AB-109 Application of Engineering Criteria in SFEBC Section 329

NO. AB-109   :
DATE   :	August 21, 2014 (Updated 01/01/2017 for code references)
SUBJECT   :	Seismic Evaluation of Private School Facilities
TITLE   :	Application of Engineering Criteria in SFEBC Section 329
PURPOSE   :	The purpose of this Bulletin is to establish acceptable evaluation criteria and reporting standards for complying with Section 329 of the 2016 San Francisco Existing Building Code, as amended by Ordinance No. 202-14.
REFERENCE   :	Chapter 4, 2016 San Francisco Existing Building Code ASCE 41-13, Seismic Evaluation and Retrofit of Existing Buildings
ATTACHMENTS   :	Template Scope Report, available at sfdbi.org Template Evaluation Report, available at sfdbi.org
DISCUSSION   :	SFEBC Section 329, created with Ordinance 202-14, mandates the seismic evaluation of certain existing buildings and non-building structures used by schools that are not under the jurisdiction of the Division of the State Architect’s Structural Safety section.
SCOPE   :	Part A of this Bulletin provides regulations to implement the general requirements of SFEBC Section 329, as well as background commentary. Part B of this Bulletin provides interpretation and additional guidance regarding the application of technical provisions in ASCE 41-13, referenced by SFEBC Section 329.

 

   Part A. Regulations and Commentary for SFEBC Section 329

Part A of this Bulletin restates the provisions of Section 329 and provides corresponding interpretations and background commentary. Commentary is shown in italic font. Section numbers refer to SFEBC Section 329.

Submittal schedule

SFEBC Sections 329.3 and 329.4 provide two submittal deadlines:

The Evaluation Scope document for each school is to be submitted within one year of the effective date of Section 329.

The Evaluation Report for each school building and non-building structure is to be submitted within three years of the effective date of Section 329.

Report templates for each submittal are provided as attachments to this Bulletin.

329.1 General.

The intent of Section 329.1 is to cover certain E-occupancy buildings that are not under the jurisdiction of the Division of State Architect’s Structural safety section and non-building structures accessory to those buildings.

The intent of Section 329.1 is to cover all the buildings and non-building structures on the school campus that are used primarily for school purposes, including cafeterias, gyms and multipurpose rooms. Schools will have the opportunity to use the Scoping Document to state buildings they intend to evaluate.

For purposes of Section 329, a “non-building structure” is defined in SFBC Chapter 2 as a structure that does not support or shelter any use or occupancy and is also defined in ASCE 7-10 Chapter 15. The intent of Section 329.1 is to include non-building structures such as retaining walls, covered walkways, patio covers, and other structures that are prone to earthquake damage, but only when these non-building structures serve buildings subject to Section 329. It is not the intent of Section 329.1 to include lightweight structures with no history of poor earthquake performance, such as well-anchored playground equipment or light wood or metal fences. Some Department judgment is expected to apply during review of the Evaluation Scope document.

It is not the intent of Section 329.1 to cover:

•   Buildings off of the school’s campus, even if used by students or faculty.

•   Buildings on the school’s campus that are used primarily for non-school purposes, such as churches or convents, including such buildings occupied by 25 or more persons for less than 12 hours per week or four hours in any given day. SFBC Section 305.1.1 applies to spaces associated with the functions of the place of religious worship to which they are accessory. It is the intent of SFEBC Section 329.1 that classrooms in buildings used for religious worship are within the scope of Section 329.1 if they are used for educational purposes for an amount of time that exceeds the time restrictions listed in 329.1 Exception 1.

•   Buildings occupied by 25 or more persons for less than 12 hours per week or four hours in any given day.

•   Schools where the average enrollment of the past three years is 25 or fewer students.

In accordance with SFBC Section 303.1.3, school gyms, auditoriums, and other spaces or structures used for assembly purposes that are nevertheless assigned an E occupancy and are thus within the scope of Section 329.1.

Evaluations shall be conducted under the supervision of a licensed design professional.

329.2 Scope and Criteria

For purposes of Section 329, previous versions of ASCE 41, specifically ASCE 31-03 and ASCE 41-06, are not acceptable as alternatives to ASCE 41-13. See Part B of this Bulletin for modifications and interpretations of ASCE 41-13 criteria.

   Commentary: The intent of the evaluation is to identify hazards known to be associated with earthquake-related severe injury or death.

   In addition to the tabulated scope, voluntary mitigation of contents hazards is encouraged. Such mitigation could include bracing, restraint, or removal of supplies, stored items, or furnishings prone to hazardous tipping or sliding. It might also include nonstructural mitigation that is not required by Section 329. References regarding contents bracing have been developed by FEMA, the Division of the State Architect, and others. For example, see “Guide and Checklist for Nonstructural Earthquake Hazards in California Schools,” available at http://www.documents.dgs.ca.gov/dsa/pubs/SB1122.pdf.

329.5 Voluntary Minimum Life-Safety Retrofit

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

   Part B. APPLICATION OF ASCE 41-13 TO EVALUATION

Part B of this Bulletin makes modifications to and interpretations of ASCE 41-13 as they relate to compliance with SFEBC Section 329. The section numbers refer to section numbers in ASCE 41-13.

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 USGS tool available at http://geohazards.usgs.gov/designmaps/us/application.p hp. From the Design Code Reference Document menu, select “2013 ASCE 41.” From the Earthquake Hazard Level menu, select “BSE-1E.”

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 USGS map available at http://earthquake.usgs.gov/regional/nca/soiltype/map/.

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 http://gmw.consrv.ca.gov/SHMP/download/pdf/ozn_sf. pdf.

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 ASCE41-13 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.       11/17/2014

Director

Department of Building Inspection

Approved by Building Inspection Commission on 8/20/2014

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

Attachment B:  Seismic Evaluation Report