Section 27-683
§ 27-683 Materials. All structural elements of foundations as defined
in section 27-585 of article one of subchapter ten shall meet the
requirements as to type and minimum quality of materials prescribed in
such subchapter. Inspection of materials and construction shall comply
with the provisions of section 27-586 of such subchapter.
Section 27-684
§ 27-684 Footings. Inspections of subgrade of footings, piers and
walls shall comply with the requirements of section 27-723 of article
thirteen of this subchapter.
(a) Wood footings. Wood footings may be used only for wood frame
structures. Wood footings shall be given a preservative treatment in
accordance with reference standard RS 11-4.
(b) Pole buildings. Buildings not more than one story high may be
supported on poles embedded in the ground. Wood poles shall conform to
the requirements of reference standard RS 11-5 and shall be given a
preservative treatment in accordance with reference standard RS 11-4.
Steel poles embedded in the soil shall be protected as required by the
provisions of paragraph one of subdivision (c) of section 27-685 of this
article.
(c) Grillages. Grillage beams shall be provided with proper spacers,
stiffners, and diaphragms, or the space between the beams shall be
filled with concrete or grout. In addition, all steel grillages shall be
fully protected against corrosion by encasement, coating with metal
protection of a type satisfactory to the commissioner or by other
approved device.
(d) Design.
(1) CONCRETE FOOTINGS. Concrete footings shall be proportioned in
accordance with the provisions of reference standard RS 10-3.
Reinforcement shall extend to within four inches of the edges of the
footing.
(2) MASONRY FOOTINGS. Masonry used for the construction of footings
shall be of solid units.
a. Reinforced masonry footings shall meet the requirements of
reference standard RS 10-2 and shall be proportioned similarly to the
proportioning of reinforced concrete footings.
b. Unreinforced masonry footings shall be of such dimension that a
sloping plane extending downward from the top of the footing where it
intersects the pier of wall, to the bottom of the footing, and measured
at the angle with the horizontal that is indicated below, will be
contained entirely within the footing:
Soil bearing capacity of three tons per square foot or less-- sixty
degrees
Soil bearing capacity between three tons per square foot and six tons
per square foot--seventy degrees
Soil bearing capacity greater than six tons per square foot shall be
investigated.
The compressive stress in the footing, based on the assumption that the
vertical load is uniformly distributed over horizontal sections bounded
by said planes, shall not exceed the values given in reference standard
RS 10-1.
Section 27-685
§ 27-685 Foundation piers. Foundation piers shall be designed as
columns. Reinforced concrete piers shall be designed in accordance with
the provisions of reference standard RS 10-3. Reinforced and
unreinforced masonry piers shall be designed in accordance with the
provisions of reference standards RS 10-2 and RS 10-1. Unreinforced
concrete piers shall be designed in accordance with subdivision (b) of
this section.
(a) Lateral support. The equivalent unbraced length of a pier
supported by lateral soil pressure may be determined by a recognized
method of elastic analysis. Alternatively, such a pier may be assumed to
be hinged, but laterally braced at intervals equal to the full height of
the pier or eight times the least lateral dimension of the pier,
whichever is the lesser value. The provisions of subdivision (e) of this
section shall apply.
(b) Unreinforced concrete piers. Where unreinforced concrete piers are
used, the allowable compressive stress shall not exceed 0.25f'c and the
center of cross section of the pier at any level shall not deviate from
the line of action of the resultant of all forces (which line of action
shall consider the eccentricities due to all loads and moments acting on
the pier) by an amount more than one-sixtieth of its height or one-tenth
of its least lateral dimension and the ratio of the height to the least
lateral dimension shall not exceed eight. For larger values of the ratio
of the height to the least lateral dimensions, or for greater
eccentricities, piers shall be reinforced.
(c) Metal shells. Where piers are encased by a metal shell, the shell
may be considered as contributing to the structural strength of the pier
provided that the thickness is one-eighth inch or greater, and subject
to the following requirements:
(1) Where boring records or site conditions indicate possible
deleterious action on the shell, where any portion of the shell is
embedded in ash, cinder fill or garbage fill, where the encased piers
are used for support of chemical plants, piles of coal, or under other
conditions conducive to chemical seepage or corrosive action, or where
the encased piers are used for support of electrical generating plants,
the metal shells shall be protected against deterioration by encasement,
coating, or other device acceptable to the commissioner.
(2) The area of the metal section of the shell multiplied by the
efficiency of the horizontal joints shall be considered as equivalent
vertical reinforcement of the pier. The area of the metal section of the
shell, multiplied by the efficiency of the vertical joints, shall be
considered as equivalent spiral reinforcement of the pier.
(d) Minimum dimensions. The provisions of subdivision (e) of this
section shall apply. In addition, the plan dimensions of the pier shall
not be less than those of the column above. If the column above is a
steel section resting on a base plate, the base plate and pier shall be
proportioned for allowable bearing pressures as prescribed in reference
standards RS 10-1, RS 10-2, and RS 10-3.
(e) Filling. The provisions of subdivisions (a) and (d) of this
section shall apply only where the fill (or backfill) is placed around
the pier as controlled fill, and wherein the level of the fill is raised
uniformly around the entire perimeter of the pier. Where the fill
operation is not controlled the least lateral dimension of a foundation
pier shall be twenty-four inches and the pier shall be proportioned for
lateral pressure equal to the pressure of a differential height of fill
equal to five feet, applied simultaneously with the other loads on the
pier specified in article three of this subchapter.
Section 27-686
§ 27-686 Foundation walls. (a) Concrete. Concrete foundation walls
shall be designed in accordance with the provisions of reference
standard RS 10-3 relating to bearing or retaining walls. The equivalent
unbraced height of a wall supported by lateral soil pressure may be
determined by a recognized method of elastic analysis. Alternatively,
such a wall may be assumed to be laterally braced at intervals as
follows:
(1) Where fill is placed against both faces of the walls: the full
height of the wall or eight times the thickness, whichever is the lesser
value.
(2) Where both faces of the wall are not in contact with soil: the
height of the unbraced section of the wall or eight times the thickness
of the wall, whichever is greater, but not more than the full height of
the wall.
(b) Masonry. Masonry foundation walls shall conform to the provisions
of reference standards RS 10-1 and RS 10-2, and the following:
(1) TYPES. Masonry foundation walls may be of plain or reinforced
masonry and shall be of solid units, except that load bearing hollow
units will be permitted for support of one- and two-story buildings.
(2) WALL THICKNESS. Foundation walls of masonry shall be designed and
constructed in accordance with the provisions of reference standards RS
10-1 and RS 10-2, supplemented by the provisions of subdivision (a) of
this section, relating to unbraced height. The thickness shall be at
least six inches.
Section 27-687
§ 27-687 Construction of footings, foundation piers, and foundation
walls. The provisions of sections 27-661 and 27-723 of this subchapter
shall apply. In addition, methods of installation and construction shall
satisfy the following conditions:
(a) Footings, piers, or walls shall be founded on undisturbed soil or
on satisfactorily compacted or prepared materials.
(b) Accurate preparation and inspection of the bearing materials
directly underlying the foundation shall be possible; and the bearing
area shall be substantially level or suitably benched.
(c) Excavation shall be kept substantially free of water during
construction of the foundation except that the use of tremie or similar
underwater construction will be permitted in the case of foundations
bearing directly on rock, provided that the construction procedure will
permit thorough cleaning and preparation of the rock surface, and that
the surface of the rock is maintained in a clean condition, unfouled by
the inflow of soil or settlement of the fluid suspension, until the
concrete is in place.
To the extent possible under law, Friends of Devin Balkind for Public Advocate has waived all copyright and related or neighboring rights to New York City Administrative Code. This work is published from: United States.
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