18-48.010.1 High seismic activity. The City of
Santa Rosa is located in an area of high seismic activity between
the Healdsburg-Rogers Creek and San Andreas Faults. It has experienced,
and will continue to experience, moderate to severe seismic activity
in the foreseeable future.
18-48.010.2 Life safety danger. Existing buildings
subject to high seismic hazard levels continue to be a serious life
safety danger to the people who live and work in, and around, them.
The primary goal of seismic retrofit is to improve building performance
and life safety during a seismic event. To improve life safety in
seismically hazardous buildings, yet keep seismic retrofits economically
feasible, the City adopted Resolution 9820 (in 1971) which was later
repealed and reenacted in certain parts as set forth in this chapter.
18-48.010.3 Goals. This chapter provides procedures
for the systematic evaluation and retrofit of existing buildings within
the City of Santa Rosa.
(Ord. 2022-015 § 13)
For the purpose of this chapter, the following words, terms,
and phrases shall be defined as follows:
The lessening of potential and/or existing life-safety hazards,
in the built environment, to occupants and neighboring uses.
An extension or increase in floor area, number of stories,
or height of a building or structure.
Any construction or renovation to an existing structure,
other than repair or addition.
An organization, political subdivision, office, or individual
responsible for administering and enforcing the requirements of a
code or standard, or for approving equipment, materials, an installation,
or a procedure.
Any structure utilized or intended for supporting or sheltering
any occupancy.
A fundamental component of building construction which may
or may not be of fireresistance-rated construction and is constructed
of materials based on the building type of construction.
The vertical distance from grade plane to the average height
of the highest roof surface.
A building classification defined in Section 3.2.1 (Table
3-1) of ASCE 41-13 that groups buildings with common seismic-force-resisting
systems and performance characteristics in past earthquakes.
A process that critically examines a building and/or building
elements for life-safety hazards based on the standards specified
and referenced in this chapter. The process involves collecting and
analyzing information about the building and/or building element characteristics,
and the resulting report stating judgments about deficiencies, hazards,
and potential solutions.
Historical building qualifications for use with the California
Historical Building Code (Title 24, Part 8), or with the Santa Rosa
City Code.
A degree of expected seismic hazard. For ASCE 41-13, levels
are categorized as very low, low, moderate, or high, based on mapped
acceleration values and site amplification factors, as defined in
Section 2.5 (Table 2-5) of ASCE 41-13.
A type of construction whose vertical and horizontal structural
elements are primarily formed by a system of repetitive wood framing
members.
The formal designation of the primary purpose of the building,
structure, or portion thereof, as defined in Chapter 3 of the California
Building Code.
A limiting damage state for a building, considering structural
and nonstructural components, used in the definition of Performance
Objective.
One or more pairings of a selected Seismic Hazard Level with
both an acceptable or desired Structural Performance Level and an
acceptable or desired Nonstructural Performance Level.
A building and/or other construction permit is/was issued
for the proposed work.
The restoration, re-classification, demolition, and/or abatement
of deficient buildings and building elements to a state of acceptable
life safety, as determined in accordance with this chapter and other
applicable codes and standards.
The reconstruction or renewal of any part of an existing
building for the purpose of its maintenance or to correct damage.
Ground-shaking demands of specified severity, developed on
either a probabilistic or deterministic basis.
An addition, alteration, repair, or any combination of the
preceding that affects, exposes, or reveals more than 10% of the existing
building area or building elements of concern.
A classification assigned to a site based on the types of
soils present and their engineering properties, as defined in ASCE
41 or ASCE 7.
One or more stories constructed above an open-front garage,
or other significant opening(s), with insufficient vertical elements
of the lateral-resisting-system in line with, and at the level of,
the open-front garage (or other significant opening(s)).
The portion of a structure between the tops of two successive
finished floor surfaces and, for the topmost story, from the top of
the floor finish to the top of the roof structural element.
The visual observation of the structural system by a licensed
design professional for general conformance to the approved construction
documents.
Construction classification as defined in Chapter 6 of the
California Building Code.
(Ord. 2022-015 § 13)
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18-48.030.1 Buildings and building elements
subject to evaluation. The classifications of buildings and building elements listed in Sections 18-48.030.1.1 through 18-48.030.1.6 are subject to abatement by demolition, or by seismic evaluation and rehabilitation in accordance with Section 18-48.040 of this chapter. If abatement is proposed by demolition, a demolition permit is required to be issued prior to demolition work on any building or building element, except as provided for "emergency repairs" in the California Building Code. Buildings, building elements, or hazards which are not voluntarily abated within 365 days of notice to correct deficiencies may be required by the City to be vacated and abated in accordance with the provisions of Chapter 18-20 of this code.
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18-48.030.1.1 All buildings constructed
prior to December 31, 1957.
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Exceptions to Section 18-48.030.1.1:
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1.
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Public school buildings.
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2.
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One-family and two-family dwellings of light-frame wood construction.
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18-48.030.1.2 All buildings, regardless
of when constructed, that do not meet the building benchmark criteria
of ASCE 41-13, Table 4-6.
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18-48.030.1.3 All buildings constructed
with unreinforced masonry walls.
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18-48.030.1.4 All buildings with concrete
or masonry walls that were constructed or permitted prior to November
1, 2002 (the effective date of the 2001 California Building Code).
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18-48.030.1.5 Suspension of lighting
fixtures in suspended grid ceilings, in all buildings, regardless
of when built.
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18-48.030.1.6 Existing multi-story
construction with one or more stories over open front or garage door
opening(s), creating a "soft story" condition, as determined by a
licensed design professional or the Authority Having Jurisdiction.
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18-48.030.2 Timing. The requirement
for seismic evaluation and abatement/rehabilitation shall be identified
by the City at the time of permit application for fire sprinklers,
change of use, addition, alteration, or repair of buildings and/or
building elements identified in Section 18-48.030.1.
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18-48.030.3 Exemptions. The project
types identified in Sections 18-48.030.3.1 through 18-48.030.3.4 are
exempt from the mandatory seismic evaluation requirements of this
chapter.
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18-48.030.3.1 Trade permits. Plumbing,
mechanical, and electrical permits, in buildings with concrete and/or
masonry walls, that do not significantly alter the roofing or ductwork,
and that do not significantly affect or expose the building elements
identified in this chapter.
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18-48.030.3.2 Repairs. Small repair
permits, in buildings with concrete and/or masonry walls, that do
not significantly alter the roofing or ductwork, and that do not significantly
affect or expose the building elements identified in this chapter.
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18-48.030.3.3 Photovoltaic systems. Photovoltaic system installations that do not significantly alter
the roofing, and that do not significantly affect or expose the building
elements identified in this chapter.
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18-48.030.3.4 Soft story alterations. Alterations, valued at less than $50,000.00, to soft story buildings
that do not include any alteration, addition, or repairs to the soft
story level, nor to the story directly above the soft story level.
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(Ord. 2022-015 § 13)
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18-48.040.1 Evaluation and rehabilitation. When a seismic evaluation is required by Section 18-48.030.1, the
building owner or authorized representative shall retain a design
professional, licensed in the State of California, to evaluate the
building and building elements in accordance with one of the standards
listed in Section 18-48.050.1 and this section. Rehabilitation and/or
demolition of all deficient buildings and building elements is required
in accordance with the evaluation of the licensed design professional
and this chapter. The licensed design professional shall submit a
written evaluation report to the Authority Having Jurisdiction which
shall include, but not be limited to, the items listed in Sections
18-48.040.1.1 through 18-48.040.1.3. Unknown building elements shall
be verified or otherwise addressed by the design professional retained.
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18-48.040.1.1 Scope and intent. The
purpose of the evaluation, a summary of the evaluation procedure(s),
and the level of investigation conducted.
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18-48.040.1.2 Design standard criteria. The seismic evaluation standard/criteria used, and the building
performance objective chosen (minimum of life safety).
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18-48.040.1.3 Site and building data. Site and building data shall include, but not be limited to, all
items listed in Sections 18-48.040.1.3.1 through 18-48.040.1.3.14.
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18-48.040.1.3.1 General building description. Building address, assessor's parcel number, year built, design standard/code
in effect at time of original permit application, number of stories,
story height, building height, building dimensions, approximate floor
area, occupancy class, type of construction, historical significance,
and building type.
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18-48.040.1.3.2 Structural systems description. Framing, seismic-force-resisting-systems, floor and roof diaphragm
construction, basement, and foundation systems. Copies of the original
construction drawings shall be submitted if available.
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18-48.040.1.3.3 Diaphragm chords. Diaphragm
chord continuity, strength, and connections to the diaphragm web and
vertical elements of the lateral force resisting system.
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18-48.040.1.3.4 Diaphragm collectors. Diaphragm collector continuity, strength, and connections to the
diaphragm web and vertical elements of the lateral force resisting
system.
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18-48.040.1.3.5 Diaphragm ties. Diaphragm
tie continuity, strength, and connection to the diaphragm web elements.
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18-48.040.1.3.6 Wall anchorage. Out-of-plane
wall anchorage to diaphragms.
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18-48.040.1.3.7 Wall strength. Out-of-plane
strength of walls.
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18-48.040.1.3.8 Seismic separation or interconnection. Separation and/or interconnection of adjacent buildings sharing
common vertical or seismic-force-resisting elements.
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18-48.040.1.3.9 Nonstructural systems description. All nonstructural elements that affect the seismic performance of
the building, or whose failure could cause serious life-threatening
injuries to occupants or persons near the building.
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18-48.040.1.3.10 General site information. Site soil factors, soil type, seismic design category, level of
seismicity, spectral response acceleration parameters, and soil site
class (buildings within risk categories I or II may assume soil site
class D unless site-specific geotechnical information is available).
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18-48.040.1.3.11 Supplemental documentation. Photographs of the building exterior and structural elements, general
condition of the structure, special features of the building, and
any general comments that pertain to life safety or structural stability.
Preliminary structural calculations, material test results, all necessary
checklists, and summary data sheets.
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18-48.040.1.3.12 General findings. A
list of observed defects including cracks, uncleanliness, evidence
of leaks, foundation settlement, sagging floors, rusting metal, rotting
wood, and general deterioration of any other building material used.
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18-48.040.1.3.13 Seismic findings. A
list of seismic deficiencies identified during the inspection and/or
evaluation of the structure.
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18-48.040.1.3.14 Recommendations. Mitigation
solutions and/or recommendations for further evaluation.
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Exceptions to Section 18-48.040.1.3:
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1.
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In lieu of the information required by Section 18-48.040.1.3,
the design professional retained may submit documentation showing
the building complies with the benchmark provisions of Sections 4.3.1
through 4.3.4 of ASCE 41-13. This exception does not include evaluations
of buildings known to have neglected or inadequately addressed the
applicable design standards in effect at the time of original building
permit application. Review of the record drawings of the structure
shall be performed to confirm that the primary elements of the seismic-force-resisting
system and their detailing were designed in accordance with the applicable
provisions listed in Table 4-6 of ASCE 41-13. This exception does
not apply to nonstructural elements, and a written report in accordance
with ASCE 41-13 Section 16.17 shall be required for all nonstructural
building elements identified in Section 18-48.030.1, as applicable.
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2.
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In lieu of the information required by Section 18-48.040.1.3,
the design professional retained may submit documentation showing
the building complies with the Uniform Building Code, 1955 Edition,
including earthquake provisions (applicable only to buildings built
prior to 1958). Documentation shall include a review of the record
drawings of the structure to confirm that the primary elements of
the seismic-force-resisting system were designed and detailed in accordance
with applicable seismic provisions. This exception does not apply
to nonstructural elements, and a written report in accordance with
ASCE 41-13 Section 16.17 shall be required for all nonstructural building
elements identified in Section 18-48.030.1, as applicable.
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3.
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As approved by the building official on a case-by-case basis,
the design professional retained may submit documentation including
all items specified in Exceptions 18-48.040.1.3a through 18-48.040.1.3c
below in lieu of the information required by Section 18-48.040.1.3.
(Structures and buildings larger than 10,000 square feet may have
additional requirements).
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3a.
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One or more completed Tier 1 Checklists, as required by Table
4-7 of ASCE 41-13 (Life Safety Performance Level), including Quick
Checks for Strength and Stiffness per Section 4.5.3 of ASCE 41-13.
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3b.
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A completed Summary Data Sheet found in Appendix C of ASCE 41-13
(Life Safety Performance Level).
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3c.
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An evaluation of diaphragms, chords, collectors, ties, and wall
anchorage per Sections 7.2.9 through 7.2.11.2 of ASCE 41-13. Alternate:
An evaluation of diaphragms, chords, collectors, ties, and wall anchorage
per sections 12.10 and 12.11 of ASCE 7-16, with a design spectral
response acceleration parameter at short periods (SDS) determined
per section 12.8.1.3 of ASCE 7-16.
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(Ord. 2022-015 § 13)
18-48.050.1 Evaluation and rehabilitation design standards. Seismic retrofit design and construction shall be performed under
the direct supervision of a design professional, licensed in the State
of California, and shall be based upon this chapter and the following
standards:
1.Â
2019
California Building Code Title 24, Part 2.
2.Â
2019
California Existing Building Code Title 24, Part 10.
3.Â
2019
California Historical Building Code Title 24, Part 8.
4.Â
ASCE
41-13 (or ASCE 41-17, Collapse Prevention Performance Level) Seismic
Evaluation and Retrofit of Existing Buildings.
5.Â
Any
other nationally recognized standard for rehabilitation of existing
buildings approved by the Building Official.
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Structural observation in accordance with Section 1704 of the
California Building Code shall be required for all structures in which
a seismic retrofit is being performed. Structural observation shall
include visual observation of work for conformance to the approved
construction documents and confirmation of existing conditions assumed
during design.
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(Ord. 2022-015 § 13)
