HomeMy WebLinkAboutOrdinance 5570 ORDINANCE NO, sry
AN ORDINANCE AMENDING PARAGRAPH (a) OF SECTION
2805, CHAVfER 28, PART VIII, OF ORDINANCE NO.
4155, THE BUILDING CODE OF THE CITY OF FORT WORTH,
BY INCREASING THE MINIMUM ULTIMATE STRENGTH RE-
QUIRED OF CONCRETE FOOTINGS AND FOUNDATIONS; REGU-
LATING FLOOR ELEVATIONS ABOVE LOT LEVEL; REQUIRING
THAT SANITARY SEWER BACKFLOW PROTECTIVE DEVICES
BE INSTALLED IN CERTAIN INSTANCES; PROVIDING A SEVER-
ABILITY CLAUSE; MAKING THIS ORDINANCE CUMULATIVE
OF OTHER ORDINANCES WITH RESPECT TO BUILDING REGU-
LATIONS; REPEALING ALL ORDINANCES IN CONFLICT HERE-
WITH; PROVIDING A PENALTY; AND PROVIDING AN EF-
FECTIVE DATE.-
BE IT ORDAINED BY THE CITY COUNCIL OF THE CITY OF
FORT WORTH, TEXAS:
SECTION 1.
That Paragraph (a) of Section 2805, Chapter 28, Part
VIII, of Ordinance No. 4155, the Building Code of the City of
Fort worth, be, and it is hereby, amended to read as follows:
Sec. 2805. (a) Footings and Foundations.
Footing and foundations, unless specifically
provided, shall be constructed of reinforced
masonry or reinforced concrete and shall in
all cases extend at least eight inches (8")
below the finished grade. Loam or soil con-
taining organic matter shall not be used to
support buildings more than one story in heights
On filled ground where solid natural ground does
not occur at the minimum footing depth, such
foundation shall be carried down to natural
solid ground or piers shall be used._ A prac-
tically level fill of good ground which has been
in place a sufficient length of time to settle
properly may be used when approved by the Build-
ing Official. Footings shall be designed to
minimize differential settlement. Mortar used
in foundation walls and footings shall be as
specified in Section 2403 (r) . Concrete and
reinforcing steel used in foundation walls, foot-
ings, piers, grade beams, and .slabs shall con-
form to the requirements of Chapter 26, and the
concrete shall have a minimum ultimate strength
of 2500 psi at 28 days.
Exterior bearing walls shall be supported
on continuous solid reinforced masonry or rein-
forced concrete beams supported on footings,
piers or piles, which shall be of sufficient size
to support safely she loads imposed as determined
by the character..pf..the soil.
Foundation wall supporting wood framing
(floor slabs) shall extend at least sight inches
(8") above anticipated finished lawn grade ad-
jacent to all points after lawns have been com-
pleted.
Where houses are constructed with floor
elevations below adjacent street curb grades,
adequate swales shall be constructed where neces-
sary fcz drainage, with the low point of the
swale being a minimum of six inches (6") below
the finished lawn grade elevation adjacent to
the house.
Floor elevations of new buildings shall be
at least twelve inches (1211) higher than the
ground surface over the sanitary sewer main at the
point the building is to be connected to such sani-
tary sewer, provided that if in the opinion of the
Building official the location of the sanitary sewer
and/or the topography of the building site is such
as to render this floor elevation impractical, the
sewer serving such building shall be provided with
a backflow protective device or other protective
measures, as approved by the Chief Plumbing In-
spector, to prevent flooding of the building.
Where pier and beam foundation is used, the
beam shall extend at least four inches (4") into
the natural ground or settled fill. The minimum
steel for pier and beam foundation shall be one
(1) number four (4) bar for piers and two (2) num-
ber four (4) bars at top and two (2) number four
(4) bars at bottom in beams. Piers over eight
diameters of least cross section in height shall
be reinforced with four (4) number four (4) bars.
The minimum height of the grade beam shall be six-
teen inches (16") . The minimum widths for grade
beams shall be ten inches (10") for masonry veneer,
eight inches (8") for frame using notches for
girders, and six inches (6") for frame not using
girder notches. The minimum depth of beam shall
be twenty-one inches (21") .
where reinforced concrete slab and beam founda-
tion is used, the beam under exterior walls shall
extend at least eight inches (8") into natural soil
or properly compacted fill. Slabs shall be not
less than four inches (411) thick and. shall be placed
on four inches (4") of coarse sand or gravel cushion
over ail habitable areas. The minimum steel in
f;labs shall be 6x6-10/10 wire mesh or number three
(3) bars at eighteen inches on center each way and
two (2) number four (4) bars at top and two (2)
number four (4) bars at bottom of oeanLs. Slabs
under interior bearing partitions shall be thickened
to eight inches (811) thickness and reinforced with
two (2) number four (4) bars at the bottom of thickened
slab.
Sills shall 'be bolted to the foundation or
foundation wall with not less than one-half inch
(1/2") bolts, imbedded at least six inches (6")
into masonry or concrete and spaced not more than
six feet (6') apart.
EXCEPTIONS: 1. Interior bearing walls in
one-story and two-story buildings may be supported
on piers.
2. For Type V Buildings (except Group H and I
Occupancies) , isolated piers of solid masonry or
concrete may be used for post and girder construc-
tion.
3. A one-story building (except Group I Occu-
pancy) which does not exceed four hundred square
feet (400 sq. ft.) in area, including additions,
may be constructed without a masonry or concrete
foundation if the walls are supported on a wood
mudsill.
Mudsills shall be no wood other than Foundation
Grade Redwood, Foundation Grade Cedar, all heartwood
cypress, or any species of wood pressure-treated with
an approved preservative, all marked or branded by
an approved agency.
4. Wood Pole Foundations may be used on one-
story Pole-Type Buildings of Type V unprotected
construction, designated for industrial or storage
purposes where designed to comply with the follow-
ing criteria and formulas:
a. Embedment depth where no constraint is pro-
vided at the ground or floor surface shall be de- '
termined by Formula (1)
d =+ ( 1 + _V/17 4.36h (1)
A
Embedment depths where constraint is provided
at the ground or floor surface; such as a rigid
floor or rigid ground surface pavement, shall be
determined by Formula (2) .
2 Ph
d = 4.25 . . . . . . . . . . . . .. .. . .. .. .. . . (2)
s-1b
2.34P
WHERE A _:
Slbl
P = Applied horizontal force in pounds
Sl= Average soil resistance above point of
rotation
S3= Soil resistance at depth d in pounds per
sq. ft.
bl= Diameter,of round post, or diagonal
dimension of square post in feet.
For Formula (1) , see Subsection b.
b2= Diameter of round post, or diagonal
dimension of square post, in feet.
For Formula (2) , see Subsection b.
h = Distance, in feet, from ground sur-
face to point of application of P.
d = Depth of embedment of post in feet
b. Minimum embedment shall be four feet (4')
into natural soils or approved compacted soils.
The back fill in the annular space around posts
shall be of concrete with ultimate strength of
2000 lbs. per sq. in. at 28 days. The hole shall
be not less than four inches (4") larger than the
diameter of the round post at the bottom, or four
inches (4") larger than the diagonal dimension
of a square or rectangular post. The dimensions
bl and b2 in Equation (1) and Equation (2) shall be
the outside diameter of the concrete casing.
Minimum foundation requirements for stud bear-
ing walls shall be as set forth in Table No. 28-A
for continuous footings and in Section 2805 for pier
and beam foundations and for concrete slab and beam
foundations.
Foundations of all buildings where the surface
of the ground slopes more than one foot (1') in
ten feet (10') shall be level or shall be stepped
so that both top and bottom of such foundations
are level.
SECTION 2.
That if any section, subsection, sentence, clause or
phrase of this ordinance is for any reason held to be uncon-
stitutional, such holding shall not affect the validity of the
remaining portions of this ordinance, and all of the remainder
of this ordinance not so held to be unconstitutional shall
continue to be in full force and effect.
SECTION 3.
That this ordinance shall be and is hereby declared to
be cumulative of all provisions of the Building Code of the
City of Fort Worth, Ordinance No. 4155, and amendments thereto,
with respect to building regulations, except in those in-
stances where the provisions of this ordinance are in direct
conflict with such Code, in which instances said conflicting
provisions of such Code are hereby repealed.
SECTION 4.
That any person, firm, association of persons, company
or corporation, their agents, servants or employees, who
violates, disobeys, omits, neglects or refuses to comply with,
or who resists the enforcement of, any of the provisions of
this Code shall be fined not less than Five and no/100 Dollars
($5.00) nor more than Two Hundred and no/100 Dollars ($200.00)
for each offense. Each day that a violation is permitted to
exist shall constitute a separate offense.
SECTION 5.
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.
APPROVED AS TO FORM AND LEGALITY:
City Attorney
�v,�,1LEE
ti ..
City of Fort Worth, Texas
GRMAM
Mayor and Council Communication,�oY
DATE REFERENCE SUBJEcT: Building Code Amendments PAGE
NUMBER
5/9/66 G-944 1 of 2
In response to prior City Council requests, the Public Works Department
has reviewed means to alleviate foundation failures and house and build-
ing flooding by runoff and sewer back-ups during and following periods
of heavy rainfall. The Public Works Department evaluation of contribut-
ing causes to reported water damage indicates that revisions in the
Building Code are desirable. One change would strengthen concrete foot-
ings and foundations. A second change would assure that floor elevations
are above site grades. A third change would require a backflow protective
device on certain sewer service lines, thus preventing damage to building
interiors when there is a stoppage or backup in the sewer system. The
Code amendments would apply to all new construction.
Floor Elevations
Surface drainage away from the structure toward streets and other drainage
facilities can be improved if it is required that the floor elevations are
at least eight inches higher than the finished grade of side, front and
rear yards. A number of instances have been found where landscaping and
additional top soil has been added around residences creating a low point
in the living area. The condition is aggravated when exceptionally heavy
rainfall such as that experienced recently in Fort Worth floods streets
and yards are overflowed. It is proposed to require proper floor eleva-
tions or drainage by amending paragraph (a) of Section 2805, Chapter 28,
Part VIII, Building Code of the City of Fort Worth (Ord. No. 4155) as
follows:
1) By adding the underlined words so that the paragraph will read as
follows:
"Foundation wall supporting wood framing (floor slabs) shall extend
at least eight inches (8'7 above anticipated finished lawn grade
adjacent to all points after lawns have been completed.
2) By adding the following paragraph:
"Where houses are constructed with floor elevations below adj e*►
street curbs, adequate swales shall be constructed where nee aY
for drainage, with the low point of the swale a minimum o
inches (6") below the finished ground elevation adjacent he
house. "
Sewer Backflow Protective Devices
A device costing about $15 is now available for installation in the se der
cleanout stub where floor elevations of new buildings are less than twe e
inches higher than the ground surface over the sanitary sewer. The device
will not obstruct outflow of sewage, but will permit backflow to drain in-
to the yard instead of inside the building. It is proposed that paragraph
(a) of Section 2805 be further amended to provide for installation of such
�'-MATE REFERENCE SUBJECT: Building Code Amendments PAGE
NUMBER 2 of
_ 5 9 66 G-944
protective devices on applicable buildings by adding the following_
"Floor elevations of new buildings shall be at least twelve
inches (12') higher than the ground surface over the sani-
tary sewer main at the point the building is to be connected
to such sanitary sewer, provided that if in the opinion of
the Building Official the location of the sanitary sewer and/
or the topography of the building site is such as to render
this floor elevation impractical, the sewer serving such build-
ing shall be provided with a backflow protective device or
other protective measures, approved by the Chief Plumbing In-
spector, to prevent flooding of the building. "
Foundation. Improvement
Review of water damage to structures and observance of building deteriora-
tion problems in general indicated that the Code provision for concrete
with a test strength of 2,000 pounds per square inch for construction of
foundation walls, footings, piers, grade beams and slabs is inadequate.
It is proposed that paragraph (a) of Section 2805 of the Code be further
amended to read " . . . concrete shall have a minimum ultimate strength
of 2,500 pounds per square inch at 28 days. " Building officials estimate
that the increased strength can be obtained by more careful handling of
the foundation concrete during construction and will not result in any
significant increase in foundation costs.
1
Recommendation
It is recommended that the attached amendment to the Building Code of
the City of Fort Worth be adopted to provide for strengthened founda-
tions, proper floor elevations with relation to building -site, and re-
quirement for protective backflow devices on sewer service lines in
order to prevent or minimize the effects of water damage as a result
of heavy rainfall.
OFFICIAL RMR0
.LB:lp CCITY SEC_;ET4RY
attach. WWoRTII, T .
SUBMITTED BY: DISPOSITIO r BY COUNCIL: P SSED
APPROVED 0115T,ER (DESCRIBE)
� WISECRETARY
Cf D
ITY MANAGER