HomeMy WebLinkAboutORD 127 1990 0801ORDINANCE NO. 127
AN ORDINANCE OF THE CITY OF MOORPARK, CALIFORNIA; AMEND-
ING TITLE 8 OF THE MOORPARK MUNICIPAL CODE BY ADDING
CHAPTER 8.08, RELATING TO EARTHQUAKE HAZARD REDUCTION IN
CERTAIN EXISTING BUILDINGS.
WHEREAS, a noticed public hearing has been held by the City
Council, at which time all interested persons had the opportunity
to appear and be heard on the matter of earthquake hazard reduc-
tion in certain existing buildings;
NOW, THEREFORE, THE CITY COUNCIL OF THE CITY OF MOORPARK,
CALIFORNIA, DOES ORDAIN AS FOLLOWS:
Section 1. Except as hereinafter provided Title 8 of the
Moorpark Municipal Code is amended by adding Chapter 8.08 to read
as set forth in Exhibit A; Seismic Safety Commission Draft Model
Ordinance for the Seismic Retrofit of Unreinforced Masonry Bear-
ing Wall Buildings dated February 1990 hereinafter referred to as
the SSC Model Ordinance.,
Section 2. Section A2341 of the SSC Model Ordinance is
amended by adding Subsection A2341(e) to read:
Sec. A2341 (e) The requirements for the Planned Development
Permit as specified by Division 8, Chapter 1: Zoning shall not be
imposed upon any property which adheres to this chapter so long
as the provisions of Article 42, Non- Conforming Buildings and
Non - Conforming Uses are adhered to.
Section 3. STANDARD No. 24 -40. The Uniform Building Code
Standards 1988 Edition, as adopted, is hereby amended by adding
Uniform Building Code Standard No. 24 -40; In -Place Masonry Shear
Tests to read as set forth in the SCC Model ordinance.
Section 4. STANDARD No. 24 -41. The Uniform Building Code
Standards 1988 Edition, as adopted, is hereby amended by adding
Uniform Building Code Standard No. 24 -41; Tests of Anchors in Un-
reinforced Masonry Walls to read as set forth in the SSC Model
ordinance.
Section 5. Standard No. 24 -42. The Uniform Building Code
Standards 1988 Edition, as adopted, is hereby amended by adding
Uniform Building Code Standard No. 24 -42; Pointing of Unrein-
forced Masonry Walls to read as set forth in the SSC Model Or-
dinance.
1
Section 6. SEVERABILITY. If any section, subsection, sen-
tence, clause, phrase or word of this Ordinance is for any reason
held to be invalid by a court of competent jurisdiction, such
decision shall not affect the validity of the remaining portions
of this Ordinance. The City Council hereby declares that it
would have passed and adopted this ordinance and each and all
provisions thereof, irrespective of the fact that any one or more
of said provisions may be declared invalid.
Section 7. The City Clerk shall certify to the passage and
adoption of this ordinance by not less than a four - fifths vote of
the City Council; shall enter the same in the book of original
ordinances of said City; shall make a minute of the passage and
adoption thereof in the records of the proceedings of the City
Council at which the same is passed and adopted; and shall,
within fifteen (15) days after the passage and adoption thereof,
cause the same to be published in the manner prescribed by law.
PASSED AND ADOPTED this is-t day of AUGUST, 1990.
Mayor of the City of Moorpark,
California
ATTEST:
2
SECTION A2341
EXHIBIT. A -
SEISMIC SAFETY COMMISSION
DRAFT MODEL ORDINANCE
for the
SEISMIC RETROFIT
of
UNREINFORCED MASONRY
BEARING WALL BUILDINGS
Sec. A2341
(a) 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 earthquakes on existing
unreinforced masonry bearing wall buildings.
The provisions of this Chapter are intended as minimum standards
for structural seismic resistance established primarily to reduce
the risk of life loss or injury. Compliance with these standards
will not necessarily prevent loss of life or injury or prevent
earthquake damage to rehabilitated buildings.
(b) Scope. The provisions of this Chapter shall apply to all
existing buildings in Seismic Zones 3 and 4 having at least one
unreinforced masonry bearing wall. Except as provided herein, all
other provisions of the Building Code shall apply.
EXCEPTIONS: This Chapter shall not apply to:
1. Detached one or two family dwellings and detached apartment
houses containing less than 5 dwelling units and used solely for
residential purposes.
2. Essential Facilities as defined in Table 23 -K of the Building
Code.
3. Hazardous Facilities as defined in Table 23 -K of the Building
Code.
February 1990 SSC Model Ordinance Page 1
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SECTION A2341
This Chapter does not require alteration of existing electrical,
plumbing, mechanical or fire safety systems.
(c) Definitions. For the purposes of this Chapter, the
applicable definitions in the Building Code shall also apply.
COLLAR JOINT is the vertical space between adjacent wythes and may
contain mortar.
CROSSWALL is a wall that meets the requirements of Section
A2346(d)3. A crosswall is not a shear wall.
CROSSWALL SHEAR CAPACITY is the length of the crosswall times the
allowable shear value, vcLo.
DIAPHRAGM EDGE is the intersection of the horizontal diaphragm and
a shear wall.
DIAPHRAGM SHEAR CAPACITY is the depth of the diaphragm times the
allowable shear value, vuD.
FLEXIBLE DIAPHRAGM is a diaphragm of wood construction or
other construction of similar flexibility.
NORMAL WALL is a wall perpendicular to the direction of seismic
forces.
OPEN FRONT is an exterior wall plane without vertical
elements in one or more stories which resist the required
lateral forces.
POINTING is the partial reconstruction of the bed
joints of a URM wall as defined in UBC Standard No. 24 -42.
UNREINFORCED MASONRY (URM) WALL is a masonry wall in which the
area of reinforcing steel is less than 25 percent of that
required by the Building Code for reinforced masonry.
UNREINFORCED MASONRY BEARING WALL. A URM wall which provides the
vertical support for a floor or roof for which the total
superimposed load is over 100 pounds per linear foot of
wall.
YIELD STORY DRIFT is the lateral displacement of one level
relative to the level above or below at which yield
stress is first developed in a frame member.
(d) Symbols and Notations. For the purposes of this Chapter,
the applicable symbols and definitions in the Building Code shall
also apply.
A = Area of unreinforced masonry pier, square inches.
February 1990 SSC Model Ordinance Page 2
SECTION A2341
Ab = Area of the bed joints above and below the test
specimen for each in -place shear test.
C = Numerical coefficient as specified in Section
2312(g) and given in Table 23 -P of the Building
Code and Table A -23 -A of this Chapter.
D = In -plane width dimension of pier, inches, or depth
of diaphragm, feet.
DCR = Demand - capacity ratio specified in Section A2346(d).
Fwx = Force applied to a wall at level x, pounds.
H = Least clear height of opening on either side of
pier, inches.
�h /t = Height /thickness ratio of URM wall. Height h is
measured between wall anchorage levels.
L = Span of diaphragm between shear walls, or
span between shear wall and open front, feet.
Lo = Length of crosswall, feet.
Li = Effective span for an open front building
specified in Section A2346(d)8, feet.
PD = Superimposed dead load at the top of the pier under
consideration, pounds.
PD +L = Actual dead plus live load in place at the time of
testing, pounds.
PW Weight of wall, pounds.
Va = vaA, the allowable shear in any URM pier, pounds.
Vcb = Total shear capacity of crosswalls in the direction
of analysis immediately below the diaphragm level
being investigated, Y-vcLo, pounds.
Vca = Total shear capacity of crosswalls in the direction
of analysis immediately above the diaphragm level
being investigated, YvcLo, pounds.
Vr = 0.5PD(D /H), the rocking shear of any URM wall or
wall pier, pounds.
Vwx = Total shear force resisted by a shear wall at the
February 1990 SSC Model Ordinance Page 3
SECTION A2341
level under consideration, pounds.
Vp = Shear force assigned to a pier on the basis of
its relative shear rigidity, pounds.
Vs = Shear force assigned to a spandrel on the
basis of the shear forces in the adjacent wall
piers and tributary dead plus live loads.
Vtest = Load in pounds at incipient cracking for each in-
place shear test per UBC Standard 23 -40.
va = Allowable shear stress for unreinforced masonry,psi.
vc = Allowable shear value for a crosswall sheathed with
any of the materials given in Tables A -23 -C or
A -23 -D, pounds per foot.
vt = Mortar shear strength as specified in Section
2343(c)3E.
vto = Mortar shear test values as specified Section
2343(c)3E.
vu = Allowable shear value for a diaphragm sheathed with
any of the materials given in Tables A -23 -C or
A -23 -D, pounds per foot.
Y-vuD Sum of diaphragm shear capacities of both ends
of the diaphragm.
Y-Y-vuD = For diaphragms coupled with crosswalls Y-Y-vuD
includes the sum of shear capacities of both ends of
diaphragms coupled at and above the
level under consideration.
Wd = Total dead load tributary to a diaphragm, pounds.
Y-Wd = Total dead load tributary to all of the diaphragms
at and above the level under consideration,
pounds.
Ww = Total dead load of an unreinforced masonry
wall above the level under consideration or
above an open front of a building, pounds.
Wwx = Dead load of a URM wall assigned to Level x
halfway above and below the level under
consideration.
February 1990 SSC Model Ordinance Page 4
SECTION A2342
Section A2342
(a) General. All buildings shall have a seismic resisting
system conforming with Section 2303(b) of the Building Code,
except as modified by this Chapter.
(b) Alterations and Repairs. Alterations and repairs required
to meet the provisions of this Chapter shall comply with all other
applicable requirements of the Building Code unless specifically
provided for in this Chapter.
(c) Requirements for Plans. The following construction
information shall be included in the plans required by this
Chapter:
1. Accurately dimensioned floor and roof plans showing
exist-tng walls and the size and spacing of floor and roof framing
members and sheathing materials. The plans shall indicate all
existing and new crosswalls and their materials of construction.
The location of the crosswalls and their openings shall be fully
dimensioned or drawn to scale on the plans.
2. Accurately dimensioned wall elevations showing openings,
piers, wall classes as defined in section A2343(c)3E, thicknesses,
and heights, wall shear test locations, cracks or damaged portions
requiring repairs. The general condition of the mortar joints and
if and where the joints require pointing. Where the exterior face
is veneer, the type of veneer, its thickness and its bonding
and /or ties to the structural wall masonry shall also be reported.
3. The type of interior wall and ceiling surfaces.
4. The extent and type of existing wall anchorage to floors
and roof when utilized in the design.
5. The extent and type of parapet corrections which were
previously performed, if any.
6. Repair details, if any, of cracked or damaged
unreinforced masonry walls required to resist forces specified in
this Chapter.
7. All other plans, sections, and details necessary to
delineate required retrofit construction including those items in
Section A2347.
February 1990 SSC Model Ordinance Page 5
SECTION A2343
Section A2343
(a) General. All materials permitted by this Chapter, including
their appropriate allowable design values and those existing
configurations of materials specified herein, may be utilized to
meet the requirements of this Chapter.
(b) Existing Materials. All existing materials utilized as
part of the required force resisting system shall be in sound
condition or shall be removed and replaced with new material.
(c) Existing Unreinforced Masonry
1. General. All unreinforced masonry walls utilized to
carry vertical loads or seismic forces parallel and perpendicular
to the wall plane shall be tested as specified in this subsection.
All masonry that does not meet or exceed the minimum standards
established by this Chapter shall be removed and replacet by new
materials or alternatively shall have its structural functions
replaced by new materials and anchored to supporting elements.
2. Lay -Up of Walls. The facing and backing shall be
bonded so that not less than 10 percent of the exposed face area
is composed of solid headers extending not less than 4 inches into
the backing. The clear distance between adjacent full- length
headers shall not exceed 24 inches vertically or horizontally.
Where the backing consists of two or more wythes, the headers
shall extend not less than 4 inches into the most distant wythe or
the backing wythes shall be bonded together with separate headers
whose area and spacing conform to the foregoing. Wythes of walls
not bonded as described above shall be considered as veneer. The
veneer wythe shall not be included in the effective thickness used
in calculating the height to thickness and the shear capacity of
the wall.
3. Mortar. A. Tests. The quality of mortar in all
masonry walls shall be determined by performing in -place shear
tests in accordance with UBC Standard 24 -40. Alternative methods
of testing may be approved by the Building Official.
B. Location of Tests. The shear tests shall be taken at
locations representative of the mortar conditions throughout the
entire building, taking into account variations in workmanship at
different building height levels, variations in weathering of the
exterior surfaces, and variations in the condition of the interior
surfaces due to deterioration caused by leaks and condensation of
water and /or by the deleterious effects of other substances
contained within the building. The exact test location shall be
determined at the building site by the engineer in responsible
charge of the structural design work. An accurate record of all
such tests and their location in the building shall be recorded
February 1990 SSC Model Ordinance Page 6
SECTION A2343
&nd these results shall be submitted to the building department
for approval as part of the structural analysis.
C. Number of tests. The minimum number of tests per
class shall be as follows:
(i) At each of both the first and top stories, not less
than two per wall or line of wall elements providing a common line
of resistance to lateral forces.
(ii) At each of all other stories, not less than one per
wall or line of wall elements providing a common line of
resistance to lateral forces.
(iii) In any case, not less than one per 1500 square feet
of wall surface nor less than a total of eight.
D. Minimum Quality Mortar. (i) Mortar shear test
values, vto, in psi shall be obtained for each in -place shear test
in accordance with the following equation:
vto = (Vtest - PD+ L ) /Ab .....................(43 -1)
(ii) Individual unreinforced masonry walls with vto
consistently less than 30 psi shall be entirely pointed prior to
retesting.
(iii) The mortar shear strength, vt, is the value in psi
that is exceeded by 800 of all of the mortar shear test values,
vto.
(iv) Unreinforced masonry with mortar shear strength, vt,
less than_30 psi shall be removed or pointed and retested.
E. Collar Joints. The collar joints shall be inspected
at the test locations during each in -place shear test, and
estimates of the percentage of the surfaces of adjacent wythes
which are covered with mortar shall be reported along with the
results of the in -place shear tests.
F. Unreinforced Masonry Classes. All existing
unreinforced masonry shall be categorized into one or more classes
based on shear strength, quality of construction, state of repair,
deterioration, and weathering. See Section A2345(b).
G. Pointing. All deteriorated mortar joints in
unreinforced masonry walls shall be pointed according to UBC
Standard No. 24 -42. Nothing shall prevent pointing with mortar of
all the masonry wall joints before the tests are made.
February 1990 SSC Model Ordinance Page 7
SECTION A2344
Section A2344
(a) Pointing. All preparation and mortar pointing shall be
done with special inspection.
Exception: At the discretion of the building
official, incidental pointing may be performed
without special inspection.
(b) Masonry Shear Tests. In -place masonry shear tests shall
comply with Standard 24 -40.
(c) Existing Wall Anchors. Existing wall anchors utilized as
all or part of the required tension anchors shall be tested in
pullout according to UBC Standard 24 -41. The minimum number of
anchors tested shall be four per floor, with two tests at walls
with joists framing into the wall and two tests at walls with
joists parallel to the wall, but not less than ten percent of the
total number of existing tension anchors at each level.
(d) New Bolts. One - fourth of all new shear bolts and combined
tension and shear bolts in unreinforced masonry walls shall be
tested according to UBC Standard 24 -41.
Exception: Special inspection may be provided during
installation in lieu of testing.
SECTION A2345
(a) Allowable Values. 1. Allowable values for existing
materials are given in Table A -23 -C and for new materials in Table
A -23 -D. The one -third increase in allowable values is not allowed
for values in these tables.
2. Allowable values not specified in this Chapter shall be as
specified elsewhere in the Building Code. Allowable values not
specified in this Chapter for dead load plus seismic load may be
increased 33 percent. Allowable values not specified in this
Chapter for existing building elements with a combination of dead
load plus floor live load plus seismic load may be increased 70
percent.
February 1990 SSC Model Ordinance Page 8
SECTION A2346
(b) Masonry Shear. The allowable unreinforced masonry shear
stress, va, shall be determined for each masonry class from the
following equation:
va = O.lvt + 0.15PD /A .................(45 -1)
The mortar shear test value, vt, shall be determined in accordance
with Section A2343, and not exceed 100 psi for the determination
Of va.
The one -third increase in allowable values of the Building Code is
not allowed for va.
(c) Masonry Compression. Where any increase in dead plus live
compression stress occurs, the allowable compression stress in
unreinforced masonry shall not exceed 100 psi. The one -third
increase in allowable stress of the Building Code is allowed.
(d) Masonry Tension. Unreinforced masonry shall-be assumed as
having no tensile capacity.
(e) Masonry Shear Modulus. The shear modulus (Ev) for
unreinforced masonry, for relative rigidity analyses when masonry
is used to resist lateral forces in combination with other
materials, may be assumed as 10,000vt, unless substantiated by
tests.
(f) Existing Tension Anchors. The allowable resistance
values of the existing anchors shall be 40 percent of the average
of the tension tests of existing anchors having the same wall
thickness and joist orientation. The one -third increase in
allowable stress of the Building Code is not allowed for existing
tension anchors.
(g) Foundations. For existing foundations new total loads may
be.increased. over existing loads by 25% for dead load only and
increased_50% for dead load plus seismic load. Higher values may
be justified only in conjunction with a geotechnical
investigation.
February 1990 SSC Model Ordinance Page 9
SECTION A2346
Section A2346
(a) General. Except as modified herein, the analysis and design
relating to the structural alteration of existing buildings shall
be in accordance with the Building Code.
(b) Selection of Procedure. Buildings shall be analyzed by
the General Procedure of Section A2346(c) which is based on
Chapter 23 of the Building Code or, when applicable, buildings may
be analyzed by the Special Procedure of A2346(d).
(c) General Procedure.
1. Minimum Design Lateral Forces. Buildings shall be
analyzed to resist minimum lateral forces assumed to act
noncurrently in the direction of each of the main axes of the
structure in accordance with the following:
v= 0.33zw ......... .........................(46 -1)
2. Lateral Forces on Elements of Structures. Parts or
portions of structures shall be analyzed as required in Chapter 23
of the Building Code.
Exceptions: i. Unreinforced masonry walls for which
height to thickness ratios do not exceed ratios set
forth in Table A -23 -B need not be analyzed for out -of-
plane loading. Unreinforced masonry walls which exceed
the allowable h/t ratios of Table A -23 -B shall be braced
according to Section A2347(e).
ii. Parapets complying with Section A2347(f) need not be
analyzed for out -of -plane loading.
3. Shear Walls (In -Plane Loading). Shear walls shall
comply with subsection A2346(e).
(d) Special Procedure. 1. Limits for the Application of
Subsection A2346(d) . The Special Procedure of this subsection
may only be applied to buildings with the following
characteristics:
A. Flexible diaphragms at all levels above the base of
structure.
B. A maximum of 6 stories above the base of the
building.
February 1990 SSC Model Ordinance Page 10
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SECTION A2346
C. The vertical elements of the lateral force
resisting system shall consist predominantly of masonry
or concrete shear walls or steel braced frames or
special moment resisting frames (see Section 2312 of
the Building Code) each with a maximum overall height -
to- length ratio of 1 -1/2 to 1.
D. The lateral force resisting system shall be regular
as defined in the Building Code. Except for a single
story building with an open front, a minimum of two
lines of vertical lateral force - resisting elements
shall be parallel to each axis of the building.
2. Lateral Forces on Elements of Structures. With the
exception of the diaphragm provisions in subsection A2346(d),
elements of structures shall comply with subsection A2346(c)2.
3. Crosswalls. Crosswalls shall meet the requirements of
this subsection.
A. Crosswall Definition. A crosswall is a wood- framed
wall sheathed with any of the materials described in Tables A -23 -C
or A -23 -D. Spacing of crosswalls shall not exceed 40 feet on
center measured perpendicular to the direction of consideration,
and shall be placed in each story of the building. Crosswalls
shall extend the full story height between diaphragms.
Exception: 1. Crosswalls need not be provided at all
levels in accordance with subsection
A2346 (d) 4B (iv) .
2. Existing crosswalls need not be continuous below
a wood diaphragm at /or within four feet of grade
provided:
(i) Shear connections and anchorage requirements
Section A2346(d)7 are satisfied at all edges of
the diaphragm.
(ii) Crosswalls with total shear capacity of
.07Y-Wd interconnect the diaphragm to the
foundation.
(iii) The demand /capacity ratio of the diaphragm
between the crosswalls that are continuous to their
foundations shall be calculated as:
DCR = [0.33Wd + Vca] /2vuD ....... (46 -2)
and DCR shall not exceed 2.5.
February 1990 SSC Model Ordinance Page 11
SECTION A2346
B. Crosswall Shear Capacity. Within any 40 feet measured
along the span of the diaphragm, the sum of the crosswall shear
capacities shall be at least 30 percent of the diaphragm shear
capacity of the strongest diaphragm at or above the level under
consideration.
C. Existing Crosswalls. Existing crosswalls shall have a
length to height ratio between openings of not less than 1.5.
Existing crosswall connections to diaphragms need not be
investigated as long as the crosswall extends to the framing of
the diaphragm above and below.
D. New Crosswalls. New crosswall connections to the
diaphragm shall develop the crosswall shear capacity. New
crosswalls shall have the capacity to resist an overturning moment
equal to the crosswall shear capacity times the story height.
Crosswall overturning moments need not be -cumulative over more
than two stories.
E. Other Crosswall Systems. Other systems such as
special moment resisting frames may be used as crosswalls provided
that the yield story drift does not exceed one inch in any story.
4. Wood Diaphragms. A. Acceptable Diaphragm Span. A
diaphragm is acceptable if the point (L,DCR) on Figure A -23 -1,
falls within Regions 1, 2, or 3.
B. Demand - Capacity Ratios. Demand - Capacity Ratios shall
be calculated for the diaphragm according to the following
formulas:
(i) For a diaphragm without qualifying Crosswalls at
levels immediately above or below:
DCR = O.83ZWd /YvuD ............. ............(46 -3)
(ii) For a diaphragm in a single -story building with
qualifying Crosswalls:
DCR = 0.83ZWd /(YvuD + Vcb) ...................(46 -4)
(iii) For diaphragms in a multi -story building with
qualifying crosswalls in all levels:
DCR = 0. 83ZYWd/( Y-Y-vuD +Vcb) ...................(46 -5)
DCR shall be calculated at each level for the set of diaphragms at
and above the level under consideration.
February 1990 SSC Model Ordinance Page 12
SECTION A2346
(iv) For a roof diaphragm and the diaphragm directly
below if coupled by crosswalls:
DCR = 0. 83Z7-Wd/ EYvuD .. .........................(46 -6)
C. Chords. An analysis for diaphragm flexure need not
be made and chords need not be provided.
D. Collectors. An analysis shall of diaphragm
collector forces shall be made for the transfer of diaphragm
edge shears into vertical elements of the lateral force
resisting system. Collector forces may be resisted by new or
existing elements.
E= Diaphragm Openings. (i) Diaphragm forces at
corners of openings shall be investigated and shall be
developed into the diaphragm by new or existing materials.
(ii) In addition to calculating demand capacity
ratios per Section A2346(d)4B, the demand capacity ratio of
the portion of the diaphragm adjacent to an opening shall be
calculated using the opening dimension as the span.
(iii) Where an opening occurs in the end quarter of
the diaphragm span vud for the demand capacity ratio
calculation shall be based on the net depth of the diaphragm.
5. Diaphragm Shear Transfer. Diaphragms shall be
connected to shear walls with connections capable of
developing a minimum force given by the lesser of the
following formulas:
V = 1/ 2ZCpWd ........... .........................(46 -7)
or
V= vuD ............... .........................(46 -8)
6. Shear Walls (In Plane Loading) - Special Procedure.
A. Wall Story Force. The wall story force distributed to
a shear wall at any diaphragm level shall be the lesser value
calculated as:
(i) For buildings without crosswalls,
February 1990 SSC Model Ordinance Page 13
SECTION A2346
Fwx = 0.33Z( Wwx+ Wd/ 2) ......... .........................(46 -9)
but need not exceed
Fwx = 0.33ZWwx + vuD ........ ........................(46 -10)
(ii) For buildings with crosswalls in all levels:
Fwx = 0.25Z( Wwx+ Wd/ 2) ......... ........................(46 -11)
but need not exceed
Fwx = 0.25Z(Wwx + Y-Wd( vuD/ YY-vuD )) ....................(46 -12)
and need not exceed
Fwx = 0.25ZWwx + v uD .......... ........................(46 -13)
B. Wall Story Shear. The wall story shear shall be the
sum of the wall story forces at and above the level of
consideration.
Vwx= Y-Fwx .................... ........................(46 -14)
C. Shear Wall Analysis. Shear walls shall comply with
subsection A2346(e).
D. Moment Frames. Moment frames used in place of shear
walls shall be designed as required in Chapter 23 of the Building
Code except that the forces shall be as specified in Section
A2346(d)6A and the interstory drift ratio shall be limited to
0.005.
7. Out of Plane Forces - URM Walls. A. Allowable URM
Wall Height to Thickness Ratios. The provisions of Section
A2346(c)2 are applicable except the allowable h/t ratios given in
Table A -23 -B shall be determined from Figure A -23 -1 as follows:
(i) In Region 1, h/t ratios for "buildings with
crosswalls" may be used if qualifying crosswalls are present in
all stories.
(ii) In Region 2, h/t ratios for "buildings with
crosswalls" may be used whether or not qualifying crosswalls are
present.
(iii) In Region 3, h/t ratios for "all other buildings"
shall be used whether or not qualifying crosswalls are present.
February 1990 SSC Model Ordinance Page 14
SECTION A2346
B. Walls with Diaphragms in Different Regions. When
diaphragms above and below the wall under consideration have DCRs
in different regions of Figure A -23 -1, the lesser h/t ratio shall
be used.
8. Buildings with Open Fronts. A building with an open
front on one side shall have crosswalls parallel to the open front
and shall be designed by the following procedure:
A. Effective Diaphragm Span, Lip for use in Figure No. A -23 -1
shall be determined in accordance with the following formula:
Li = 2[(Ww /Wd) L + L) ..... ........................(46 -15)
B. Diaphragm Demand /capacity ratio shall be calculated as:
DCR = 0.83Z(Wd + Ww) /[(vu D) + Vc] ....... ......(46 -16)
(e) . Analysis of Vertical Elements of the Lateral Force -
Resisting System. Applicable to both General Procedure and
Special Procedure Buildings.
1. Existing URM Walls. A. Flexural Rigidity. Flexural
rigidity may be neglected in determining the rigidity of an URM
wall.
B. Shear Walls with Openings. Wall piers shall be
analyzed according to the following procedure:
(i) For any pier,
(1) The pier shear capacity shall be
calculated as:
Va = vaDt ....... ........................(46 -17)
(2) The pier rocking shear capacity shall be
calculated as:
Vr = 0. 5PDD/ H ... ........................(46 -18)
(ii) The wall piers at any level are acceptable
if they comply with one of the following modes of
behavior:
(1) Rocking Mode. Where all piers at a level
have shear capacities capable of sustaining
rocking, i.e., the pier shear capacity is
greater than or equal to the pier rocking
shear capacity for each pier, forces in in
the wall at that level, Vwx, shall be
February 1990 SSC Model Ordinance Page 15
SECTION A2346
distributed to each pier, Vp, in proportion
to PDD /H.
For each pier at that level: Va ? Vr ........ (46 -19)
and for the wall at that level:
Vwx SEVr ......... (46 -20)
(2) Non - rocking Mode. Where at least one pier at
a level is incapable of sustaining a rocking
mode, i.e., the pier shear capacity is less than
the pier rocking shear capacity, forces in the
wall at that level, Vwx, shall be distributed to
each pier,Vp, in proportion to D /H, such that
Vwx = EVp•
For at least one pier at that level:
Va < Vr ............ (46 -21)
For each pier at that level:
Vp <- Va ........... (46 -22)
and
Vp <_ Vr ........... (46 -23)
If Vp >Vr in one or more piers, omit
such piers from the analysis and repeat the
procedure for the remaining piers or
strengthen and reanalyze the wall.
(iii) Masonry Pier Tension Stress. Unreinforced
masonry wall piers need not be analyzed for tension
stress.
C. Shear Walls Without Openings. Shear walls without
openings shall be analyzed as for walls with openings except that
Vr shall be calculated as follows:
Vr = (0.50PD + 0.25Pw)D /H ....................(46 -24)
2. Plywood sheathed shear walls. Plywood sheathed shear
walls may be used to resist lateral loads for buildings with
flexible diaphragms analyzed according to provisions of Section
A2346(c). Plywood sheathed shear walls may not be used to share
lateral loads with other materials along the same line of
resistance.
3. Combinations of Vertical Elements. A. Lateral Force
Distribution. Lateral forces shall be distributed among the
February 1990 SSC Model Ordinance Page 16
SECTION A2346
vertical resisting elements in proportion to their relative
rigidities, except that moment frames shall comply with Section
A2346(e)3B.
B. Moment Resisting Frames. A moment frame shall not be
used with a URM wall in a single line of resistance unless the
wall has piers that are capable of sustaining rocking in
accordance with A2346(e)1B and the frames are designed to carry
1000 of the lateral forces.
February 1990 SSC Model Ordinance Page 17
SECTION A2347
DETAILED SYSTEM DESIGN REQUIREMENTS
SECTION A2347
(a) General.
(b) Wall Anchorage. 1. Anchor Locations. All unreinforced
masonry walls shall be anchored at the roof and floor levels as
required in Section A2346(c)2. Ceilings with substantial rigidity
and abutting masonry walls shall be connected to walls with
tension bolts at a maximum anchor spacing of 6 feet. Ceiling
systems with substantial mass shall be braced at the perimeter to
diaphragms.
2. Anchor Requirements. Anchors shall be tension bolts
through the wall as specified in Table No. A -23 -D, or by an
approved equivalent at a maximum anchor spacing of 6 feet. All
existing wall anchors shall be secured to the joists to develop
the required forces. The Building Official may require testing to
verify the adequacy of the embedded ends cf existing wall anchors.
3. Minimum Wall Anchorage. Anchorage of masonry walls tc
each floor or roof shall resist a minimum force determined by
Section 2312(g)2 of the Building Code or 200 pounds per linear
foot, whichever is greater, acting normal to the wall at the level
of the floor or roof. Existing wall anchors, installed under
previous permits, must meet or must be upgraded to meet the
requirements of this Chapter.
4. Anchors at Corners. At the roof and all floor levels,
both shear and tension anchors shall be provided within two feet
horizontally from the inside of the corners of the walls.
5. Anchors with Limited Access. When access to the
exterior face of the masonry wall is prevented by proximity of an
existing building, wall anchors conforming to Item 5b in Table A-
23-D may be used.
(c) Collectors. Collector elements shall be provided which are
capable of transferring the seismic forces originating in other
portions of the building to the element providing the resistance
to those forces.
(d) Ties and Continuity. Ties and continuity shall conform to
Section 2312(h)2E.
(e) Wall Bracing. 1. General. Where a wall height- thickness
ratio exceeds the specified limits, the wall may be laterally
supported by vertical bracing members per Section A2347(e)2 or by
reducing the wall height by bracing per Section A2347(e)3.
2. Vertical Bracing Members. Vertical bracing members shall
be attached to floor and roof construction for their design loads
February 1990 SSC Model Ordinance Page 18
SECTION A2347
independently of required wall anchors. Horizontal spacing of
vertical bracing members shall not exceed one -half the unsupported
height of the wall nor 10 feet. Deflection of such bracing members
at design loads shall not exceed one -tenth of the wall thickness.
3. Wall Height Bracing. The wall height may be reduced by
bracing elements connected to the floor or roof. Horizontal
spacing of the bracing elements and wall anchors shall be as
required by design but shall not exceed 6 feet on center. Bracing
elements shall be detailed to minimize the horizontal displacement
of the wall by the vertical displacement of the floor or roof.
(f) Parapets. Parapets and exterior wall appendages not
conforming to this Chapter shall be removed, or stabilized or
braced to ensure that the parapets and appendages remain in their
original position.
The maximum height of an unbraced unreinforced masonry parapet
above —the lower of either the level of tension anchors or roof
sheathing, shall not exceed one and one -half (1 -1/2) times the
thickness of the parapet wall. If the required parapet height
exceeds this maximum height, a bracing system designed for the
force factors specified in Table 23 -P of the Building Code for
walls shall support the top of the parapet. Parapet corrective
work must be performed in conjunction with the installation of
tension roof anchors.
The minimum height of a parapet above the wall anchor shall be
twelve (12) inches.
EXCEPTION: If a reinforced concrete beam is provided at the
top of the wall, the minimum height above the wall anchor may
be six (6) inches.
(g) Veneer. 1. Unreinforced masonry walls which carry no design
loads other than their.own weight may be considered as veneer if
they are adequately anchored to new supporting elements.
2. Veneer shall be anchored with approved anchor ties,
conforming to the required design capacity specified in
the Building Code and placed at a maximum spacing of 24 inches
with a maximum supported area of two (2) square feet.
EXCEPTION: Existing veneer anchor ties may be acceptable
provided the ties are in good condition and conform to the
following minimum size, maximum spacing and material
requirements.
Existing veneer anchor ties shall be corrugated galvanized
iron strips not less than one inch in width, eight inches
in length and one - sixteenth of an inch in thickness (1" X
8" X 1/16 ") or equal and shall be located and laid in
February 1990 SSC Model Ordinance Page 19
SECTION A2347
every alternate course in the vertical height of the wall
at a spacing not to exceed 17 inches on centers
horizontally. As an alternate, such ties may be laid in
every fourth course vertically at a spacing not to exceed
nine (9) inches on centers horizontally.
3. The location and condition of existing veneer anchor ties
shall be verified as follows:
A. An approved testing laboratory shall verify the
location and spacing of the ties and shall submit a report
to the Building Official for approval as a
part of the structural analysis.
B. The veneer in a selected area shall be removed to-
expose a representative sample of ties (not less than four)
for inspection by the Building Official.
(h) Truss and Beam Supports. Where trusses and beams other
than rafters or joists are supported on masonry, independent
secondary columns shall be installed to support vertical loads of
the roof or floor members. The loads shall be transmitted down to
adequate support.
(i) Adjacent Buildings. 1. Where elements of adjacent
buildings, do not have a separation of 5 inches, the allowable
height /thickness ratios for "buildings with crosswalls" per Table
A23B shall not be used in the direction of consideration.
2. Where buildings do not have a separation of at least 5 inches
and the diaphragm levels of the adjoining structures differ by
more than one and one -half time the wall thickness, supplemental
vertical gravity load carrying members shall be added to support
the loads normally carried by the wall and such members shall not
be attached to the wall. The loads shall be transmitted down to
the foundation.
February 1990 SSC Model Ordinance Page 20
r
SECTION A2348
•ADMINISTRATIVE PROVISIONS
Section A2348
(a) Definitions. For the purposes of this Chapter, the applicable
definitions in the Building Code shall also apply.
HIGH RISK BUILDING is any building, other than an essential or
hazardous building, having an occupant load of 100 occupants or
more as determined by Section 3302(a) of the Building Code.
Exception: A high risk building shall not include the
following:
1. Any building having exterior walls braced with masonry
crosswalls or woodframe crosswalls spaced less than 40 feet
apart in each story. Crosswalls shall be full -story height
with a minimum length of 1 -1/2 times the story height.
2. Any building used for its intended purpose, as
determined by the building official for less than 20 hours
per week.
LOW RISK BUILDING is any building, other than an essential or
hazardous building, having an occupant load as determined by
Section 3302(a) of the code of less than 20 occupants.
MEDIUM RISK BUILDING is any building, not classified as a high -
risk building or an essential or hazardous building, having an
occupant load as determined by Section 3302(a) of the code of 20
occupants or more.
(b) Rating Classifications. The rating classifications
identified in Table A -23 -E are hereby established and each
building within the scope of this Chapter shall be placed in one
such rating classification by the building official. The total
occupant load of the entire building as determined by Section
3302(a) of the Building Code shall be used to determine the rating
classification.
Exception: For purposes of this chapter, portions of
buildings constructed to act independently when resisting
seismic forces may be placed in separate rating
classifications.
(c) Compliance Requirements. 1. The owner of each building
within the scope of this Chapter shall, upon service of an order
and within the time limits set forth in this Chapter, cause a
structural analysis to be made of the building by an engineer or
architect licensed by the state to practice as such and, if the
building does not comply with earthquake standards specified in
this Chapter, the owner shall cause it to be structurally altered
to conform to such standards or shall cause the building to be
demolished.
February 1990 SSC Model Ordinance Page 21
i
SECTION A2348
2. The owner of a building within the scope of this Chapter
shall comply with the requirements set forth above by submitting
to the building official for review within the stated time limits:
A. Within 270 days after service of the order, a structural
analysis, which is subject to approval by the building official,
and which shall demonstrate that the building meets the minimum
requirements of this Chapter; or
B. Within 270 days after service of the order, the structural
analysis and plans for structural alterations of the building to
comply with this Chapter; or
C. Within 120 days after service of the order, plans for the
installation of wall anchors in accordance with the requirements
specified in Section A2347; or
D. Within 270 days after service of the order, plans for the
demolition of the building.
3. After plans are submitted and approved by the building
official, the owner shall obtain a building permit and then
commence and complete the required construction or demolition
within the time limits set forth in Table No. A -23 -F. These time
limits shall begin to run from the date the order is served in
accordance with Section A2348(d)2, except that the time limit to
commence structural alteration or demolition shall begin to run
from the date the building permit is issued.
4. Owners electing to comply with Item 2C of this subsection
are also required to comply with Items 2B or 2D of this subsection
provided, however, that the 270 -day period provided for in Item 2B
or 2D and the time limits for obtaining a building permit and to
complete structural alterations or building demolition set forth
in Table A -23 -F shall be extended in accordance with Table No. A-
23-G. Each such extended time limit shall begin to run from the
date the order is served in accordance with Section A2348(d),
except that the time limit to commence structural alterations or
demolition shall begin to run from the date the building permit is
issued.
(d) Administration. 1. Order - Service. A. The building
official shall, in accordance with the priorities set forth in
Table No. A -23 -G, issue an order as provided in this section to
the owner of each buildings within the scope of this Chapter.
B. Prior to the service of an order as set forth in Table No.
A -23 -G, a bulletin may be issued to the owner as shown upon the
last equalized assessment roll or to the person in apparent charge
or control of a building considered by the building official to be
within the scope of this Chapter. The bulletin may contain
information the building official deems appropriate. The bulletin
may be issued by mail or in person.
February 1990 SSC Model Ordinance Page 22
SECTION A2348
2. Order - Priority of Service. Priorities for the service of
the order for buildings within the scope of this Chapter shall be
in accordance with the rating classification as shown on Table No.
A -23 -G. Within each separate rating classification, the priority
of the order shall normally be based upon the occupant load of the
building. The owners of the buildings housing the largest occupant
loads shall be served first. The minimum time period prior to the
service of the order as shown on Table No. A -23 -G shall be
measured from the effective date of this Chapter. The building
official may, upon receipt of a written request from the owner,
order such owner to bring his building into compliance with this
Chapter prior to the normal service date for such building set
forth in this Chapter.
3. Order - Contents. The order shall be in writing and shall be
served either personally or by certified or registered mail upon
the owner as shown on the last equalized assessment roll, and upon
the p�e rson, if any, in apparent charge to control of the building.
The order shall specify that the building has been determined by
the building official to be within the scope of this Chapter and,
therefore, is requireed to meet the minimum seismic standards of
this Chapter. The order shall specify the rating classification of
the building and shall be accompanied by a copy of Section
A2348(c), which sets forth the owner's alternatives and time
limits for compliance.
4. Appeal from Order. The owner of the building may appeal the
building official's initial determination that the building is
within the scope of this Chapter to the Board of Appeals
established by Section 204 of the Building Code. Such appeal shall
be filed with the Board within 60 days from the service date of
the order described in Section A2348(d)3. Any such appeal shall be
decided by the Board no later than 90 days after writing and the
grounds thereof shall be stated clearly and concisely. Appeals or
requests for modifications from any other determinations, orders
or actions by the building official pursuant to the Chapter shall
be made in accordance with the procedures estalished in Sections
105 and 106 of the Building Code.
5. Recordation. At the time that the building official serves the
aforementioned order, the building official shall also file with
the office of the county recorder a certificate stating that the
subject building is within the scope of this Chapter and is a
potentially earthquake hazardous building. The certificate shall
also state that the owner thereof has been ordered to structurally
analyze the building and to structurally alter or demolish it
where compliance with this Chapter has not been demonstrated.
If the building is either demolished, found not to be within the
scope of this Chapter, or is structurally capable of resisting
minimum seismic forces required by this Chapter as a result of
structural alterations or an analysis, the building official shall
file with the office of the county recorder a form terminating the
February 1990 SSC Model Ordinance Page 23
SECTION A2348
status of the subject building as being classified within the
scope of this Chapter.
6. Enforcement. If the owner in charge or control of the subject
building fails to comply with any order issued by the building
official pursuant to this Chapter within any of the time limits.
set forth in Section A2348(c), the building official shall verify
that the record owner of this building has been properly served.
If the order has been served on the record owner, then the
building official shall order that the entire building be vacated
and that the building remain vacated until such order has been
complied with. If compliance with such order has not been
accomplished within 90 days after the date the building has been
ordered vacated or such additional time as may have been granted
by the Board of Appeals, the building official may order its
demolition in accordance with the provisions of Section 203 of the
Building Code.
February 1990 SSC Model Ordinance Page 24
TABLE NO. A -23 -A
HORIZONTAL FORCE FACTOR C
CONFIGURATION OF MATERIALS
C
Roofs with straight or diagonal
0.5
sheathing and roofing applied
directly to the sheathing, or
floors with straight tongue and
groove sheathing.
Diaphragms with double or
multiple layers of boards
0.75
with edges offset and blocked
plywood systems.
February 1990 SSC Model Ordinance Page 25
TABLE NO. A -23 -B
ALLOWABLE VALUE OF HEIGHT - THICKNESS RATIO OF
UNREINFORCED MASONRY WALLS
Wall Types
Seismic Zone 3
Buildings
Seismic Zone 4
Buildings with
Crosswallsl
Seismic Zone 4
All Other
Buildings
Walls of one -story
16
162,3
13
buildings
First -story wall
18
16
15
of multi -story
building
Walls in top story
14
142,3
9
of multi -story
buildings
All other walls
16
16
13
lApplies to the Special Procedures of Section A2346(d) only. See
Section A2346(d)7 for other restrictions.
2This value of height -to- thickness ratio may be used only where
mortar shear tests in accordance with Section A2343 establish a
tested mortar shear strength, vt, of not less than 100 psi or
where the tested mortar shear strength, vt, is not less than 60
psi and a visual examination of the collar joint indicates not
less than 50% mortar coverage.
3Where a visual examination of the collar joint indicates not less
than 50% mortar coverage and the tested mortar shear strength,
vt,when established in accordance with Sections A2343 is greater
than 30 psi but less than 60 psi, the allowable height -to-
thickness ratio may be determined by linear interpolation between
the larger and smaller ratios in direct proportion to the tested
mortar shear strength, vt.
February 1990 SSC Model Ordinance Page 26
r
TABLE NO. A -23 -C
ALLOWABLE VALUES FOR EXISTING MATERIALS
February 1990 SSC Model Ordinance Page 27
EXISTING MATERIALS OR CON -
FIGURATIONS OF MATERIALS1
ALLOWABLE VALUES
1.
HORIZONTAL DIAPHRAMS4
a.
Roofs with straight
100
lbs. per foot
sheathing and roofing
for
seismic shear
applied directly to the
sheathing.
b,.
Roofs with diagonal
250
lbs. per foot
sheathing and roofing
for
seismic shear
applied directly to
the sheathing.
c.
Floors with straight
100
lbs. per foot
tongue- and - groove
for
seismic shear
sheathing.
d.
Floors with straight
500
lbs. per foot
sheathing and finished
for
seismic shear
wood flooring with
board edges offset or
perpendicular.
e.
Floors with diagonal
600
lbs. per foot
sheathing and finished
for
seismic shear
wood flooring.
2.
CROSSWALLS-2,4
a.
Plaster on wood or metal
Per
side: 200 lbs.
lath
per
foot for
seismic shear
b.
Plaster on gypsum lath
175
lbs. per foot
for
seismic shear
C.
Gypsum wall board,
75 lbs. per foot
unblocked edges
for
seismic shear
d.
Gypsum wall board,
125
lbs. per fcot
blocked edges
for
seismic shear
February 1990 SSC Model Ordinance Page 27
TABLE NO. A -23 -C
ALLOWABLE VALUES FOR EXISTING MATERIALS (Cont.)
1Material must be sound and in good condition.
2Shear values of these materials may be combined, except the total
combined value shall not exceed 300 lbs. per foot.
3Stresses given may be increased for combinations of loads as
specified in Section A2345.
4A one -third increase in allowable stress is not allowed.
February 1990 SSC Model Ordinance Page 28
EXISTING MATERIALS OR CON-
FIGURATIONS OF MATERIALS1
ALLOWABLE VALUES4
3.
EXISTING FOOTINGS, WOOD
FRAMING, STRUCTURAL STEEL,
AND REINFORCED STEEL
a.
Plain concrete footings
f'c = 1500 psi unless
otherwise shown by
tests
b.
Douglas fir wood.
Allowable stress same
as No. 1 D.F.3
C.
Reinforcing steel.
ft = 18,000 lbs. per
square inch maximum.3
d.
Structural Steel.
ft = 20,000 lbs. per
square inch maximum.3
1Material must be sound and in good condition.
2Shear values of these materials may be combined, except the total
combined value shall not exceed 300 lbs. per foot.
3Stresses given may be increased for combinations of loads as
specified in Section A2345.
4A one -third increase in allowable stress is not allowed.
February 1990 SSC Model Ordinance Page 28
540 --- -, - - -� - -r - -� -- ,----- 1--- 1-- -,- - -� - -�
480
420 --- +- - -� - -� - 1 - --+ -- ' - - + -- '----- 1 - -� - -�
l O_ 1 1 1
-1-
�
E! 360
a 300
cnTom"` - -1 -- --- ,--- +—-- r-- +----- +—- -, - - -t
�' '
a 240
180 -- -- - - - — --1 ; --� --' - -1 -- '-- -' - - -'
� ,
120 ---- - -r — —� ----— If -I - - -, — —r - -� -- r - - — —�
60
0 1 1 1 i 1
0 1 2 3 4 5 6
Demand - Capacity Ratio, DCR
FIGURE N0. A -23 -1. ACCEPTABLE DIAPHRAGM SPAN
February 1990 SSC Model Ordinance Page 29
TABLE NO. A -23 -D 4
ALLOWABLE VALUES OF NEW MATERIALS USED
IN CONJUNCTION WITH EXISTING CONSTRUCTION
February 1990 SSC Model Ordinance Page 30
NEW MATERIALS OR CONFIGURATIONS
OF MATERIALS
ALLOWABLE VALUES4
1.
HORIZONTAL DIAPHAGMS
Plywood sheathing applied
225 lbs. per foot
directly over existing
straight sheathing with
ends of plywood sheets
bearing on joists or
rafters and edges of
plywood located on center
of individual sheathing
boards.
2.
CROSSWALLS
a.
Plywood sheathing applied
1.33 times the value
directly over wood studs.
specified in Table
No value shall be given to
No. 25 -K -1 Uniform
plywood applied over existing
Building Code for
plaster or wood sheathing.
shear walls.
b.
Drywall or plaster applied
100 percent of the
directly over wood studs.
values in Table No.
47 -I of the Uniform
Building Code.
C.
Drywall or plaster applied
50 percent of the
to sheathing over existing
values plywood
wood studs.
specified in Table
No. 47 -I of the
Uniform Building
Code.
February 1990 SSC Model Ordinance Page 30
TABLE NO. A -23 -D 4
ALLOWABLE VALUES OF NEW MATERIALS USED
IN CONJUNCTION WITH EXISTING CONSTRUCTION
(continued)
February 1990 SSC Model Ordinance Page 31
NEW MATERIALS OR CONFIGURATIONS
OF MATERIALS
ALLOWABLE VALUES4
4.
TENSION BOLTS
Bolts extending entirely
1800 lbs. per bolt.
through unreinforced
masonry walls secured
900 lbs. for 2 wythe
with bearing plates on far side
walls.
o-t a 3 wythe minimum wall with at
least 30 square inches of area.2,3
5.
SHEAR BOLTS
Bolts embedded a
133 percent of the
minimum of 8 inches into
values for plain
unreinforced masonry walls.
masonry specified for
Bolts shall be centered in
solid masonry in
2 -1/2 inch - diameter hole with
Tables No. 24 -E of
the dry -pack or non - shrink grout
Uniform Building
around circumference of bolt.1,3
Code. No values
larger than those
given for 3/4 inch
bolts shall be used.
6.
COMBINED TENSION AND SHEAR BOLTS
a.
Through Bolts - Combined Shear and Tension
Bolts meeting the above requirements
Tension: Same as for
for tension bolts and shear boltsl,2,3
tension bolts
Shear: Same as for
shear bolts
b.
Embedded Bolts - Combined Shear and Ten
ion
Bolts extending to the exterior
Tension: Same as for
face of the wall with a 2 1/2
tension bolts
inch round plate under the head
Shear: Same as for
and drilled at an angle of
shear bolts
22 -1/2 degrees to the horizontal.
Installed as specified for shear
bolts. 3-,2,3
February 1990 SSC Model Ordinance Page 31
TABLE NO. A -23 -D 4
ALLOWABLE VALUES OF NEW MATERIALS USED
IN CONJUNCTION WITH EXISTING CONSTRUCTION
(continued)
NEW MATERIALS OR CONFIGURATION
OF MATERIALS
ALLOWABLE VALUES4
7. INFILLED WALLS
Reinforced masonry infilled
Same as values
openings in existing unrein-
specified for unrein-
forced masonry walls. Provide
forced masonry walls.
keys or dowels to match rein-
forcing.
8. REINFORCED MASONRY
Masonry piers and walls rein-
Same as values
forced per Chapter 24.
specified in Section
2409.
9. REINFORCED CONCRETE
Concrete footings, walls and
Same as values
piers reinforced as specified
specified in
in Chapter 26 of the Uniform
Chapter 26 of the
Building Code and designed for
Uniform Chapter
tributary loads.
Building Code.
1Bolts to be tested as specified in Section A2344.
2Bolts to be 1/2 -inch minimum in diameter.
3Drilling for bolts and dowels shall be done with an electric
rotary drill. Impact tools shall not be used for drilling holes
or tightening anchors and shear bolt nuts.
4A one -third increase in allowable stress is not allowed.
February 1990 SSC Model Ordinance Page 32
TABLE NO. A -23 -E
RATING CLASSIFICATIONS
TYPE OF BUILDING
CLASSIFICATION
Essential Building
I
Hazardous Building
I
High -Risk Building
II
Medium -Risk Building
III
Low -Risk Building
IV
TABLE NO. A -23 -F
TIME LIMITS FOR COMPLIANCE
Required Action
By Owner
Obtain Building
Permit
Within
Commence
Construction
Within
Complete
Construction
Within
Structural Alterations
or Building Demolition
1 year
180 daysl
3 years
Wall Anchors
180 days
270 days2
1 year
1Measured from date of servicer of order.
2Measured from date of building permit issuance.
February 1990 SSC Model Ordinance Page 33
TABLE A -23 -G
EXTENSIONS OF TIME AND SERVICE PRIORITIES
Rating
Classification
Occupant
Load
Extension of Time
if Wall Anchors
are Installed
Periods for
Service of
Order
I
N/A
N/A
N/A
(Highest
Priority)
II
100 or more
1 year
180 days
III -A
100 or more
1 year
1 year
III -B
More than 50 but
Less than 100
1 year
2 years
III -C
More than 19 but
Less than 51
1 year
3 years
IV
Less than 20
1 year
4 years
(Lowest
Priority)
February 1990 - SSC Model Ordinance Page 34
f U
UNIFORM BUILDING CODE STANDARD NO. 24 -40
IN -PLACE MASONRY SHEAR TESTS
See Appendix Chapter 1, Uniform Code for Building Conservation
The bed joints of the outer wythe of the masonry shall be tested
in shear by laterally displacing a single brick relative to the
adjacent bricks in the same wythe. The head joint opposite the
loaded end of the test brick shall be carefully excavated and.
cleared. The brick adjacent to the loaded end of the test brick
shall be carefully removed by sawing or drilling and excavating to
provide space for a hydraulic ram and steel loading blocks. Steel
blocks, the size of the end of the brick, shall be used on each
end of the ram to distribute the load to the brick. The blocks
shall not contact the mortar joints. The load shall be applied
horizontally, in the plane of the wythe, until either a crack can
be seen or slip occurs. The strength of the mortar shall be
calculated by dividing the load at the first crack or movement of
the test brick by the nominal gross area of the sum of the two bed
joints.
February 1990 SSC Model Ordinance Page 35
l
UNIFORM BUILDING CODE STANDARD NO. 24 -41
TESTS OF ANCHORS IN UNREINFORCED MASONRY WALLS
See Appendix Chapter 1, Uniform Code for Building Conservation
Existing Anchors
The test apparatus shall be supported on the masonry wall at a
minimum distance of the wall thickness from the anchor tested.
Existing wall anchors shall be given a preload of 300 pounds prior
to establishing a datum for recording elongation. The tension
test load reported shall be recorded at 1/8 -inch relative movement
of the anchor and the adjacent masonry surface. Results of all
tests shall be reported. The report shall include the test
results as related to the wall thickness and joist orientation.
Combined Shear and Tension Bolts
Combined shear and tension bolts embedded in unreinforced masonry
walls shall be tested using a torque calibrated wrench to the
following minimum torques:
1/2- inch - diameter bolts -- 40 foot lbs.
5/8- inch - diameter bolts -- 50 foot lbs.
3/4- inch - diameter bolts -- 60 foot lbs.
All nuts shall be installed over malleable iron or plate washers
when bearing on wood and heavy cut washers when bearing on steel.
February 1990 SSC Model Ordinance Page 36
z zt n
UNIFORM BUILDING CODE STANDARD NO. 24 -42
POINTING OF UNREINFORCED MASONRY WALLS
See Appendix Chapter 1, Uniform Code for Building Conservation
POINTING
The old mortar should be cut out, by means of a toothing chisel or
a special painter's grinder, to a uniform depth of 3/411, or until
sound mortar is reached. Care must be taken not to damage the
brick edges. All dust and debris must be removed from the joint by
brush -ing, blowing air or rinsing with water.
Mortar mix shall be Type "S" or "N" proportions as called for in
the construction specifications. The tuck - pointing mortar should
be pre- hydrated to reduce excessive shrinkage. The proper pre -
hydration process is as follows:
All dry ingredients should be thoroughly mixed. Only enough clean
water should be added to the dry mix to produce a damp, workable
consistency which will retain its shape when formed into a ball.
The mortar should stand in this dampened condition for one to one
and one -half hours.
The joints to be tuck - pointed should be dampened, but to ensure a
good bond, the brickwork must absorb all surface water. Water
should be added to the pre- hydrated mortar to bring it to a
workable consistency (somewhat drier than conventional mortar).
The mortar should be packed tightly into the joints in thin layers
(1/4" maximum). Each layer should be come "thumbprint hard" before
applying the next layer. The joints should be tooled to match the
original profile after the last layer of mortar is "thumbprint
hard."
RELAYING OF BRICK
Replacement bricks must match the originals with respect to size,
color, and texture where exposed. A tuck - pointing toothing chisel
should be used to cut out the mortar which surrounds the affected
units. Power driven impact tools are not allowed. Once the units
are removed, all of the old mortar shall be carefully chiseled out
and all dust and debris shall be swept out with a brush.
If used brick is to be relayed, it shall be cleaned of all old
mortar. The brick surfaces in the wall shall be dampened before
new units are placed, but the masonry should absorb all surface
February 1990 SSC Model Ordinance Page 37
moisture to ensure a good bond. The appropriate surfaces of the
surrounding brickwork and the replacement brick should be buttered
with mortar. The replacement brick should be centered in the
opening and pressed into position. The excess mortar should be
removed with a trowel. Pointing around the replacement brick will
help to ensure full head and bed joints. When the mortar becomes
"thumbprint hard," the joints shall be tooled to match the
original profile.
February 1990 SSC Model Ordinance Page 38
Existing IIRM Financial Incentives
• Proposition 77 and 84 20 -year loans (30 y ears for
Three- percent- interest,
acquisition) for strengthening low- income, multiunit, rovid
residential URMs. These propositions, passed in 1988, p e
$150 million, of -which $35 million has been allocated so far.
Buildings are eligible only if local government has a URM
mitigation program. Amendments are pending in the Legislature.
• Exemptions from Increased Property Tax
This exemption applies to seismic retrofits of unreinforced
masonry bearing -wall buildings. Nonbearing wall URMs are
currently not exempt from property tax increases. Amendments
are pending in the Legislature.
• Construction Loan Doss Guarantee Program
This is a new law as of January 1990 and is managed by the
California Housing Finance Agency. It is designed to reduce
private lender reluctance to finance seismic retrofits of URMs
by guaranteeing 25 percent of the loans. Amendments are pending
in the Legislature.
• Local Government (Rosenthal) Bond Act of 1984
Existing law, amended last year by AB810(Costa) allows local
governments to sell revenue bonds to fund low cost loans to
private owners for seismic retrofit of unreinforced masonry
buildings. Although technical corrections made in the last
session broadened the definition of residential structures
and essential services buildings, and eligible costs,
the Federal Tax Reform Act of 1986 prevents their use for
refinancing existing debt. However, this program may help
nonprofit participation. Tax - exempt bonds are subject to a
state volume cap, which limits fund availability. Amendments
are pending in the Legislature.
• HCD Deferred Payment Loans
Loans only up to $200,000. This program is not adequately
funded.
• HCD Residential Hotel Loan program
This is a small program of $9.5 million statewide.
• Federal historic building tax credits
Tax Credits for seismic retrofit of up to 20 percent for
rehabilitation of certain historical buildings.
• HUD Community Development Block Grant Programs
• HUD Rental Rehabilitation Programs
Proposed Incentives / Financial Assistance Bills
• AB 1279 (Hauser) - provides local governments procedures and
ji;dicial remedies to improve enforcement capabilities for
seismic retrofits.
• AB 1497 (Hauser) - Expands the loan loss guarantee program to
commercial buildings.
• AB 3209 (Costa) - Cleanup language for local earthquake bond
programs.
• AB 3286 (Areias) - Directs the Office of Emergency Services
to provide financial assistance to local agencies for projects
that provide hazard mitigation measures under the Natural
Disaster Assistance Act.
• AB 3556, AB 17X (Cortese) - Require redevelopment funds to
provide for seismic retrofit of existing buildings.
• AB 3966 (Floyd) and SCA 33 (Rogers) - Exempts broader
definitions of seismic retrofit from property tax increases.
• AB 4177, ACA 60 (Cortese) - Would impose a statewide
property tax to fund a Disaster Assistance Fund.
• AB 15X (Cortese) and SB 25X (Torres) - $1000 state income
tax credit for seismic retrofit.
• SB 2226 (Roberti) - Would establish the Housing and
Earthquake Safety Bond Act of 1990 of $450,000,000.
• SB2428 (Mello) - Would allow the establishment of assessment
districts to finance seismic retrofit buildings.
• SB 8X (Roberti) - Extends Proposition 77 to $450 million and
single - family residences.
• SB 27X (Mello) - Establishes assessment districts in Loma
Prieta disaster areas.
If you would like to obtain copies of and review these bills,
please call Brian Stoner or Fred Turner at the Seismic Safety
Commission, 916/322 -4917.
• SBA Loans
Small Business Administration loans of $588,000 maximum for 1.5
to 2.75 percent above prime rate through private lenders; 90
percent of the loan is guaranteed by SBA.
• Long -term (Section 8) rent subsidy contracts
• Locally generated tax increments
Subject to voter approval.
General Obligation bond funds
Subject to voter approval.
• Restructure existing owner debts at lower interest
rates.
• Special Assessment Districts
Currently under consideration by some cities.
MOORPARK
BERNARDO M. PEREZ
Mayor
SCOTT MONTGOMERY
Mayor Pro Tern
ELOISE BROWN
Councilmember
CLINT HARPER, Ph.D.
Councilmember
PAUL W. LAWRASON, Jr.
Councilmember
LILLIAN KELLERMAN
City Clerk
STATE OF CALIFORNIA )
COUNTY OF VENTURA )
CITY OF MOORPARK )
SS.
STEVEN KUENY
City Manager
CHERYL J.KANE
City Attorney
PATRICK RICHARDS, A.I.C.P.
Director of
Community Development
R. DENNIS DELZEIT
City Engineer
JOHN V. GILLESPIE
Chief of Police
RICHARD T. HARE
City Treasurer
I, Lillian E. Kellerman, City Clerk of the City of Moorpark,
California, do hereby certify under penalty of perjury that
the foregoing Ordinance No. 127 was adopted by the
City Council of the City of Moorpark at a meeting held on
the 1st day of AUGUST , 1990, and that the
same was adopted by the following vote:
AYES: COUNCILMEMBERS BROWN, HARPER, ALWRASON, MONTGOMERY AND
MAYOR PEREZ
NOES: NONE
ABSENT: NONE
ABSTAIN: NONE
WITNESS my hand and the official seal of said City this
7th day of
ATTEST:
AUGUST
, 1990.
799 Moorpark Avenue Moorpark, California 93021 (805) 529 -6864