This chapter establishes regulations as amendments to the California
Existing 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 codified in this chapter.
In accordance with California Government Code Section 50022.6, at
least one true copy of the California Existing Building Code has been
on file with the city clerk since fifteen days prior to enactment
of the ordinance codified in this chapter. While this chapter is in
force, a true copy of this chapter shall be kept for public inspection
in the office of the city clerk. A reasonable supply of this chapter
shall be available in the office of the city clerk for public purchase.
(Ord. 682 § 1, 2008; Ord. 736 § 1, 2016; Ord. 757 § 1, 2019)
"Definitions" has been replaced with the definitions as indicated
in Section 202 of the California Existing Building Code, which are
stricter.
(Ord. 682 § 1, 2008; Ord. 736 § 1, 2016)
For the purposes of this chapter, the following repair requirements
are added as a new subsection 405.3 to Section 405.4 Repairs in the
2019 California Existing Building Code:
405.3.1 Repairs. Repairs of structural elements
shall comply with this section in addition to California Existing
Building Code Section 404.
405.3.1.1 Seismic evaluation and design. Seismic
evaluation and design of an existing building and its components shall
be based on the following criteria.
405.3.1.1.1 Evaluation and design procedures. The
seismic evaluation and design shall be based on the procedures specified
in the building code, ASCE 31 Seismic Evaluation of Existing Buildings
(for evaluation only) or ASCE 41 Seismic Rehabilitation of Existing
Buildings. The procedures contained in Appendix A of the International
Existing Building Code shall be permitted to be used as specified
in Section 405.3.1.1.3 of the California Existing Building Code.
405.3.1.1.2 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.
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100 percent of the values in the building code. The R factor
used for analysis in accordance with current adopted version of ASCE
7 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."
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2.
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Forces corresponding to BSE-1 and BSE-2 Earthquake Hazard Levels
defined in ASCE 41. Where ASCE 41 is used, the corresponding performance
levels shall be those shown in Table 405.3.1.1.2.
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TABLE 405.3.1.1.2
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ASCE 41 and ASCE 31 PERFORMANCE LEVELS
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RISK CATEGORY (BASED ON CBC TABLE 1604.5)
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PERFORMANCE LEVEL FOR USE WITH ASCE 31 AND WITH ASCE 41 BSE-1
EARTHQUAKE HAZARD LEVEL
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PERFORMANCE LEVEL FOR USE WITH ASCE 41 BSE-2 EARTHQUAKE HAZARD
LEVEL
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I
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Life Safety (LS)
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Collapse Prevention (CP)
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II
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Life Safety (LS)
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Collapse Prevention (CP)
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III
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Note (a)
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Note (a)
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IV
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Immediate Occupancy (IO)
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Life Safety (LS)
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a.
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Performance Levels for Risk Category III shall be taken as halfway
between the performance levels specified for Risk Category II and
Risk Category IV.
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405.3.1.1.3 Reduced CBC level seismic forces. When
seismic forces are permitted to meet reduced building code levels,
they shall be one of the following:
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1.
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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 405.3.1.1.2.
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2
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In accordance with the applicable chapters in Appendix A of
the California Existing Building Code as specified in Items 2.1 through
2.4 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 requirements for reduced building code force levels.
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2.1.
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The seismic evaluation and design of unreinforced masonry bearing
wall buildings in Risk Category I or II are permitted to be based
on the procedures specified in Appendix Chapter A1.
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2.2.
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Seismic evaluation and design of the wall anchorage system in
reinforced concrete and reinforced masonry wall buildings with flexible
diaphragms in Risk Category I or II are permitted to be based on the
procedures specified in Appendix Chapter A1.
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2.3.
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Seismic evaluation and design of cripple walls and sill plate
anchorage in residential buildings of lightframe wood construction
in Risk Category I or II are permitted to be based on the procedures
specified in Appendix Chapter A3.
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2.4.
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Seismic evaluation and design of soft, weak, or open-front wall
conditions in multiunit residential buildings of wood construction
in Risk Category I or II are permitted to be based on the procedures
specified in Appendix Chapter A4.
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3.
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In accordance with ASCE 31 based on the applicable performance
level as shown in Table 405.3.1.1.2.
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4.
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Those associated with the BSE-1 Earthquake Hazard Level defined
in ASCE 41 and the performance level as shown in Table 405.3.1.1.2.
Where ASCE 41 is used, the design spectral response acceleration parameters
Sxs and Sx1 shall not be taken less than 75 percent of the respective
design spectral response acceleration parameters SDS and SD1 defined
by the California Building Code and its reference standards.
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405.3.1.2 Wind design. Wind design of existing
buildings shall be based on the procedures specified in the building
code.
405.3.2 Repairs to damaged buildings. Repairs to
damaged buildings shall comply with this section.
405.3.2.1 Unsafe conditions. Regardless of the
ex-tent of structural damage, unsafe conditions shall be eliminated.
405.3.2.2 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-force-resisting system shall be evaluated and repaired
in accordance with the applicable provisions of Sections 405.3.2.2.1
through 405.3.2.2.3.
405.3.2.2.1 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.
Seismic forces for this evaluation are permitted to be the reduced
level seismic forces specified in Code Section 405.3.1.1.3.
405.3.2.2.2 Extent of repair for compliant buildings. If the evaluation establishes compliance of the predamage building
in accordance with Section 405.3.2.2.1, then repairs shall be permitted
that re-store the building to its pre-damage state, using materials
and strengths that existed prior to the damage.
405.3.2.2.3 Extent of repair for non-compliant buildings. If the evaluation does not establish compliance of the pre-damage
building in accordance with Section 405.3.2.2.1, then the building
shall be rehabilitated to comply with applicable provisions of the
building code for load combinations including wind or seismic forces.
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. 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 405.3.1.1.3. 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.
405.3.2.3 Substantial structural damage to vertical load-carrying
components. Vertical load-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.
405.3.2.3.1 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 Section 405.3.2.2.1
and, if non-compliant, rehabilitated in accordance with Section 405.3.2.2.3.
405.3.2.4 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.
405.3.3 Referenced Standards
Standard Referenced
Reference In Code
Number Title Section Number
ASCE 31-03 Seismic Evaluation of Existing Buildings 405.3.1.1.1,
TABLE 405.3.1.1.2, 405.2.1.1.3
ASCE 41-06 Seismic Rehabilitation of Existing Buildings 405.3.1.1.1,
405.3.1.1.2, TABLE 405.3.1.1.2, 405.3.1.1.3
(Ord. 682 § 1, 2008; Ord. 736 § 1, 2016; Ord. 757 § 1, 2019)
