Ordinance 2008-08
ORDINANCE NO. 2008-08
AN ORDINANCE OF THE CITY COUNCIL OF THE CITY OF GILROY,
AMENDING THE 2007 CALIFORNIA BUILDING CODE (CBC) ADOPTED BY
THE CITY COUNCIL AS ORDINANCE 2007-24, TO MODIFY, ADD AND
AMEND SECTIONS 3402 AND 3403 REGARDING REPAIR OF DAMAGED
STRUCTURES.
WHEREAS, Section 6.1 of the Gilroy City Code provides that the latest edition of
the uniform codes shall be submitted to the City Council for adoption subject to local
changes and modifications; and
WHEREAS, on December 17, 2007 by Emergency Ordinance No. 2007-24 the
City Council adopted the 2007 California Building Code (CBC) as the City of Gilroy
Building Code and made findings therein pursuant to California Health and Safety Code
9 17958.5 and 17958.7 with regard to local climatic, geological or topographical
conditions necessitating changes to the provisions of the CBC; and
WHEREAS, the City Council hereby adopts those findings which are on file with
the California Building Standards Commission by reference hereto; and
WHEREAS, the City Council finds that the Silicon Valley area, which includes
the City, is within a very active seismic area and local soil conditions can be highly
expansive and are prone to shrink and swell during seasonal drying and wetting; and
WHEREAS, the City Council further finds that portions of the City are in hillside
areas that are hazardous fire areas that have only limited fire suppression forces and
facilities available for the protection of life and property; and
WHEREAS, the City Council further finds fire protection and suppressIOn
services for multi-family dwellings and other buildings of three stories or more than
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thirty feet in height are limited and therefore reqmre supplemental fire suppreSSIOn
services such as automated fire sprinkler systems; and
WHEREAS, the City Council further finds the City has local climatic
considerations including temperatures ranging from below freezing to over one hundred
degrees, local geological considerations including the presence of seismic activity and
expansive clay soils, and local topographical considerations including extensive hillside
construction that is prone to erosion; and
WHEREAS, a duly noticed public hearing was held prior to the adoption of the
City of Gilroy Building Code by the City Council on December 17, 2007; and
WHEREAS, the City Council adopted Ordinance 2007-24 as the Gilroy Building
Code with an effective date of January 1,2008; and
WHEREAS, City staff recommends that additional local amendments to the City
of Gilroy Building Code are necessary as are set forth herein; and
WHEREAS, this Ordinance is exempt from the requirements of the California
Environmental Quality Act of 1970 ("CEQA"), as amended, because it does not involve
an activity that may cause either a direct physical change in the environment or a
reasonably foreseeable indirect physical change in the environment; and
WHEREAS, the City Council has reviewed all of the written materials and
considered all of the oral testimony presented to it on this matter.
NOW, THEREFORE, THE CITY COUNCIL OF THE CITY OF GILROY
DOES HEREBY ORDAIN AS FOLLOWS:
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SECTION I
This Ordinance establishes regulations as amendments to the City of Gilroy
Building Code for the expeditious repair of damaged structures. In the event an
amendment to the California Building Standards Code results in differences between
these building standards and the California Building Standards Code, the text of these
building standards shall govern. In accordance with California Health and Safety Code
Section 17958.7, express findings that modifications to the California Building Standards
Code are reasonably necessary because of local climatic, geological or topographical
conditions are either already on file with the California Building Standards Commission,
or will be filed prior to the effective date of the ordinance. In accordance with California
Government Code Section 50022.6, at least one true copy of the California Building
Code has been on file with the City Clerk since fifteen (15) days prior to enactment of the
ordinance.
SECTION II
The following modifications and changes as recommended by the Building Official
are adopted to the City of Gilroy Building Code (Ordinance 2007-24) as
amendments to the California Building Code, 2007 Edition, which is the 2006
International Building Code as amended by the State of California:
AMEND: 2007 CBC SECTION 3402.1
ADD SECTION 3402.1 - Substantial Structural Damage, to read:
Section 3402.1 - Substantial Structural DamageA condition where:
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1. In any story, the vertical elements of the lateral-foree-resisting system,
have suffered damage such that the lateral load-carrying capacity of the
structure in any direction has been reduced by more than 20 percent from
its pre-damaged condition, or
2. The capacity of any vertical gravity load-carrying component, or any
group of such components, that supports more than 30 percent of the total
area of the structure's floor (s) and roof (s) has been reduced more than 20
percent from its pre-damaged condition, and the remaining capacity of
such affected elements with respect to all dead and alive loads is less than
75 percent of that required by the building code for new buildings of
similar structure, purpose, and location.
AMEND: 2007 CBC Section 3403
ADD: Section 3403.5 to read:
Section 3403.5. - Repairs.
3403.5.1 Scope. Repairs of structural elements shall comply with this section.
3403.5.1.1. Seismic evaluation and design. Seismic evaluation and design of an existing
building and its components shall be based on the following criteria:
3403.5.1.1.1. Evaluation and design procedures. The seismic evaluation and design
shall be based on the following procedures:
1. As specified in the building code (Chapter 16)
2. ASCE 31 (American Society of Engineers) Seismic Evaluation of Existing
Buildings (for evaluation only)
3. ASCE 41 Seismic Rehabilitation of Existing Buildings
4. The procedures contained in Appendix Chapter A2 and A3 of the International
Existing Building Code (IEBC) and Appendix Chapter Al of California Existing
Building Code (CEBC) shall be permitted to be used as specified in Section
3403.1.1.3.
3403.5.1.1.2. CBC level seismic forces. When seismic forces are required to meet the
building code level, they shall be one of the following:
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1. 100 percent of the values in the building code. The R factor used for
analysis in accordance with Chapter 16 of the building code shall be the R
factor specified for structural systems classified as "Ordinary" unless it
can be demonstrated that the structural system satisfies the proportioning
and detailing requirements for systems classified as "Intermediate" or
"Special" .
2. Forces corresponding to BSE-l and BSE-2 (Basic Safety Earthquake)
Earthquake Hazard Levels defined in ASCE 41. Where ASCE 41 is used,
the corresponding performance levels shall be those shown in Table
3403.5.1.1.2.
TABLE 3403.5.1.1.2
ASCE 41 and ASCE 31 PERFORMANCE LEVELS
OCCUPANCY
CATEGORY
(BASED ON CBC
TABLE 1604.5)
PERFORMANCE LEVEL
FOR USE WITH ASCE 31
AND WITH ASCE 41
BSE-1 EARTHQUAKE
HAZARD LEVEL
I
II
III
IV
Life Safety (LS)
Life Safety (LS)
Note (a)
Immediate Occupancy (10)
PERFORMANCE
LEVEL FOR
USE WITH ASCE 41
BSE-2
EARTHQUAKE
HAZARD LEVEL
Collapse Prevention (CP)
Collapse Prevention (CP)
Note (a)
Life Safety (LS)
a. Performance Levels for Occupancy Category III shall be taken as halfway
between the performance levels specified for Occupancy Category II and
Occupancy Category IV.
3403.5.1.1.3 Reduced CBC level seismic forces When seismic forces are permitted to
meet reduced building code levels, they shall be one of the following:
1. 75 percent of the forces prescribed in the Building Code. The R factor
used for analysis in accordance with Chapter 16 of the building code shall
be the R factor as specified in Section 3403.5.1.1.2.
2. In accordance with the applicable chapters in Appendix A of the
International Existing Building Code and California Existing Building
Code, as specified in Items 2.1 through 2.3 below. Structures or portions
of structures that comply with the requirements of the applicable chapter
in Appendix A shall be deemed to comply with the requirement for
reduced Building Code force levels.
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2.1 The seismic evaluation and design of unreinforced masonry
bearing wall buildings in Occupancy Category I or II are permitted to
be based on the procedures specified in part 10 of 2007 CBC.
2.2 Seismic evaluation and design of the wall anchorage system in
reinforced concrete and reinforcements for reduced building code
force levels. Masonry wall buildings with flexible diaphragms in
Occupancy Category I or II are permitted to be based on the
procedures specified in Appendix Chapter A2 of IEBC.
2.3 Seismic evaluation and design of cripple walls and sill plate
anchorage in residential buildings of light-frame wood construction in
Occupancy Category I or II are permitted to be based on the
procedures specified in Appendix Chapter A3 of IEBC.
3. In accordance with ASCE 31 based on the applicable performance level as
shown in Table 3403.5.1.1.2.
4. Those associated with the BSE-l Earthquake Hazard Level defined in
ASCE 41 and the performance level as shown in Table 3403.5.1.1.2.
Where ASCE 41 is used, the design spectral response acceleration
parameters Sxs and Sxl shall not be taken less than 75 percent of the
respective design spectral response acceleration parameters SDS and SDl
defined by the California Building Code and its reference standards.
3403.5.1.2. Wind Design. Wind design of existing buildings shall be based on the
procedures specified in the building code.
3403.5.2. Repairs to damaged buildings. Repairs to damaged buildings shall comply
with this section.
3403.5.2.1. Unsafe conditions. Regardless of the extent of structural damage, unsafe
conditions shall be eliminated.
3403.5.2.2 Substantial structural damage to vertical elements of the lateral-force-
resisting system. A building that has sustained substantial structural damage to the
vertical elements of its lateral-foree-resisting system shall be evaluated and repaired in
accordance with the applicable provisions of Section 3403.5.2.2.1 through 3403.5.2.2.3.
3403.5.2.2.1. Evaluation. The building shall be evaluated by a registered design
professional, and the evaluation findings shall be submitted to the code official. The
evaluation shall establish whether the damaged building, if repaired to its pre-damage
state, would comply with the provisions of the building code.
- Wind forces for this evaluation shall be those prescribed in the Building Code.
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-Seismic forces for this evaluation are permitted to be the reduced level seismic
forces specified in Code Section 3403.5.1.1.3.
3403.5.2.2.2. Extent of repair for compliant buildings. If the evaluation establishes
compliance of the pre-damage building in accordance with Section 3403.5.2.2.1, then
repairs shall be permitted that restore the building to its pre-damage state, using materials
and strengths that existed prior to the damage.
3403.5.2.2.3. Extent of repair for non-compliant buildings. If the evaluation does not
establish compliance of the pre-damage building in accordance with Section
3403.5.2.2.1, then the building shall be rehabilitated to comply with applicable provisions
of the building code for load combinations including wind or seismic forces.
1. Wind
The wind design level for the repair shall be as required by the building
code in effect at the time of original construction unless the damage was
caused by wind, in which case the design level shall be as required by the
code in effect at the time of original construction or as required by the
building code, whichever is greater.
2. Seismic
Seismic forces for this rehabilitation design shall be those required for the
design of the predamaged building, but not less than the reduced level
seismic forces specified in Section 3403.5.1.1.3. New structural members
and connections required by this rehabilitation design shall comply with
the detailing provisions of the building code for new buildings of similar
structure, purpose, and location.
3403.5.2.3. Substantial structural damage to vertical load-carrying
components. V erticalload-carrying components that have sustained substantial
structural damage shall be rehabilitated to comply with the applicable provisions
for dead and live loads in the building code. Undamaged vertical load-carrying
components that receive dead or live loads from rehabilitated components shall
also be rehabilitated to carry the design loads of the rehabilitation design. New
structural members and connections required by this rehabilitation design shall
comply with the detailing provisions of the building code for new buildings of
similar structure, purpose, and location.
3403.5.2.3.1. Lateral force-resisting elements. Regardless of the level of
damage to vertical elements of the lateral force-resisting system, if substantial
structural damage to vertical load-carrying components was caused primarily by
wind or seismic effects, then the building shall be evaluated in accordance with
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Section 3403.5.2.2.1 and, if non-compliant, rehabilitated m accordance with
Section 3403.5.2.2.3.
3403.5.2.4. Less than substantial structural damage. For damage less than
substantial structural damage, repairs shall be allowed that restore the building to
its pre-damage state, using materials and strengths that existed prior to the
damage. New structural members and connections used for this repair shall
comply with the detailing provisions of the building code for new buildings of
similar structure, purpose, and location.
3403.5.3 Referenced Standards
Standard Reference In Code
Referenced Section Number
Number TITLE
ASCE 31-03 Seismic Evaluation of Existing Buildings 3403.5.1.1.1,
TABLE 3403.5.1.1.2,
3403.5.1.1.3
ASCE 41-06 Seismic Rehabilitation of Existing 3403.5.1.1.1,
Buildings 3403.5.1.1.2,
TABLE 3403.5.1.1.2,
3403.5.1.1.3
SECTION III
The City of Gilroy is located in an area of high seismic activities as indicated by
the United States Geological Survey and California Division of Mines and Geology.
Recent earthquake activities have indicated the lack of adequate design and detailing,
flexibility of materials and/or building systems are contributing factors to damages that
reduce the protection of the life safety of building occupants.
The amendments
contained in this Ordinance will assist the property owners and the City of Gilroy in the
repair and reconstruction of damaged building in the community to their pre-existing
condition and more importantly will reduce the likelihood of future structural damages.
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SECTION IV
If any section, subsection, sentence, clause or phrase of this Ordinance is for any
reason held to be invalid or unconstitutional, such decision shall not affect the validity of
the remaining portions of this ordinance. The City Council of the City of Gilroy hereby
declares that it would have passed and adopted this Ordinance, and each section,
subsection, sentence, clause or phrase hereof, irrespective of the fact that anyone or more
sections, subsections, sentences, clauses or phrases may be declared invalid or
unconstitutional.
SECTION V
This Ordinance shall take effect immediately and be in full force and effect thirty
(30) days after its adoption.
PASSED AND ADOPTED BY THE COUNCIL OF THE CITY OF GILROY
this 4th day of August, 2008, by the following vote:
AYES: COUNCILMEMBERS:
ARELLANO, BRACCO, DILLON, GARTMAN,
TUCKER, WOODWARD, and PINHEIRO
NONE
NONE
NOES: COUNCILMEMBERS:
ABSENT: COUNCILMEMBERS:
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ATT~T: .~
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~~"'na Freels, City Clerk
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APPROV ~ ~
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I, SHA WNA FREELS, City Clerk of the City of Gilroy, do hereby certify that the
attached Ordinance No. 2008-08 is an original ordinance, or true and correct copy of a city
ordinance, duly adopted by the Council of the City of Gilroy at a regular meeting of said Council
held on the 4th day of August, 2008, at which meeting a quorum was present.
IN WITNESS WHEREOF, I have hereunto set my hand and affixed the Official Seal of
the City of Gilroy this 11th day of September, 2008.
(Seal)