Section 27-603
§ 27-603 General requirements. Concrete materials, design,
construction, quality, inspection and testing shall meet the
requirements of reference standard RS 10-3. Precast concrete
construction utilizing a thin skin or slab stiffened or supported by a
system of ribs shall conform to the requirements of reference standard
RS 10-4.
Section 27-604
§ 27-604 Identification of metal-reinforcement. Reinforcing bars shall
be rolled so as to identify type and grade of steel, and size. Bundles
and rolls of wire, strands, or welded wire fabric shall be tagged so as
to identify the type and grade of steel and the size.
Section 27-605
§ 27-605 Mixes. Concrete may be proportioned, batched, and mixed by
any of the following methods:
(a) Method I. Mixes with minimum cement content.
(1) MINIMUM CEMENT CONTENT. The cement content used in the work shall
not be less than the content given in table 10-3 for the corresponding
strength of concrete.
TABLE 10-3
MINIMUM CEMENT CONTENT
________________________________________________________________________
Specified Compressive Minimum Pounds of Cement
Strength in 28 Days Per Cubic Yard of Concrete
(f'c) - psi (all aggregates)
________________________________________________________________________
3,000 540
3,500 610
4,000 660
5,000 800
Over 5,000 Permitted only by reference
standard RS 10-3
6,000 and over Permitted only by reference
standard RS 10-3,
"Special Requirements for
High Strength Concrete."
NOTE: Minimum pounds of cement may be reduced up to 8 percent by the
addition of an accepted admixture.
(2) WATER-CEMENT OR STRENGTH-CEMENT RATIO.
Normal weight concrete proportioned on the basis of preliminary tests
shall be produced by using a water-cement ratio corresponding to a point
on a strength-cement or water-cement ratio curve. Proportioning of
lightweight and heavyweight concrete, and concrete using an aggregate
other than natural sand, gravel or stone shall be by using a
strength-cement content curve. The point on the respective curves shall
represent a strength of concrete at the slump and age called for on the
plans at least twenty-five percent higher than the specified strength,
f'c. The cement content shall not be less than the content shown in
table 10-3.
(3) PRELIMINARY TESTS. Preliminary tests of concrete shall be made in
advance of any concreting operation by a licensed concrete testing
laboratory acceptable to the architect or engineer of record.
Preliminary tests shall consist of compression strength tests of molded
concrete cylinders made in accordance with reference standards RS 10-17
and RS 10-21. A curve representing the relation between the average
strength of the concrete at twenty-eight days, or at any other specified
age filed with the department, and the strength-cement ratio or the
water-cement ratio shall be established for the range of strength values
at the slump required for the work. The tests shall include at least
four mixes with different strength-cement ratios or four mixes with
different water-cement ratios and at least four cylinder specimens for
each mix. The cylinder strength tests shall be supplemented by tests to
confirm that the cement and aggregates conform to the provisions of
reference standard RS 10-3.
(4) PREVIOUSLY ACCEPTED MIXES. In lieu of the requirements of
paragraph three of this subdivision, the architect or engineer
designated for controlled inspection may permit the use of mix
proportions of aggregates having the same specific gravity, size and
gradation; cements of the same type and batch weight; admixtures of the
same type and quantity; and other ingredients the same as or equal to
those that have been previously submitted with applicable preliminary
tests which complied with paragraphs one and two of this subdivision,
and which have been accepted by the commissioner within the past year.
If any of the mix proportions or ingredients are changed, a separate
submission for acceptance shall be required.
(5) QUALITY CONTROL AND INSPECTION OF MATERIALS AND OF BATCHING. Where
concrete materials are used for structural elements defined in section
27-585 of article one of this subchapter, quality control and inspection
shall be provided at the batch plant by a licensed concrete testing
laboratory under the supervision of the architect or engineer designated
for controlled inspection, in accordance with the requirements of table
10-1 and in sufficient scope to:
a. Determine and record the actual batched weights of the ingredients
and the volume of water charged into the mixer;
b. Verify that such weights conform to the weights and proportions
required by the preliminary test mix, adjusted for moisture content,
fineness modulus and gradation of aggregates;
c. Verify conformance of the quality and condition of the materials to
reference standard RS 10-3;
d. Verify that the aggregates have the same specific gravity, size and
gradation; the cement is the same type and batch weight, the admixtures
are the same type and quantity; and that any other ingredients are the
same as or equal to those used for the preparation of the preliminary
test mixes;
e. For all concrete, whether or not designated for controlled
inspection, attestation of the results of quality control and inspection
at the batch plant shall appear on a ticket accompanying each load of
concrete. The attestation for subparagraphs a, b, c and d of this
paragraph shall be executed by the licensed concrete testing laboratory.
f. The licensed concrete testing laboratory shall also attest that the
slump entrained air content and unit weight of the fresh concrete, as
discharged from the mixer at the job site, were tested in accordance
with reference standards RS 10-49, RS 10-51, RS 10-52, RS 10-61, RS
10-62, RS 10-63 and RS 10-64, and that all were in compliance with the
accepted mix design.
(b) Method II. Proportioning on the basis of field experience.
(1) PROPORTIONING. For the computation of the standard deviation in
accordance with reference standard RS 10-14, mixes with test data from
previous projects, similarly proportioned in accordance with the
provisions of subdivision (a) of this section, and having materials of
similar density and admixtures and having a slump equal to or greater
than that at which the concrete is to be placed shall be used. Such
mixes may be accepted subject to the approval of the architect or
engineer designated for controlled inspection.
(2) STRENGTH. The required average strength, fcr, to be used as the
basis for the selection of mix proportions, shall in no case be less
than fifteen percent higher than the specified strength called for on
the plans.
(3) BATCHING. The concrete shall be produced either in the concrete
production facility used to produce the concrete from which the tests
were made to develop the field experience data referred to in paragraph
one of this subdivision or, subject to the approval of the architect or
engineer designated for controlled inspection, in any concrete
production facility that has data showing a record of standard deviation
equal to or less than that of the original facility. All concrete
proportioned according to field experience shall be produced in a plant
with automatic recording equipment for all ingredients.
(4) QUALITY CONTROL AND INSPECTION OF MATERIALS AND OF BATCHING. When
the concrete is batched in a plant where automatic recording equipment
documents the batched weights or volumes of cement, aggregates,
admixtures and water, no inspection of the materials or of the batching,
nor any attestation by a licensed concrete testing laboratory
responsible to the architect or engineer designated for controlled
inspection, shall be required. A concrete producer shall:
a. Verify that such weights conform to the required weights and
proportions, and to the strength-cement ratio or water-cement ratio
required by the proportioning established pursuant to paragraph one of
this subdivision, adjusted for moisture content, fineness modules and
gradation of aggregates.
b. Verify conformance of the quality and condition of the materials to
reference standard RS 10-3.
c. Attest, on a ticket accompanying each load, to the specified
strength of the concrete, the actual weights or volume of the
ingredients, and the weight or volume of water charged into the mixer at
the batch plant or to be added at the job site. A statement that
subparagraph b of this paragraph has been complied with shall also be
included.
d. If at any time the automatic recording equipment becomes
inoperative, the concrete production facility may be permitted, but only
with the approval of the architect or engineer designated for controlled
inspection, to batch and mix concrete for a period not to exceed three
consecutive working days. During such a period, the concrete production
facility shall engage a concrete batch plant inspector from a licensed
concrete testing laboratory to observe and record the actual weights of
the cement, aggregates, admixtures and other ingredients, and the weight
or volume of water charged into the mixers. If the automatic recording
equipment is inoperative for a period longer than three consecutive
working days the concrete production facility shall not batch or mix
concrete and the architect or engineer designated for controlled
inspection shall notify the commissioner in writing that such equipment
is inoperative.
(c) Method III. Average Concrete. (1) in lieu of making preliminary
tests, average concrete limited to the concrete strengths shown in table
10-3A below may be used, and the cement content shall not be less than
the value given in table 10-3A for the corresponding specified
compressive strengths, nor shall the total volume of water (moisture
plus added water) exceed that specified therein, provided that the total
yardage placed does not exceed fifty cubic yards and the levels of
calculated stress do not exceed seventy percent of the basic allowable
stresses.
TABLE 10-3A
________________________________________________________________________
Specified Minimum pounds of Maximum permissible
compressive strength in cement per cubic yard of total volume of
twenty-eight days (f'c) concrete water, U.S. gallons
pounds per square inch per cubic yard of
concrete
________________________________________________________________________
2000 520 40
2500 560 41
3000 610 42
________________________________________________________________________
(2) Each load of concrete shall be certified by the producer to the
owner, whether produced at a ready mixed plant or site mixed, as to the
total quantity of concrete, concrete strength and actual quantities per
cubic yard of each material, including water, contained therein. A copy
of such certificate shall be available to the department during the
progress of the work and for two years thereafter.
Section 27-606
§ 27-606 Documentation. All mix proportions and supporting data shall
be submitted for acceptance to the commissioner or to the architect or
engineer designated for controlled inspection, as required, prior to the
start of any work. All required attestations shall become a part of the
documentation to be filed with the commissioner, and shall be subject to
verification by strength tests, as hereinafter described, by check
sampling of ingredients, or by such other inspections as the
commissioner or the architect or engineer designated for controlled
inspection may elect. Copies of all documentation filed with the
commissioner, all the licensed concrete testing laboratory test data and
required attestations, together with the tapes recording the batch
weight where automatic recording equipment is used shall be available
for inspection for a period of two years after the completion of the
project. Such records shall be maintained by the architect or engineer
designated for controlled inspection.
Section 27-607
§ 27-607 Inspections. Inspection of concrete and concrete construction
shall conform to the requirements of tables 10-1 and 10-2 and the
provisions of this subchapter.
(a) Controlled inspection. Controlled inspection of concrete
construction shall include:
(1) STRENGTH TESTS. Strength tests shall be performed on all
structural concrete. The provisions of reference standard RS 10-3 shall
apply. A licensed concrete testing laboratory shall, in compliance with
reference standards RS 10-17, RS 10-51 and RS 10-52, sample the
concrete, make and cure the test specimens at the job site, transport
the specimens to the laboratory and test the specimens for compressive
strength. Written reports of the results shall be furnished to the
architect or engineer designated for controlled inspection and to the
concrete producer immediately, but not more than five days following the
conclusion of the compression strength tests. Test specimens shall be
stored on the job site in an insulated curing box of sufficient size and
strength to contain all the specimens made in any four consecutive
working days and to protect the specimens from falling over, being
jarred or otherwise disturbed during the period of initial curing. The
box shall be erected, furnished and maintained by the concrete
contractor. Such box shall be equipped to provide the moisture and to
regulate the temperature necessary to maintain the proper curing
conditions required by reference standard RS 10-52. Such box shall be
located in an area free from vibration such as pile driving and traffic
of all kinds. No concrete requiring inspection shall be delivered to the
site until such storage curing box has been provided. Specimens shall
remain undisturbed in the curing box until ready for delivery to the
testing laboratory but not less than sixteen hours. Specimens delivered
to the laboratory prior to an age of forty-eight hours shall not be
demolded prior to delivery. All specimens shall be carefully removed
from the box and transported to the laboratory by the licensed concrete
testing laboratory in accordance with the provisions of reference
standard RS 10-52. All specimens shall be delivered to the laboratory
before the laboratory closes at the end of the second working day
following the day the specimens were molded. The date of arrival at the
laboratory shall be recorded on the specimen test reports. All concrete
failing to meet the specified minimum strength requirements shall be
rejected by the architect or engineer designated for controlled
inspection pending verification of the adequacy of the construction as
described in section 27-598 of article three of this subchapter.
(2) ADDITIONAL TESTS. Each sample of fresh concrete made in accordance
with reference standard RS 10-51 for the purpose of molding strength
test specimens shall be made under the supervision of the architect or
engineer designated for controlled inspection. Each sample shall be
tested by the licensed concrete testing laboratory to determine its
slump in accordance with reference standard RS 10-49, its entrained air
content in accordance with reference standards RS 10-61 and RS 10-62,
its unit weight in accordance with reference standards RS 10-63 and RS
10-64 and its temperature. If any of the tests fail to meet the
specified requirements, the concrete shall be sampled again and the
particular test that failed shall be repeated. If the second test fails
to meet the specified requirements, then, with the approval of the
architect or engineer designated for controlled inspection, adjustments
shall be made to the concrete in the mixer to correct the deficiency.
Test specimens shall not be molded from any sample that did not meet the
specified requirements nor shall the concrete from which the sample was
taken be placed in the structure, provided, however, that such concrete
may be used elsewhere in the work where it meets or exceeds the
specified requirements, but only with the approval of the architect or
engineer designated for controlled inspection. In such case, test
specimens shall be molded by the licensed concrete testing laboratory
which shall also record the precise location where the concrete was
placed in the structure.
(3) CONTROLLED INSPECTION LOG BOOK. A controlled inspection log book,
limited solely to the concrete construction work, readily available to
inspectors and representatives of the department, concrete suppliers and
the architect and/or engineer of record, shall be maintained at the job
site by the architect or engineer designated for controlled inspection,
who shall make therein daily entries pertaining to the progress of the
work. The entries shall describe, but not be limited to, the location,
size and dimensions of the concrete members for which forms were
constructed that day; the reinforcement installed in, and the specific
locations and time spans of, every concrete placement; the air
temperature, wind velocity and direction and other weather conditions
during the twenty-four hours after concrete has been placed, speci-
fically at eight a.m., noon and four p.m., the protections taken against
excessive temperatures and adverse weather conditions at each placement
made that day; the methods used, to cure the concrete and the period
during which such methods were maintained; the actual hour when forms
were stripped and shores were reinstalled and tensioning was applied to
all prestressed members. The log shall become a part of the
documentation to be filed with the commissioner as provided in section
27-606 and shall include the attestation of the architect or engineer
designated for controlled inspection that the concrete construction work
complies with the approved plans and the provisions of this code.
(b) Other required inspection. Quality control or inspection shall be
provided with respect to all operations of mixing and placing concrete
and reinforcement that are not designated for controlled inspection. In
the case of sidewalks, curbs, paving, slabs-on-grade and any work
designated in table 10-1 under the caption "Elements That Are Not
Subject to Controlled Inspection" or in table 10-2 under the caption
"Operations on Structural Elements That Are Not Subject to Controlled
Inspection," all inspections shall be subject to and in accordance with
the requirements of subdivision (b) of section 27-132. If any test to
determine the quality or compressive strength of the concrete is
required, the fresh concrete shall be sampled and tested for slump,
entrained air content, unit weight and temperature. Compression strength
test specimens shall be molded only by a licensed concrete testing
laboratory or by a person certified by the American Concrete Institute
as qualified to perform such function. Attestation shall be executed by
the person superintending the use of the material in accordance with the
requirements of subdivision (b) of section 27-132 of article seven of
subchapter one of this chapter.
Section 27-608
§ 27-608 Admixtures. Admixtures may be used in the concrete only where
included in the preliminary test mixes made in accordance with paragraph
three of subdivision (a) of section 27-605 or mixes proportioned in
accordance with the provisions of reference standard RS 10-3. In the
case of mixes proportioned in accordance with subdivision (c) of section
27-605, there shall be no reduction of the cement content called for in
table 10-3A because admixtures are used in the mix. Where admixtures are
used, the provisions of reference standards RS 10-3 and RS 10-44 shall
apply. In addition, no anti-freeze agents shall be used. Admixtures
shall be added in measured quantities in conformance with the accepted
mix design.
Section 27-609
§ 27-609 Licensed concrete testing laboratories. All strength tests of
concrete and testing of concrete materials required by the provisions of
this section shall be performed by concrete testing laboratories
licensed in accordance with the requirements of article nine of
subchapter two of chapter one of title twenty-six of the administrative
code and rules promulgated by the commissioner. The licensed concrete
testing laboratory shall, among other things, analyze, evaluate and test
concrete materials; determine whether the materials comply with
specifications and pertinent referenced national standards in reference
standard RS 10-3; select mix proportions for preliminary tests;
recommend the mix proportions to be used on the project for which the
tests were made; analyze data from previous projects and compute the
standard deviation; and recommend the mix proportions to be used based
on such field experience data. At the batch plant or at the job site,
the licensed concrete testing laboratory shall, among other things,
sample concrete and test for slump, entrained air content, unit weight
and temperature, mold compression test specimens; store and cure such
specimens on the job site; remove, transport and deliver such specimens
to the laboratory; demold, store, cure, cap and test such specimens at
the laboratory and furnish written reports of the results of all tests
of the materials and concrete to the architect or engineer designated
for controlled inspection and to the concrete producer. When tests of
the hardened concrete are required, they shall be made by the licensed
concrete testing laboratory in accordance with reference standard RS
10-3 and the national standards for making tests for penetration
resistance, rebound number, pullout strength and of drilled cores. The
architect or engineer designated for controlled inspection is authorized
either to dismiss or to employ a particular licensed concrete testing
laboratory at any time during the progress of the work.
Section 27-610
§ 27-610 Short-span concrete floor and roof construction supported on
steel beams. In lieu of analysis, the following empirical procedures may
be used for the design of short-span concrete floor and roof slabs
containing draped reinforcement and supported on steel beams. The
empirical equations described in subdivisions (c) and (d) of this
section shall apply only where the steel beams are placed, or are
encased, in a manner that will provide section for the transfer of shear
from slabs to beams equivalent to, or in excess of, the slab thickness
required by said equations.
(a) Concrete. The concrete shall have a minimum compressive strength
at twenty-eight days of seven hundred psi.
(b) Reinforcement. Reinforcement shall consist of steel fabric, rods,
or other suitable shapes that shall be continuous or successively lapped
to function as a continuous sheet. The main reinforcement shall be at
least 0.15% of the gross cross section where continuous steel fabric is
used and at least 0.25% of the gross cross section where other forms of
steel reinforcement are used. All reinforcing shall be draped, with the
center of the reinforcement at the center of the span one inch above the
bottom of the slab and the center of reinforcement over the support one
inch below the top of the slab.
(c) Minimum slab thickness. The minimum total thickness of concrete
floor and roof construction shall be determined by the following
formula, but shall not be less than four inches:
L w-75
t = ___ + ______
2 200
where: t = total thickness (in.)
L = clear span between steel flanges (ft.)
w = gross uniform load (dead load plus reduced live load) (psf).
(d) Allowable Load. The allowable load shall be determined by the
following formula:
3CAs
w = ______
L2
where: w = gross uniform load (psf)
As = cross-sectional area of main reinforcement (sq. in. per ft.
of slab width)
L = clear span between steel flanges in feet. (L shall not
exceed ten feet in any case, and when the gross floor
load exceeds two hundred psi shall not exceed eight feet)
C = the following coefficient for steel having an ultimate
strength of at least fifty-five thousand psi;
1. For lightweight aggregate concrete:
a. twenty thousand when reinforcement is continuous.
b. fourteen thousand when reinforcement is hooked or attached to one
or both supports.
2. For stone concrete:
a. twenty-three thousand when reinforcement is continuous.
b. fifteen thousand when reinforcement is hooked or attached to one or
both supports.
(1) When the above formula is used the reinforcement shall be hooked
or attached to one or both supports or be continuous.
(2) If steel of an ultimate strength in excess of fifty-five thousand
psi is used, the above coefficient may be increased in the ratio of the
ultimate strength to fifty-five thousand but at most by thirty percent.
(e) Openings in floors and roofs. Openings more than one foot six
inches on a side shall be framed. All areas encompassing multiple
openings aggregating more than one foot six inches in any ten foot width
or span of floor or roof slab shall be framed.
Section 27-611
§ 27-611 Pneumatically placed concrete. Construction methods shall
conform to the applicable provisions and recommendations of reference
standard RS 10-15.
Section 27-611.1
§ 27-611.1 Conveying concrete by pumping methods. All classes and
strengths of concrete may be conveyed by pumping methods. All materials
and methods used shall conform to the rules promulgated by the
commissioner for conveying concrete by pumping methods.
Section 27-612
§ 27-612 Formwork, slip form construction, lift method construction,
precast and prestressed construction. The provisions of subchapter
nineteen of this chapter shall apply.
Section 27-613
§ 27-613 Concrete utilizing preplaced aggregate. The use of concrete
formed by the injection of grout into a mass of preplaced coarse
aggregate will be permitted where it can be demonstrated by successful
prototype installation that the proposed mix, materials, and method of
placement will produce a concrete of the specified strength and free of
areas or inclusions of uncemented aggregate.
(a) Prototypes. At least two prototypes, from either previous work or
samples prepared for the proposed project shall be prepared. The forms
shall be stripped, and a minimum of six cores recovered and tested to
demonstrate the strength of the concrete produced by the proposed
materials and methods of installation. In addition, the homogeneity of
the prototypes shall be demonstrated by demolishing the prototypes.
(b) In-place concrete. The concrete, as finally placed in the work,
shall be prepared using the same materials, mix, equipment, and
procedures utilized to prepare the successful prototype installations.
(c) Inspection. All preparation and placement of structural concrete
utilizing preplaced aggregates shall be subject to controlled
inspection. Compression test specimens shall be prepared and tested as
required for premixed concrete, except that the specimens shall be
prepared under conditions that will simulate the conditions under which
the concrete in the work is installed.
Section 27-613.1
§ 27-613.1 Precast and prestressed concrete. The provisions of
reference standard RS 10-3 shall apply.
Section 27-613.2
§ 27-613.2 Thin-section precast concrete construction. The provisions
of reference standard RS 10-4 shall apply.
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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