Chapter 4A
EARTHQUAKE HAZARD REDUCTION  IN UNREINFORCED MASONRY BEARING WALL BUILDINGS

Add Chapter as follows:

Chapter 4A
EARTHQUAKE HAZARD REDUCTION  IN UNREINFORCED MASONRY BEARING WALL BUILDINGS

(NOTE: The time limits for compliance with the provisions of Chapters 4A and 4B have passed, but the ordinance and the time limits therein are still in effect.)

SECTION 401A – PURPOSE

   The purpose of this chapter is to promote public safety and welfare by reducing the risk of death or injury that may result from the effects of an earthquake on existing unreinforced masonry bearing wall buildings.

   The provisions of this chapter are intended as minimum standards for structural seismic resistance for earthquake ground shaking and are established primarily to reduce the risk of life loss or injury. Compliance with these provisions will not necessarily prevent loss of life or injury, or prevent earthquake damage to rehabilitated structures, or protect against the release of hazardous materials, or protect the function of essential facilities. These provisions are not intended to mitigate ground failure hazards such as liquefaction. The Community Safety Element of the General Plan of the City and County of San Francisco should be consulted for areas most susceptible to ground failure.

   Time limits are given for owners of unreinforced masonry bearing wall buildings to submit an inventory of each building and an evaluation of the degree of risk presented by the building. Priorities and time limits are established for work to be completed.

   Requirements for seismic strengthening of unreinforced buildings are contained in Chapter 4B.

SECTION 402A – SCOPE

   The provisions of this chapter shall apply to all existing buildings having one or more bearing walls of unreinforced masonry as defined in Chapter 4B.

   EXCEPTIONS:

      1.   Buildings housing Group R Occupancies containing less than five dwelling units or guest rooms and used solely for residential purposes.

      2.   Buildings accessory to and on the same lot as those described in Exception 1.

      3.   Buildings which have been brought into full compliance with the requirements of SFEBC Section 301.2 in effect on or after May 21, 1973.

   Compliance with the provisions of Chapters 4A and 4B does not supersede the requirement for compliance with SFEBC Section 301.2 when otherwise required under SFEBC.

   A permit issued solely for compliance with any of the procedures of Chapters 4A and 4B of this code shall not be considered “substantial change” or “structural work” as defined in SFEBC and compliance with SFEBC Section 301.2 will not be required.

SECTION 403A – DEFINITIONS

   For the purpose of Chapters 4A and 4B, certain terms are defined as follows:

   BOLTS-PLUS is the installation of shear and tension anchors at the roof and floors and, when required, the bracing of the unreinforced masonry bearing walls upon evaluation of the height-to-thickness ratio of these walls.

   POOR SOIL is all soil lying bayward of the line indicating the landward limit of Bay Mud deposits as shown on the U.S. Geological Survey Map MF-1376, title “Map Showing the 200-feet thickness contour of surficial deposits and the landward limit of Bay Mud deposits of San Francisco, California,” by William B. Joyner, 1982.

      EXCEPTION: A building need not be considered as being located on poor soil when a subsurface exploration demonstrates that the soil is not underlain by Bay Mud.

   UNREINFORCED MASONRY BEARING WALL BUILDING is a building or structure having at least one unreinforced masonry bearing wall.

SECTION 404A – COMPLIANCE REQUIREMENTS

404A.1  General.  The owner of each unreinforced masonry bearing wall building within the scope of this chapter and Chapter 4B shall cause a structural analysis to be made of the building by a registered civil or structural engineer or licensed architect, and, if the building does not meet the minimum standards specified in this code except as provided for in Chapters 4A and 4B, the owner shall cause the building to be structurally altered to conform to such standards or cause the building to be demolished pursuant to the program implementation schedule set forth.

404A.2  Program Implementation.  The requirements stated in Section 404A.1 above shall be accomplished by submitting to the Building Official the following:

404A.2.1  Inventory form.  The owner is required to submit to the Department, within the time limits set forth in Table 4A-A, a properly completed inventory form, signed and sealed by the owner’s civil or structural engineer or architect. See San Francisco Building Code Section 110A, Table 1A-S for the applicable fee for the review of the inventory form. A failure to respond within the time limits set forth in Table 4A-A is a violation of this code.

404A.2.2  Risk assessment.

404A.2.2.1  General.  When filling out the required information on the inventory form, the owner’s architect or civil or structural engineer shall assign to the building a relative level of risk depending upon the occupancy, soil conditions at the site and the density of the population exposed.

404A.2.2.2  Level of risk assigned.

   1.   Level 1 buildings are buildings containing Groups A Occupancies with an occupant load of 300 or more; or Group E Occupancies, and those buildings greater than three stories in height which are located on poor soil.

   2.   Level 2 buildings are all non-Level 1 buildings which are located on poor soil in the Downtown, North of Market/Civic Center, South of Market, South of Market Residential and Chinatown Unreinforced Masonry Building Study Areas as delineated on Figure 4A-1.

   3.   Level 3 buildings are buildings in the above areas which are not located on poor soil and buildings located on poor soil outside the above areas.

   4.   Level 4 buildings are all other unreinforced masonry bearing wall buildings.

404A.2.3  Engineering reports.  The owner shall engage a registered civil or structural engineer or licensed architect to prepare an engineering report on the building when:

   1.   An owner desires to demolish a qualified historical building or any building containing a nonexempt Group R Occupancy rather than retrofit the building, and a report is requested by the Building Official or the Building Official of the Planning Department; or

   2.   The Bolts-plus level of strengthening is proposed; or

   3.   Strengthening to comply with the State Historical Building Code is proposed; or

   4.   The owner believes the building complies with Chapters 4A and 4B without any further alteration.

   The engineering report shall detail applicable retrofit requirements of the least restrictive retrofit procedure for which the building qualifies. The required retrofit measures shall be developed schematically, and a conceptual construction cost estimate shall be included. If the Bolts-plus level of strengthening defined above and described in Exception 1 to Section 409B.2 is proposed, the necessary measures for compliance with the Special Procedure of Section 411B shall also be designated, and a second cost estimate for this option shall also be included in the report. If the engineering report demonstrates that no deficiencies exist, and the report is approved by the Department, the structure will be considered to conform to the requirements of this chapter. Except as noted in 1. above, the report shall be submitted not later than the date when the application for the building permit to either strengthen or demolish the building would otherwise be required. The format and content of the engineering report shall comply with the provisions of rules and regulations to be issued by the Building Official pursuant to San Francisco Building Code Section 104A.2.1 after consultation with the Seismic Safety Retrofit Bond Program Board. See San Francisco Building Code Section 110A, Table 1A-S for the applicable fee for the review of the engineering report.

404A.2.4  Application for building permit.  The owner shall submit to the Department an application for a structural alteration permit accompanied by structural plans, specifications and calculations for the proposed mitigation solution or a permit application to demolish the building. Time limits for submission of the application and for permit processing and approval are established in Table 4A-A.

404A.2.5  Commencement and completion of construction.  Construction work shall commence and a Certificate of Final Completion and Occupancy or final inspection of work under a demolition permit shall be obtained within the time limits set forth in Table 4A-A.

404A.2.6  Transfer of title.  No transfer of title shall alter the time limits for compliance set forth in Table 4A-A.