HomeMy WebLinkAboutORD 1059 (1991)] ORDINANCE NO. 1059
2 AN ORDINANCE OF THE CITY COUNCIL OF THE CITY
OF TUSTIN AMENDING ARTICLE 8 OF THE TUSTIN
3 CITY CODE BY ADOPTING EARTHQUAKE HAZARD
MITIGATION REQUIREMENTS FOR EXISTING
4 UNREINFORCED MASONRY BUILDINGS.
5 The City Council of the City of Tustin doeshereby ordain
as follows:
Section 1: Article 8 of the Tustin City Code is
7 amended by adding a new Chapter 9A to read as
follows:
8
CHAPTER 9A
9
EARTHQUAKE HAZARD MITIGATION FOR
10 UNREINFORCED MASONRY BUILDINGS
~] A8901 PURPOSE
]2 The purpose of this Chapter is to protect the public
health, safety and general welfare by reducing the risk
]3 of death or injury that.may result from the effects of
earthquakes on existing u~reinforced masonrybearing wall
]4 buildings. Such buildings have been widely recognized
for sustaining hazardous damages as a result of partial
]5 or complete collapse during past moderate to strong
earthquakes.
]6
The provisions of this Chapter are intended as minimum
]7 standards for structural seismic resistance established
primarily to reduce the risk of life loss or injury.
]8 Compliance with these provisions will not necessarily
prevent loss of life or injury or prevent earthquake
19 damage to rehabilitated buildings.
20 A8902 SCOPE
2] The provisions of this Chapter shall apply to all
existing building having at least one unreinforced
masonry bearing wall constructed prior to the effective
date of this Chapter.
Exception: This Chapter shall not apply to
24 detached one or two family dwellings and detached
apartment houses containing less than 5 dwelling
25 units and used solely for residential purposes.
26 This Chapter shall not require existing electrical,
plumbing, mechanical or fire safety systems to be altered
27 unless they constitute a hazard to life or property or
the character or the occupancy of an existing building is
28
Ordinance No. 1059
Page .2
changed.
This Chapter provides systematic procedures'and standards
for identifications and classification of unreinforced
masonry bearing .wall buildings based on their present
use. Priorities and standards are also established under
which these buildings are required to be structur~lly
analyzed and anchored. Where the analysis finds
deficiencies, this Chapter requires the building to be
strengthened.
A8903 DEFINITIONS ..
For the purpose of this Chapter, the following ·
definitions shall apply in addition to those contained in
the Uniform Building Code:
COLLAR JOINT is the vertical space between adjacent
wythes. It may contain ~ortar.
CROSSWALL is a wall that meets the requirements of
Section A8909D,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 isa wall perpendicular to the direction of
seismic forces.
OPEN FRONT is an exterior building wall pfane on one side
only without vertical elements of the lateral force
resisting system in one or more stories.
POINTING is the partial reconstruction of the bed joints
of a U~ wall as defined in UBC Standard No. 24-42.
Ordinance No. 1059
Page 3
SHEAR WALL is a wall utilized to resist the required
seismic forces parallel to the wall (not including
crosswalls). All reinforced orunreinforced masonry or
concrete walls shall be considered shear walls. Braced
frames shall be considered as shear walls. Movement-
resisting frames may be designed as crosswalls or shear
walls.
UBC is the most recent Uniform Building Code and all
amendments as adopted by the City of Tustin.
UBC STANDARD is the most recent Uniform Building Code
Standards as a~opted by the City of Tustin.
UNREINFORCED MASONRY (URM) WALL is a masonry wall in
which .the area of reinforcing steel is less.than
percent of the minimum required by the Building Code for
reinforced masonry.
UNREINFORCEDMASONRY (URM) BEARING WALL is a masonrywall
having all of the following characteristics: provides
the vertical support for a ~floor or roof; the total
superimposed load exceeds 100 pounds per linear foot of
wall, and; the masonry wall does not have vertical
reinforcement.
YIELD STORY DRIFT OR DEFLECTION 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.
A8904 SYMBOLS AND NOTATIONS
For the purpose'of this Chapter, the following symbols
and notations shall apply in addition to those contained
in the UBC:
A = Area of unreinforced masonry pier in square
inches.
Ab = Total area of the bed joints above and below
the test specimen for each in-place shear
test.
C = Numerical coefficient as specified in UBC
P SectiOn 2312(g) and given in UBC Table 23-P
and Table A1-A of this Chapter.
I Ordinance No. 1059
Page 4
4
D = In-plane width dimension of pier in inches, or
$ depth of diaphragm in feet.
6 DCR = Demand-capacity ratio specified in Section
i~ A8909D.
8 Ev = Shear ModuluS, psi. ... ~
9 F~, Fn, Fx
1 = lateral force applied to level i, n or x,
10 respectively. .. ·
11 Fp lat ral force on a part of the structure and
in the direction under consideration
12
13 Fwx = Force applied to a wall at level x in pounds.
H = Least clear height of opening on either side
]4 of pier in inches.
15 h/t = height/thickness ratio of URMwall. Height is
measuredbetween wall anchorage levels, and/or
16 slab on grade.
]7 L = Span of diaphragm between shear walls, or span
between shear wall and open front in feet.
18
~9~ L° =~ Length of crosswall in feet.
20 Li = Effective span for an open. front building
specified in Section A8909D.8.
21 PD = Superimposed dead load at the top of the pier
under consideration in pounds.
22
23 PD+L = Actual dead plus live load in place at the
time of testing in pounds.
24 Pw = Weight of wall in pounds.
25 Va a
= v A, the allowable shear in any URM pier in
26 pounds.
27 Vcb = Total shear capacity of crosswalls in the
direction of analysis immediately below the
28~ diaphragm level being investigated, Zvc~ in pounds.
I Ordinance No. 1059
Page 5
4
5 Vca = Total shear capacity of crosswalls in the
direction of analysis immediately above the
diaphragm level being investigated, ZvcLo in
6 pounds.
7 Vr = Pier rocking shear capacity of any URMwall or
wall pier in pounds, based on the cracked pier
8 analysis.
9 Vwx = Total shear force resisted by a shear wall at
the level under consideration in pounds.
10 ·
11 Vp = Shea~ force assigned to a pie~ on the basis of
its relative shear rigidity in pounds.
12 V$ = Shear force assigned to a spandrel on the
basis of the shear forces in the adjacent wall
13 piers and tributary dead plus live loads.
]4 Vtest= Load in pounds at incipient cracking for each
inplace .masonry shear test per UBC Standard
]5 23-40.
]6 v = Allowable shear stress in pounds per square
inch for unreinforced masonry.
17
18 vc = Allowable shear value for a crosswall sheathed
with any of the materials given in Tables A1-C
or A1-D in pounds per foot.
19
20 vt = Mortar shear strength as specified in Section
A8906C.3.
2] vto = Mortar shear test values as specified in
Section A8906C.3.
22
23 vu = Allowable shear value for a diaphragm sheathed
with any of the materials-given in Table A1-C
24 or A1-D in pounds per foot.
Zv D = Sum of diaphragm shear capacities of both ends
25 u of the diaphragm-
~vuD= For' diaphragms coupled with crosswalls ~vuD
includes the sum of shear capacities of both
27 ends of diaphragms coupled at and above the
28 leveI under consideration.
] Ordinance No. 1059
Page 6
4
Wd = Total dead load tributary to a diaphragm in
5 pounds. .
6 EWd = Total dead load tributary to all on the
diaphragms at and above the level under
7 consideration in pounds.
8 W = Total dead load of an unreinforCed masonry
W
wall above the level under consideration or
9 above an open front of a building in pounds.
10 W = Dead load of a URM wall assigned to Level x
~ halfway above and below the level under
]l consideration.
12 A8905 GENERAL REQUIREMENTS
13 A. General. All buildings shall have a seismic
resisting system conforming with UBC Section 2303(b)
]4 except as modified by this Chapter.
15 B. Alterations and Repairs. Alterations and repairs
required to meet the provisions of this Chapter shall
16 comply with all other applicable requirements of the UBC
unless specifically provided for in this Chapter.
]7
C. Requirements for Plans. The following construction
18 information shall be included in the plans required by
this Chapter:
I9
1. Dimensioned floor and roof plans showing
20 existing walls and the size and spacing of floor and roof
framing members and sheathing materials. The plans shall
21 indicate all existing and new crosswalls and their
materials of construction. The location of the
22 crosswalls and their openings shall be fully dimensioned
or drawn to scale on the plans.
2. Dimensioned wall elevations showing openings,
24 piers, wall classes as defined in Section A8906C.3.,
thicknesses, heights, wall shear test locations, and
25 cracks or damaged portions requiring repairs. The
general condition of the mortar joints and if and where
26 the joints require pointing. Where the exterior face is
veneer, the type of veneer, its thickness and its bonding
27 and/or ties to the structural wall masonry wall shall
also be reported.
28
1 Ordinance No. 1059
Page 7
4
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.
7 5. The extent and type of parapet corrections
which were previously performed, if any. ~
6. Repair details, if any, of cracked or damaged
9 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 A8910.
A8906 MATERIAL REQUIREMENTS
A. General. All materials permitted by this Chapter
]4 and the UBC, including their appropriate allowable design
values, and those existing configurations of materials
]5 specified' herein, may be utilized to meet the
requirements of this Chapter.
· B. Existing Materials. ~All existing materials utilized
]7 as part of the required force resisting system shall be
~ in sound condition or shall be repaired or removed and
18! replaced with new material.
]9 C. Existing Unreinforced Masonry
20 1. General. All unreinforced masonry walls
utilized to carry vertical loads or seismic forces
2] parallel and perpendicular to the wall plane shall be
tested as specifiedin this subsection. All masonrythat
22 does not meet the minimum standards established by this
Chapter shall be removed and replaced with new materials
23 or alternatively shall have its structural functions
replaced by new materials and shall be anchored to
24 supporting elements.
25 2. Lay-Up of Walls. The facing and backing
shall be bonded so that not less than 10 percent of the
26 exposed face area is composed of solid headers extendin~
not less than 4 inches into the backing. The clear
27 distance between adjacent full-length headers shall no~
exceed 24 inches vertically or horizontally. Where the
] Ordinance No. 1059
Page 8
3
4
backing consists of two or more wythes, the headers shall
5 extend not less than 4 inches into the most-distantwythe
or the backing wythes shall be bonded together with
6 separate headers whose area and spacing conform to the
foregoing. Wythes Of walls not bonded as described above
7 shall be considered as veneer. A veneer wythe shall not
be included in the effective thickness used- in
8 calculating the height to thickness ratio and the shear
capacity of the wall.
9
3. Mortar
10
a) Test. The quality of morta~ in all masonry
l] walls shall b~determined by performing shear
in-place
tests in accordance with UBC Standard 24-40. Alternative
12 methods of testing may be approved by the Building
Official.
]3
b) Location of Tests. The shear tests shall be
]4 taken at locations representative of the mortar
conditions throughout the entire building, taking into
]5 account variations in workmanship at different building
height levels, variations in weathering of the exterior
]6 surfaces, and variations in the condition of the interior
surfaces due to deterioration caused by leaks and
]7 condensation of water and/or by the deleterious effects
of other substances contained within the building. The
]8 exact test location shall be determined at the building
site by the licensed engineer responsible for the
]9 structural design analysis of the building. An accurate
record of all such tests and their location in the
20 building shall be recorded and these results shall be
submitted to the building department for approval as part
2] of the structural analysis.
22 c) Number of tests. The minimum number of tests
shall be as follows:
./ (i) At each of both the first and top
24 stories, not less than two tests per wall or line of wall
elements providing a common line of resistance to lateral
25 forces.
26 (ii) In any case, not less than one test
per 1500 'square feet of wall surface nor less than a
27 total of eight tests.
Ordinance No. 1059
Page 9
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:
Vt° = (Vt~t - ~+k)/Ab ............ ~. ~.. (06-1)
(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 80%Qf all of the mortar
shear test values, v~0.
(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 ~r
more classes based on -shear strength, quality of
construction, state of repair, deterioration, and
weathering. A class shall be characterized by the
allowable masonry shear stress determined in accordance
with Section A8908B. Classes shall be defined for whole
walls, not for small areas of masonry within a wall.
g) Pointing. All deteriorated mortar joints in
unreinforced masonry walls shall be pointed according to
UBC Standard 24-42. Nothing shall prevent pointing with
mortar of all the masonry wall joints before the tests
are made.
A8907 QUALITY CONTROL
A. Pointing. All preparation and mortar pointing shall
be performed with special inspection.
Ordinance No. 1059
Page 10
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 UBC 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 add two tests at walls with joists parallel
to the wall, b~t 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.
A8908 ALLOWABLE DESIGN VALUES
A. Allowable Values.
1. Allowable values for existing materials are
given in Table A1-C and for new materials in Table A1-D.
2. Allowable values not specified in this Chapter
shall be as specified elsewhere in the UBC.
B. Masonry Shear. The allowable unreinforced masonry
shear stress, va, shall be determined for each masonry
class from the following equation:
va = 0'lvt + 0'15PD/A .......................... (08-1)
The mortar shear test value, vt, shall be determined in
accordance with Section A8906.C., and not exceed 100 psi
for the determination of va.
The one-third increase in allowable values of the UBC is
not allowed for v .
] Ordinance No. 1059
Page 11
4
C. Masonry Compression. Where any increase in dead
5 plus live compression stress occurs, the allowable
compression stress in unreinforced masonry shall not
6 exceed 100 psi. The one-third increase in allowable
' stress of the UBC 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
]0 masonry is used to resist lateral forces in combination
with other materials, may be assumed as 10,000v~, unless
]] substantiated by tests.
]2 F. Existing Tension Anchors. T h e a 11 o w a b 1 e
resistance values of the existing anchors shall be 40
]3 percent of the average of the tension tests of existing
anchors having the sa~e wall thickness and joist
]4 orientation. The one-third increase in allowable stress
of the UBC iS not allowed for existing tension anchors.
]5 .
G. Foundations. For existing foundations new total
]6 dead load may be increased over existing dead load by 25
percent. New total dead load plus live load plus seismic
]7 may be increased over existing dead load plus live load
by 50 percent. Higher values may be justified only in
]8 conjunction with a geotechnical investigation,
]9
A8909 ANALYSIS AND DESIGN
20
A. General. Except as modified herein, the analysis
and design relating to the structural alteration of
existing buildings shall be in accordance with the UBC.
The elements of buildings required to be analyzed by this
Chapter shall be as specified in Table No. A1-H.
B. Selection of Procedure. Buildings shall be analyzed
24 by the General Procedure of Section A8909C which is based
on Chapter 23 of the UBC or, when applicable, buildings
may be analyzed by the Special Procedure of ASg09D.
26 C. General Procedure.
27 1. Minimum Design Lateral Forces. Buildings
shall be analyzed to resist minimum lateral forces
] Ordinance No. 1059
Page 12
3
4
assumed to act concurrently in the direction of each of
5 the main axes of the structure in accordance with the
following:
V = 0.33ZW .......................... (09-1)
7
'2. Lateral Forces on Elements of Structures-'~
8 Parts or portions .of structures shall be analyzed as
required in Chapter 23 of the Building code.
9
Exceptions:
10
a) Unre'nforced masonry walls fo~ which height to
1] thickness~ratios do not exceed ratios set forth in
Table No. A1-B need not be analyzed for out-of-
]2 plane loading. Unreinforced masonry walls which
exceed the allowable"h/t ratios of Table No. A1-B
13 shall be braced according to Section A8910E.
]4 b) Parapets complying with Section A8910F need not
be analyzed for out-of-plane loading.
3. Shear Walls (In-plan Loading). Shear walls
16 shall comply with subsection A8909E.
17 D. Special Procedure.
18 1. Limits for the application of Subsection
A8909D. The Special Procedure of this subsection ~ay
]9 only be applied to buildings with the following
characteristics:
20
a) Flexible diaphragms at all levels above the
base of structure.
22 b) A maximum of.2 stories above the base of the
building.
23
c) The vertical elements of the lateral force
resisting system shall consist predominantly of masonry
or concrete-shear walls.
d) New vertical elements of the lateral force
resisting system consisting of steel ,braced frames or
special moment resisting frames shall have a maximum
overall height-to-length ratio of 1.5 to 1.
Ordinance No. 1059
Page 13
e) A minimum of two lines of vertical elements of
the lateral force resisting system parallel to each axis
of the building except for single storybuildings with an
open front on one side only. (See A8909D.8. for open
front buildings-)
2. Lateral Forces on Elements of Structures.'
With the exception of the diaphragm provisions in
subsection A8909D., elements of structures shall comply
with subsection A8909C.2-
3. Crosswalls. Crosswalls shall ~eet the
requirements o'~ this subsection.
\
a) Crosswall Definition. A crosswall is a wood-
framed wall sheathed with any of the materials described
in Tables No. A1-C or A1-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:.
i) Crosswalls need not be provided at all levels
in accordance with subsection A8909D 4b. (iv).
ii) Existing crosswalls need not be continuous
below a wood diaphragm at/or within four feet of
grade provided:
a) Shear connections and anchorage
requirements Section A8909D.5. are satisfied
at all' edges of the diaphragm.
b) Crosswalls with total shear capacity of
.07 ZWd interconnect the diaphragm to the
foundation.
c) The demand/capacity ratio of the
diaphragm between the crosswalls that are
continuous to their foundations shall be
calculated as:
DCR = {0.83Wd+Vca}/2vuD ........ (09-2)
and DCR shall not exceed 2.5.
Ordinance No. 1059
Page 14
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 diaphragmshear 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 ~rosswalls. New crosswall connections
to the diaphragm shall develop the crosswall shear
capacity. New crosswalls shall have the capacity to
resist an overturning moments equal to the crosswall
shear capacity times'the story height. Crosswall
overturning moments need Rot 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 AI-1 falls
within Regions 1, 2, or 3.
b) Demand-Capacity Ratios. Demand-CapacityRatios
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 = 0.83ZWJZ vuD ............ (09-3)
(ii) For a diaphragm in a single-story building
with qualifying crosswalls:
DCR = 0.83ZWd/(~ V D ~ Vcb) .... (09-4)
(iii) For diaphragms in a multi'story building
Ordinance No. 1059
Page 15
with qualifying crosswalls in all levels:
DCR = 0.83ZZWJ (ZZvuD + Vcb) .... (09--5)
DCR shall be calculated at each level for the set of
diaphragms at and'above the level under consideration.
(iv) For a roof diaphragm and the diaphragm
directly below if coupled by crosswalls:
DCR = 0.83ZZW~/ZZvuD ........... (09-6)
c) Chords. An analysis for diaphragm flexure
need not be ma~e 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 A8909D.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 diaphragmspan 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 minimum force given by the lesser of the
following formulas:
V = .5ZCpWd ......... * ........... (09-7)
or
v = v D ........................ (09-8)
] Ordinance No. 1059
9 Page 16
3
4
6. Shear Walls (In Plane Loading) - Special
5 Procedure.
6 a) Wall Story Force. The wall storydistributed
to a shear wall at any diaphragm level shall be the
7 lesser value calculated as:
8 (i) For buildings without crosswalls,
9 F~x = 0.33Z (W~x + wJ2) .......... ' ....(09-9)
]0 but need not exceed
~] \F = 0.33ZWw× + vuD (09-10)
12 (ii) For buildings with crosswalls in all
levels:
F~ = 0.25z.(Wwx+wJ2) ................ (09-11)
14
but need not exceed
15
F~x = 0.25Z(Wwx + ZWd(VuD/ZZVuD)) .... (09-12)
and need not exceed
17
F = 0.25ZWwx + vuD ................. (09-13)
b) Wall Story Shear. The wall story shear sh~ll
~9 be the sum of the wall story forces.at and above the
level of consideration.
Vwx= ZFw× .......................... (09-14)
c) Shear Wall Analysis. Shear walls shall comply
22 with subsection A8909E.
23 d) Moment Frames. Moment frames used in place of
shear walls shall be designed as required in Chapter 23
24 of the Building Code except that the forces shall be as
specified in Section A8909D.6a) and the interstory drift
25 ratio shall be limited to 0.005.
26 7. Out of Plane Forces - URMWalls.
27 a) Allowable URMWall Height to Thickness Ratios.
The provisions of Section A8909C.2. are applicable except
] Ordinance No. 1059
Page 17
the allowable h/t ratios given in Table A1-B shall be
determined from Figure AI-1 as follows:
6 (i) In Region 1, .h/t ratios for "buildings
with crosswalls" may be used if qualifying crosswalls are
7 present in all stories.
8 (ii) In Region 2., h/t ratios for "'buildings
with crosswalls" may be used whether or not qualifying
9 crosswalls are bresent-
10 (iii) In Region 3, h/t ratios for "all other
buildings" shall be used whether or not qualifying
\
]] crosswalls are present.
]2 b) Walls with Diaphragms in Different Regions.
When diaphragms above and below the wall under
]3 consideration have DCRs in different regions of Figure
AI-1, the lesser h/t ratio shall be used.
]4
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:
17 a) Effective DiaphragmSpan, L~, for use in Figure
No. AI-1 shall be determined in accordance with the
]8 following formula:
i9 L~ = 2 [ (W/W~) L + L] ............. (09-1~)
20 b) Diaphragm Demand/capacity ratio shall be
calculated as:
DCR = 0.83Z(Wd + Ww)/[(vu D) + Vc]---(09-16)'
E. Analysis of Vertical Elements of the Lateral Force-
Resisting System. Applicable to both General Procedure
and Special Procedure Buildings.
1. Existing URMWalls.
a) Flexural Rigidity. Flexural rigidity may be
neglected in determining the rigidity of an URM wall.
b) Shear Walls with Openings. ~<all piers shall
be analyzed according to the following procedure:
] Ordinance No. 1059
Page 18
3
4
5 (i) For any pier,
(a) The pier shear capacity shall be
calculated as:
Va = VaDt ................. (09-17)
7
(b) The pier rocking shear. capacity
8 shall be calculated as:
9 Vr= 0.5poD/H ................ (09-18)
10 (ii) The wall piers at any level are
acceptable if they comply With one of the
l] foll6wing modes of behavior:
]2 (a) Rocking Controlled Mode. When the
pier rocking shear capacity is less than
]3 the pier shear capacity, i.e..Vr < Va for
each pier,in a level, forces in the wall
]4 · at that level, Vwx~ shall be distributed
to each pier, V in proportion to %/H.
15 P'
For the wall at that level:
16
V < Vr .............. (09-19)
(b) Shear Controlled Mode. Where the
]8 pier shear capacity is less than the pier
rocking capacity, i.e. Va <Vr in at leagt
~9 one pier -in a level, Vwx, shall be
distributed to each pier, Vp, in
20 proportion to D/H.
2] For'each pier at that level:
Vp < Va .................. (09-20)
22 'and
23 vp < v .
-- r ......... ~ ....... (09-21)
If Vp < Va for each pier and Vp. > Vr for
24 one or more piers, omit such piers from
the analysis and repeat the procedure for
25 the remainin9 piers or strengthen and
26 reanalyze the wall.
(iii) Masonry Pier Tension Stress.
27 Unreinforced masonry wall piers need not be
28 analyzed for tension stress.
] Ordinance No. 1059
Page 19
c) Shear Wall Without Openings. Shear walls
5 without openings shall be analyzed as for walls with
openings except that Vr shall be calculatedTM as follows:
Vr'= (0.50PD + 0.25P~)D/H ...... (09-22)
2. Plywood sheathed shear walls. Plywood sheathed
8 shear walls may be used to resist lateral loads for
buildings with flexible diaphragms analyzed according to
9 provisions of Section A8909C. Plywood sheathed shear
walls may not be used to share lateral with other
]0 materials along the same line of resistance.
3. Combinations of Vertical Elements.
]2 a) Lateral Force Distribution. Lateral forces
shall be distributed among the vertical resisting
]3 elements in proportion to their relative rigidities,
except that moment frames shall comply with Section
]4 A8909E.3.b).
]5 b) Moment Resisting Frames. A moment frame shall
not be used with a URM wall in a single line of
36 resistance unless the wall has piers that are capable of
sustaining rocking in accordance with A8909E.lb) and the
]7 frames are designed to,carry 100% of the lateral forces
and the interstory drift ratio shall be limited to
]8 0.0025.
]9 A8910 DETAILED SYSTEM DESIGN REQUIREMENTS
20 A. Wall Anchorage.
2] 1. Anchor Locations. All unreinforced masonry
walls shall be anchored at the roof and flood levels as
22 required in Section A8909C.2. Ceiling with substantial
rigidity and abutting masonry walls shall be connected to
23 walls with tension bolts at a maximum anchor spacing of
6 feet. Ceiling systems with substantial mass shall be
24 braced at the ceiling perimeter to the roof or floor
diaphragms.
2. Anchor Requirements. Anchors shall be
26 tension bolts through the wall as specified in Table No.
A1-D, or by an approved equivalent at a maximum anchor
27 spacing of 6 feet. All existing wall anchors shall be
secured to the joists to develop the required forces.
28
] Ordinance No. 1059
Page 20
3
4
The Building Official may require testing to verify the
5 adequacy of the embedded ends of existing'wall anchors.
6 3. Minimum Wall Anchorage. Anchorage of masonry
walls to each floor or roof shall resist a minimum force
7 determined by Section 2312(g) 2 of the UBC or 200 pounds
per linear foot, whichever is greater, acting normal to
8 the wall at the level of the floor or roof.' Existing
wall anchors, installed under previous permits, must meet
9 or must be upgraded to meet the requirements of this
Chapter. .
4. Anch9rs 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
12 corners of the walls.
13 5. Anchors with Limited Access. When access to
the exterior face of the masonry wall is prevented by
]4 proximity of an existing building or if architectural
conditions warrant them,. wall anchors conforming to Items
]5 4 and 5b in Table No. A1-D may be used. (See footnote 6
of Table A1-D for an alternative System).
B. DiaphragmShear Transfer. Shear bolt spacing shall
17 have a maximum bolt spacing of 6 feet.
]8 C. Collectors. Collector elements shall be provided
which are capable of transferring the seismic forces
i9 originating in other portions of the building to ~he
element providing the resistance to those forces.
20
D. Ties and Continuity. Ties and continuity shall
2] conform to Section 2312(h)2E of the UBC.
22 E. Wall-Bracing.
23 1. General. Where a wall height-thickness ratio
exceeds the specified limits, the wall may be laterally
24 supported by vertical bracing members per Section
A8910E.2. or by reducing the wall height by bracing per
25 Section A8910E.3.
26 2. Vertical Bracing Members. Vertical bracing
members shall be attached to floor and roof construction
27 for their design loads independently of required wall
anchors. Horizontal spacing of vertical bracing members
28
] Ordinance No. 1059
Page 21
3
4
shall not exceed one-half the unsupported height of the
5 wall nor 10 feet. Deflection of such bracing members at
design loads shall not exceed one-tenth of the wall
6 thickness.
7 3. Intermediate Wall Bracing. The wall height may
be by bracing elements connected to the floor or roof.
8 Horizontal spacing of the bracing elementS' and wall
anchors shall be as required by design but shall not
9 exceed 6' feet on center. Bracing elements shall be
detailed to minimize the horizontal displacement of the
10 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
]2 stabilized or braced to ensure that the parapets and
appendages remain in their original position.
]3
The maximum height~ of an unbraced unreinforced
]4 masonry parapet above the lower of either the level of
the tension anchors or roof sheathing, shall not exceed
15 one and one-half (1.5) times the thickness of the parapet
wall. If the required parapet height exceeds this
]6 maximum height, a bracing system designed for the force
factors specified in Table 23-P of the Building Code for
17 walls shall support the top of .the parapet. Parapet
corrective work must be performed in conjunction with the
]8 installation tension roof anchors.
39 The minimum height of a parapet above the w~ll
anchor shall be 12 inches.
20
EXCEPTION: If a reinforced concrete beam is
2] provided at'the top of the wall, the minimum height
above the wall anchor may be 6 inches.
G. Veneer.
1. Unreinforced masonry walls which carry no
24 design loads other than- their own weight may be
considered as veneer if they are adequately anchored to
25 new supporting elements.
20 2. Veneer shall be anchored with approved anchor
ties, conforming to the required design capacity
27 specified in the UBC and placed at a maximum spacing of
24 inches with a maximum supported area of 2 square feet.
Ordinance No. 1059
Page 22
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 ~eneer 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 every alternate course
in the vertical height of the wall at a ~pacing 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 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.
· Adjacent Buildings.
1. Where elements of adjacent buildings do not
have a separation of at least 5 inches, the allowable
height/thickness ratios for "buildings with crosswalls"
per Table A1-B shall not be used in the direction of
consideration.
2. Where an exterior URM bearing wall does 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 times the wall thickness, supplemental
vertical gravity load carrying members shall be added to
] Ordinance No. 1059
Page 23
3
4
support the loads normally carried by the wall and such
5 members shall not be attached to the wall. The loads
shall be transmitted down to the foundation.
A8911 ADMINISTRATIVE PROVISIONS
7
A. Definitions. The following definitions shall apply
8 to Section A8911 as follows:
9 VERY HIGH RISK BUILDING is any building, other than an
essential or hazardous building, having an occupant load
]0 of 100 occupants or more as determined by Section 3302(a)
of UBC.
HIGH RISK BUILDING is any building, not classified as a
]2 very high risk building~ having an occupant load as
determined by Section 3302(a) of the UBC of 99 occupants
]3 to 20 occupants.
]4 MODERATE RISK BUILDING is any building, other than an
essential or hazardous building, having an occupant load
]5 as determined by Section 3302a of the UBC of less than 20
occupants.
]8
B. Rating Classifications.
]7
1. The hazard rating classifications identified in
]8 Section A8911A. and on Table A1-E are hereby established
and each building within the scope of this Chapter shell
19 be placed in one such rating classification by the
Building Official. The total occupant load of the entire
20 building as determined by Section 3302(a) of the UBC
shall be used to determine the rating classification.
2]
Exception: For purposes of this Chapter,
22 portions of buildings constructed to act
independently when resisting seismic forces, and
23 having required exits with- independent travel
paths, may be placed in separate rating
24 classifications.
2. Buildings placed in a particular hazardous
rating classification may be changed to a lesser
hazardous rating if corrective repairs are undertaken and
accomplished. Hazardous rating may also be changed when
competent engineering data is submitted substantiating
such a change. Such data may consist of analytical
Ordinance No. 1059
Page 24
assessments, tests, data substantiating a higher capacity
ratio or a modification of use or occupancy potential.
Corrective repair plans and/or data substantiating a
change in hazardous rating shall be prepared by a
structural or civil engineer or architect licensed under
the laws of the state to practice said profession.
Partial repair designed to correct or strengthen
individualand/or critical elements of a building will be
permitted pursuant to Table A1-G provided a suitable plan
indicating the method of total and eventual correction is
submitted and the method of eventual correction is
approved and installed. Buildings so ~epaired will be
regarded reflecting repairs so accomplished,
3. Complete repair and removal from any hazardous
rating classification will be deemed to have been
accomplished when the building has been repaired in
accordance with this Chapter.
4. Special and Intermediate Hazardsl In addition
to evaluation of the primary structural systems, any
structural or non-structural element of the building,
including parapets, ornamentation or other appendages
attached to the building or any structural or non-
structural architectural, mechanical or electrical system
that is determined by reason of lack of attachment,
anchorage or condition to become dangerous to persons in
the building or in the vicinity will be classed. as an
immediate hazard. Any immediate hazard identified in
buildings classified as very high or high risk.buildings
shall be treated under the procedures established by the
Uniform Code for the Abatement of Dangerous Buildings.
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 with experience in rehabilitation of unreinforced
masonry structures 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 vacated. and/or demolished as determined necessary by
the Building Official.
] Ordinance No. 1059
Page 25
4
As part of the design criteria, it is incumbent upon the
5 owner and his engineer or architect to utilize materials
and details of construction which will not adversely
8 affect the architectural appearance or historical
significance of the building. Where details are visible,
7 they shall be reviewed by the Planning Division of the
Community Development Department of the City of Tustin
8 and a Certificate of Appropriateness shall be'issued for
any improvements which' affect the exterior condition of
9 a building and which require a building permit. In all
cases, the necessary reviews will not increase the
]0 allowable time for compliance with the order..
1] 2. The ~wner of a building within the scope of
this Chapter shall comply with the requirements set forth
12 above by submitting to the Building Official for review
within the stated time limits:
a) Within 270 days after service of the order, a
]4 structural analysis, which is subject to approval by the
Building Official, and which shall demonstrate that the
]5 building meets the minimum requirements of this Chapter;
or
b) Within 270 days after service of the order, the
17 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,
]9 plans for the installation of wall anchors in accordance
with the requirements specified in Section A8910; or
d) Within 270 days after service of the order,
2] plans for the vacation or demolition of the building
where demolition is authorized by the Community
22 Development Director.
23 3. After plans are submitted and approved by the
Building Official and Community Development Director
24 where a Certificate of Appropriateness is first required,
the owner shall obtain a building permit and. then
25 commence and complete the required construction or
demolition within the time limits set forth in Table No.
26 A1-F. These time limits shall begin to run from the date
the order is served in accordance with Section A8911D.2,
27 except that the time limit to commence structural
alterations, vacation or demolition shall begin to run
28
Ordinance No. 1059
Page 26
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
of obtaining a building permit and to complete structural
alterations or building demolition set forth in Table A1-
F shall be extended in accordance with Table No. A1-Go
Each such extended time limit shall begin to run from the
date the order is served in accordance with Section
A8911D., except that the time limit to. commence
structural alterations, vacation or demolition shall
begin to run from the date the building permit is issued.
5. This Chapter does not require alteration of
existing electrical, plumbing, mechanical or fire safety
systems-
D Administration-
1. Order - Service.
a) The Building Official shall, in accordance with
the priorities set forth in Table No. A1-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. A1-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.
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. A1-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. A1-G shall be measured from the
] Ordinance No. 1059
Page 27
4
effective date of this Chapter. The Building Official
5 may, upon receipt of a written request from the owner,
order such owner to bring his building into compliance
6 with this Chapter prior to the normal service date for
such building set forth in this Chapter.
7
3. Order - Contents. The order shall be- in
8 writing and shall be served by certified or'registered
mail upon the owner a shown on the last equalized
9 assessment roll. The order shall specify that the
building has been determined by the Building Official to
10 be within the scope of this Chapter and, therefore, is
required to meet the minimum seismic standards of this
31 Chapter. T~e order shall specify the rating
classification of the building, a procedure to be
32 followed if the owner is in disagreement with the hazard
rating classification and that the ra~ing will be
~3 recorded with the County Recorder with the County
Recorder after 60 days unless a change in grade has been
']4 approved by the Building Official pursuant to Section
A8911B, and information which sets forth the owner's
]5 alternatives and time limits for compliance under this
Chapter.
4. -Appeal from Order. The owner of the building
37 may appeal the Building Official's initial determination
that the building is within the scope of t~is Chapter to
18 the Board of Appeals established by Section 204 of the
UBC. Such appeal shall be filed with the Board within 30
~9 days from the service date of the order described in
Section A8911D. Any such appeal shall be decided by the
20 Board not less than 10 days nor more than 60 days 'after
writing and the grounds thereof shall be stated clearly
2] and concisely. The form, processing and schedule of
appeals shall be handled consistent with Section 501 of
22 the Uniform Code for the Abatement of Dangerous
Buildings. Other requests for modifications from any
23 other determinations, orders or actions by the Building
Official pursuant to this Chapter shall be made in
24 accordance with the procedures established in Sections
105 and 106 of the UBC.
5. Recordation. Upon expiration of a sixty day
26 period after the Building Official serves the
aforementioned order pursuant to Subsection D1 and if
such hazard rating has not been changed, the Building
Official shall file with the office of the County
Ordinance No. 1059
Page 28
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 as approved by the
Building Official, 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 status of the
subject building as being classified within the scope of
this Chapter.
6. Enforcement. If the owner in charge or in
control of the subject building fails to comply with any
order issued by the Building Officials pursuant to this'
Chapter within any of the time limits set forth in
Section A8911C, 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. In any
event, no permit for demolition shall be issued without
approval of the Director of Community Development.
PASSED AND ADOPTED at a regular meeting of the Tustin
City Council held on the 19th day of February, 1991.
R~CHARD EDGAR /
Mayor
City Cler~ 9 CAS:kbc/quake. ord
TABLE NO. Al-A
HORIZONTAL FORCE FACTOR CP
CONFIGURATION OF MATERIALS CP
Roofs with straight or diagonal sheathing 0.5
and roofing applied directly to the
sheathing, or floors with straight tongue
and groove sheathing.
Diaphragms with double or multiple layers of
boards with edges offset and blocked plywood
systems.
0.75
29
TABLE NO. Al-B
ALLOWABLE VALUE OF HEIGHT-THICKNESS RATIO OF
UNREINFORCED MASONRY WALLS
Wall Types Buildings with
Crosswalls~ All Other
Buildings
Walls of one-story 16 2~3 13
buildings
First-story wall 16 15
of multi-story
building
Walls in top story 14 z,s 9
of two-story
buildings
' Applies to the Special Procedures of Section A8909D. only.
See Section A8909D.7. for other restrictions.
z This value of height-to-thickness ratio may be used only where
mortar shear tests in accordance with Section A8906 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 60psi and a visual examination of the collar joint
indicates not less than 50% mortar coverage.
3 Where 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
A8906 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.
30
TABLE NO. Al-C
ALLOWABLE VALUES FOR EXISTING MATERIALS
EXISTING MATERIALS OR
CONFIGURATIONS OF MATERIALS ALLOWABLE VALUES
1. HORIZONTAL DIAPHRAGMS
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
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, blocked 125 lbs. per foot
edges. for seismic shear
31
TABLE NO. Al-C
ALLOWABLE VALUES FOR EXISTING MATERIALS (Cont.)
EXISTING MATERIALS OR
CONFIGURATIONS OF MATERIALS ~ ALLOWABLE VALUES
3. EXISTING FOOTINGS, WOOD
FRAMING, STRUCTURAL
STEEL, AND REINFORCING
STEEL
a. Plain concrete footings f'c = 1500 psi unless
otherwise shown by tests3
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
~ Material must be sound and in good condition.
z Shear values of these materials may be combined, except the
total combined value shall not exceed 300 lbs. per foot.
3 Stresses given may be increased for combinations of loads as
specified in the Building Code.
4 A one-third increase in allowable stress is not allowed.
32
TABLE NO. Al-D~
ALLOWABLE VALUES OF NEW MATERIALS USED
IN CONJUNCTION WITH EXISTING CONSTRUCTION
NEW MATERIALS OR CONFIGURATIONS
OF MATERIALS ALLOWABLE VALUES
1. HORIZONTAL DIAPHRAGMS4
Plywood sheathing applied 225 lbs. per foot
directly over existing
straight sheathing with
ends plywood sheets
bearing on joists or
rafters and edges of
plywood located on center
of individual sheathing
boards.
2. CROSSWALLS4
a. Plywood sheathing applied The value specified
directly over wood studs. in Table No. 25-K-1
No value shall be given to of the UBC for shear
plywood applied over walls.
existing plaster or wood
sheathing.
b. Drywall or plaster applied 100 percent of the
directly over wood studs. values in Table No.
47-I of the UBC.
c. Drywall or plaster applied Add to the sheathing
to sheathing over existing allowable values 50
wood studs. percent of the values
specified in Table
No. 47-I of the UBC.
33
TABLE NO. Al-D
ALLOWABLE VALUES OF NEW MATERIAL USED
IN CONJUNCTION WITH EXISTING CONSTRUCTION
(CONTINUED)
NEW MATERIALS OR CONFIGURATIONS
OF MATERIALS ALLOWABLE VALUES
3. TENSION BOLT84
Bolts extending entirely through 1800 lbs. per bolt.
unreinforced masonry walls
secured with bearing plates on 900 lbs. for 2 wythe
far side of a 3 wythe minimum walls.
wall with at least 30 square
inches of area. z,3
4. SHEAR BOLTS 4
Bolts embedded a minimum of 8 133 percent of the
inches into unreinforced masonry values for plain
walls. Bolts shall be centered masonry specified for
in 2-1/2 inch- diameter hole solid masonry in Table
with the dry-pack or non-shrink 24-E of the UBC. No
grout around circumference of values larger than
bolt. ~•3 those given for 3/4
inch bolts shall be
used.
5. COMBINED TENSION AND SHEAR
BOLT84
a. Through Bolts - Combined Shear Tension: Same as for
and Tension tension bolts.
Shear: Same as for
Bolts meeting the above shear bolts
requirements for tension bolts
and shear bolts. 1.2,3
b. Embedded Bolts - Combined Shear Tension: 1200 lbs.
and Tension per bolt.
Shear: Same as for
Bolts extending to the exterior shear bolts.
face of the wall with a 2 1/2
inch round plate under the head
and drilled at an angle of 22-
1/2 degrees to the horizontal.
Installed as specified for shear
bolts . ~ •2.3
34
TABLE NO. Al-D
ALLOWABLE VALUES OF NEW MATERIALS USED
IN CONJUNCTION WITH EXISTING CONSTRUCTION
(continued)
NEW MATERIALS OR CONFIGURATION
OF MATERIALS ALLOWABLE VALUES
6. INFILLED WALL84
Reinforced masonry infilled Same as values specified
openings in existing for the adjacent
unreinforced masonry walls. unreinforced masonry
Provide keys or dowels to walls.
match reinforcing.
7. REINFORCED MASONRY
Masonry piers and walls Same as values specified
reinforced per Chapter 24. in Section 2409. 5
8. REINFORCED CONCRETE
Concrete footings, walls and Same as values specified
piers reinforced as in Chapter 26 of the UBC.S
specified in Chapter 26 of
the UBC and designed for
tributary loads.
~ Bolts to be tested as specified in Section A8907.
2 Bolts to be 1/2-inch minimum in diameter.
3 Drilling 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.
4 A one-third increase in allowable stress is not allowed.
5 Stresses given may be increased for combinations of loads as
specified in the UBC.
6 ICBO approved anchors installed in accordance with the
approval and the manufacturer's recommendation may be used in
lieu of the system shown.
35
TABLE NO. Al-E
RATING CLASSIFICATIONS
TYPE OF BUILDING
Very High-Risk Building
High-Risk Building
Moderate Risk Building
I
II
III
TABLE NO. Al-F
TIME LIMITS FOR COMPLIANCE
Required Action Obtain Commence Complete
By Owner Building Construction Construction
Permit Within Within2 Within2
Structural 1 year 180 days 3 years
Alterations or
Building
Demolition
180 days 270 days 1 year
Wall Anchors
Measured from date of service of order.
Measured from date of building permit issuance.
CLASSIFICATION
36
TABLE Al-G
EXTENSIONS OF TIME AND SERVICE PRIORITIES
Rating Occupant Load Extension of Time Periods for
Classification if Wall Anchors Service of
are Installed Order
I 100 or more 1 year 180 days
II Less than 100 1 year 2 years
to 20
III Less than 20 1 year 3 years
37
TABLE NO. Al-H
ELEMENTS REGULATED BY THIS CHAPTER
BUILDING ELEMENTS SEISMIC ZONE
4
Parapets ~
Walls, Anchorage ~
Walls, h/t Ratios ~
Walls, In-Plane Shear ~
Diaphragms
Diaphragms, Shear Transfer2 ~
Diaphragms, Demand-Capacity Ratios2 ~
Elements of Structures ~
Nonstructural Components ~
Applies only to buildings designed according to the General
Procedures of Section A8909C.
2 Applies only to buildings designed according to the Special
Procedures of Section A8909D.
38
~1
Gu
a
a
E
N
3-f
a
_~,
0
590 --~---1---~---r-- ~ --~-- ~--~---+---,---~---~
1 + ' , ' 1 1 , 1 1 , I
1 ' 1 ' + ' + ' + ' ' '
-- r---r--1---y---1-.--+-----r -- r---~ -- -~---,---1-
1 ~ + ' + ' + ' + ' ' '
480 ' ~ ~ --a---~---~---~ +--- ~ -+---1---+
1 r - - ~ - -
~ , + 1 ~ ~ ~ , 1 r , 1
--1---~---r - 1--1---'---I---~---r--1---~--J
+ I ' 1 1 1 1 1 , 1 , 1
1 ' 1 ' + ~ + ~ + t ' ~
920 _-~---! --L !--~-- --+---------- --s--
~ 1 , ~ , ~ 1 + i , 1 , 1
_ IO I t , , ' ~ ' ' + ' '
-- 1-- - ' ---~- ' --'---~---~--- ~ --1 -- ~---'---'
I ' 1 ' + i + ' + •' 1 '
1 i 1 1 1
360 --'- ----'---r--'---T---'--1---'---,
- - ~ - - 7 - - + , 1 , I 1
1 ' ~ '
- ._ - ~ - - C" - - ~ - - T - - ~ - - -i - - -+- - - ~- - - ~ - - T - - ~ - - -1
1 1 , f' , 1 , 1 , 1 1 1
300 ' ' + + -' 1 + 1 1 1 1
--T-------`-- ~-- ---,-- ~----r--+--~ ---~---,---+
1 ~ 1 ' + ' + ' + ' '
1 ,~ ~ 1 ~ 1 ~ , , 1 , 1
, ` 1 , 1 1 - I 1 I 1 , I
240 ' ~ ' ' + 1 1
t , ~- , 1 I , , , 1 , 1
1 1~ '
- - - 1- - - ~ - - 1' -~- ~ - - - .~ -i - - -1- - - i- - - L - - ~ - - 1 - - ~
1 ' 1 ' + ' ~ ' + ' ' 1
1 i ' ~ 1 ' I + i , 1 , 1
18O _ L _ ' --1-- v- --~- 1---~--- ~ --1 -- ~---'---+
- ~ - ~ - ~ , ~ 1 + 1 , 1 , 1
1 ' 1 ' 1 , + ' 1 1 1 1
1 1 I 1 + + ' ! - ' - ~ - '
---+---r---~ --Y-- ~--l-1- -1---r---~ -T- 1 -1
1 ; O I 1 ' /' ' + 1 ' 1
120 ---~---r--~ --T-- ~-f--1---, --r--~ --r-- ~---~
' 1 1 , 1 ~ I + I , t , t
--r---~--~---+---,-~--~---~-- -z---+---,---1.
i ; ,/ ~Of i i ~ ; ~
60 --r--1---~---'---j --~---r--1-- --J---1---1
1 1 1 , I I i I 1 1 1
1 ~ 1 I + ~ '
--+---1 ---+-- '---f-- ' --~--1---+-- ---1---'
1 - , - ~ , -i , 1 , , 1
0 1 1 ' ' '
0 1 2 3 4 S 6
Demand-Capacity Ratio, DCR
FIGURE NO. Al-l. ACCEPTAIILE DIAPHRAGM SPAN
39
City of Tustin
ORDINANCE CERTIFICATION
STATE OF CALIFORNIA
COUNTY OF ORANGE
CITY OF TUSTIN
ORDINANCE NO. 1059
SS
MARY E. WYNN, City Clerk and ex-officio Clerk of the City Council of
the City of Tustin, California, does hereby certify that the whole
number of the members of the City Council of the City of Tustin is
five; that the above and foregoing Ordinance No. 1059 was duly and
regularly introduced and read at a regular meeting of the City Council
held on the 4th day of February, 1991, and was given its second reading
and duly passed and adopted at a regular meeting held on the 19th day
of February, 1991, by the following vote:
COUNCILMEMBER AYES: Edgar, Puckett, Pontious, Potts, Prescott
COUNCILMEMBER NOES: None
COUNCILMEMBER ABSTAINED: None
COUNCILMEMBER ABSENT: None
~_
Mary Wynn, ity,Clerk
.,