Section 27-706
§ 27-706 Scope. Types of pile construction and installation that are
not described in this section will be permitted for use only where
acceptable to the commissioner.
Section 27-707
§ 27-707 Timber piles. (a) Materials. Timber piles shall conform in
quality to class A or B of reference standard RS 11-7.
(1) SIZE OF PILES. Piles shall be of adequate size to resist the
applied loads without creating stresses in the pile materials in excess
of twelve hundred psi for piles of southern pine, Douglas fir, oak, or
other wood of comparable strength; or eight hundred fifty psi for piles
of cedar, Norway pine, spruce or other wood of comparable strength.
Except as provided in paragraph two of this subdivision, for piles forty
feet or more in length and of thirty tons capacity or less, the
following sizes or classes of piles shall be deemed to be adequate for
considerations of stress in the pile material:
a. Piles of twenty-five to thirty tons capacity--Class A or minimum
eight inch tip with uniform taper.
b. Piles of less than twenty-five tons capacity--Class A or B or
minimum six inch tip with uniform taper.
(2) PILES DRIVEN TO END BEARING. All timber piles, regardless of
capacity, driven to end bearing on soils of classes 1-65 through 5-65
shall be class A or shall have a minimum eight inch tip and a uniform
taper.
(3) SPECIES OF WOOD. Any species of wood may be used that conforms to
the provisions of reference standard RS 11-7 and that will stand the
driving stresses.
(4) PEELING. Unless treated, piles need not be peeled.
(b) Limitations on use. Where timber piles are to be driven to end
bearing on soils of classes 1-65 through 5-65 by use of an impact
hammer, the installation of each such pile shall be under the personal
supervision of an architect or engineer, and the operations of driving
such piles, the observations of penetration resistance, and the
operation of the equipment shall be so conducted as to terminate driving
directly when the pile reaches bearing on the hard material. A report,
prepared by the architect or engineer, describing the procedures,
equipment, and precautions followed to prevent injury to the piling
shall be submitted to the commissioner.
(c) Lagged and inverted piles. The use of lagged or inverted piles
will be permitted. Double lagging shall be adequately connected to the
basic pile material to transfer the full pile load from the basic pile
material to the lagging without exceeding values of allowable stress as
established in subchapter ten of this chapter. The connection for single
lagging shall be proportioned for half the pile load. The diameter of
any inverted timber pile at any section shall be adequate to resist the
applied load without exceeding the stresses indicated in paragraph one
of subdivision (a) of this section, but in no case shall it be less than
eight inches.
(d) Installation.
(1) All broomed, crushed, or otherwise damaged materials at the head
of the piles shall be removed before capping.
(2) Any sudden decrease in driving resistance shall be investigated
with regard to the possibility of breakage of the pile, and if such
sudden decrease in driving resistance cannot be correlated to boring
data or some incident in the driving, and if the pile cannot be removed
for inspection, it shall be considered as adequate cause for rejection
of the pile.
Section 27-708
§ 27-708 Precast concrete piles (including prestressed sections). (a)
Materials. Materials for precast concrete piles shall conform to the
requirements of article five of subchapter ten of this chapter.
(b) Construction.
(1) HANDLING. Precast concrete piles shall be proportioned, cast,
cured, handled, and driven so as to resist the stresses induced by
handling and driving as well as by loads. Handling stresses shall be
computed on the basis of fifty per cent of the weight of the pile as an
allowance for impact. Handling equipment shall be constructed so as to
equalize the reactions on the several lines of the pile pickups. Loading
conditions induced by handling and driving shall be considered as of
infrequent occurrence.
(2) DIMENSIONS. The minimum lateral dimension of the pile shall be ten
inches, except for the taper at the tip.
(3) STRUCTURAL DESIGN. Piles shall be proportioned in accordance with
the provisions of article eight of this subchapter, subject to the
following additional requirements:
a. For a length equal to at least three times the minimum lateral
dimension at each end of the pile, lateral tie reinforcement consisting
of 0.225 in. diameter rods or larger shall be spaced not more than three
inches center-to-center, or an equivalent spiral shall be provided.
Elsewhere, the spacing of the ties or the pitch of the spiral may be
increased to twelve inches The minimum amount of longitudinal
reinforcement shall be two per cent of the concrete section placed in a
symmetrical pattern of at least four bars. If prestressed piles are
used, the minimum residual compression in the pile section shall be
seven hundred psi. For piles designed with voids, the three inch spacing
of the ties or spiral at each end of the pile shall be extended for a
distance of twelve feet or one-third the length of the pile, whichever
is smaller.
b. For piles designed with voids, the minimum wall thickness of the
concrete in any section of the piles shall be four inches. Voids may
extend through either or both ends of the pile. If the void extends
through the lower end of the pile, the pile head shall be vented to
prevent buildup of internal hydraulic pressure during driving.
c. Reinforcing steel shall be covered with at least one and one-half
inches of concrete on the surface against the ground.
(c) Tolerances. Voids, when used, shall be located within
three-eighths of an inch of the position shown in the plans. The maximum
departure of the pile axis from a straight line, measured while the pile
is not subject to bending forces, shall not exceed one-eighth of an inch
in ten feet or three eighths of an inch in forty feet, or 0.1 per cent
of the pile length.
(d) Installation. Precast concrete piles shall not be handled or
driven until they have cured sufficiently to develop the necessary
strength.
Section 27-709
§ 27-709 Cast-in-place concrete piles. (a) Description. Cast-in-place
concrete piles shall be cast in shells previously installed in the
ground or, with the limitations indicated in section 27-697 of article
seven of this subchapter, may be cast in an uncased hole. Cast-in-place
piles may be tapered or cylindrical, or a combination of tapered and
cylindrical shapes.
(b) Materials. Concrete for cast-in-place concrete piles shall conform
to the requirements of article five of subchapter ten of this chapter.
Slump shall be five inches plus or minus one inch. Where the pile shell
is assumed to contribute to the capacity of the pile as a structural
member, the shell shall be of metal and shall conform to the provisions
of article six of subchapter ten of this chapter or section 27-712 of
this article. Where the pile shell is not assumed to contribute to the
capacity of the pile as a structural member, the shell may be of any
material that will adequately resist the driving stresses and maintain
an open well to receive the concrete. End closures for shells shall not
project more than one-half inch beyond the outer limits of the pile when
bearing in soils of class 6-65 or lower.
(c) Installation.
(1) After installation to final depth and immediately before filling
with concrete, the inside of the tube, shell, or bore shall be
thoroughly cleaned to the bottom and inspected by lowering a drop light
or by means of a light beam. To be accepted: (a) the pile shall be free
of collapsed sections of shell and the pile shell shall not show any
tears; (b) the pile shall be free of water except that a minor amount of
water may be allowed to occur in the pile if it be absorbed by placing a
suitable amount of dry cement-sand mixture in the tip end of the pile;
and (c) the alignment of the pile shall conform to the provisions of
section 27-691 of article seven of this subchapter. If the bottom of the
casing is out of sight, the shape and alignment of the casing shall be
surveyed with a suitable instrument, or the pile rejected.
(2) Concrete shall be placed by such methods that the entire volume of
the tube, shell, or bore is filled and in a manner that will preclude
separation of the ingredients.
(3) No concrete shall be placed in a cast-in-place pile until all
piles within a radius of fifteen feet, or within the heave range, have
been driven.
(4) Rejected pile shells shall be filled with concrete or sand.
(5) The concrete cap shall not be placed until at least one hour after
all piles within the cap group are completely filled.
Section 27-710
§ 27-710 Compacted concrete piles. (a) Description. A "compacted
concrete pile" shall denote a concrete pile formed with an enlarged base
in which the concrete in the base is placed in small batches that are
compacted prior to attaining an initial set. The concrete in the shaft
of the pile shall be placed as specified in section 27-709 of this
article for cast-in-place concrete piles if a permanent casting is
provided, or in small batches that are compacted.
(b) Materials. Concrete for compacted concrete piles shall conform to
the requirements of article five of subchapter ten of this chapter.
Concrete to be compacted shall have a minimum compressive strength at
the age of twenty-eight days of four thousand psi and shall be mixed
with sufficient water to permit hydration of the cement, but the slump
shall be zero. The concrete shall be placed and compacted before initial
set can occur. Non-compacted concrete, if used for the pile shafts,
shall conform to the requirements for cast-in-place concrete piles.
(c) Spacing. Minimum spacing between compacted concrete piles shall be
four feet six inches, center to center except that where the shafts of
such piles are cased for their full length, this spacing may be reduced
to three feet six inches. Where a question exists as to possible damage
to adjacent previously driven piles, these minimums shall be increased.
(d) Installation.
(1) The base shall be formed by ramming concrete, in batches of
approximately five cubic feet or less, from a drive casing and into the
soil. Unless specifically otherwise permitted by the commissioner, a
minimum of twenty blows of at least one hundred forty thousand
foot-pounds per blow shall be required for extrusion of the last five
cubic feet of concrete. The total quantity of concrete extruded from the
drive casing to form the base shall be equal to or greater than the
quantity so extruded in the case of the nearest successful applicable
test pile, except that a compactive effort in excess of thirty blows,
each of one hundred forty thousand foot-pounds, will not be required for
extrusion of the last five cubic feet.
(2) After the expanded base has been formed, the shaft shall be
constructed. Where a cased shaft is to be used, a steel shell shall be
inserted into the drive casing and anchored to the expanded base by
placing a fresh charge of concrete in the shell and driving it into the
base. The shell may then be filled with concrete to cut-off elevation
after the removal of the drive casing, in accordance with the provisions
relating to cast-in-place concrete piles. Any annular space remaining
between the shell and surrounding soil shall be suitably filled to
assure proper lateral support of the shaft, unless there is sufficient
recovery of the ground to provide the necessary support. Where an
uncased shaft is to be used, the provisions of section 27-697 of article
seven of this subchapter shall apply, and the concrete for the shaft
shall be placed by ramming or by the use of approved pressure devices as
the drive casing is withdrawn. Where ramming is used, the concrete
batches being rammed shall not exceed five cubic feet in volume, not
less than two blows of thirty thousand foot-pounds each shall be applied
to compact each batch of concrete, and the bottom of the drive casing
shall be kept below the level of the concrete at all times.
(3) The outside diameter of the permanent shaft shall not be more than
four inches less than the inside diameter of the drive casing.
(4) Except where uncased shafts are used, as described in section
27-697 of article seven of this subchapter, no concrete shall be placed
in the pile shafts until all piles within a radius of fifteen feet, or
within the heave range, have been driven.
(e) Bearing material. The enlarged base of the pile shall be formed
in, or on the same type of bearing material as is used to support the
nearest applicable load test pile and at a similar depth therein. In
addition, the enlarged base shall be underlain by a minimum depth of ten
feet (measured from the junction of the shaft and base) of soil
materials of classes 1-65 to 7-65, except that, where installation of
the base is permitted to be performed with blows of less energy than the
one hundred forty thousand foot-pounds indicated in paragraph one of
subdivision (d) of this section, the requirement for a ten foot depth of
class 1-65 to 7-65 material may be reduced, subject to the approval of
the architect or engineer and the aproval of the commissioner.
Section 27-711
§ 27-711 Steel H sections. (a) Materials. Steel H sections may be of
any type of steel permitted by the provisions of reference standard RS
10-5. The use of built-up sections or sections of other than "H" form
will be permitted if the several components of the section are
adequately connected to develop the strength of the adjacent components
and if the ratio of width to thickness of the component parts does not
exceed the values for conventional "H" sections.
(b) Limitations on use. The tips of all steel H piles having a
thickness of metal less than one-half inch, which are driven to end
bearing on rock of class 1-65 through 3-65 by an impact hammer, shall be
reinforced. The installation of all steel H piles by impact hammer to
end bearing on rock of classes 1-65 through 3-65 shall be under the
personal inspection of an architect or engineer, and the operations of
driving such piles, the observations of penetration resistance, and the
operation of the equipment shall be conducted so as to terminate driving
directly when the pile reaches refusal on the rock surface.
Section 27-712
§ 27-712 Concrete-filled pipe piles. (a) Materials. The pipe shall
conform to the provisions of reference standard RS 11-8. Concrete shall
conform to the requirements of article five of subchapter ten of this
chapter.
(b) Minimum dimensions. (1) Pipe installed open-end and having a
nominal outside diameter of less than fourteen inches shall be at least
one-quarter inch thick. For diameters from fourteen inches to eighteen
inches, the minimum thickness shall be 0.310 in. For diameters over
eighteen inches, the minimum thickness shall be 0.375 in.
(2) Steel pipe piles installed with ends closed shall have a minimum
nominal wall thickness of at least 0.125 in.
(3) For piles which receive their principal support by friction,
closure or splice plates shall not project more than three-eighths of an
inch beyond the outer limit of the pipe section.
(c) Installation.
(1) Pipe shells driven open-end shall be cleaned to the bottom of the
shell after driving.
(2) After driving and cleaning the pipe, open-end piles driven to end
bearing on rock or hardpan shall be reseated to full bearing by
redriving, to the resistance indicated in table 11-4. If the pipe shell
shows two inches or more of penetration on redriving, the pipe shall be
recleaned and redriven in successive cycles until the penetration on
redriving is less than two inches.
(3) Pipe shells shall be inspected before filling with concrete, shall
be clean, and shall meet the requirements for alignment and condition of
the shell as specified with regard to the shells of cast-in-place piles.
If leakage of water into the pipe occurs, the provisions of paragraph
five of subdivision (e) of section 27-713 of this article shall apply.
(4) Placing of concrete fill in pipe shells shall conform to the
requirements for placing concrete fill in cast-in-place piles.
Section 27-713
§ 27-713 Caisson piles. (a) Description. Caisson piles shall denote
concrete filled pipe piles that are socketed into bedrocks of class
1-65, 2-65 or 3-65 and constructed with steel cores.
(b) Materials. Pipe or shell and concrete shall conform to the
requirements for concrete filled pipe piles, except that the minimum
compressive strength of the concrete at the age of twenty-eight days
shall be thirty-five hundred psi. Steel cores shall conform to the
requirements for steel H piles. Reinforcing steel cages shall be covered
with at least one and one-half inches of concrete.
(c) Design of rock socket. The design of the rock socket shall be
predicated on the sum of the allowable bearing pressure on the bottom of
the socket plus bond along the sides of the socket. The allowable
bearing pressure on the surface of the rock at the bottom of the socket
shall be as established in section 27-678 of article four of this
subchapter increased for embedment in accordance with note eight of
table 11-2, provided that the strength of the concrete fill in the
socket, computed as 0.45f'c is of comparable magnitude. The allowable
bond stress between the concrete and the sides of the socket shall be
taken as two hundred psi. The provisions of subdivision (c) of section
27-700 of article eight of this subchapter relative to penetration
resistance shall not apply.
(d) Spacing and minimum dimensions.
(1) Minimum diameter of a caisson shall be eighteen inches with a
minimum shell thickness of three-eighths of an inch. Minimum depth of
the rock socket shall be equal to the diameter of the pipe.
(2) The center-to-center spacing of caissons shall be at least two and
one-half times the outside diameter of the shell.
(e) Installation.
(1) The steel shell shall be installed through overburden, the
material within the shell shall be removed, and the shell seated in the
rock sufficiently to stop the inflow of soil. Where required to extend
the shells, splices are to be welded. A suitable steel driving shoe
shall be welded to the bottom of each caisson.
(2) A socket shall then be drilled in the rock to the required depth
and shall be approximately of the same diameter as the inside diameter
of the shell. Before placement of concrete, the socket and shell shall
be thoroughly cleaned and the rock inspected to verify that the rock is
of the class on which the design has been predicated, or of a better
class. In case visual inspection cannot be made because of inability to
unwater the caissons by standard pumping methods, drilling logs and
screenings from the rock drilling operation may be utilized to determine
the class of rock in the socket.
(3) Where more than one section of steel core is required, the mating
ends of the sections shall be spliced so as to safely withstand the
handling stresses to which they may be subjected. The ends shall be
milled or field ground to insure contact. The steel core shall be
centrally installed in the caisson before grouting and concreting, shall
not be more than one inch above the rock at the bottom of the socket,
and shall be full length of the caisson or extend a sufficient distance
up into the shaft to transmit the load in the steel core into the
concrete of the caisson. A minimum-weight thirty-six pounds stub core
beam shall be installed in the socket for caissons not requiring steel
cores in order to lock the caissons into the rock. In these cases, the
length of the steel cores shall be twice the socket depth.
(4) Concrete and grout shall be placed so that it completely fills the
shell, the socket, and the space between the steel core and shell, and
in a manner that will preclude separation of the ingredients.
(5) If the leakage of water into the caisson is minor, the caisson
shall be pumped out and one cubic yard of grout shall be placed in the
caissons and then the balance of the concrete installed. If the leakage
of water makes it inadvisable to attempt to place concrete in the dry,
the shell shall be filled to its top with clean water, and the concrete
placed by the tremie method to the top of the caisson in one continuous
operation or by using a seal of grout of the same strength as the
specified concrete. The grout seal, if used, shall be deposited by means
of a grout pipe to an elevation of at least three feet above the cutting
edge, and after a sufficient time has elapsed to allow the grout to set,
the caisson shall be pumped dry and the remaining space filled with
concrete.
Section 27-714
§ 27-714 Composite piles. Composite piles include those consisting of
two types of pile joined together. The maximum allowable load shall be
that allowed for the component of lesser strength used to make up the
full pile length. The connection or joint between the two components
shall be constructed so as to prevent the separation of the upper and
lower components during construction and thereafter. The details and
methods of making joints shall be designed.
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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