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.

1.4 Seismic Evaluation Process

With reference to Figure C1-1, Tier 3 Systematic evaluation is required for certain buildings, subject to Bulletin modifications to Section 3.3. Where Tier 3 Systematic evaluation is not required, Tier 1 Screening is required for all evaluations, and Tier 2 Deficiency-Based Evaluation is optional.

1.4.1 Selection of Performance Objective

Omit. The evaluation objective is given in SFEBC Section 329.2.

1.4.2 Level of Seismicity

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

1.4.4 Evaluation Procedures

Tier 1 Screening is required. Tier 2 Deficiency-Based Evaluation is optional. Tier 3 Systematic evaluation is not required.

1.4.5 Evaluation Report

Omit. The template report required by ASCE 41 is not to be used in this case. Evaluation reports should use the attached Template Evaluation Report.

1.5 Seismic Retrofit Process

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

2.1 Scope - 2.3 Target Building Performance Levels

Omit. Evaluation objectives are given in SFEBC Section 329.2.

2.4 Seismic Hazard

Per SFEBC Section 329.2, all evaluations are required to consider only the BSE-1E hazard.

For purposes of compliance with SFEBC Section 329, the Site-Specific Procedure of Section 2.4.2 need not be used.

2.4.1 General Procedure for Hazard Due to Ground Shaking

Per SFEBC Section 329.2, all evaluations are required to consider only the BSE-1E hazard.

Seismicity parameters for the BSE-1E hazard may be obtained using the Seismic Design Maps tool available at https://www.seismicmaps.org/.

For purposes of calculating seismicity parameters with the USGS tool, Site Class F need not be assumed.

2.4.1.6.1 Site Classes

Where the Site Class is known from available documents, the known Site Class should be used. Where the Site Class is not known, for purposes of compliance with SFEBC Section 329, the Site Class may be estimated from the SEAOC Seismic Design Map available at https://www.seismicmaps.org/.

Unless site-specific investigations indicate otherwise, Site Class F shall be assumed for any site located within a zone of required investigation for liquefaction on the 2000 Department of Conservation map available at https://earthquake.usgs.gov/hazards/urban/sfbay/liquefaction/sfbay/.

Otherwise, Site Class F need not be assumed.

For purposes of compliance with SFEBC Section 329, site-specific investigation of potential Site Class F sites is not required as long as potential liquefaction is noted on the Deficiency List in the seismic evaluation report.

2.5 Level of Seismicity

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

3.2.4 Site and Foundation Information

For purposes of compliance with SFEBC Section 329, any requirement in ASCE 41-13 for site-specific soils or geotechnical investigation is waived. Owners may perform and report the results of such investigations voluntarily.

3.3.1 Limitations on the Use of the Tier 1 and 2 Evaluation and Retrofit Procedures

For purposes of compliance with SFEBC Section 329, Tier 3 evaluation is not required. However, if ASCE 41-13 Section 3.3.1 would require Tier 3 evaluation, each Tier 1 checklist item subject to that requirement (which in some cases might be only those on Immediate Occupancy but not Life Safety checklists) shall be listed in the Deficiency List with a note indicating potential non-compliance subject to Tier 3 analysis.

Originally signed by:

Tom C. Hui, S.E., C.B.O. November 17, 2014

Director

Department of Building Inspection

Approved by Building Inspection Commission on August 20, 2014

Attachment A: Earthquake Evaluation of Private School Structures; Scope Report

A tt achment B: Seismic Evaluation Report

AB-110 Building Façade Inspection and Maintenance

NO. AB-110:

DATE: August 21, 2024

SUBJECT: Permit Review and Operations

TITLE: Building Façade Inspection and Maintenance

The purpose of this bulletin is to establish policies for implementing San Francisco Existing Building Code PURPOSE: Chapter 5F regarding building façade inspection and maintenance.

San Francisco Building Code (SFBC), Current Edition San Francisco Existing Building Code (SFEBC), Chapter 5F, Building Façade Inspection and Maintenance –

REFERENCE:

Retroactive Provisions California Historical Building Code, Current Edition San Francisco Planning Code, Articles 10 and 11, as well as properties defined as Category A – Historic Resource Present. American Society for Testing and Materials (ASTM) E2270-14 Standard Practice for Periodic Inspection of Building Facades for Unsafe Conditions ASTM E2841-19 Standard Guide for Conducting Inspections of Building Façades for Unsafe Conditions Code of Federal Regulations, Part 61, Secretary of the Interior’s Standards for the Treatment of Historic Properties

The Building Façade Inspection & Maintenance Program was established by Ordinance 67-16 which amended the 2016 San Francisco Existing Building Code to require certain San Francisco building facades be regularly inspected by a California licensed architect or engineer and maintained. The program was subsequently updated by Ordinances 97-23 and 16-24 which amended the 2022 San Francisco Existing

BACKGROUND: Building Code. The inspections are meant to ensure public safety and reduce the risk of death or injury

resulting from deteriorated building façade elements falling onto streets and sidewalks below. The inspection and maintenance work are to be documented in a report submitted to the San Francisco Department of Building Inspection. After the initial inspection, buildings must be inspected, and reports submitted every five years, alternating between a detailed comprehensive inspection and a general supplemental inspection.

DISCUSSION: San Francisco Existing Building Code Chapter 5F requires that building façades undergo initial and subsequent inspections according to a schedule based on the original construction date of a building. These inspections, as well as reporting and maintenance, are to be done as detailed in this Administrative Bulletin and in accordance with the San Francisco Existing Building Code (SFEBC). SFEBC Section 504F.1

APPLICABILITY:

I. INSPECTORS

specifies that the basis for inspection and reporting is ASTM E2270 Standard Practice for Periodic Inspection of Building Facades for Unsafe Conditions, as modified and interpreted by this Administrative Bulletin. The report due dates are as specified in SFEBC Section 503F. Facade inspections are primarily intended to identify unsafe conditions that could jeopardize public safety and to identify other conditions that could deteriorate into unsafe conditions before the next scheduled inspection. The intent of Chapter 5F is to verify that façade elements and systems are maintained to perform in accordance with the code under which they were installed or improved.

All buildings that are five or more stories and of construction Type I, II, III, or IV are required to have comprehensive facade inspection and maintenance undertaken in accordance with San Francisco Existing Building Code Chapters 5F and this Administrative Bulletin. Among the buildings requiring comprehensive façade inspections, those of 15 or more stories are additionally required to have supplemental façade inspections undertaken in accordance with San Francisco Existing Building Code Chapter 5F and this Administrative Bulletin.

n and maintenance undertaken in accordance with San Francisco Existing Building Code Chapters 5F and this Administrative Bulletin. Among the buildings requiring comprehensive façade inspections, those of 15 or more stories are additionally required to have supplemental façade inspections undertaken in accordance with San Francisco Existing Building Code Chapter 5F and this Administrative Bulletin.

A. Required façade inspection and maintenance shall be performed under the direct supervision of a qualified professional. The qualified professional shall be a California licensed architect or engineer, retained by the property owner. The qualified professional shall oversee all work of qualified inspectors and all reporting.

B. For inspection of buildings considered historic resources, the qualified professional shall have expertise in inspection and maintenance of historic resources. Such expertise must include a documented history of successful projects, detailed investigations of historic structures, and the preparation of recommendations or repair documents. All work must be in accordance with the Secretary of the Interior’s Standards for the Treatment of Historic Properties: Standards for Rehabilitation .

II. INSPECTION STANDARDS AND PROCEDURES

A. To meet the requirements of SFEBC Chapter 5F, the provisions of ASTM E2270-14 Standard Practice for Periodic Inspection of Building Facades for Unsafe Conditions, shall apply as modified by this Administrative Bulletin. Subsequent revisions of ASTM E2270 may apply if specifically referenced in an updated version of this Administrative Bulletin or through a directive issued by the Department of Building Inspection.

B. Prior to inspection, the owner should check with SF Planning to determine whether the building qualifies as a historic resource. Such information is available on the SF Planning Property Information Map website at sfplanninggis.org/pim/ or by contacting the SF Planning Preservation Program staff at the Planning Information Center at 49 South Van Ness Ave, 2nd Floor, San Francisco, 628-652-7300, or pic@sfgov.org. Special requirements outlined here apply to buildings defined by SF Planning as Category A – Historic Resource Present:

1. Assessment and recommendations related to facades of historic resources shall be performed in conformance with the Secretary of the Interior’s Standards for the Treatment of Historic Properties: Standards for Rehabilitation .

2. Inspection methods for historic resources shall use the least intrusive or invasive means feasible to effectively assess hidden conditions.

3. When practical, building materials removed to allow for detailed inspection shall be salvaged and reinstalled, or stored by the property owner for future reinstallation.

4. Qualified historic resources may be evaluated using the provisions in the California Historical Building Code regarding strength, performance, utilization, and other properties of archaic materials, provided that such provisions result in acceptable performance as detailed in the SFEBC and in this Administrative Bulletin.

C. Comprehensive façade inspection per SFEBC Chapter 5F shall be in accordance with ASTM E2270 and clarifications made in this Administrative Bulletin.

1. Comprehensive façade inspections shall be per ASTM E2270 Item 10.3 General Inspection and Item 10.4 Detailed Inspection and shall encompass 100 percent visual inspection and 25 percent tactile inspection of the exterior façades per ASTM E2270 Table A1.1.

2. The qualified professional shall assess the watertight integrity of the façade by performing a cursory interior leak survey of the exterior facades per ASTM E2270 Section 9 as well as consulting with the property owner and/or building manager regarding any locations of known water leakage or infiltration. This information may be useful in selecting locations for detailed inspection.

3. As part of a detailed inspection, probes, per ASTM E2270, Item 10.4.8, are not mandatory and need not be undertaken unless considered necessary by the qualified professional. Inspection should include careful visual inspection of external indicators of façade deterioration before probing or removing elements to observe concealed façade components.

D. Supplemental façade inspection per SFEBC Chapter 5F shall be in accordance with ASTM E2270, Item 10.3 General Inspection.

1. As part of a supplemental façade inspection, general inspections under Item 10.3 of ASTM E2270 shall comprise 100 percent visual inspection of the exterior glazing. The general inspection shall be a visual observation of exterior glazing system from an appropriate distance with or without magnification or remote optical devices. The qualified professional shall methodically scan façade areas and check for out-of-plane displacement, deterioration and defects of glazing elements, and for glass breakages.

2. As part of the supplemental façade inspection, detailed inspections, per ASTM E2270, Item 10.4, and interior leak survey per ASTM E2270, Item 9, are not mandatory and need not be undertaken unless considered necessary by the qualified professional conducting the inspection and reporting.

E. Remote sensing techniques, including 3-D survey, remote aerial vehicles, and other non-traditional inspection methods are considered a “means and methods” and may be deployed by the qualified professional for achieving General Inspections under Item 10.3 of ASTM E2270 and this Administrative Bulletin. All applicable laws and regulations associated with the “means and methods” for performing the inspections are the responsibility of the qualified professional. All applicable laws and regulations relating to the operation of remote vehicles and equipment must be followed.

F. Persons conducting building façade inspections are encouraged to review ASTM E2841 Standard Guide for Conducting Inspections of Building Façades for Unsafe Conditions . The document provides recommended procedures and methodologies for conducting inspections of building façades.

III. INSPECTION WAIVERS OR EXEMPTIONS

A. Procedures for obtaining a waiver of the initial comprehensive inspection based on previous inspection, maintenance work, and report are as follows:

1. To request a waiver of the initial inspection under Chapter 5F, Section 503F.1, Exception 2, the owner must submit all materials required in a comprehensive inspection report, as specified in this Administrative Bulletin. The request must also include documentation of the completed repairs, such as reports, plans, specifications, and building permits

2. A waiver of the initial comprehensive façade inspection may be requested and granted if the following criteria are met:

a. A comprehensive façade inspection and necessary maintenance, restoration, or replacement was performed and completed within ten years prior to the initial inspection report due date listed in Table 503F of the SFEBC for the building’s specific compliance tier.

Where only partial inspection, maintenance, restoration, or replacement was performed and completed within ten years prior to the inspection due date, the remaining facades/areas/elements are required to undergo comprehensive façade inspection to provide for a complete report that thoroughly addresses all requirements outlined in SFEBC Section 504F and ASTM E2270, and this Administrative Bulletin.

b. A complete inspection report meeting the requirements this Administrative Bulletin must be submitted, reviewed, and accepted.

c. Documentation of the scope of completed repairs, such as reports, plans and specifications, and building permits, is submitted with the inspection report.

3. Special approval of waivers of initial inspection may be approved by the Department of Building Inspection on a case-by-case basis for other reasons, such as for previously submitted reports or studies, or for work undertaken in previous phases.

B. A supplemental inspection report shall be submitted in accordance with the due dates presented in SFEBC Chapter 5F unless all of the following is confirmed and documented by the qualified professional in the report compliance affidavit provided in AB-110 Attachment B, each time a supplemental inspection report is due:

1. The building contains no spandrel glass.

2. The building has maintained a maintenance log documenting all glass and glazing replacement or repairs. The log shall be available for review by the qualified professional.

3. The building has no history of glass breakage within the last five years.

IV. INSPECTION REPORTS, AFFIDAVITS, AND REPORT CONCLUSIONS

A. Comprehensive inspection reports must meet the following requirements:

1. All comprehensive inspection reports shall include the Comprehensive Building Facade Inspection Report Compliance Affidavit, as provided in AB-110 Attachment A, completed and signed by both the owner and the qualified professional.

2. A comprehensive façade inspection report shall document the qualified professional’s inspection findings, observations, discussions, conclusions and recommendations as required by SFEBC Chapter 5F, ASTM E2270, and this Administrative Bulletin. The report shall be written and presented in a clear, well-organized and detailed manner. It shall have obvious references to photos and sources and be structured in a formal technical report format. A complete list of requirements is provided in AB-110 Attachment C Comprehensive Façade Inspection Report Submittal Preparation Checklist, along with a suggested report structure.

3. Detailed floor plans, construction details, and other detailed documentation per ASTM E2270, Item 7 are required only as necessary to undertake inspection or communicate inspection findings to the property owner or the Department of Building Inspection. Sufficient building plan information should be assembled to identify areas of inspection, locations or elements requiring maintenance work, locations of unsafe conditions and other inspection findings.

B. Supplemental inspection reports must meet the following requirements:

1. A supplemental inspection report shall consist of the Supplemental Building Façade Inspection Report and Compliance Affidavit, as provided in AB-110 Attachment B, completed and signed by both the property owner and the qualified professional, with other attachments as necessary. The supplemental inspection report shall briefly document information, observations, conclusions, and recommendations as applicable based on SFEBC Chapter 5F, ASTM E2270, and this Administrative Bulletin and attachments.

2. Where the supplemental inspection finds that the condition of the exterior glass and glazing system is classified as either Conclusion Category 1 Repair/Stabilization following Temporary Mitigation of Unsafe Conditions or Conclusion Category 2 Requires Repair, Stabilization and Maintenance, or where broken glass is identified, the report shall describe the nature and extent of repairs, maintenance, or corrective actions recommended to be performed immediately or before the next reporting period deadline. The report shall include descriptions of the conditions observed, possible cause, and recommended mitigation measures. The report shall include photographs locating and identifying the conditions. A complete list of requirements is provided in AB-110 Attachment D Supplemental Façade Inspection Report Submittal Preparation Checklist .

rmed immediately or before the next reporting period deadline. The report shall include descriptions of the conditions observed, possible cause, and recommended mitigation measures. The report shall include photographs locating and identifying the conditions. A complete list of requirements is provided in AB-110 Attachment D Supplemental Façade Inspection Report Submittal Preparation Checklist .

C. Each Comprehensive and Supplemental inspection report shall assign the overall building to one of the three report conclusion categories described below. Note that the report conclusion categories described below are distinguished from façade condition categories defined in ASTM E2270 in that, the façade conclusion categories are for categorizing the overall building, whereas the façade condition categories are for categorizing the conditions of the façade elements. An unsafe condition is not a façade inspection report conclusion category, but rather a condition that requires immediate notification and mitigation action as discussed in a subsequent section of this document.

1. Conclusion Category 1 – Repair/Stabilization following Temporary Mitigation of Unsafe Conditions:

A building in the category Repair/Stabilization following Temporary Mitigation of Unsafe Conditions has exhibited deterioration that constituted one or more unsafe conditions and has undergone actions to mitigate or repair the unsafe conditions.

The report shall identify all unsafe conditions addressed in previous mitigation as well as all other conditions that require repair, stabilization or maintenance to prevent existing deterioration from progressing to an unsafe condition before the next required inspection. The report shall recommend repair/stabilization actions to restore the building to its approved condition and a timeline for implementation of such repairs. The report shall also contain general repair and maintenance recommendations.

2. Conclusion Category 2 – Requires Repair, Stabilization and Maintenance:

A building in the category Requires Repair, Stabilization and Maintenance exhibits deterioration that, if not repaired, stabilized or maintained, could progress to an unsafe condition before the next required inspection.

The report shall identify building elements that require repair, stabilization and maintenance before the next required inspection, and shall include repair recommendations and a timeline for implementation so that the building performance meets a condition that ensures the building’s safety and compliance with applicable codes. The report should also contain general repair and maintenance recommendations.

The property owner shall follow the recommendations in the report for stabilization and repair necessary to maintain the façade.

3. Conclusion Category 3 – Ordinary Maintenance:

A building in the category Ordinary Maintenance requires on-going general repair and maintenance.

The report should make general maintenance and repair recommendations.

V. ACTIONS BY CITY FOLLOWING SUBMITTAL OF REPORTS

A. Within 60 days of receipt of a façade inspection report, the Department of Building Inspection shall review reports and notify both the owner and the qualified professional that the report is acceptable as submitted, or provide comments identifying any revisions or additional information that may be required.

B. All reports shall become part of the permanent records of the Department of Building Inspection. The Department of Building Inspection will maintain a publicly accessible database containing façade inspection reporting data and related information.

VI. PROCEDURE FOR PROCESSING BUILDING FACADE INSPECTION REPORTS

A. The owner/owner’s representative shall submit the Building Façade Inspection Report to the Department of Building Inspection for review, either:

1. By e-mail: dbi.facade@sfgov.org

2. By mail: Department of Building Inspection, Technical Service Division, 49 South Van Ness Ave, Suite 500, San Francisco, CA 94103

3. In person: Technical Services Division Key Programs Counter on the 2nd Floor of the Department of Building Inspection at 49 South Van Ness Ave, San Francisco, CA 94103.

B. Once the Department of Building Inspection has completed its review of the report, the department will issue an invoice to the owner or owner’s representative with instructions on how to make the payment. The number of plan review and administrative hours will be indicated on the invoice.

C. After all fees are paid, the property will be deemed compliant with the program compliance deadline for which the report was submitted. An acceptance letter may be requested by the owner or owner’s representative to confirm compliance with the program.

VII. NOTIFICATION AND ACTION REGARDING SIGNIFCANT DAMAGE AND UNSAFE CONDITIONS

A. Either during the normal passage of time or following an earthquake, windstorm or other cause, building facades that appear to exhibit significant damage must be inspected within 60 days of the discovery of such damage per SFEBC 503F.3. Immediate action is also required to address any unsafe conditions. Significant damage includes items that have fallen from a building or items that have cracked or dislodged to become potential falling hazards. Determination of such significant damage shall be by a qualified professional.

B. If an unsafe condition is identified at any time during the façade inspection and reporting process, the qualified professional shall immediately notify both the property owner and the Department of Building Inspection of such condition.

C. If what appears to be an unsafe condition is observed by an inspector or a qualified professional during a post-earthquake evaluation or under any other circumstance, such person shall immediately notify the Director of the Department of Building Inspection of such apparent condition. The director shall immediately arrange to have a qualified professional or other appropriate investigator evaluate the conditions. If such condition is determined to be unsafe, the owner shall be immediately contacted.

a post-earthquake evaluation or under any other circumstance, such person shall immediately notify the Director of the Department of Building Inspection of such apparent condition. The director shall immediately arrange to have a qualified professional or other appropriate investigator evaluate the conditions. If such condition is determined to be unsafe, the owner shall be immediately contacted.

D. Immediate contact with the Department’s Building Inspection Division shall be by telephone at 628-652-3400. Notice shall also be sent to the Façade Unit by email to dbi.facade@sfgov.org. In case of emergencies such as earthquakes, other notification contact methods may be established.

E. Upon receipt of notification from the inspector of an unsafe condition, the property owner shall, as soon as reasonably possible, take action to protect the public and property. Such actions may require the owner to coordinate with various City agencies in the installation of barriers or closure of sidewalks or streets. For such coordination in an emergency to mitigate unsafe conditions, contact:

1. San Francisco Police Department – 911

2. Department of Public Works – Radio Room 415-695-2134

3. Department of Building Inspection – Building Inspections Division 628-652-3400

F. The owner shall, within 72 hours of notification of an unsafe condition, provide a mitigation plan and schedule of implementation to the Department of Building Inspection at dbi.facade@sfgov.org. The plan and schedule shall be prepared by a qualified professional engineer or architect, for the installation of protective barriers, stabilization, repair or other actions to provide temporary or long-term mitigation of all imminent hazard conditions. The mitigation plan, which shall include photographs, shall be reviewed and approved by the Director of the Department of Building Inspection. Work shall be completed within a time frame acceptable to the director but shall not exceed five days. Requests for extensions may be requested and approved on a case-by-case basis.

G. A Notice of Violation may be issued where (1) a mitigation plan is not submitted within 72-hours of reporting, and/or (2) stabilization does not occur within the agreed upon time frame in the mitigation plan. For buildings classified by SF Planning as Category A – Historic Resource Present (including Article 10 and 11 buildings), any elements removed as part of stabilizing the façade for safety shall be preserved.

H. Issuance of Emergency Orders, permits, or other City approval and actions to mitigate unsafe conditions shall be done in accordance with the San Francisco Building Code, Section 102A – Unsafe Buildings, Structures or Property, and other applicable regulations.

I. If the subject property is a historic resource, SF Planning Preservation staff shall be contacted for review and advice before the issuance of an Emergency Order or approval of any other emergency action that might impact the historic fabric.

J. The qualified professional shall notify the Department of Building Inspection at dbi.facade@sfgov.org when unsafe conditions have been mitigated.

K. Notwithstanding timely reporting and mitigation of the unsafe condition, a completed inspection report is required to be subsequently submitted within the time frame required by SFEBC Section 503F.

VIII. UNDERTAKING STABILIZATION, REPAIR AND MAINTENANCE WORK

A. Building permits and other City permits are required to undertake work as required under the San Francisco Building Code and other applicable codes and regulations. A standard building permit review and issuance process shall be followed except when expedited permit processing is requested

and authorized under Administrative Bulletin AB-004, Priority Permit Processing Guidelines. Repair work shall be performed in accordance with the applicable provisions of the San Francisco Building Code.

B. SF Planning Preservation staff shall review and approve permit applications for the stabilization and repair of historic resources. For buildings that are listed as historic properties defined by SF Planning as Category A – Historic Resource Present (including Article 10 and 11 buildings), facade repair, stabilization and maintenance shall be performed in conformance with the Secretary of the Interior’s Standards for the Treatment of Historic Buildings: Standards for Rehabilitation . Methods of repair, stabilization and maintenance for historic resources shall use the least intrusive or least invasive means feasible and shall preserve existing materials and features to the maximum extent feasible.

Qualified historic buildings may be maintained and/or repaired using the provisions in the California Historical Building Code regarding strength, performance, utilization, and other properties of archaic materials, provided that such provisions result in acceptable performance.

C. Contractors and workers engaged in façade maintenance shall be experienced and skilled in façade maintenance operations. Workers shall have training and/or on-the-job experience at least equivalent to requirements for graduation from an apprenticeship program for this occupation as approved by the Chief of the Division of Apprenticeship Standards of the California Department of Industrial Relations. Alternatively, workers may be registered apprentices working under the supervision of such trained and/or experienced workers. Compliance with this training and experience standard shall be verified by the owner, owner’s agent, or qualified professional representing the owner.

IX. ENFORCEMENT AND ABATEMENT

The Director of the Department of Building Inspection shall implement the procedures detailed in San Francisco Building Code Section 102A, Unsafe Buildings, Structures or Property, and related abatement actions when any of the requirements for façade inspection, reporting, mitigation, repair or maintenance are not met in a timely manner.

Signed by:

Patrick O’Riordan, C.B.O., 8/26/2024

Director

Department of Building Inspection

Approved by the Building Inspection Commission on 6/21/2017 and 8/21/2024

Attachment A: Comprehensive Building Façade Inspection Report Compliance Affidavit

Attachment B: Supplemental Façade Inspection Report and Compliance Affidavit

Attachment C: Comprehensive Façade Inspection Report Submittal Preparation Checklist

A tt achment D: Supplemental Façade Inspection Report Submittal Preparation Checklist

AB-111 Guidelines for Preparation of Geotechnical and Earthquake Ground Motion Reports for Foundation Desi n and Construction of Tall Buildin s g g

NO. AB-111 :

DATE : June 15, 2020 (Updated 01/01/2023 for code references)

SUBJECT : Permit Processing and Issuance

Guidelines for Preparation of Geotechnical and Earthquake Ground Motion TITLE : Reports for Foundation Design and Construction of Tall Buildings

PURPOSE :

REFERENCES :

DISCUSSION:

The purpose of this Administrative Bulletin is to present requirements and guidelines for developing geotechnical site investigations and preparing geotechnical reports for the foundation design and construction of tall buildings.

Current edition of the San Francisco Building Code (SFBC) Administrative Bulletin AB-082: Guidelines and Procedures for Structural, Geotechnical, and Seismic Hazard Engineering Design Review CCSF (2014) – Guidance for Incorporating Sea Level Rise into Capital Planning In San Francisco: Assessing Vulnerability and Risk to Support Adaptation. CCSF (2016) – San Francisco Sea Level Rise Action Plan. NRC (2012) – Sea Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, and Future. NIST / NEHRP (2012) – Soil-Structure Interaction for Building Structures, GCR 12917-21. PEER (2017) – Tall Buildings Initiative, Guidelines for Performance-Based Seismic Design of Tall Buildings, Version 2.01, PEER Report No. 2017/06, May. Poulos, H.G. 2017 – Tall Building Foundation Design, publishing house CRC Press, ISBN 9781138748033. Ellen Plane, Kristina Hill, and Christine May “A Rapid Assessment Method to Identify Potential Groundwater Flooding Hotspots as Sea Levels Rise in Coastal Cities,” October 25, 2019 K. Yasuhara; S. Murakami; N. Mimura; H. Komine; and J. Recio, “Influence of global warming on coastal infrastructural instability,” December 2006 Many relevant and useful references are provided in the following document: ATC 119 (2019) – Seismic Safety and Engineering Consulting Services for the Earthquake Safety Implementation Program (ESIP), City and County of San Francisco, 2019.

1. SCOPE OF THIS BULLETIN

This bulletin presents guidelines for developing a geotechnical site-investigation program and preparing geotechnical reports for foundation design and construction of tall buildings in San Francisco. Sections 2 and 3 of this bulletin are requirements and therefore are stated in mandatory language. The remaining sections are guidelines, which use non-mandatory language.

For the purposes of this bulletin, tall buildings are defined as those with hn (ASCE 7), greater than 240 feet.

The height, hn, is defined in the San Francisco Building Code (SFBC) as the height of level n above the average level of the ground surface adjacent to the structure. Level n is permitted to be taken as the roof of the structure, excluding mechanical penthouses and other projections above the roof whose mass is small compared with the mass of the roof.

Early in a project, the Geotechnical Engineer of Record (GEOR) shall develop a geotechnical site-investigation program and geotechnical report document in accordance with this bulletin.

2. GEOTECHNICAL DESIGN REVIEW

The review of geotechnical design shall meet the requirements of AB-082. The geotechnical member(s) of the Engineering Design Review Team (EDRT) shall participate in the Early Site Permit phase of the project to review the GEOR’s plan for geotechnical site investigations and the GEOR’s geotechnical basis-of-design document. During the subsequent design review, the EDRT will use the guidelines below to review the geotechnical report prepared for foundation design and construction.

At the conclusion of the review, the geotechnical members of the EDRT shall provide a written statement that, in their professional opinion, the geotechnical site-investigation plan and geotechnical reports meet the requirements of the SFBC and this bulletin.

Commentary: The Draft of this bulletin was developed by a volunteer group of experienced geotechnical engineers as an ad-hoc committee of the Structural Engineers Association of Northern California (SEAONC). The draft was requested of SEAONC by SFDBI. Subsequently, the draft of this bulletin was processed (and in some places revised) through subcommittees of the Building Inspection Commission according to the Administrative Bulletin process.

3. SUBMITTAL REQUIREMENTS

Project submittal documents shall be in accordance with the SFBC and Department of Building Inspection (DBI) interpretations, Administrative Bulletins, and policies. In addition, documents relevant to the Geotechnical Design Review shall be submitted by the Engineer of Record to the Director and to the geotechnical members of the EDRT.

4. PROJECT DEFINITION AND DESIGN CRITERIA

In coordination with the project architect and structural engineer, the following information (if available at the time of preparation of the geotechnical report) should be provided: The project description; a site location map; height of the structure; number of stories; number of basement levels; lateral and gravity loads resisting systems; anticipated gravity foundation loads or bearing pressures; applicable codes and design guidelines for seismic

design of the building (e.g., PEER TBI 2017 performance-based design of tall buildings); description of the energy dissipation system (if used); and the approach for development of design ground motions.

5. SITE SURFACE CONDITIONS

Description of existing structure(s) on the site should be presented with information related to the foundations (if known); the site’s historical and current use; site surface elevation including, the reference datum; and description of adjacent facilities and structures with information related to their foundation system (if known) within the foundation zone of influence. The GEOR should determine the foundation zone of influence based on site’s subsurface conditions, foundation type, and building configuration.

Commentary: For a mat foundation bearing on the Colma sand layer, the lateral extent of the zone of influence could be estimated as approximately ½ of distance between the base of the mat and bedrock.

6. REGIONAL AND LOCAL GEOLOGY

This section should include a description of regional and local geology, including fill placement as part of land reclamation, if any. The description of local site geology should provide information about the anticipated engineering soil and rock properties likely to be encountered. Hazard maps and information from the USGS and the State should also be presented including anticipated sea level rise during the design life of the structure (e.g., NRC 2012, CCSF 2014, and CCSF 2016), seismic ground motion, soil liquefaction and lateral spreading, landslides, and tsunami/seiche (for sites near the shoreline).

7. SEISMICITY

A fault map should be provided showing the location of Holocene active faults within a 100 km radius of the site, with the epicenter and magnitude of historical earthquake events shown on the map. A table should be provided containing the pertinent fault information for sources that contribute significantly to the probabilistic seismic hazard analysis (PSHA) performed for a return period of 2,475 years at the key periods of interest to the building design using Uniform California Earthquake Rupture Forecast (UCERF) fault data file.

Commentary: The version of UCERF fault data file that is referenced by the latest California Building Code (CBC)/SFBC and ASCE 7 Standard should be identified and used. In current practice, when performing deterministic seismic hazards analysis (DSHA), maximum fault magnitudes are obtained either from UCERF2 fault data file or mean/mode magnitude from deaggregation of 2,475-year PSHA results.

8. FIELD INVESTIGATION AND LABORATORY TESTING

The subsurface conditions should be explored by drilling borings, and if appropriate, conducting cone penetration test (CPT) soundings. When considering the plan area of the proposed development and the magnitude of building loads, the number of borings and CPTs should be sufficient for characterizing the site’s subsurface conditions and physical properties of soils and bedrock encountered.

The quality of samples should be appropriate for the anticipated laboratory strength or compressibility tests conducted to obtain load-deformation characteristics of soil in support of advanced numerical modeling.

Commentary: Integrated field and laboratory tests should be performed as appropriate to support the anticipated methods of analysis, which commonly include standard general limit equilibrium (GLE) methods and 2D or 3D nonlinear seismic soil-structure interaction (SSI) analyses. Historically, the selection of soil properties for static and seismic design of building foundations has been accomplished through parameter correlations with field tests such as the CPT and field vane shear test (FVST). Correlations with the results of field and soil-index tests are useful; however, it is recommended that relationships used in support of tallbuilding design in San Francisco be checked against local geotechnical data and adjusted, if need be, to provide representative properties of local soils. With the evolution and widespread adoption of performancebased seismic design for tall buildings, advanced numerical analyses incorporating soil-structure interaction (SSI) may be performed. Appropriate SSI analyses require substantial characterization of soil behavior such as strain-dependent shear modulus and material damping curves, and residual shear strength. The use of field test data should be supplemented with laboratory tests that provide soil parameters across the range of deformation anticipated for the project. Strain-dependent soil parameters must also account for the rate effects and the potential for cyclic degradation of soil stiffness and strength. Laboratory tests on soil, such as cyclic direct simple shear and cyclic triaxial, can provide insight into the soil behavior during seismic loading. The integration of suitability extensive field and laboratory test programs improves the reliability of site characterization, thereby reducing uncertainty.

Information and data from existing geotechnical borings and CPTs could be used to supplement new borings as long as existing geotechnical borings and CPTs are located reasonably close to the project site and are drilled in accordance with currently acceptable methods and standards. However, borings drilled only for environmental soil and/or groundwater sampling and testing or for water wells should not be used as a substitute for projectspecific geotechnical borings or CPTs.

For sites with depth-to-bedrock of more than 100 feet, at least one boring should extend a minimum of 50 feet below the surface of bedrock; other borings should be as deep as deemed appropriate as determined by the GEOR and reviewed by the geotechnical members of the EDRT, based on the site’s subsurface conditions, structural loads, and below-grade structural geometry.

For depth-to-bedrock of less than 100 feet, all borings should extend to the bedrock surface with one boring extending at least 50 feet below bedrock surface.

If used, CPTs should be pushed to refusal using a 20-ton CPT rig, if it is possible to access the site with it. At least one CPT sounding should be near a geotechnical boring for calibration purposes. If site conditions prohibit access for a CPT rig within the site, additional CPTs and/or borings adjacent to the site may be necessary and may be required by the EDRT.

Commentary: Field vane shear tests (FVST) are useful for evaluating the peak and remolded undrained shear strength of soft clay. For evaluation of soil liquefaction potential, lateral spreading, and slope instability adjacent to the site, it is suggested that CPT soundings be performed as much as practical because they provide continuous, reliable measurements that can be correlated to physical soil properties. CPTs are also useful for characterizing denser and stiffer units, such as Old Bay Clay (OBC) and for characterizing groundwater conditions with a pore pressure dissipation test. However, because liquefiable and soft soils are

bypassed by using deep foundations or by using ground improvement to provide appropriate bearing support for building foundation, CPT soundings are of limited use under the building footprint because CPTs will most likely encounter refusal within the dense sand layer present at many sites in San Francisco. A sufficient number of borings should be drilled for adequate sampling within the OBC layer. Typically, at least one boring should be drilled or one CPT sounding should be performed in every 5,000 square feet of plot area.

Shear-wave velocity should be measured at least at one location using downhole techniques, seismic CPT, suspension logging, or surface-wave method, as appropriate. The number of tests should reflect the lateral variability of the soil deposits across the site. The shear-wave-velocity measurement should be conducted in such a manner as to allow for accurate determination of variation of shear-wave velocity with depth for computing the Vs30 parameter and for conducting site response analysis (if performed). If downhole logging is used, the shear-wave velocity of bedrock should be measured within the boring that extends at least 50 feet below the surface of bedrock.

To capture the variability in groundwater conditions over time, at least one piezometer should be installed, and piezometric levels should be observed from the time of original geotechnical exploration. In some cases, additional piezometers may be necessary and may be required by the EDRT.

Soil borings should be drilled using rotary wash drilling methods (unless the groundwater table is below the bottom of the boring). Drilling fluid or casing should be used to prevent collapse of borings and bottom instability.

Where compressibility and strength tests are planned in soft clays (e.g., Bay mud - BM), samples should be obtained using a thin-walled tube sampler.

Commentary: Osterberg-type hydraulic fixed-piston sampler with thin-wall tubes of constant inside diameter can provide high-quality samples.

In stiff clays (e.g., OBC) where strength and consolidation tests are planned, Pitcher Barrel sampler or approved equivalent should be used.

Standard penetration tests (SPT) should be performed in cohesionless soils. California modified sampler or Sprague and Henwood (S&H) sampler may be used in the alluvium often found between the bottom of OBC and bedrock and where strength and compressibility tests are not required. Hammer energy measurements should be performed for drive sample system (e.g., SPT and S&H) on at least one boring for the project.

Commentary: Pressuremeter test results have been successfully correlated with large strain modulus of various geological units in the east coast of the United States and overseas.

Rock coring should be used to obtain rock cores within bedrock for borings that extend at least 50 feet into rock. Rock cores should be reviewed and classified by a registered professional geologist. Parameters defining degree of rock weathering, rock strength, rock hardness, and rock mass properties such as the RQD, spacing of discontinuities, conditions of discontinuities, and dip angle should be recorded as directed by the GEOR.

For all soil types, sample intervals should be no greater than 5 feet or at layer interface unless a larger interval is deemed appropriate by the GEOR based on thickness and uniformity of soil layer, data from field vane tests or CPT soundings.

For sandy soils, one or more of the following laboratory tests, as deemed appropriate by GEOR, should be conducted: moisture-density (if S&H sampler is used), moisture test (if SPT sampler is used), fines content (minus sieve No. 200), sieve analysis, and plastic and liquid limits (if silty or clayey sand).

For cohesive soils, one or more of the following tests, as deemed appropriate by the GEOR, should be conducted: (1) unconsolidated or consolidated undrained triaxial tests, or (2) a direct simple shear test. Unconfined compressive strength may be used on representative rock samples but should not be used for cohesive soils.

The GEOR should determine the adequate number of pairs of consolidation and undrained shear strength tests to be performed on undisturbed samples of OBC for evaluation of settlement if a mat foundation is not supported by a deep foundation and is placed above the surface of OBC or if the foundation bears above or within OBC. One pair of consolidation and undrained shear strength tests should be considered for every 30 feet of OBC depth in four representative borings, unless the variability of the site is evaluated through CPTs. The minimum number of pairs should be four. Additional tests would be required if the preconsolidation stress is exceeded.

If OBC is expected to be subjected to vertical effective stresses higher than the preconsolidation pressure, additional tests are also required to measure the secondary consolidation characteristics of the OBC.

Field “index” tests such as the Pocket Penetrometer or Torvane tests may be used on clayey soil samples but should not be considered as a substitute for any laboratory tests described above.

9. SUBSURFACE CONDITIONS

At least two perpendicular cross sections should be provided. A full description of soil layers and geologic units with engineering properties (consistency and consolidation characteristic for clayey soils and potential for soil liquefaction and settlement for sand layers) should be provided.

A design groundwater elevation with consideration of sea level rise during the design life of the structure and seasonal fluctuation of groundwater level (if known) should be presented. The groundwater table expected to be encountered during construction should also be identified.

Commentary: The GEOR should use her/his judgement as to how far inland the influence of sea level rise would impact the groundwater level.

10. FOUNDATION AND GEOTECHNICAL EARTHQUAKE ENGINEERING STUDIES