HomeMy WebLinkAboutOrdinance 6088 ORDINANCE NO. 6088
AN ORDINANCE AMENDING CHAPTER 25 (WOOD) OF THE BUILDING CODE OF THE CITY OF
FORT WORTH PERMITTING THE USE OF NONSTRESS--GRADED LUMBER IN CERTAIN TYPES
OF CONSTRUCTION AND PERMITTING ALTERNATE METHODS OF ASSEMBLY AND CONSTRUC-
TION INVOLVING WOOD; PROVIDING A SEVERABILITY CLAUSE; MAKING THIS ORDINANCE
CUMULATIVE OF OTHER PROVISIONS OF THE BUILDING CODE; REPEALING ALL ORDI-
NANCES IN CONFLICT HEREWITH; PROVIDING A PENALTY FOR ANY VIOLATION HEREOF;
DIRECTING THE CITY SECRETARY TO ENGROSS AND ENROLL THIS ORDINANCE BY COPY-
ING THE CAPTION OF SAME IN THE MINUTE BOOK OF THE CITY COUNCIL AND BY
FILING THE COMPLETE ORDINANCE IN THE APPROPRIATE ORDINANCE RECORDS OF THE
CITY AND DIRECTING THE CITY SECRETARY TO PUBLISH SAME IN PAMPHLET FORM;
AND PROVIDING AN EFFECTIVE DATE.
BE IT ORDAINED BY THE CITY COUNCIL OF THE CITY OF FORT WORTH, TEXAS:
SECTION 1
That Chapter 25 (Wood) of Part VI of the Building Code of the City of
Fort Worth, Texas, is hereby amended, and after having been amended, shall
hereafter read as follows:
CHAPTER 25--WOOD
GENERAL SECTION 2501. (a) QUALITY AND DESIGN. The quality and design of
wood members and their fastenings used for load-supporting purposes
shall conform to the provisions of this Chapter, and to the following
standards:
U.B.C.
MATERIALS AND DESIGN DESIGNATION
GRADING--LIGHT FRAMING, JOISTS AND PLANKS, DECKING
BEAMS AND STRINGERS, POSTS AND TIMBERS
All species of Lumber -------------------------- 25- 1-67
Cedar, Incense and Western Red ----------------- (25- 3-67
(25- 4-67
Cypress--Tidewater Red ------------------------- 25- 2-67
Douglas Fir, Coast Region ---------------------- 25- 3-67
Douglas Fir ------------------------------------ 25- 4-67
Fir, White ------------------------------------- (25- 3-67
(25- 4-67
Fir, Balsam ------------------------------------ 25- 8-67
Hemlock, Eastern ------------------------------- 25- 5-67
Hemlock, West Coast ---------------------------- 25- 3-67
Hemlock, Western ------------------------------- 25- 4-67
Larch ------------------------------------------ 25- 4-67
Pine (Idaho White, Lodgepole, Ponderosa
and Sugar -------------------------------- 25- 4-67
Pine, Norway ----------------------------------- 25- 5-67
Pine, Southern --------------------------------- 25- 6-67
Redwood ---------------------------------------- 25- 7-67
Spruce, Eastern -------------------------------- 25- 8-67
Spruce, Engelmann ------------------------------ 25- 4-67
Spruce, Sitka ---------------------------------- 25- 3-67
PLYWOOD--CONSTRUCTION AND INDUSTRIAL SOFTWOOD ----- 25- 9-67
STRUCTURAL GLUED-LAMINATED TIMBER
All Species of Lumber -------------------------- 25-10-67
Douglas Fir ------------------------------------ 25-11-67
Pine, Southern -------------------------------- 25-11-67
Hardwood -------------------------------------- 25-11-67
Hemlock, West Coast ---------------------------- 25-11-67
Larch ----------------------------------------- 25-11-67
PRESERVATIVE TREATMENT BY PRESSURE PROCESSES ------ 25-12-67
WOOD POLES --------------------------------------- 25-13-67
ROUND TIMBER PILES -------------------------------- 25-14-67
SPACED COLUMNS ------------------------------------ 25-15-67
FLEXURAL AND AXIAL LOADING ------------------------ 25-16-67
JOINTS
Timber Connector Joints ------------------------ 25-17-67
Bolted Joints --------------------------------- 25-17-67
Drift Bolts and Wood Screws -------------------- 25-17-67
Lag Screws ------------------------------------- 25-17-67
STRUCTURAL GLUED BUILT-UP MEMBERS
PLYWOOD COMPONENTS ------------------------------ 25-18-67
ADHESIVES ---------------------------------------- 25-19-67
TEST FOR GLUE JOINTS IN LAMINATED WOOD PRODUCTS --- 25-20-67
GENERAL DESIGN CRITERIA --------------------------- 25-21-67
PLANK-AND-BEAM FRAMING --------------------------- 25-22-67
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TESTS FOR STRUCTURAL GLUED-LAMINATED LUMBER ------- 25-23-67
NAILS AND STAPLES --------------------------------- 25-24-67
(b) WORKMANSHIP. All members shall be framed, anchored, tied,
and braced so as to develop the strength and rigidity necessary for
the purposesfnr which they are used.
(c) FABRICATION. Preparation, fabrication, and installation of
wood members, and glues and mechanical devices for the fastening
thereof, shall conform to good engineering practices and to the re-
quirements of this Code.
(d) REJECTION. The Building Official may deny permission for the
use of a wood member where permissible grade characteristics or de-
fects are present in any wood member in such a combination that they
affect the serviceability of the member.
DEFINITIONS SECTION 2502. Except where otherwise provided, the following terms
AND
NOTATIONS and symbols used in this Chapter have the meaning indicated in this
Section;
GLUED-LAMINATED LUMBER, lumber composed of an assembly of wood
laminations bonded with adhesives in which the laminations are too
thick to be classed as veneers. See definition of Structural Glued-
laminated Lumber.
GLUED BUILT-UP MEMBERS, structural members, the sections of which
are composed of built-up sawn lumber alone, plywood alone, or plywood
in combination with sawn or glued-laminated lumber; all parts bonded
together with adhesives.
GRADE (Dumber), the classification of lumber in regard to strength
and utility in accordance with U.B.C. Standards No. 25-1-67 to No.
25-8-67.
GRADE--STRESS (Lumber), a lumber grade defined in such terms that a
definite working stress may be assigned to it as set forth in U.B.C.
Standard No. 25-1-67.
MACHINE STRESS-RATED LUMBER, is lumber which has been individually
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pretested by an approved nondestructive mechanical means supplemented by
visual grading as required in U.B.C. Standard No. 25-1-67, Section 25.113,
in order to establish unit working stresses.
NOMINAL SIZE (Lumber), the commercial size designation of width, and
depth, in standard sawn lumber and glued-laminated lumber grades; some-
what larger than the standard net size of dressed lumber, in accordance
with U.B.C. Standard No. 25-1-67 for sawn lumber and U.B.C. Standard No.
25-10-67 or No. 25-11-67 for glued-laminated lumber.
NORMAL LOADING, a design load that stresses a member or fastening to
the full allowable stress tabulated in this Chapter. This loading may be
applied for approximately 10 years, either continuously or cumulatively,
and 90 per cent of this full maximum design load may be applied for the
remainder of the life of the structure. See U.B.C. Standard No. 25-1-67.
PLYWOOD -- CONSTRUCTION AND INDUSTRIAL SOFTWOOD is a built-up panel
of laminated veneers conforming to U.B.C. Standard No. 25-9-67.
STRUCTURAL GLUED-LAMINATED LUMBER, any member comprising an assembly
of laminations of lumber in which the grain of all laminations is approxi-
mately parallel longitudinally; in which the laminations are bonded with
adhesives; and which is fabricated in accordance with U.B.C. Standard No.
25-10-67 or No. 25-11-67.
SYMBOLS AND NOTATIONS, as used in these regulations, are defined as
follows:
A ==area in square inches of net cross section.
b ==breadth of beam or of cross section in inches.
c =-compressions parallel to grain, allowable unit stress in pounds
per square inch.
d ==least dimension of column, in inches.
E ==modulus of elasticity.
f ==extreme fiber in bending, allowable unit stress in pounds per
square inch.
h ==depth of section, in inches.
H ==horizontal shear, allowable unit stress in pounds per square inch.
4
' r
I ==moment of inertia of member.
1 ==span in inches or laterally unsupported length of a column
in inches.
N ==allowable unit stress on inclined surface in pounds per
square inch.
P ==total load in pounds.
q ==compression perpendicular to grain, allowable unit stress in
pounds per square inch.
R ==reaction, in pounds.
t -tension parallel to grain, allowable unit stress in pounds
per square inch.
V ==vertical shear at section under consideration.
1/d==ratio of length to least dimension.
P/A==compressive strength or maximum axial load, in pounds per
square inch.
0 ==angle between direction of load and the direction of grain, in
degrees.
TREATED WOOD. Pressure treatment or the term "pressure impregnated
with an approved preservative" is that treatment of wood which is in
accordance with U.B.C. Standard No. 25-12-67.
SIZE OF SECTION 2503. (a) REQUIRED SIZES. Wood members shall be of suf-
STRUCTURAL
MEMBERS ficient size to carry the dead and required live loads without exceed-
ing the allowable unit stresses as hereinafter specified.
(b) SIZE DETERMINATION. Minimum sizes of lumber and glued-laminated
members required by this Code refer to nominal sizes. U.B.C. Standards
No. 25-1-67 for lumber, and No. 25-10-67 or No. 25-11-67 for glued-
laminated dressed sizes shall be accepted as the minimum net sizes con-
forming to nominal sizes. Nominal sizes may be shown on the plans.
Computations to determine the required sizes of members shall be based
on the net dimensions (actual sizes) and not the nominal sizes. If
rough sizes or sizes or shapes other than U.B.C. Standard No. 25-1-67
5
or No. 25-11-67 dressed sizes are to be used, the actual net sizes shall
be specified on the plans.
ALLOWABLE SECTION 2504. (a) ALLOWABLE UNIT STRESS ON PLANS. Where structures
UNIT
STRESSES are designed for use of stress grade lumber, structural glued-laminated
lumber, for plywood used structurally, the allowable unit stresses for
the species and the grade shall be shown on the plans filed with the
Building Department.
(b) STRESSES. 1. GENERAL. Except as hereinafter provided,
stresses shall not exceed the allowable unit stresses in pounds per
square inch for the respective species and grades and grade combinations
as set forth in Table No. 25-A and Table No. 25-B for solid sawn stress
grade lumber; and Table No. 25-C for softwood plywood; and Tables No.
25-D, No. 25-E, No. 25-F, No. 25-G and No. 25-H for structural glued-
laminated lumber.
For modification of allowable unit stresses for structural glued-
laminated lumber, see also Section 2513.
The allowable unit stresses in extreme fiber in bending "f" as set
forth in Tables No. 25-D, No. 25-F, No. 25-G and No. 25-H apply to
members with the wide face of the lamination perpendicular to the direc-
tion of the load. When the wide face of the lamination is parallel to
the direction of the load and the beam is composed of not less than
three laminations, 115 per cent of the bending stresses as set forth
in Table No. 25-A shall apply, except as provided in Tables No. 25-E
and No. 25-G.
The allowable unit stresses as set forth in Tables No. 25-A, No.
25-B, No. 25-D, No. 25-E, No. 25-F, No. 25-G and No. 25-H and adjust-
ments thereof, and stresses as set forth in Table No. 25-C apply also
to lumber, to structural glued-laminated lumber and to exterior type
plywood that have been pressure impregnated by an approved preservative.
Studs, joists, rafters, foundation plates or sills, planking two
inches (2") or more in depth, beams, stringers, posts, structural
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sheathing and similar load-bearing members shall be of at least the
minimum grades set forth in Table No. 25-A or No. 25-B and in Groups
I, II, and III set forth in Table No. 25-I. Lumber set forth in Group
IV of Table No. 25-I may be used for load-bearing members in one-story
buildings and in the top story of a multi-story building.
Stresses for grade and species other than those tabulated shall be
established by the Building Official in accordance with U.B.C. Standard
No. 25-1-67 and in accordance with U.B.C. Standard No. 25-10-67 for
species and grade combinations used in structural glued-laminated lumber.
Allowable unit stresses of plywood other than as provided in Table
No. 25-C shall be determined according to species.
2. STRESSES IN POLES OR PILES USED AS STRUCTURAL MEMBERS. Induced
stresses in pounds per square inch for normal loading of round poles or
piles when used as structural members, except modulus of elasticity
which shall be the same as for sawn lumber, shall not exceed 60 per cent
of the basic unit working stresses for clear lumber for the species as
set forth in U.B.C. Standard No. 25-1-67, and the pieces shall meet the
requirements of U.B.C. Standard No. 25-13-67 for poles or U.B.C. Standard
No. 25-14-67 for piles.
(c) IDENTIFICATION. All species set forth in Tables No. 25-A, No.
25-B and No. 25-I shall be used only when identified by a grade mark of
an approved lumber grading or inspection bureau or agency.
All plywood used structurally, including applications such as siding,
roof and wall sheathing, subflooring, diaphragms, and built-up members,
shall conform to performance standards set forth in U.B.C. Standard No.
25-9-67; it shall be properly identified and grade marked by an approved
agency. In addition to the above requirements, all plywood when perma-
nently exposed in outdoor applications shall be of exterior type.
The allowable unit stresses for structural glued-laminated lumber as
set forth in U.B.C. Standard No. 25-10-67 and in Tables No. 25-D, No.
25-E, No. 25-F, No. 25-G and No. 25-H shall be used only when the material
7
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and workmanship are in accordance with U.B.C. Standard No. 25-10-67
or No. 25-11-67, respectively, and are inspected and identified in a
manner meeting the approval of the Building Official.
(d) CONDITIONS OF SERVICE. The allowable unit stresses as set
forth in Table No. 25-A for visually graded lumber, and adjustments
thereof apply to lumber used under conditions continuously dry, such
as in most covered structures. Under such conditions of use the
modulus of elasticity may be increased 10 per cent for lumber that is
surface seasoned before loading to the maximum allowable load. Except
for compression parallel and compression perpendicular to the grain,
they also apply to lumber used under conditions where the moisture con-
tent of the wood is permanently at or above the fiber saturation point,
as when continuously submerged.
When used under continuously wet conditions, the allowable unit
stresses as set forth in Table No. 25-A for compression parallel to
grain shall be reduced 10 per cent and for compressions perpendicular
to grain shall be reduced one-third.
The allowable unit stresses set forth in Table No. 25-B for machine
stress-rated lumber shall be adjusted for conditions of use as specified
in the footnote to the Table.
The allowable unit stresses as set forth in Tables No. 25-A, No. 25-B,
No. 25-D, No. 25-E, No. 25-F, No. 25-G and No. 25-H and adjustments thereof,
and stresses as set forth in Table No. 25-C apply also to lumber, to
structural glued-laminated lumber and to exterior type plywood that has
been pressure-impregnated by an approved process and to the heartwood of
durable species under dry or other conditions of use.
The allowable unit stresses for structural glued-laminated lumber as
set forth in Tables No. 25-D, No. 25-E, No. 25-F, No. 25-G and No. 25-H
shall be for dry conditions of use where the moisture content in service
is 16 per cent or less, as in most covered structures. For wet conditions
of use, the maximum percentage of the dry-use stress permitted shall be
8
as specified in the footnotes applicable to the respective tables.
(e) ADJUSTMENT OF ALLOWABLE UNIT STRESSES FOR DURATION OF LOAD.
The allowable unit stresses as set forth in Tables No. 25-A and No.
25-B for sawn lumber, Table No. 25-C for plywood and Tables No. 25-D,
No. 25-E, No. 25-F, No. 25-G and No. 25-H for structural glued-lami-
nated lumber, and the values for mechanical fastenings as hereinafter
established, shall be applicable as follows for the various durations
of loading:
1. Idlere a member is fully stressed to the maximum allowable stress,
either continuously or cumulatively for more than 10 years under the
condition of maximum design load, the allowable unit stresses used in
the design shall not exceed 90 per cent of those in the tables.
2. When the duration of the full maximum load does not exceed the
period indicated below, the allowable unit stresses shall be increased
in the tables as follows:
15 per cent for two months duration, as for snow
25 per cent for seven days duration
33 1/3 per cent for wind or earthquake
100 per cent for impact
Allowable unit stresses given in the tables for normal loading con-
ditions may be used without regard to impact if the stress induced by
impact does not exceed the allowable unit stress for normal loading.
The above increases are not cumulative. For combined durations of
loading, the resulting structural members shall not be smaller than
required for a longer duration of loading.
(f) HORIZONTAL SHEAR ADJUSTMENT. The unit stress in horizontal
shear in members of rectangular section stressed in flexure shall be
computed by use of the following formula:
3 R
H =_
2 b h
'WHERE:
9
R == reaction, pounds, under the following conditions:
(1) Distribution of load to adjacent beams through flooring or other
members shall be considered.
(2) All loads uniform or concentrated, within a distance of the
height of the beam from the nearest support, shall be neglected.
(3) All concentrated loads located at a distance from the support
of one to three times the height of the beam shall be considered
as placed at three times the height of the beam from the support.
(g) ADJUSTMENTS OF ALLOWABLE UNIT STRESSES FOR JOINT DETAILS.
1. COMPRESSION. In joists supported on a ribbon or ledger board and
spiked to the studding, the allowable stress in compression perpendicular
to grain may be increased 50 per cent.
Allowable unit stresses in compression perpendicular to grain as set
forth in Tables No. 25-A and No. 25-B shall be increased in accordance
with the following factors for bearing less than six inches (6") in
length and located three inches (3") or more from the end of a timber.
Length of bearing
(inches) 1/2 1 1 1/2 2 3 4 6 or more
Factor 1.75 1.38 1.25 1.19 1.13 1.10 1.00
For stress under washers or small plates the same factor may be taken
as for a bearing, the length of which equals the diameter of the washer.
2. SHEAR. Allowable unit stresses in shear for joint details shall
be 150 per cent of the horizontal shear values as set forth in Tables No.
25-A, No. 25-B, No. 25-D, No. 25-E, No. 25-F, No. 25-G and No. 25-H.
In computing the horizontal shear in eccentric joints the effective
depth of the member shall be assumed as its actual depth less the dis-
tance from the unloaded edge to the nearest edge of the nearest connector.
Where bolts alone are used, the distance from the unloaded edge to the
center of the nearest bolt shall be subtracted.
(h) HOLES AND NOTCHES. Girders, beams, or joists may be notched or
10
bored in any part of the section within three times the beam depth
from either support. Such notches or holes shall not exceed one-fifth
of the depth of beam except at point of support and as hereinafter
provided.
%ere girders, beams, or joists are notched at points of support,
they shall meet design requirements for net section in bending and in
shear. The shear at such point shall not exceed the value calculated
by the following formula:
2 bd2 H
V ==
3 h
WHERE:
d == actual depth of beam at the notch.
h total depth of beam.
Where notches or holes are made in other portions of the beam, the
net remaining depth of beam shall be used in determining the bending
strength.
(i) COMPRESSION ON INCLINED SURFACES. The unit stress (compression)
normal to a plane inclined to the fiber of a wood member shall not ex-
ceed that determined from the formula:
cq
N =_
c sin29 + q cos29
COLUMNS SECTION 2505. (a) GENERAL. Columns, posts, struts, and other members
in compression parallel to grain shall be designed structurally as provided
in this Section.
(b) SOLID COLUMNS. Simple solid wood columns consist of a single piece
of sawn lumber or structurally glued-laminated lumber.
The safe load in pounds per square inch of net cross-sectional area,
for simple columns or other solid members stressed in compression parallel
to grain, shall be determined by the following formula, but the maximum
unit load "P(A" shall not exceed the values for compression parallel to
grain "c" in Tables No. 25-A, No. 25-B, No. 25-D, No. 25-E, No. 25-F, No.
11
25-G and No. 25-H adjusted in accordance with the provisions of Sub-
section 2504 (e):
3.619E
P/A ==
For columns of square or rectangular section the following formula
shall be used:
0.30E
P/A =_ -'--
(1/a
WHERE:
d == least dimension of square or rectangular columns, in inches.
1 == unsupported length in inches.
r == least radius of gyration of the section.
Columns shall be limited in maximum length between points of lateral
support to 1 == 50d, except that the individual members of spaced columns
shall be limited in maximum length to 1 == 80d.
(c) SPACED COLUMNS. Spaced columns or compression members shall be
based upon design principles acceptable to the Building Official, or the
design principles set forth for spaced columns in U.B.C. Standard No.
25-15-67.
(d) AXIAL LOADING. The allowable axial unit stresses are subject to
adjustment for duration of load and conditions of service as specified in
Section 2504.
(e) COMBINED FLEXURAL AND AXIAL LOADING. Members subjected to both
flexural and axial loading shall be designed in accordance with the pro-
visions set forth in U.B.C. Standard No. 25-16-67.
TIMBER SECTION 2506. (a) TIMBER CONNECTORS. Timber connectors may be used
CONNECTIONS
AND to transmit stress between wood members and between wood and metal members.
FASTENINGS
The allowable loads and installation of timber connectors shall be as set
forth in U.B.C. Standard No. 25-17-67.
Safe loads and design practices for types of connectors not mentioned
or fully covered in U.B.C. Standard No. 25-17-67 may be determined in a
12
manner approved by the Building Official.
(b) BOLTS. Bolted joints wherein bolts are used to resist or trans-
fer stresses in wood structures shall be designed in accordance with the
provisions set forth in U.B.C. Standard No. 25-17-67. Safe loads in
pounds for bolts in double shear and in seasoned lumber of the following
species: Douglas fir (Coast Region) and Douglas fir; larch; pine, south-
ern; in joints consisting of three members in which the side members are
one-half the thickness of the main member, shall not exceed values set
forth in Tables No. 25-J and No. 25-K. (For other species see U.B.C.
Standard No. 25-17-67.)
(c) DRIFT BOLTS OR PINS. Connections of wood structural members in-
volving the use of drift bolts or drift pins shall be designed in accord-
ance with the provisions set forth in U.B.C. Standard No. 25-17-67.
(d) WOOD SCREWS. Connections involving the use of wood screws shall
be designed in accordance with the provisions set forth in U.B.C. Standard
No. 25-17-67.
(e) LAG SCREWS. Connections involving the use of lag screws shall be
designed in accordance with the provisions set forth in U.B.C. Standard
No. 25-17-67.
(f) NAILS AND SPIKES. 1. SAFE LATERAL STRENGTH. A common wire nail
driven perpendicular to grain of the wood, when used to fasten wood members
together, shall not be subjected to a greater load causing shear and bend-
ing than the safe lateral strength of the wire nail or spike as set forth
in Table No. 25-L.
A wire nail driven parallel to the grain of the wood or toe-nailed
shall not be subjected to more than two-thirds of the lateral load allowed
when driven perpendicular to grain.
2. SAFE RESISTANCE TO WITHDRAWAL. A wire nail driven perpendicular to
grain of the wood shall not be subjected to a greater load, tending to
cause withdrawal, than the safe resistance of the nail to withdrawal, as
set forth in Table No. 25-M.
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Nails driven parallel to grain of the wood shall not be allowed for
resisting withdrawal forces.
3. SPACING AND PENETRATION. Common wire nails shall have penetra-
tion into the piece receiving the point as set forth in Table No. 25-L.
Nails or spikes for which the wire gauges or lengths are not set forth
in Table No. 25-L shall have a required penetration of not less than 11
diameters, and allowable loads may be interpolated.
For wood to wood joints the spacing center-to-center shall be not less
than the required penetration.
Edge and end distances shall be not less than one-half of the required
penetration.
Holes for nails, where necessary to prevent splitting, shall be bored
of a diameter smaller than that of the nails.
4. GROUPS I AND J OCCUPANCIES. The number and size of nails connect-
ing wood members of Groups I and J Occupancies shall be not less than the
amount set forth in Table No. 25-N. Other connections shall be nailed to
provide equivalent strength.
Plywood subflooring and roof sheathing shall be nailed at six inches
(611) on center at panel edges and boundary members and twelve inches (12")
on center at intermediate supports. The nails shall be of sufficient size
to provide the minimum penetration required in Table No. 25-L. See Section
2511 for nailing of plywood required at vertical or horizontal diaphragm.
(g) JOIST HANGERS AND FRAMING ANCHORS. Connections depending upon
joist hangers or framing anchors, ties, and other mechanical fastenings
not otherwise covered may be used where approved.
VERTICAL SECTION 2507. (a) COLUMNS OR POSTS. All wood columns and posts shall
MEMBERS OR
ASSEMBLIES be framed to true end bearings; shall extend down to supports of such design
as to hold the column or post securely in position and to protect its base
from deterioration; and shall be supported in basements or cellars by piers
projecting at least two inches (2") above the finished floor and separated
therefrom by an approved metal barrier, or when pressure-impregnated timber
14
is used, it may be placed directly on concrete or masonry.
Untreated wood columns in basement or cellars, when built into
masonry partitions or walls, shall be exposed on at least two sides.
(b) STUD WALLS AND BEARING PARTITIONS. 1. PLACING. Studs in walls
and partitions may be placed with their wide faces parallel to the wall
or partition, provided the studs are considered as columns and are de-
signed accordingly. Stud walls shall have top and bottom plates except
that joists may be supported by a let-in ribbon as provided in Section
2509 (a).
2. SIZE. Except as otherwise provided, exterior stud walls and
bearing partitions for buildings of two stories or less shall consist
of not less than two-inch by four-inch (2" x 4") studs; for buildings
of three stories, the studding shall be not less than three inches by
four inches (3" x 4") or two inches by six inches (2" x 6") to the
bottom of the second floor joists, and two inches by four inches (2" x 4")
for the two upper stories.
3. HEIGHT. Unless supported laterally by adequate framing, the
maximum allowable height shall be ten feet (10') for two-inch by three-
inch (2" x 311) stud framing; fourteen feet (14') for two-inch by four-
inch (2" x 4") stud framing; sixteen feet (16') for three-inch by four-
inch (3" x 4") stud framing; and twenty feet (20') for two-inch by six-
inch (2" x 6") stud framing.
When Table No. 25-I, Group IV studs are permitted to be used, the
maximum allowable height shall be eight feet (8') for load-bearing studs
and ten feet (10') for nonload-bearing studs. When used in bearing walls,
Group IV studs shall support not more than a roof and ceiling load.
4. SPACING. Except for one-story detached buildings of Group J
Occupancy, where twenty-four-inch (24") spacing may be used, no studding
shall be spaced more than sixteen inches (16") on center unless vertical
supporting members in the walls are designed as columns, or such walls
may be constructed of not less than four-inch by four-inch (4" x 4")
15
posts spaced not more than five feet four inches (5'411) on center, or
of larger members designed as required in this Chapter, or may be of
post and beam framing with plank sheathing not less than one and one-half
inches (1'k") thick.
5. CORNERS AND BRACING. Angles or corners where stud walls or par-
titions meet shall be blocked for one-third the stud length with one
foot minimum length blocking. All exterior walls and main cross stud
partitions shall be effectively and thoroughly braced or sheathed with
approved panels adequately nailed along all edges or by cut-in or let-in
bracing.
6. PIPES IN WALLS. Stud partitions containing plumbing, heating, or
other pipes shall be so framed and the joists underneath so spaced as to
give proper clearance for the piping. Where a partition containing such
piping runs parallel to the floor joists, the joists underneath such
partitions shall be doubled and spaced to permit the passage of such
pipes and shall be bridged. Where plumbing, heating, or other pipes are
placed in or partly in a partition, necessitating the cutting of the soles
or plates, a metal tie not less than one-eighth inch (1/8") thick and one
and one-half inches (1' ") wide shall be fastened to the plate across and
to each side of the opening with not less than four 16d nails.
7. SEPARATIONS FROM CHIMNEYS. For clearance space between chimneys
and combustible materials, see Section 3702 (1).
8. TOP PLATES. In bearing partitions the top plate shall be doubled
and lapped at each intersection with walls or partitions. Joints in the
upper and lower members of the top plates shall be staggered not less than
four feet (4').
9. FOUNDATION PLATES. Stud walls resting on masonry or concrete shall
have foundation plates or sills as provided in Sections 2806 (e) and
2517 (c).
10. FOUNDATION STUDS. Foundation studs shall be not less in size than
the studding above with a minimum of length of fourteen inches (14").
16
Mien exceeding four feet (41) in height, studs shall be of the size required
for an additional story.
Foundation studs under bearing walls and partitions shall be thoroughly
and effectively braced.
11. BRIDGING. All stud partitions or walls over ten feet (10') in
height shall have bridging, not less than two inches (2") in thickness
and of the same width as the stud, fitted snugly and spiked into the studs
at their mid-height, or other means for giving adequate lateral support to
the studs. Bridging meeting the requirements of Section 2508 may serve as
required firestopping.
12. HEADERS. All openings four feet (4') wide or less in bearing walls
shall be provided with headers equivalent to double headers not less than
two inches (2") thick, placed on edge, securely fastened together, and all
openings more than four feet (4') wide shall be trussed or provided with
headers or lintels. Such headers or trusses shall have not less than two-
inch (21') solid bearing at each end to the floor or bottom plate, unless
other approved framing methods or joint devices are used.
(c) WALLS WITHOUT STUDS. Detached one-story buildings of Group J Occu-
pancy may have exterior walls framed without studs when of vertical two-inch
(211) or thicker planks, or when having a total floor area of not more than
five hundred square feet (500 sq. ft.) may be of vertical one-inch (111)
boards and battens.
(d) LAMINATED WALLS AND PARTITIONS. Walls and partitions may be of
laminated construction of not less than four inches (4") nominal thickness,
with the structural assembly designed to support all loads.
(e) INTERIOR WALLS AND PARTITIONS. Interior partitions shall be con-
structed, framed, and firestopped as specified for exterior walls, except
that interior nonbearing partitions may have a single top plate. In Group
I Occupancies, nonbearing partitions constructed of two-inch by three-inch
(2" x 3") studs spaced sixteen inches (16") on center may be used.
Were wood-frame walls and partitions are covered on the interior with
17
plaster, tile, or similar materials and are subject to water splash, the
framing shall be protected with 15-pound asphalt-saturated felt.
For provisions covering maximum allowable spacing of gypsum, wood, and
fiber insulation lath, see Section 4703.
For provisions covering maximum allowable spacing of supports for metal
and wire lath on wood studs and rafters and method of attachment, see Sec-
tion 4705.
For provisions covering maximum allowable spacing of gypsum wallboard
on wood studs and rafters and method of attachment, see Section 4710.
(f) EXTERIOR WALL COVERINGS. 1. GENERAL. Exterior wood stud walls
shall be covered on the outside with the materials and in the manner
specified in this Section.
2. WEATHERBOARDING. Studs or sheathing shall be covered on the out-
side face with one layer of building paper when required in Section 1707(a).
Weatherboarding shall have an average thickness in place of not less
than five-eighths inch (5/8") and a minimum thickness of not less than
three-eighths inch (3/8"). Horizontal joints in the weatherboarding shall
be tongued and grooved or shiplapped joints, or such weatherboarding shall
be laid shingle fashion and lapped not less than one-half inch (1/2").
Siding patterns known as rustic, drop siding, or shiplap shall have an
average thickness in place of not less than nineteen thirty-seconds inch
(19/32") and shall have a minimum thickness of not less than three-eighths
inch (3/811). Bevel siding shall have a minimum thickness measured at the
butt section of not less than seven-sixteenths inch (7/16") and a tip
thickness of not less than three-sixteenths inch (3/16"). Siding of lesser
dimensions may be used, provided such wall covering is placed over sheathing
which conforms to the provisions specified in Section 2202.
All weatherboarding or siding shall be securely nailed to each stud
with not less than one nail, or to solid nominal wood sheathing with not
less than one line of nails spaced not more than twenty-four inches (24")
on center in each piece of the weatherboarding or siding.
Nails shall be so located as to hold the bottom of the weatherboarding
18
or siding secure and thereby to hold tight the top of the piece below.
Wiere such nailing is not possible, two nails to each stud shall be used
to hold each piece.
3. PLYWOOD. Fhere plywood is used for covering the exterior of outside
walls, it shall be of the exterior type not less than three-eighths inch
(3/8") thick. Joints shall occur over framing members not less than two
inches (2") thick, unless wood or plywood sheathing is used, or joints
are lapped horizontally or otherwise made waterproof to the satisfaction
of the Building Official.
EXCEPTION: Exterior Specialty Siding may be used provided the minimum
panel thickness at any point is 9/32 inch and the average thickness of
any 16-inch cross section is a minimum of 5/16 inch.
4. SHINGLES OR SHAKES. Wood shingles or shakes and asbestos cement
shingles may be used for exterior wall covering provided the frame of the
structure is covered with building paper as specified in Section 1707 (a).
All shingles or shakes attached to sheathings other than wood shall be
secured with approved mechanically-bonding nails or by approved corrosion-
resistant nails on furring strips attached to the studs. Wood shingles or
shakes may be applied over fiberboard shingle backer and sheathing with
annular grooved nails. The thickness of wood shingles or shakes between
wood nailing boards shall be not less than three-eighths inch (3/8").
Wood shingles or shakes and asbestos shingles or siding may be nailed
directly to approved nail-base fireboard sheathing not less than one-half-
inch (1/2") nominal thickness with approved corrosion-resistant annular
grooved nails. Nail-base fiberboard sheathing shall comply with U.B.C.
Standard No. 22-1-67.
19
i
-SECTION 2508. Should any section, clause or provision of this
ordinance be declared by any court of competent jurisdiction to be
unconstitutional, such decision shall not affect any other portions
of this ordinance other than the section, clause or provision so
declared to be unconstitutional.
SECTION 2509. That this ordinance shall repeal the provisions
of the Building Code of the City of Fort Worth which are in conflict
herewith, but only insofar as those provisions of the Building Code
of the City of Fort Worth are in conflict, and as to all other pro-
visions of the Building Code of the City of Fort Worth not in direct
conflict herewith, this ordinance shall be and is hereby made cumu-
lative except as to such provisions of the Building Code as are
expressly repealed hereby.
SECTION 2510. That any person or the agent, servant, or employee
of any person who violates, disobeys, omits, neglects or refuses to
comply with any provision of this ordinance shall be guilty of a
misdemeanor and shall be punished by a fine not to exceed Two Hundred
Dollars ($200.00), and that each day a violation exists is hereby
declared to be a distinct and separate offense.
SECTION 2511. That this ordinance constitutes a revision of
Chapter 25 of the Building Code of the City of Fort Worth as provided
by Section 2, Chapter XXVI of the Charter of the City of Fort Worth, and
the City Secretary is hereby directed to publish this ordinance in
pamphlet form for general distribution among the public, and this
ordinance, as so published in pamphlet form, shall be admissible as
evidence as provided by Section 3 of Chapter XXVI of the Charter of the
City of Fort Worth. That in addition the City Secretary shall cause
the caption hereof and Sections 2508, 2509, 2510, 2511 and 2512 to
be published in the official newspaper of the City of Fort Worth for
5 days.
x.
SECTION 2512. That this ordinance shall become effective and
be in full force and effect from and after its passage and publica-
tion as required by law, and it is so ordained.
APPROVED AS TO FORM AND LEGALITY:
City Attorney
TABLE NO.25-A—ALLOWABLE UNIT STRESSES FOR VISUALLY STRESS-GRADED LUMBER* Y
Normal Loading—See also Section 2504 (d) and (e)
fABBREVIATIONS;J.&P.: Joists and Planks;B.&S.: Beams and Stringers; P.&T.: Posts and Timbers; L.F.: Ligbt Framing; K.D.: Kiln
Dried;S.R.:Stress Rated.
ALLOWABLE UNIT STRESSES,POUNDS PER SQUARE INCH
Extreme Fiber
SPECIES AND COMMERCIAL GRADE in Gentling CompPer Cdnpres• RULES
(and Tendon Maximum Sion Per. lion UNDER
Parallel Harirontal pendicular Parallel Modulus of WHICH
to Grain) Shear to Grain to Grain Elasticity GRADED
SYMBOL.t f(or P) H q E"
DOUGLAS FIR, COAST REGION
Dense Select Structural L.F. 2050 12023-5 455 1500
Select Structural L.F. 1900 12023-5 415 1400
1750f:Industrial L.F. 1750 120 455 1400
1500f:Industrial L.F. 1500 120 390 1200
1200f.-Industrial L.F. 1200 95 390 1000
Dense Select Structural J.&P. 2050 12023-5 455 1650
Select Structural J.&P. 1900 12023s 415 1500
Dense Construction J.&P. 1750 12024-5 455 1400
Construction J.&P. 1500 120245 390 1200 (All) U.B.C.
Standard J.&P. 1200 952-1s 390 1000 1,600,000 Standard
Dense Select Structural B.&S. 2050 1207 455 1500 No.25-3-67
Select Structural B.&S. 1900 1207 415 1400
Dense Construction B.&S. 1750 1207 455 1200
Construction B.&S. 1500 1207 390 1000
Dense Select Structural P.&T. 1900 1207 455 1650
Select Structural P.&T. 1750 1207 415 1500
Dense Construction P.&T. 1500 1207 455 1400
Construction P.&T. 1200 1207 390 1200
HEMLOCK, WEST COAST
Select Structural L.F. 1600 10023-9 365 1100
1500f.Industrial L.F. 1500 100 365 1000
1200f.Industrial L.F. 1200 80 365 900 U.B.C.
Select Structural J.&P. 1600 100233 365 1200 (All)
Construction J.&P. 1500 100233 365 1100 1,400,000 Standard
Standard J.&P. 1200 802-8-9 365 1000 No.25-3-67
Construction B.&S. 1500 10010 365 1000
Construction P.&T. 1200 10010 365 1100
DOUGLAS FIR,COAST REGION U.B.C.
Select Dex Decking 1500 — 390 — 1,600,000 Standard
Commercial Des Decking 1200 — 390 — 1,000,000 No.25-3-67
HEMLOCK,WEST COAST U.B.C.
Select Dex Decking 1300 — 365 — 1,400,000 Standard
Commercial Dex Decking 1060 — 365 — 1,400,000 No.25-3-67
SPRUCE,SITKA U.B.C.
Select Dex Decking 1100 — 305 — 1,200,000 Standard
Commercial Dex Decking 850 — 305 — 1,200,000 No.25-3-67
CEDAR, INCENSE U.B.C.
Select Dex Decking 1100 — 305 — 900,000 Standard
Commercial Dex Decking 850 — 305 — 900,000 No.25-3-67
CEDAR,WESTERN RED
U.S.C.
Select Dex Decking 900 — 240 — 1,000,000 Standard
Commercial Dex Decking 700 — 240 — 1,000,000 No.25-3-67
FIR,WHITE U.B.C.
Select Dex Decking 1100 — 365 — 1,100,000 Standard
Commercial Dex Decking 850 — 365 — 1,100,000 No.25-3-67
DOUGLAS FIR AND LARCH"
Dense Select Structural MC15** L.F.Le 2300 13523-5 455 1700
Dense Select Structural DRY* L.F. 2150 130 455 1500
Select Structural MC15 L.F.Io 2100 13523-5 415 1550
Dense Select Structural L.F. 2050 12023s 455 1500
Select Structural DRY L.F. 1950 130 415 1400
Select Structaral L.F. 1900 12023-5 415 1400
1750f.Industrial MC15 L.F. 2050 135 455 16W U.B.C.
1750f.Industrial DRY L.F. 1850 130 455 1450 1600,000 Standard
1750f.Industrial L.F. 1750 120 455 1400No.25-4-67
1500f.Industrial MC15 L.F.Ia 1750 135 390 1400
1500f.Industrial DRY L.F. 1600 130 390 1200
1500f.Indstrial LF. 1500 120 390 1200
1200f.Industrial MC15 L.F.Ie 1500 110 390 1200
1200f.Industrial DRY L.F. 1350 115 390 1050
1200f.Industrial L.F. 1200 95 390 1000
Dense Select Structural MC15 J.&P.16 2300 13523-5 455 1850
DOUGLAS FIR AND LARCHI7
Dense Select Structural DRY J.&P. 2150 130 455 1750
Select Structural MC15 J.&P.16 2100 13523.5 415 1650
Dense Select Structural J.&P. 2050 12023-5 455 1650
Dense Construction MC15 J.&P.15 2050 1352-4-5 455 1600
Select Structural DRY J.&P. 2000 130 415 1600
Select Structural J.&P. 1900 12023.5 415 1500
Dense Construction DRY J.&P. 1850 130 455 1450
Dense Construction J.&P. 1750 1202 15 455 1400
Construction MC15 J.&P.16 1750 1352-4-5 390 1400 U.B.C.
Construction DRY J.&P. 1600 130 390 1200 (All) Standard
Construction J.&P. 1500 12024-5 390 1200 1,600,000 No.25-4-67
Standard MC15 J.&P.16 1500 11024S 390 1200
Standard DRY J.&P. 1350 105 390 1100
Standard J.&P. 1200 952ds 390 1000
Dense Select Structural B.&S. 2050 1207 455 1500
Select Structural B.&S. 1900 1207 415 1400
Dense Construction B.&S. 1750 1207 455 1200
Construction B.&S. 1500 1207 390 1000
Dense Select Structural P.&T. 1900 1207 455 1650
Select Structural P.&T. 1750 1207 415 1500
Dense Construction P.&T. 1500 1207 455 1400
Construction P.&T. 1200 1207 390 1200
20
TABLE NO.25-A—ALLOWABLE UNIT STRESSES FOR VISUALLY STRESS-GRADED LUMBER (Continued] -
ALLOWABLE UNIT STRESSES,POUNDS PER SQUARE INCH
Extreme Fiber
in Bending Compres• Compros- RULES
SPECIES AND COMMERCIAL GRADE (and Tension Maximum sign Per. sign VNBER
Parallel Horizontal pendicular Parallel Modulus of WHICH
to Grain) Shear to Grain to Grain Elasticity GRADED
SYMBOL:t f(or 0) H q c E°
HEMLOCK,WESTERN
Select Structural MC15 L.F.10 1Soo 11523-9 365 1200
Select Structural DRY L.F. 1600 110 365 1100
Select Structural L.F. 1600 10023-9 365 1100
1500f.Industrial MC15 L.P le 1650 115 365 1150
1500f.Industrial DRY L.F. 1550 110 365 1100
1500f.Industrial L.F. 1500 100 365 1000
1200f.Industrial MC15 L.F.16 1450 90 365 1050
1200f.Industrial DRY L.F. 1300 100 365 900
1200f.Industrial L.F. 1200 80 365 900
Select Structural MC15 J.&P.lo 1800 11523-9 365 J 1300 (All) U.B.C.
Select Structural DRY J.&P. 1650 110 365 1250 1,400,000 Standard
Select Structural J.&P. 1600 10023.9 365 1200 No.25-4-67
Construction MC15 J.&P.lo 1650 1152.9-9 365 1250
Construction DRY J.&P. 1550 110 365 1150
Construction J.&P. 1500 100L-b-9 365 1100
Standard MC15 J.&P.16 1450 90L-d-9 365 1150
Standard DRY J.&P. 1300 85 365 1000
Standard J.&P. 1200 802-8-9 365 1000
Construction B.&S. 1500 10010 365 1000
Construction P.&T. 1200 10010 365 1100
DOUGLAS FIR AND LARCH U.B.C.
Selected Decking Decking 1500 — 390 — 1,600,000 Standard
Commercial Decking Decking 1200 — 390 — 1,600,000 No.25-4-87
WHITE FIR U.B.C.
Selected Decking Decking 1100 — 365 — 1,100,000 Standard
Commercial Decking Decking 850 — 365 — 1,100,000 No.25-4-67
PINE, NORWAY
Prime Structural J.&P.15,16 1200 75 360 900 1200,000 U.B.C.
Common Structural J.&P.15.16 1100 75 360 775 1:200,000 Standard
Utility Structural J.&P.15,le 950 75 360 650 1,200,000 No.25-5-67
PINE(1DAHO WHITE,LODGEPOLE,
PONDEROSA AND SUGAR) U.B.C.
Selected Decking Decking 900 — 305 — 1,000,000 Standard
Commercial Decking Decking 700 — 305 — 1,000,000 No.25-4-67
CEDAR,INCENSE AND WESTERN RED U.B.C.
Selected Decking Decking 900 — 240 — 1,000,000 Standard
Commercial Decking Decking 700 — 240 — 1,000,000 No.25-4-67
SPRUCE, ENGELMANN U.B.C.
Selected Decking Decking 750 — 215 — 1,000,000 Standard
Commercial Decking Decking 600 — 215 — 1,000,000 No.254-67
HEMLOCK,WESTERN U.B.C.
Selected Decking Decking 1300 — 365 — 1,400,000 Standard
Commercial Decking Decking 1000 — 365 — 1,400,000 No.25-4-67
HEMLOCK,EASTERN
Select Structural J.&P 15-B.&S.15 1300 85 360 850
Prime Structural J.&P.15-16 1200 60 360 775 U.B.C.
Common Structural J.&P,15-1e 1100 60 360 650 (All) Standard
Utility Structural J.&P15-16 950 60 360 600 1,100,000 No.255-67
Select Structural P.&T. — — 360 850
PINE,SOUTHERN
Select Decking 1500 105 390 1250 (All) U.B.C.
Select No.1 Decking 1200 105 390 900 1,600,000 Standard
No.2 Decking 1200 105 390 900 No.25-8-67
PINE,SOUTHERN"
Dense Structural 86 KDIS-14 2"thick only 3000 165 455 2250
Dense Stnlctural 72 KD13-14 2500 150 455 1950
Dense StEuctura165 KD13-14 2250 135 455 1800
Dense Structural 58 KD13-14 2050 120 455 1650 (All) U.B.C.
Standard
No.1 Dense KDIa-14 2050 135 455 1750 1,600,000
No.25-6 67
No.1 KD13 1750 135 390 1500
No.2 Dense KD13-14 1750 120 455 1300
No.2 KD13 1500 120 390 1100
PINE, SOUTHERN"
Dense Structural8614 2"thick only 2900 150 455 2200
Dense Structural 7214 2350 135 455 1800
Dense Structural 6514 2050 120 455 1600
Dense Structural 5814 1750 105 455 1450
No.1 Dense14 1750 120 455 1550
No.1 1500 120 390 1350
No.2 Dense14 1400 105 455 1050
No.2 1200 105 390 900
Dense Structural 8614 3"and 4"thick 2900 150 455 2200
Dense Structural 7214 2350 135 455 1800
Dense Slltretural 6514 2050 120 455 1600 U.B.C.
Dense Structural 5814 1750 105 455 1450 (All) Standard
No.1 Dense SR14 1750 120 455 1750 1,600,000 No.25-6-67
No.1 SR 1500 120 390 1500
No.2 Dense SR14 1400 105 455 1050
No.2 SR 1200 105 390 900
Dense Structural 8614 5"thick and upl 240012 150 455 1800
Dense Structural 7219 200012 135 455 1550
Dense Structural 6514 ! 180012 120 455 1400
Dense Structural 5814 160012 105 455 1300
No.1 Dense SR14 160012 120 455 1500
No.1 SR 1400. 120 390 1300
No.2 Dense SR14 140012 105 455 1050
No.2 SR 120012 105 390 900
21
TABLE NO.25-A—ALLOWABLE UNIT STRESSES FOR VISUALLY STRESS-GRADED LUMBER (Continuer])
ALLOWABLE UNIT STRESSES,POUNDS PER SQUARE INCH
Extreme Fiber
in Bending Campres- Campres- RULES
SPECIES AND COMMERCIAL GRADE (and Tension Maximun Per- lion UNDER
Parallel Narimntm sig I pendicular Parallel Modulus of WHICH
to Grain) Shear to Grain to Grain Elasticity GRADED
SYMBOL:# f(or f') H q c E"
PINE, SOUTHERN"
Industrial 86 KD13 1",I Y4"and 2600 [165 390 1950
Industrial 72 KD13 11z"thick 2200 0 390 1650
Industrial 65 KD13 2000 5 390 1550
Industrial 58 KD13 1750 0 390 1400 U.B.C.
Industrial50KD13 1500 0 390 1100 (All) Standard
Industrial86 1",1'A"and 2500 0 390 1900 1,600,000 No.25-6-67
Industrial72 1%,,thick 20�O 135 390 1550
Industrial65 1750 120 390 1350
Industrial58 1500 105 390 1250
Industrial50 1200 105 390 900
SPRUCE, EASTERN
1450f.Structural Grade J.&P.15 1450 110 300 1050 (All) U.B.C.
1300f.Structural Grade J.&P.15 1300 95 300 975 1,200,000 Standard
1200f.Structural Grade J.&P.15 1200 95 300 900 No.25-8-67
REDWOOD
Dense Structural J.&P.15-B.&5.15 1700 110 320 1450 (All) U.B.C.
Heart Structural J.&P.15-B.&5.15 1300 95 320 1100 1,200,000 Standard
Dense Structural P.&T. — — 320 1450 No.25-7-67
Heart Structural P.&T. — — 320 1100
SPRUCE
(White and Western U.B.C.
Standard
White) No.
Selected Decking Decking 1100 — 305 1,200,000 25-4-671s
Commercial Decking Decking 850 — 305 — 1,200,000
EXPLANATORY NOTES—TABLE NO. 25-A
'In tension members the slope of grain limitations ap- 'The value of"E"may be increased 10 per cent where
plicable to the middle portion of the length of the the lumber is surface seasoned before being fully
joist and plank and beam and stringer grades used loaded,
shall apply throughout the length of the piece. For +For Beams and Stringers and for Posts and Timbers:
exception see footnote No. 11. H=120 when length of split is equal to one-half the
'Value applies to pieces used as planks. nominal narrow face dimension.
'Value applies to two-inch (2") thick pieces of Select H=100 when length of split is equal to the nominal
Structural Grade used as joists. narrow face dimension.
'For two-inch (2") thick pieces of Construction and H= 80 when length of split is equal to one and one-
Standard Grades used as joists: half times the nominal narrow face dimension.
H=120 when length of split is approximately equal
to one-half the width of piece. NOTE:Values for lengths of split other than those given
H=100 when length of split is approximately equal in Notes 4,5 and 7 are proportionate.
to the width of piece.H= 70 when length of split is approximately equal 'For two-inch (2") thick pieces of Construction and
to one and one-half times width of piece. Standard Grades used as joists:
`For three-inch (3") thick pieces of Select Structural, H=100 when length of split is approximately equal
Construction and Standard Grades used as joists: H
H=120 when length of s lit is approximately two = 80 when length of split is approximately equal
and one-fourth inches (2114"� to H the width piece.
H= 80 when length of split is approximately four = 60 whenn length of split is approximately equal
to one and one-half times width of piece.
and one-half inches (4%"), and
For four-inch (4") thick pieces of Select Structural, 'For three-inch (3") thick pieces of Select Structural,
Construction and Standard Grades used as joists: Construction and Standard Grades used as joists:
H=120 when length of split is approximately three H=100 when length of split is approximately two
inches(W), and one-fourth inches (21/4").
H= 80 when length of split is approximately six H= 70 when length of split is approximately four
inches(8") and one-Lialf inches (4'h") and
For four-inch (4") thick pieces of Select Structural, cated for thicknesses of five inches (5") and up; (b)
Construction and Standard Grades used as joists: the allowable unit stresses for compression parallel to
H=100 when length of split is approximately three grain shall be limited to the stresses indicated for
inches (3") thicknesses of five inches (5") and up reduced by 10
H= 70 when length of split is approximately six per cent; (c) the allowable unit stresses for compres-
inches(W). Sion perpendicular to grain shall be reduced one-third.
"For Beams and Stringers and for Posts and Timbers: 'These stresses apply for loading either on narrow face r
H=100 when length of split is equal to three- or on wide face, which is an exception to U.B.C.
fourths the nominal narrow face dimension. Standard No. 25-6-67.
H= 90 when length of split is equal to the nominal "KD Kiln dried in accordance with the provisions of
narrow face dimension. U.B.C. Standard No. 25-6-67.
H= 70 when length of split is equal to one and one- "Longleaf may be specified by substituting"Longleaf"
half times the nominal narrow face dimension. for `Dense' in the grade name, and when so speci-
NOTE: Values for lengths of splits other than those fied the same allowable stresses shall apply.
given in Notes 8,9 and 10 are proportionate. `The allowable unit stresses for tension parallel to grain
"All stress-grades under U.B.C. Standard No. 25-6-67 "t"and compression parallel to grain c"are applica-
are all-purpose grades and apply to all sizes. Pieces ble when the following additional provisions are ap-
so ggraded may be cut to shorter lengths without im- plied to the grades:
pa14•tiSf eft&the stress rating of the shorter pieces. The sum of the sizes of all knots in any six inches (W)
Grade restrictions provided by U.B.C. Standard No. of the length of the piece shall not exceed twice the
25-6-67 apply to the entire length of the piece, and maximum permissible size of knot.Two knots of maxi-
each piece is suitable for use in continuous spans,over mum permissible size shall not be within the same six
double spans, or under concentrated loads without inches (6") of length of any face.
regrading for special shear or other special stress '"Mese grades applicable to two-inch (2") thickness
requirements, only.
The following variations apply to the provisions of "Working stresses for Douglas Fir (Western Pine Re-
U.B.C. Standard No. 25-6-67 for lumber in service on shall be adjusted in accordance with basic
stresses
under wet conditions or where the moisture content is )
at or above fiber saturation point, as when continu-
ously submerged: (a) the allowable unit stresses in '"Spruce (White and Western White) decking is graded
bending,t!erosion parallel to grain and horizontal shear under the requirements of Section 25.406 of U.B.C.
shall be limited jp all thicknesses to thel�sses_indi- Standard No.25-4-67
—Grades designated as MC-15 are required to have a maximum moisture content of 15 per cent.The modulus of elasticity for such grades
ay be increased 20 per cent,however such increase shall not be cumulative with that specified in footnote No.6.
...Grades designated as DRY are required to have a maximum moisture content of 19 per cent.The modulus of elasticity,"E",for such
grades may be increased 14 per cent,however,mob increase shall not be cumulative with that specified in footnote No.6.
22
yTABLE NO.254--ALLOWABLE•UaIT STRESSES FOR MACHINE STRESS-RATED LUMBER
NORMAL LOADING"
TENSION
AND
CO SIGN COMPRESSION PERPENDICULAR
EXTREME SIGN TO GRAIN(In p.s.i.)
FIBER MDOF 'PARALLEL HORIZDNTAL SHEAR "ff"
IN OF III GRAIN Western
BENDING ELASTICITY "7"AND Douglas Hemlock Pon- Engel- (In p.s.i.)
"P' IV, Fir and and derosa mann Douglas F r Western White Fir and ponderosa Pine
(In p.s.r.) (In p.s.i.) (In p.s.l.) Larch White Fir Pine Spruce and Larch Hemlock Engelmann Spruce
900 1,000,000 725 390 365 310 215 75 65 60 70
1200 1,200,000 950 390 365 310 215 75 65 60 70
1500 1,400,000 1200 390 365 310 215 105 85 80 90
1800 1,600,0001 1450 390 365 310 215 105 85 80 90
2100 1,800,000 1700 415 365 310 215 105 85 80 90
2400 2,000,000 1925 455 365 310 215 105 85 80 90
'For visual grading rules which also apply,see U.B.C.Standard No.25-1-67,Section 25.113.
'The above stresses are for lumber used on edge.When loaded Batwise"/"may be increased 18 per cent.
'The values for compression perpendicular and parallel to the grain are for lumber that will be continuously dry in use as in most covered struc-
tunes.For wet conditions of use reduce the values 33%per cent for compression perpendiculaz to the grain and 10 per cat for compression
parallel to the grain.
TABLE NO. 25-C--ALLOWABLE UNIT STRESSES FOR CONSTRUCTION AND INDUSTRIAL SOFrWODD PLYWOOD
(In Pounds per Square Inch)
(To be used with section properties in Plywood-Design Specification—See U.B.C.Standard No.25-9-67)
EXTERIOR A-B,B-B,B-C,
C-C(PLUGGED)
STRUCTURAL I C-0
(Use Group t Stresses)
STRUCTURAL II C-D
(Use Group 3 Stressesl
STANDARD SHEATHING
EXTERIOR A-A,A-C,C-C' (Exterior Glue)' ALL OTHER GRADES OF
TYPE OF STRESS SPECIES' STRUCTURAL I A-C,C-C ALL INTERIOR GRADES WITH INTERIOR INCLUDING
GROUP (Use Group t Stresses) EXTERIOR GLUE STANDARD SHEATHING'
Extreme fiber in bending
Tension 1 2000 1650 1650
Face grain parallel or perpendicular 2,3 1400 1200 1200
to span 4 1200 1000 1000
(at 45'to face grain use%)
Compression 1 1650 1550 1550
Parallel or perpendicular to face 2,3 1200 1100 1100
grain 4 1000 950 950
(at 45'to face grain use%)
1 340
Bearing(on face) 2,3 220
4 160
Shear jn plane perpendicular to plies3 250 1 250 230
Parallel or perpendicular to face 2 3 250 185 230
gram 4 175 175
(at 45'increase 100 per cent) 160
Shear,tolling in plane of plies,paral-
lel or perpendicular to face grain All 53 53 48
(at 45'increase%)4
Modulus of Elasticity in bending.Face 1 1,800,000
grain parallel or perpendicular to 2 1,500,000
span 3 1,200,000
4 900,000
'See U.B,C.Standard No,25-9-67 for plywood species groups.
'Exterior C-C and Standard Sheathing: The combination of Identification-Index designation and panel thickness determines the minimum
species group and,therefore,the stress permitted,w follows:
5/16-20/0,3/8-24/0,1/2-32/16,5/8-42/20,3/4-48/24—use Group 2 working stresses.
All other combinations—use Group 4 working stresses.
'Shear through the thickness stresses are based on the most common structural applications where the plywood is attached to framing around
its boundary.Where the plywood is attached to framing at only two sides,such as in the heel joint of a truss,reduce the allowable shear
through the thickness values by 11 per cent where framing is parallel to face grain and 25 per cent where it is perpendicular.
4For Structural I and Structural II use 75 pounds per square inch and 56 pounds per square inch respectively.
WET OR DAMP LOCATION:
Where moisture content is 16 per cent or more,decrease the dry location values an follows:All grades of Exterior and Interior plywood with
Exterior.glue:Extreme fiber In bending,25 per cent Tension,31 per cent; Compression,39 pe, centi Bearing,33 per cent; Shear, 16
per cent; Modulus of Elasticity, 11 per cent.For ah other grades of Interior: Extreme fiber in bending, 31 per cent; Tension,31 per
cent;Compression,39 per cent;Bearing,33 per cent; Shear, 16 per cent;Modulus of Elasticity,20 per cent.
23
TABLE NO.25-D—ALLOWABLE UNIT STRESSES—STRUCTURAL GLUED-LAMINATED LARCH,AND WEST COAST HEMLOCK
LUMBER—DRY CONDITIONS OF USE1
Allowable unit stresses are for normal conditions of loading,pounds per square inch.
TENSION COMPRESSION
R SPECIES AND COMMERCIAL EXTREME FIBER PARALLEL PARALLEL TO
GRADE COMBINATION IN BENDING"I" TO GRAIN"t" GRAIN"e" `
as
x„ 1 2 3 4 5 0 7 B 9
amNORIZONTA COMPRESSION
Grade o1 Number Gratle Jr._
15 or From 15 or Fram 15 or SNEAII PERPENDICUTAtions at at Top and of Inner to 74 Moro 4 to 74 More 4 to 14 Mare 'x" TO GRAIN"sill
TOP and Bottom Bottom Laminationo nations Wminations Laminations Laminou ns;Laminations Lamination to 11
LAR H-2" THICKNESS
L-1 D Select One Dense 3000 3000 3000 3000 2400 2400 200 450
(Dense) Construction
L-2 D Select One Select 2600 2600 2600 2600 2200 2200 200 415
Structural
L-3 D Select One Construction 2500 2500 2600 2600 2100 2100 200 390
or Standard
L4 Dense Select Two Construction 2400 2600 3000 3000 2300 2300 200 430
Structural or Standard
L-5 Select All Select 2300 2600 2700 2700 2200 2200 200 415
Structural Structural
L-6 Select One Construction 2200 2400 2700 2700 2200 2200 200 415
Structural or Standard
L-7 Dense 1/14 Construction 22002 2600 2800 2800 2300 2300 200 450
Construction or Standard
L-8 Construction All Construction 19002 2200 2600 2600 2000 2000 200 390
or Standard or Standard
LARCH—I' TIICKNESS
L-9 D Select One No.2 2600 2600 2100 2100 200
Common
L-10 D Select One No.3 or 4 2500 2500 All All 2100 2100 200 All
Common
L-11 CNo on All Common 21002 2400 2600 2600 2100 2100 200 390
L-12 No.2 One No.3 or 4 20002 2200 2000 2000 200
Common Common
L-13 No.3 or 4 All No.3 or 4 17002 2100 2000 2000 200
Common Common
WEST COAST HEMLOCK
1 Clear One Select 2200 2200 2200 2200 1700 1700 140 365
Structural
2 Clear One Construction 2200 2200 2200 2200 1600 1700 140 365
3 Select All Select
Structural Structural 2200 2200 2200 2200 1700 1700 140 365
4 Select One Construction 2000 2200 2000 2200 1600 1700 140 365
Structural
5 Select Two Construction 2000 2200 2200 2200 1700 1700 140 365
Structural
6 Select Two Standard 2000 2200 2200 2200 1600 1600 140 365
Structural
7 Construction All ,onstnlction 1800 2000 2000 2200 1600 1700 140 365
8 Clear One Standard 2000 2000 1800 2000 1500 1600 140 365
9 Select
Structural One Standard 2000 2000 1800 2000 1500 1600 140 365
10 Construction One Standard 1800 2000 1800 2000 1500 1600 140 365
11 Standard All I Standard - 1600 1800 1 1800 2000 1 1500 11600 1 140 1 365
'Modulus of elasticity,"E,"dry conditions of use for larch, 1.800.000;for West Coast Hemlock,1,540,000.
Allowable stress values for dry conditions of we shall be applicable for normal loading when the moisture eontent in service Is less than
18 per cent as in most covered structures.
For wet conditions of toe,the following maximum percentages of Dry Use Stresses shall be permitted:
P(bending)and"t"(tension)80 per cent.
(h"d.2ontal shear) and"NI" (medulus of elasticity) 90 per cent. "H"for all combinations of Larch shall not exceed 165 pounds
r square inch.
•c, orid q" (compression parallel and perpendicular) 71)per cent.
,Values are for combinations having 6-14 laminations.
24
•TABLE NO. 25-E—STRUCTURAL GLUED-LAMINATED DOUGLAS FIR (COAST REGION) TIMPER
PART A—MEMBERS STRESSED PRINCIPALLY IN BENDING—LOADED PERPENDICULAR
TO WIDE FACE OF LAMINATIONS
DRY CONDITIONS OF USE
EXTREME COMPRESSION
FIBER IN TENSION PARALLEL TO GRAIN COMPRESSION PARALLED TO GRAIN HORIZONTAL PERPENDICULAR
COMBI- BENDING SHEAR TO GRAIN
NATION "f" "f" "r"Special' "c" "c"Special'
A 2600 1600 2200 1500 1900 165 450
B 2400 1600 2000 1500 1800 165 450
C 2200 1600 1800 1500 1800 165 450
Modulus of Elasticity"E"Dry Conditions of Use,1,800,000.
WET CONDITIONS OF USE'
A 2000 1300 1800 1100 1400 145 305
B 1800 1300 1600 1100 1300 145 305
C 1600 1300 1400 1100 1300 145 305
Modulus of Elasticity"E"Wet Conditions of Use,1,600,000,
'Allowable unit stresses for normal conditions of loading. Pounds per square inch.
'For the Special values for tension parallel to pain, `t,'sad for compression parallel m graia,"c,"the slope of grain of an laminations in the
member must not be steeper than that urr-ed Ln the outer l0 er cent of 7emin tiona.
TABLE N0. ZS-E (Continued) '
PART B—MEMBERS STRESSED PRINCIPALLY IN AXIAL COMPRESSION, AXIAL TENSION, OR
LOADED PARALLEL OR PERPENDICULAR TO WIDE FACE OF LAMINATIONS
DRY CONDITIONS OF USE'
TENSION PARALLEL TO
GRAIN "t" AND EXTREME HORIZONTAL SHEAR"tf"
FIBER IN BENDING
WHEN LOADED PARALLEL Loaded Loaded COMPRESSION
COMPRESSION PARALLEL
OR PERPENDICULAR Perpendltuiar Parallel to PERPENDICULAR
TO GRAIN TO WIDE FACE OF to Wide Face Wide Face TO GRAIN
COMBINATION c LAMINATIONS of Laminations of Laminations 'c 1"
E 2200 2600 165 145 450
F 2100 2200 165 145 450
G 1800 1800 165 145 385
H 1500 1200 165 145 385
Modulus of Elasticity"E"Dry Conditions of Use,1,800,000.
WET CONDITIONS OF USE' i
E 1600 2000• 145 120 305
F 1500 1800 145 120 305
G 1300 1400 145 120 260
H 1100 950 145 120 260
Modulus of Elasticity"E"Wet Conditions of Use,1,600,000,
4ABbsnble unit Neva for normal conditions of loading.Pounds pa squaw Each.
TABLE NO.25-E (Continued)
PART C—GRADE REQUIREMENTS FOR THE TABULATED ALLOWABLE UNIT STRESSES
MINIMUM GRADE OF LAMINATIONS-
Tap and Bottom Zone Intermediate Zone Inner Zone SLOPE OF GRAIN
Outer Neat Inner
NUMBER OF Grade Number Grade Number Grade 10 per Cent of 10 per Cent of
COMBINATION LAMINATIONS Laminations Laminations
4to8 L1 2 L3 — L3
A 9to20 L1 2 L2 2 L3 1:14 1:12
21 or more L 1 3 L 2 2 L 3
B 4to8 L1 1 L2 1 L3 1:12 1:10
9 or more L 1 1 L 2-D 2 L 3
C 4 or more L 2-D 2 L 3 — L 3 1:12 1:10
E All L 1 1:14 All
F All L 2-D 1:12 All
G All L 2 1:12 All
H All L 3 1:8 All
'See Section 25.312 of U.B.C.Standard No.25-3-67 for the characteristics and limiting provisions of the laminating grades.
N'1ft-
25
TABLE NO. 254-P11IRT A-ALLOWABLE UNIT STRESSES F6R.GLUED'HARDWOOD LAMINATED LUMBER' FOR N09MAL LOAIfING DURAYION-
DRY CONDITIONS OF USE=
MULTIPLY THE APPROPRIATE
STRESS MODULE IN PART B ALLOWABLE UNIT STRESS
BY THE FACTORS BELOW TO (Pounds per Square Inch)
DETERMINE ALLOWABLE
SPECIES STRESS FOR
Extreme Fiber in Compression Horizontal Compression Modulus of
Y Rending" •or Parallel Shear Perpendicular Elasticity
Tension Parallel to to Grain•'q" "E"
to Grain'•t" Grain"c"
Hickory,true and pecan 3,90 3.05 260 730 2,000,000
Beech,American 3.05 2.45 230 610 1,800,000
Birch,sweet and yellow 3.05 2.45 230 610 1,800,000
Elm,rock 3.05 2.45 230 610 1,400,000
Maple,black and sugar(hard maple) 3.05 2A5 230 610 1,800,000
Ash,commercial white 2.85 2.20 230 610 1,600,000
Oak,commercial red and white 2.85 2.05 230 610 1,600,000
Elm,American and slippery(white or soft elm) 2.20 1.60 190 310 1,300,000
Sweet gum(red or sap gum) 2.20 1.60 190 370 1,300,000
Tupelo,black(black gum) 2.20 1.60 190 370 1,300,000
Tupelo,water 2.20 1.60 190 370 1,300,000
Ash,black 2.00 1.30 170 370 1,200,000
Poplar,yellow 1.80 1.45 150 270 1,200,000
Cottonwood,Eastern 1.55 1.20 110 180 1,100,000
TABLE NO. 25•F-PART B-VALUES FOR USE IN COMPUTING WORKING STRESSES WITH FACTORS OF PART A
TOGETHER WITH LIMITATIONS REQUIRED TO PERMIT THE USE OF SUCH STRESSES'
RAT 110 OF
SIZE OF EXTREME FIBER IN BENDING TENSION PARALLEL TO GRAIN COMPRESSION
MAXIMUM PARALLEL TO GRAIN
PERMITTED NUMBER OF
KNOT TO LAMINATIONS - --
FINISHED Stress Steepest Steepest Stress Steepest Steepest Stress Steepest
WIDTH IO Module Grain Slope Sdarf Slope Module Grain siope Scarf Slope Module Grain Slope
LAMINATION'
0.1 4to 14 800 1:16 1:10 800 1:16 1:10 970 1:15
,1 15 or more 800 1.16 1:10 800 1:16 1:10 980 1:15
.2 4to 14 800 1:16 1:10 800 1:16 1:10 930 1:15
.2 15 or more 800 1:16 1:10 800 1:16 1:10 950 1:15
.3 4to 14 670 1:12 1:8 800 1:16 1:10 870 1:15
.3 15 or more 770 1:16 1:10 800 1:16 1:10 900 1:15
.4 4 to 14 520 1:8 1:5 640 1:12 1:8 810 1:12
.4 15 or more 660 1:12 1:8 750 1:15 1:8 860 1:14
.5 4to 14 390 1:8 1:5 480 1:8 1:5 730 1:10
.5 15 or more 550 1:10 1:15 630 1:12 1:8 800 1:12
'The allowable unit stresses in bending obtained from Table No.25-F apply when the wide faces of the lamination are
normal to the direction of the load.
'Allowable stresses for dry conditions of use shall be applicable when the moisture content in service is 16 per cent or less
as in most covered structures.For wet conditions of use the following maximum percentage of the dry use stresses shall
be permitted:
'f' (bending)and"t"(tension)80 per cent
"H" (horizontal shear) and"E" (modulus of elasticity) 90 per cent
"c' (compression parallel to grain)70 per cent
"q" (compression perpendicular to grain)67 per cent
'For modification of allowable unit stresses for structural glued-laminated lumber see Section 2504.
'Factors for knot sizes of 0.1 and 0.2 are identical in case of extreme fiber in bending and in tension parallel to grain because
a slope of grain of 1:16 is a greater limitation than knot size.The smaller knot size may be specified for reasons other than
strength.
• TABLE NO. 25•G-STRUCTURAL GLUED-LAMINATED CALIFORNIA REDWOOD TIMBER
PART A-MEMBERS STRESSED PRINCIPALLY IN BENDING-LOADED PERPENDICULAR TO r
WIDE FACE OF LAMINATIONS'
DRY CONDITIONS OF USP
EXTREME TENSION PARALLEL COMPRESSION HORIZONTAL COMPRESSION
FIRER IN To GRAIN PARALLEL TO GRAIN SNEAK PERPENDICULAR
COMBINATION -. - TO GRAIN
BENDING - ^H"
A 2200 20003 2200 125 325
B 2200 20003 2000 125 325
C 2200 2000 2000 125 325
Modulus of Elasticity"E"Dry Conditions of Use,1,300,000.
WET CONDITIONS OF USE'
A 1800 16003 1600 1105
B 1800 16003 1500 110 215
C 1800 1600 1500 110 215
Modulus of Elasticity"E"Wet Conditions of Use,1,200,000.
'When a load that produces bending stress is parallel to the wide faces for members of combinations A,B,and C in Part A,the allowable
brade
in ending
mstress and ember. Theo llowable ,ion narbending el to grain tress,value horizontal shear,andmP�pre sum weighted average
gtofor
grainthe
alue�forfeach grade are ieces of each
re those
hown in Part B. a ' an
'Allow.ble unit tresses are for normal conditions of loading,pounds per square inch.
'If slope of grain in all laminations r o steeper than one in 20,the tension stress of combinations A and B can be increased to 2200
pounds per square inch for dry rnnditions of nae,and 1800 pounds per square inch for wet conditions of use.
26
TABLE NO. 25-G-(Continued)
PART B—MEMBERS STRESSED PRINCIPALLY IN AXIAL COMPRESSION, AXIAL TENSION, OR LOADED IN
BENDING PARALLEL AND PERPENDICULAR TO WIDE FACE OF LAMINATIONS
DRY CONDITIONS OF USE'
EXTREME FIBER IN EXTREME FIBER IN HORIZONTAL SHEAR
COMPRESSION TENSION BENDING"/"WHEN BENDING"f"WHEN "H"WHEN COMPRESSION
COMBINATION PARALLEL PARALLEL LOADED PERPEN- LOADED PARALLEL LOADED PERPENDIC• PERPENDICULAR
TO GRAIN TO GRAIN DICULAR TO WIDE TO WIDE FACE ULAR TO WIDE FACE TO GRAIN
FACE OF LAMINATION OF LAMINATION OF LAMINATION
..c,. „f.. ..1.. ..1., ..H., ..c 1..
D 2200 2200 2200 2200 125 325
E 2000 2000 2000 1400 125 325
F 1800 1800 1400 1000 I25 325
Modulus of Elasticity"E"Dry Conditions of Use,1,300,ODO.
WET CONDITIONS OF USE'
D 1600 1800 1800 1800 110 215
E 1500 1600 1600 1100 110 215
F 1300 1500 1100 800 110 215
Modulus of Elasticity"E"Wet Conditions of Use,1,200,000.
'Allowable unit stresses are for normal condition of loading,pounds per square inch,
PART C--GRADE REQUIREMENTS FOR TABULATED ALLOWABLE UNIT STRESSES
MINIMUM GRADE OF LAMINATIONS SLOPE OF GRAIN
COMBINATION NUMBER OF Top and Bottom _ Inner Outer 10 Per Cent Remainder
LAMINATIONS Grade Number Grade of Laminations of Laminations
A 4ormore L1orL2 — L1orL2 1:20 1:15
A—All Heart 4 or more L 1 — L 1 1:20 1:15
B 4ormore L1orL2 1 L3 1:20 1:15
B—All Heart 4 or more L 1 1 L 3 1:20 1:15
C 4ormore L1orL2 2 L4orL5 1:20 1:15
C—All Heart 4 or more L 1 2 L 4 1:20 1:15
D ALL L 1 or L 2 — L I or L 2 1:20 ALL
D—All Heart ALL L 1 — L 1 1:20 ALL
E—All Heart ALL L 3 — L 3 1:15 ALL
F ALL L4orL5 — L4orL5 1:15 ALL
F—All Heart ALL L 4 — L 4 1:15 ALL
TABLE NO. 25-H—STRUCTURAL GLUED-LAMINATED SOUTHERN PINE TIMBER
PART A—ALLOWABLE UNIT STRESSES'
Dry Conditions of Use
TENSION COMPRESSION COMPRESSION
COMBINATION NUMBER EXTREME FIBER PARALLEL PARALLEL HORIZONTAL PERPENDICULAR
NUMBER OF IN BENDING TO GRAIN TO GRAIN SHEAR TO GRAIN
LAMINATIONS "/" "I'll "c"Q "H" "q"
1 9 or mores 2600 385
2 14 or 21 2600 450
A 3 22 or more 2600 2600 450
4 13 or more 2400 2000 450
1 4 or more 2600 385
2 12 or more 2600 450
B 3 25 or more 2400 2600 385
4 9 or more 2400 200 385
1 6 or more4 2400 1900 450
C 2 14 or more 2200 2600 2000 385
3 18 or more 2400 1900 385
D 1 10 or more9 2000 2400 1900
2 10 or more 2200
385
E 1 4 or more 1800 2200 1900
2 12 or more 1800
Modulus of Elasticity"E"Dry Conditions of Use—1,800,000
27
TABLE NO. 25-H—STRUCTURAL GLUED-LAMINATED SOUTHERN PINE TIMBER—Continued
PART A—ALLOWABLE UNIT STRESSES'
Wet Conditions of Use
TENSION COMPRESSION COMPRESSION
COMBINATION NUMBER EXTREME FIBER PARALLEL PARALLEL HORIZONTAL PERPENDICULAR
NUMBER OF IN BENDING TO GRAIN TO GRAIN SHEAR TO GRAIN
LAMINATIONS "/" "f"' "c"' "H" "q"
1 9 or mores 2000 1500 260
A 2 14 to 21 2000 1400 300
3 22 or more 2000 1400 300
4 13 or more 2100 2000 1400 300
1 4 or more 1900 260
B 2 12 or more 2000 300
3 25 or more 1900 260
4 9 or more 1900 1400 175 260
1 6 or more' 1800 1800 300
C 2 14 or more 1800 2000 260
3 18 or more 1700 1800 260
D 1 10 or more' 1600 2000
2 10 or more 1600 1800
260
E 1 4 or more 1400 1800 1400
2 12 or more 1300
Modulus of Elasticity"E"Wet Conditions of Use—1,600,000
'Allowable unit stresses for normal conditions of loading,pounds per square mch.
'Where slope of grain is limited to that required for bending members,the allowable unit stresses in tension and compression parallel to grain
shall not exceed the following:
Dry Conditions of Use Wet Conditions of Use
Tension parallel al grain 100 1300
Compression parallel to grain 1500 1100
'For fewer than nine laminations add one No.1 lamination to each outer zone.
'Where fewer laminations are required a combination with a higher allowable stress can be selected.
TABLE NO. 25-H—STRUCTURAL GLUED-LAMINATED SOUTHERN PINE TIMBER—Continued
PART "RADE REQUIREMENTS FOR THE TABULATED ALLOWABLE UNIT STRESSES
Dry Conditions of Use
COMPRES.
BENDING MEMBERS TENSION SIGN
MEMBERS MEBERS
NUMBER GRADE OF LAMINATIONS' Slope al Grain STEEPEST STEEPEST
COMBINATION OF Outer Intermediate Inner Outer 10 Next 10 I GRAIN GRAIN
NUMBER LAMINATIONS Zone Zone Zone Per Cent Per Cent Balance SLOPE SLOPE
1 9 or more 2 No.1 No.2 No.2 1:18 1:18
A 2 14 to 21 2 No.2 Dense No.2 No.2 1:14 1:18
3 22 or more 1 No.2 Dense No.2 No.2 1:14 1:18
4 13 or more 2 No.1 Dense 4 No.2 No.3 1:14 1:12 1:16 1:15
1 4 or more 1 No.1 No.2 No.2 1:16 I 1:18
B 2 12 or more 1 No.2 Dense No.2 No.2 1:12 1:18
3 25ormore No.2 No.2 No.2 1:16 1:18
4 9 or more 1 No.1 3 No.2 No.3 1:16 1:8 1:16
1 6 or more 1 No.2 Dense No.2 No.2 1:12 1:16 1:14
C 2 14 or more No.2 No.2 No.2 1:14 1:10 1:18 1:15
3 18 or more 1 No.1 1 No.2 No.3 1:14 1:16 1 1:14
D 1 10ormore No.2 No.2 No.2 1.12 1:16 1:14
2 2 No.2 No.3 No.3 1:8 1:14
1 4 or more No.2 No.2 No.2 1:14
E 2 12 or more 1 No.2 No.3 No.3 1:10 1:14 1:12
'No.3 refers to medium grain boards and to No.3 MC dimension.
PART B--GRADE REQUIREMENTS FOR THE TABULATED ALLOWABLE UNIT STRESSES
Wet Conditions of Use
COMPRES-
TENSION SION
BENDING MEMBERS EMBERS MEMBERS
NUMBER GRADE OF LAMINATIONS' Slope of Grain TEE PEST STEEPEST
COMBINATION OF Outer Intermediate Inner Outer 10 Next fO GRAIN GRAIN
NUMBER LAMINATIONS Zane Zone Zone Per Cent Per Cent Balance SLOPE SLOPE
1 9 or more 2 No.1 No.2 No.2 1:18
A 2 14 to 21 2 No.2 Dense No.2 No.2 1:14
3 22 or more 1 No.2 Dense No.2 No.2 1:14
4 13 or more 2 No.1 Dense 4 No.2 No.3 1:15
1 4 or more 1 No.1 No.2 No.2 1:16 1:12 1:18
B 2 12 or more 1 No.2 Dense No.2 No.2 1:12
3 25 or more No.2 No.2 No.2 1:16 1:15
4 9 or more 1 No.1 3 No.2 No.3 1:16
1 6 or more 1 No.2 Dense No.2 No.2 1:12 1.8 1:14
C 2 14 or more No.2 No.2 No.2 1:14 1:10 1:18
3 18 or more 1 No.1 1 No.2 No.3 1:16 1:14
1 10 or more No.2 No.2 No.2 2 1:18
D 2 10 or more 2 No.2 No.3 No.3 1:12 1:14
1 4 or more No.2 No.2 No. 1:15
E 2 12 or more 1 No.2 No.3 No.3 1:10 1:8 1:14 1:12
28
TABLE NO. 25-I—GROUP CLASSIFIBATION—NONSTRESS-GRADED LUMBER
UNIFORM
• BUILDING
SPECIES MINIMUM CODE '
GRADE STANDARD
NUMBER
GROUP I
Douglas Fir(Coast Region)1 Construction 25-3-67
'onglas Fir1 Construction 25 4-87
Larch,Western' Construction 25-4-67
Pine,Southern' No.3 MCKD 25-6-67
GROUP 11
Bald Cypress(Tidewater
Red Cypress) No.2 25-2-67
Fir,White Construction 25-3-67
25-4-67
Hemlock,Eastern No.1 25-5-67
Hemlock,West Coast' Construction 25-3-67
Hemlock,Western' Construction 25-4-67
Pine,Red(Norway Pine) No.1 25-5-67
Pine,Southern Special 25-6-67
Redwood,California Select Heart 25-7-67
Spruce,Eastern No.1 25-8-67
Spruce,Sitka Construction 25-3-67
Spruce,White and Western White Construction 25-4-672
GROUP III
Cedar,Western Construction 25 3-67
Cedar,Western Red and Incense Construction 25-4-67
Douglas Fir(Coast Region)I Standard 25-3-67
Douglas Fir' Standard 25-4-67
Fir,Balsam No.1 25-8-67
Fir,White Standard 25-3-67
25-4-67
Hemlock,Eastern No.2 25-5-67
Hemlock,West Coast' Standard 25-3-67
Hemlock,Western' Standard 254-67
Larch,Western' Standard 25-4-67
Pine,Ponderosa,Lodgepole,
Sugar,Idaho White Construction 25-4-67
Pine,Southern No.3 MCKD 25-6-67
Pine,Southem' No.3 25-6-67
Redwood,California Sap Common 25-7-67
Redwood,California(studs only) Two Star 25-7-67
Spruce,Engelmann Construction 25-4-67
Spruce,Sitka Standard 25-3-67
Spruce,White and Western White I Standard 25-4-672
GROUP IV [See Section 2504 (b) para.51
Cedar,Western Utility 25-3-67
Cedar,Western Red and Incense Utility 25-4-67
Douglas Fir(Coast Region) Utility 25-3-67
Douglas Fir Utility 25-4-67
Fir,White Utility 253-67
125-4-67
Hemlock,West Coast Utility 25-3-67
Hemlock,Western Utility 25-4-67
Larch,Western Utility 25-4-67
Pine,Ponderosa,Lodgepole,
Sugar,Idaho White. Utility 25-4-67
Pine,Southern No.3 25-6-67
Redwood,California Merchantable 25-7-67
Redwood,California(studs only) One Star 25-7-67
Spruce,Engelmann Utility 25-4-67
Spruce,Sitka Utility 25-3-67
Spruce,White and Western White Utility 25-4-672
'Two-inch by four-inch(2"x 4.)only.
'Spruce (White and Western White)shell he graded under the require-
ments of Section 25.409 of U.B.C. Standard No. 25-4-67.
TABLE NO. 254—HOLDING POWER OF BOLTS
Loads Parallel to Grain(p)
In Double Shear in Douglas Fir(Coast Region),
Douglas Fir,Larch Southern Pine
(See U.B.C.Standard No.25-17-67 for values in other species.)
LENGTH OF
BOLT IN MAIN DIAMETER OF BOLT(Inches)
MEMBER' % / 1 I% I%
(Inches)
1% 1010 1290 1550 1810 2070
2% 1280 1890 2430 2900 3340
3% 1290 2010 2860 3680 4430
41A 1290 2010 2890 3920 4980 5980
5% 2010 2890 3940 5120 6440
61/2 2010 2890 3940 5140 6500
73h 2010 2890 3940 5140 6500
91A 2890 3940 5140 6500 8040
11% 1 5140 6500 8040
'This assumes dressed sae lumber.Safe loads for other lengths of bolt in
main member may be obtained by mterpolaton.
TABLE NO.25-K—HOLDING POWER OF BOLTS
Loads Perpendicular to Grain(q)
In Double Shear in Douglas Fir(Coast Region),
Douglas Fr,Larch.Southern Pine
(See U.B.C.Standard Me.25.11.67 for values in other species.)
LENQTN OF DIAMETER OF BOLT(Inches)
BOLT IN MAIN
MEMBER' � % / Y I 1% I%
(Inches)
1% 480 540 600 670 730
2% 780 880 980 1080 1170
3% 1020 1210 1350 1490 1620
4% 1020 1440 1680 1840 2010 2190
5% 1450 1940 2250 2460 '2680
6'A 1390 1940 2510 2880 3170
7% 1300 1880 2500 3130 3610
9% 1690 2350 3050 3830 4590
11% 2850 3660 4490
'This assumes dressed sae lumber.Safe loads for other lengths of bolt in
main member may be obtained by interpolation.
99
TABLE NO. 25-L—SAFE LATERAL STREN&H AND REQUIRED
PENETRATION OF COMMON WIRE NAILS'
DRIVEN PERPENDICULAW TO GRAIN OF WOOD
LOADS(Pounds)2
SIZE STANDARD PENETRATION Douglas Fir
OF LENGTH WIRE REQUIRED Larch or Other
NAIL (Inches) GAUGE (Inches) Southern Pint Species
6d 2 11'/2 1'/4 63
8d 23A 10'/4 1'/2 78
10d 3 9 15/8 94
12d 31/4 9 1% 94 See
16d 3'/2 8 1 s4 107 U.S.C.
20d 4 6 2b6 139 Standard
30d 4% 5 2% 154 No.
40d 5 4 2'/2 176 25-17-67
50d 5',z 3 2% 202
60d 6 2 27/s 223
'The lateral strength values of box wire nails shall not exceed 75 per cent
of the values for common wire nails.The safe lateral strength values
may be increased 25 per cent where metal side plates are used.
'For wood diaphragm calculations these values may be increased 30 per
cent.(See U.B.C.Standard No.25-17-67.)
TABLE NO. 25-M—SAFE RESISTANCE TO WITHDRAWAL
OF COMMON WIRE NAILS
Inserted Perpendicular to Grain of the Wood,in Pounds per Linear Inch
of Penetration into the Main Member
KIND OF WOOD SIZE OF NAIL
id ed 100 12d 16d 20tl 30d 4od Sod 80tl
Douglas Fir,Larch a
or Southern Pine 33 39 44 44 48 57 61 67 72 78
Other Species See U.B.C.Standard No.25-17-67
TABLE NO.25-N—NUMBER OF NAILS FOR CONNECTING
WOOD MEMBERS
Groups I and 1 Occupancies
CONNECTION BOX OR COMMON
joist to sill or girder—toe nail 2-16d
Bridging to joist—toe nail 2-8d
1 x 6 sub600r to joist—face nail 2- 8d
2-inch subHoor to joist or girder 2-16d
Plate to joist or blocking 16d-16"o.c.
Stud to plate—end nail 2-16d
Stud to plate—toenail 3-16d or 4-8d
Top plates spike to
16d-24"o.c.
—laps and intersections 2-16d
Ceiling joists—to plate—toenail 2-16d
—laps over partitions 3-16d
—to parallel alternate rafters 3-16d
Rafter to plate 3-16d
Continuous 1-inch brace to stud 2- 8d
2-inch cut-in bracing to stud 2-16d
1-inch sheathing to bearing 2- 8d
Comer studs and angles 16d-30"o.c.
Plywood roof or floor sheathing See Section
2508(f)4
TABLE NO. 25.0—MAXIMUM DIAPHRAGM DIMENSION RATIOS
HORIZONTAL VERTICAL
DIAPHRAGMS DIAPHRAGMS
Maximum Maximum
Span-Width Helgght-Width
Ratios Ratios
1. Diagonal sheathing,conventional 3:1. 2:1
2. Diagonal sheathing,special 4:1 3'/%:1
3. Plywood,nailed all edges 4:1 3%:1
4. Plywood,blocking omitted at 4:1 2:1
intermediate joints
TABLE NO. 25-P—ALLOWABLE SHEAR FOR WIND OR SEISMIC FORCES
IN POUNDS PER FOOT FOR HORIZONTAL PLYWOOD DIAPHRAGMS'
UNBLOCKED DIAPHRAGMS
BLOCKED DIAPHRAGMS Nails Spaced 6"Maximum at
Nail Spacing at Diaphragm Boundaries Supported Edges
(AII Cases)and continuous Panel Edges Load Perpen-
MINIMUM MINIMUM Parallel to Load(Cases 3 and 4)r dicular to
NAIL MINIMUM NOMINAL B 2j 1 _ Z Unblocked
PENETRA. NOMINAL WIDTH OF Nail S Spacing at Other Plywood Panel Edges and All Other
COMMON TION IN PLYWOOD FRAMING p g Ed es Continuous Configurations
NAIL FRAMING THICKNESS MEMBER g __ Panel Joints (Cases 2,3
PLYWOOD GRADE SIZE (Inches) (Inches) llaches) 6 6 4 3 (Case 1) and d)
2 188 250 375 420 167 125
6d 1'/4 #s 3 210 280 420 475 187 140
STRUCTURAL 1 8d 1'/2 % 2 300 400 600 675 267 200
3 300 400 600 675 207 200
„ 2 318 425 640 730 283 212
�%10d I% 3 360 480 720 820 320 240
30
TABLE N0,25-P—Coptinued
'2 125 167 250 280 ill 84
3 140 187 280 317 125 93
STRUCTURAL II, ,
C-C Exterior, 6d 11/i 2 150 201 300 336 133 101
Standard Sheathing and 3 168 224 336 380 150 112
Other grades covered in
U.B.C. Standard % 2 180 240 353 400 160 120
No.25-9-67 3 200 267 400 450 178 133
Sd 1'/a 2 215 288 424 480 192 144
1/23 240 320 480 540 214 160
lOd is % 2 255 340 512 584 227 169
3 288 384 576 656 256 192
'These values are for short time loads due to wind or earthquake and most be reduced 25 per cent for normal loading.
,pace nails at twelve inches(12")on center along intermediate framing members.
LOAD CASE I FRAMING CASE Z BLOCKING IF USED CASE 3 LOAD CASE 4
DIAPHRAGM BOUNDARY CONTINUOUS PANEL JOINTS—
TABLE NO. 25-Q—ALLOWABLE SHEAR FOR WIND OR SEISMIC FORCES IN POUNDS PER FOOT FOR PLYWOOD SHEAR WALLS'
MINIMUM MINIMUM PLYWOOD APPLIED OVER'/a-INCH
NAIL SIZE NAIL PENE- NOMINAL pLYW000 APPLIED DIRECT TO FRAMING NAIL SIZE GYPSUM SHEATHING
(Common o TRATION IN PLYWOOD YWOS spacing a _ E Common-. —
Galvanized FRAMING THICKNESS P g t Plywood Panel Edges Galvanized Nail Spacing at Plywood Panel Edges
PLYWOOD GRADE Box) (Inches) (Inches) 6 1 4 2% 2 Box) 64 TV7.j 2
6d 1yi Y 200 300 450 510 8d 200 300 450 510
STRUCTURAL I 8d 11/2 % 280 430 640 730 10d 280 430 640 730
10d 1% 1/z 340 510 770 870 — —
STRUCTURAL II,
C-C Exterior,
Standard Sheathing, 6d 11{i 180 270 400 450 8d 180 270 400 450
Panel Siding Plywood 11/a 260 380 570 640 lOd 260 380 570 690
and other grades lOd Covered in 13s 1/2310 460 690 770 — — — — —
U.B.C. Standard
No.25-9-67
NAIL SIZE NAIL SIZE
(Gavanized (Galvanized
Casingl Casing)
Plywood Panel
Siding in Grades 6d 114 'If 140 210 320 360 8d 140 216 320 360
Covered in U.S.C. 8d 11/z % 160 240 360 410 lOd 160 240 360 410
Standard No.
25-9-67
'All panel edges backed with two-inch (2")nominal or wider framing. Plywood installed either horizontally or vertically. Space nails at
twelve incites(12")on center along intermediate framing members. These values are for short time loads due to wind or earthquake and
must be reduced 25 per cent for normal loading.
TABLE NO. 25-R—ALLOWABLE SPANS FOR PLYWOOD FLOOR AND
ROOF SHEATHING CONTINUOUS OVER TWO OR MORE SPANS
AND FACE GRAIN PERPENDICULAR TO SUPPORTS'
ROOF
PANEL Maximum
IDENTIFICATION SP46 LOAD(IN POUNDS PER FLOOR
INDEX' (in inches) SQUARE FOOT, Maximum
Edges Edges Total Live Spam TABLE NO. 25-S—ALLOWABLE SPAN FOR PLYWOOD COMBINATION '
Blocked Unblocked Load Lead_ (in Inches)
12i0 12 130 100 0 SUBFLOOR-UNDERLAYMENT'
16%0 16 75 55 0 Plywood Continuous over Two or More Spans and
20/0 20 55 45 0 Face Grain Perpendicular to Supports
24/0 24 16 60 45 0
30/12 30 26 55 40 125 MAXIMUM SPACING OF JOISTS
32/16 326 28 507 40 168 SPECIES GROUPS' Is" m' 24"
36/16 36 30 507 357 168 5/.v - aA.
42/20 42 32 457 357 208 2 3 %/ aA'r 7/se
48/24 48 36 407 40 24 4 �4 n vArr 1„
'These values apply for Structural I and II,Standard Sheathing and C-C
Exterior grades unly. Spans shall be limited to values shown because 'Applicable to Underlayment Grade C-C (plugged) and all grades of
of possible effect of concentrated],ads. sanded Exterior type plywood. Spans limited to values hown be-
=Uniform load deflection limitation: 1/180th of the span under live load cause of possible effect of concentrated loads.Allowable uniform load
plus dead load,1/240th under live load only. based on deflection of 1/360 of span is 100 pounds per square foot.
'Identification Index appears an all panels in the construction grades Plywood edges shall have approved tongue and groove joints or shall
listed in Footnote No.1. he supported with blocking, unless one-Fourth-inch,(/") minimum
'Plywood edges shall have approved tongue nd groove joints or shall be thickness underlayment is installed,m finish floor is twenty-five-thirty-
supported with blocking,unless one-fourthainch (9')mird.um thick- seconds-inch (37 ) wood strip. if wood strips are perpendicular'to
ness underlaynnect is installed, or finish floor is twenty-five-thirty- supports, thicknesses shown for sixteen-inch (16") and twenty-inch
seconds-inch (; ") wood strip.Allowable uniform load based on de- (20")spans may he used on twenty-four inch(24")span.
Election of 1/360 of span is 100 pounds per square foot. 'See U.B.C.Standard No.25-9-67 for plywood species groups.
°May be sixteen-inch (16") if twenty-five-thirty-second-inch (,'�5")
wood strip flooring is installed at right angles to joists
'One-half inch thick Structural I, when continuous over two or
more spans,may be laid with face grain parallel to supports provided
all panel edges are blocked or other approved type edge support is pro-
vided,the spacing of the supports does not exceed twenty-four inches
1241) on center,and the live load does not exceed 30 pounds per
square foot. For other grades,a thickness of five-eighths-inch
is required.
'For roof live load of 40 pounds per square foot or total load of 55
pounds per equate foot,decrease spans by 13 per cent or use panel
with next greater identification index.
,May be twenttyy-four-inch (24" if twenty-five-thirty-secands-inch (111")
wood strip 9oorirtg is installed at right angles to joists.
31
TABLE NO.25-T—ALLOWABLE SPANS FOR FWOR JOISTS USING NONSTRESS-GRADED LUMBER'
_-• MAXIMUM ALLOWABLE SPAN
SIZE SPACING (Feet and Inches)
OF OF GROUP I GROUP 11 GROUP III •GROUP IYr
FLOOR FLOOR
JOISTS JOISTS Plastered Without Plastered Without Plastered Without Plastered Without
(Inches) (Inches) Ceiling Plastered Ceiling Plastered Ceiling Plastered Ceiling Plastered
Below Ceiling Below Ceiling Below Ceiling Below Ceiling
Below Below Below Below
12 10-6 11-6 9-0 10-0 7-6 8-0 5-6 6-0
2 x 6 16 9-6 10-0 8-0 8-6 6-8 7-0 5-0 5-0
24 7-6 8-0 6-6 7-0 5-6 6-0 4-0 4-0
" 12 14-0 15-0 12-6 13-6 10-6 11-6 8-0 8-6
2 x 8 16 12-6 13-6 11-0 11-6 9-0 10-0 7-0 7-6
24 10-0 11-0 9-0 9-6 7-6 8-0 6-0 6-6
12 17-6 19-0 16-6 17-6 13-6 14-6 10-6 11-6
2 x 10 16 15-6 16-6 14-6 15-6 12-0 13-0 9-6 10-0
24 13-0 1 14-0 12-0 1 13-0 1 10-0 1 10-6 1 7-8 j 8-6
12 21-0 23-0 21-0 21-6 17-6 19-0 13-6 14-6
2 x 12 16 18-0 20-0 18-0 19-6 15-6 16-6 12-0 13-0
24 15-0 16-6 15-0 16-6 12-6 13-6 10-0 10-6
DESIGN LOADING AND DEFLECTION CRITERIA:
Live load—Forty pounds per square foots; Dead load weight of floor—Five pounds per square foot—plus weight of
joists; eight pounds per square Foot—weight of lath and plaster; Deflection with or without plaster—Not to exceed
1/360th of the span with live load nor 1/240th with dead load and live load.
'Species of lumber are divided into groups s set Forth in Table No. 25-1.The allowable spans are based upon stress and deflection criteria
set forth in U.B.C.Standard No. 25-21-67.Span lengths For stress-graded]umber as sal forth in Tables No.25-A and No.25-B may be
based on the stresses therein.Spans fn Group I are suitable for any species of stress-graded lumber given in Table No.25-A or No.25-B
which has a modulus of elasticity of 1,600,000 pounds per square inch and m allowable extreme fiber stress in bending of 1100 pounds
per square inch.
'Lumber in Growp IV may be used only under conditions apeciScally approved by the Building Official.
'For live loads oaf 50 pounds par square foot,spans shall Fx reduced to 00 per cent of the tabulated values.
TABLE NO. 25-Y—ALLOWABLE SPANS FOR RAFTERS'
(Slopes 4:12 or greater)
SRE SPACING MAXIMUM ALLOWABLE SPAN
OF OF (Feet and Inches Measured Along the Horizontal Projection)
RAFTER RAFTER
(Inches) (Inches) Group I Group 11 Group III Group Iv-
12 10-0 9-0 7-0 4-0
16 9-0 7-6 6-0 3-6
2 x 4
24 7-6 6-6 5-0 3-0
TABLE NO.25-U—ALLOWABLE SPANS FOR CEILING JOISTS USING 32 6-6 5-6 4-6 2-6
NONSTRESS-GRADED LUMBER' 12 17-6 15-0 12-6 9-0
Size Spacing MAXIMUM ALLOWABLE SPAN 2 x 6 16 1 -6 13-0 11-0 8-
of of (Feet and Inches) 24 122-6 11- 9-0 -66
Calling Ceiling 32 11-0 9-86 8-0 5 5-8
Joists foists GROUP I GROUP 11 GROUP III GROUP IV
(Inches) (Inches) 12 23-0 20-0 17-0 13-0
12 11-6 11-0 9-6 5-8 16 20-0 18-0 15-0 11-6
2 x 4 16 10-6 10-0 8-6 5-0 2 x 8 24 17-0 15-0 12-6 9-6
32 14-6 13-0 11-0 8-6
2 x 6 12 18-0 16-6 15-6 12-6
16 16-0 15-0 14-6 11-0 12 28-6 26-6 22-0 17-6
12 24-0 22-6 21-0 19-0 L
x 10 16 25-6 23-6 19-6 15-6
2 x 8 16 21-6 20-6 19-0 16-6 24 21-0 19-6 16-0 12-6
32 18-6 17-0 14-0 11-0
DESIGN LOADING AND DEFLECTION CRITERIA: DESIGN LOADING CRITERIA:
Live Load—None. Dead Load—Ten pounds per square Live Load-16 pounds per square foot on horizontal projec-
foot—weight of joists and lath and plaster;Deflection— tion. Dead load weight of roof—seven pounds per square
Not to exceed 1/360 of the span. foot on horizontal projection plus weight of rafters.
'Species of lumber are divided into groups as set forth in Table No.25-I. 'Species of lumber are divided into groups as set forth in Table No.25-1.
Span lengths for stress-graded lumber as set forth in Tables No.25-A Allowable stresses increased 25 per cent for roof loading[Section 2504
and No.25-B may be based on the stresses therein.Spans in Group I (e) 21. Span length for stress-graded lumber set forth in Tables No.
are suitable for any species of stress-graded lumber given in Table No. 25-A and No. 25-B may be based on the stresses therein. Spans in
25-A or No. 25-B which has a modulus of elasticity of 1,600,000 Group I are suitable for any species of stress-graded lumber given in
pounds per square inch and an allowable extreme fiber stress in bend- Table No. 25-A or No. 25-B which has a modulus of elasticity of
ing of 1100 pounds per square inch. The allowable spans are based - 1,600,000 pounds per square inch and an allowable extreme fiber
upon stress and deflection criteria set forth in U.S.C. Standard No. stress in bending of 1100 pounds per square inch.The allowable spans
25-21-67, are based upon stress and deflection criteria set forth in U.B.C.Stand-
zLumber in Group TV may be used only under conditions specifically and No. 25-21-67.
approved by the Building Official. 'Lumber in Group IV may be used only under conditions specifically ap-
proved by the Budding OfflciaL
32
iABLE NO.25-W—ALLOWABLE SPANS.FOR RODE RAFTERS USING NONSTRESS-GRADED LUMBER'
• (Slopes less than 4:12)
MAXIMUM ALLOWABLE SPAN
31ZE SPACING (Feet and Inches Measured Along the Horizontal Projection)
OF OF
ROOF ROOF GROUP I GROUP II GROUP III GROUP IN
RAFTERS RAFTERS
(Inches) (Inches) pNot porting
Not pNot
3ugeCing g 3 t telling porting Supporting ng Sugelig Supporting 1 ng Supporting ilin Supporting ili SCeil ng g
12 gelling
9-6 7-0 8-0 5-6 6-6 3-0 4-0
2 x 4 16 7-0 8-0 6-0 7-0 5-0 5-6 3-0 3-6
24 5-6 6-6 5-0 6-0 4-0 4-6 2-6 3-0
32 5-0 6-0 4-6 5-0 3-6 4-0 2-0 2-6
12 13-0 16-6 12-0 14-0 10-6 11-6 7-0 8-6
2 x 6 16 11-6 14-6 10-6 12-0 8-6 10-0 6-0 7-6
24 10-0 12-0 8.6 10-0 7-0 8-6 5-0 6-0
32 8-6 10-6 7-6 9-0 6-0 7-6 4-6 5-6
12 17-0 21-6 16-0 19-0 13-6 16-0 10-6 12-6
2 x 8 16 15-6 19-0 14-0 16-6 12-0 14-0 9-0 11-0
24 13-6 15-6 11-6 13-6 10-0 11-6 7-6 9-0
32 11-6 13-6 10-0 12-0 8-6 10-0 6-6 8-0
12 21.-6 27-0 20-0 25-0 17-6 20-6 14-0 16-0
2 x 10 16 19-6 23-6 18-6 22-0 15-6 18-0 12-0 14-0
24 16-6 19-6 15-6 18-0 13-0 15-0 10-0 12-0
32 14-6 17-0 13-6 16-0 11-0 13-0 9-0 10-6
12 25-6 32-0 24-0 31-0 22-6 26-6 17-6 20-6
2 x 12 16 23-6 28-0 22 0 27-6 22-0 23-6 15-6 18-0
24 20-0 23-6 19-6 23-0 16-6 19-6 13-0 15-0
32 17-6 20-6 17-0 20-0 14-6 17-0 11-0 13-0
DESIGN LOADING AND DEFLECTION CRITERIA:
Live load-20 pounds per square foot on the horizontal projection. Dead load weight of roof—seven pounds per square
foot on the horizontal projection—plus weight of rafters.Eleven pounds per square foot on the horizontal projection—
weight of lath and plaster ceiling; Deflection—With plastered ceiling—not to exceed 1/360 of the span with live load
nor 1/240 of the span with dead and live load—Without plastered ceiling—not considered.
'Species of lumber are divided into groups as set forth in Table No.25-I.Allowable stresses are increased 25 per cent for roof loading[Section
2504 (e) 21.Span lengths for stress-graded lumber set forth in Tables No. 25-A and No. 25-B may be based on the stresses therein.
Spans in Group I are suitable for any species of stress-graded lumber in Table No.25-A or No.25-B which has a modulus of elasticity of
Oioo,000 pounds per square inch and an allowable extreme fiber stress in bending of 1100 pounds per square inch.The allowable spans
re based upon stress and deflection criteria set forth in U.B.C.Standard No.25-21-67.
'Lumber in Group IV may he used only under conditions specifically approved by the Building Official.
TABLE NO. 25-X—ALLOWABLE SPANS FOR TWO-INCH (2") TONGUE
AND GROOVE PLANKING USING NONSTRESS-GRADED LUMBER
MAXIMUM ALLOWABLE SPAN1,'
(Feet and Inches Measured Along the Horizontal Projection)
FLOOR PLANKING ROOF PLANKING
With or Without Supparting No
GROUP Finish Flooring Finish Ceiling Finish Calling
I 4'6" 7'6" 901,
II 4'6" 7'0" 8'6"
III 4'6" 616" 810"
IV3 4'6" 5'6" 6'0"
DESIGN LOADING AND DEFLECTION CRITERIA:
Floor: Live Load-40 pounds per square foot. Dead Load—
weight of planking and finish flooring seven pounds per
square foot. Weight of lath and plaster ceiling eight pounds
per square foot.The allowable spans for Groups I,II and III
have been reduced to values shown based upon practical
field problems and experience.
Roof: Live Load-20 pounds per square foot. Dead Load—
weight of planking and roofing 10 pounds per square foot.
Weight of lath and plaster ceiling eight pounds per square
foot.
Deflection: See,Table No.23-D.
'For planking placed diagonally across supports spans shall be measured
along the planking.See U.B.C.Standard No.25-21-67 for criteria used
in developing table.For live load of 50 pounds per square foot on
floor planking spans shall be reduced to 90 per cent of tabulated values.
'Spans are based on a net thickness of one and one-half inches(]%").
Spam for planking of one and five-eighths-inch (1%") net thickness
may be increased by six inches(O").
'Lumber in Group IV may be used only under conditions specifically ap-
proved by the Building Official.
TABLE NO.25-Y—ALLOWABLE SHEARS FOR WIND OR SEISMIC LOADING
ON VERTICAL DIAPHRAGMS OF FIBERBOARD SHEATHING BOARD
CONSTRUCTION FOR TYPE V CONSTRUCTION ONLY'
SHEAR VALUE 3"NAIL SPACING
SIZE AND AROUND PERIMETER AND 6"
APPLICATION NAIL SIZE AT INTERMEDIATE SUPPORTS
rra"x 4'x 8' 11 ga.gal.roofing nail 125
1%"long,in"head
39"x 4'x 8' 11 ga.gal.roofing nail 175
1%"long,ta"head
'Fiberboard sheatbmg eliaphmgms shall not be used to brace concrete or
masonry walls.
33
City of Fort Worth, `lr'exas
uNE
UNE Mayor and Council Communication
MORPHIS
R.a Be
DATE REFERENCE SUBJECT: Proposed Amendment to Fort PAGE
GRAHAM NUMBER
4/28/69 G-1359 Worth Building Code for 2
BUILDING -
Council action on the following is requested.
Background
On July 1, 1968, the City Council authorized the appointment of three code
review committees comprised of City and industry leaders to review avail-
able model codes and to recommend possible revisions to the City's $wilding,
Fire, Electrical and Plumbing Codes (M&C G-1255). This step was taken in
an effort to encourage optimum community development by updating construction
codes to reflect new developments in the building industry.
On October 14, 1968, the Building and Fire Code Review Committee voted to
recommend adoption of the latest Uniform Building Code as the model for the
Cityls new code with amendments to fit local conditions. To date some
eighty per cent of the model code has been reviewed and approved.
Regulations for Wood Construction
Chapter 25 of the present Building Code relates to wood construction and
restricts the use of lumber in load-bearing members to species and grades
of lumber that can be stress graded. Up to 1965 this restriction caused no
problem because stress graded Southern Pine and Douglas Fir were in ample
supply and were in active competition. There is now a shortage of these
woods which,'has eliminated this competition and increased the price of the
specified Moods.
In 1967 the Uniform Building Code was amended to allow the wider use of
other woods of different species and grades comparable in strength to be
used in specific locations within the building.
A proposed ordinance has been prepared by the Building and Fire Code Review
Committee with the assistance of the staff based on the amended portion
of the Uniform Building Code. The Building and Fire Code Review Committee
believes that the change in specifications would help reduce the overall
cost of lumber in wood structures and still provide adequate protection to
the public. The Committee and the staff recommend that the attached
ordinance be adopted amending Chapter 25 of the Building Code.
It is estimated that another three months will be needed for drafting the
entire new code and that two additional months will be spent in preparing
the final draft, holding public hearings, and presenting the proposed
code to the City Council.
DATE REFERENCE SUBJECT: Proposed Amendment to Fort PAGE
NUMBER Worth Building Code 2 of 2
4/28/69 G-1359
Under current market and supply conditions, a minimum of six months is
required to order and completely stock the supply lines of a major item
such as lumber. It would therefore be approximately a year before the
local builders fully benefit from the cost .advantages of the new code.
Therefore, the amendment to Chapter 25 is being submitted in advance of
the remainder of the code revisions.
Recommendation
It is recommended that an ordinance amending Chapter 25 of the Fort Worth
Building Code be approved permitting the substitution of woods of
comparable strength for the species and grades of wood now specified in
the Building Code for use in wood construction.
HDM:ms
Attachment
SUBMITTED BY: DISPOSITI Y COUNCIL: PROCESSED BY
APPROVED ❑ OTHER (DESCRIBE)
` CITY SECRETARY
� E��2�Gx-' �Cf/�2�C/:��-Cr �/J tTJ L•/ DATE
CITY MANAGER l`� [i 6