23 ^ American Society of Civil Engineers Standard for Seismic Evaluation and Retrofits of Existing Buildings ^^ qualified buildings may also choose to use the California Historical Building Code standards Evaluation and Retrofit Standards by Building Category 29 Jurisdiction(s)Seismic Retrofit Program Residential Applicability West Hollywood 1 or more units Albany, San Jose 3 or more units Los Angeles 4 or more units Alameda, Berkeley, Oakland, San Francisco 5 or more units Unit Thresholds Established by California Jurisdictions for Various Seismic Retrofit Programs