Section 27-556
§ 27-556 General. In addition to the applicable dead, wind, and other
loads, the building shall be designed for uniform live loads, for
concentrated live loads, or for concurrent combinations of uniform and
concentrated live loads, whichever produce the greatest stress.
Section 27-557
§ 27-557 Floor live loads. (a) Uniformly distributed live loads. The
minimum design values established in reference standard RS 9-2 for
various occupancies or uses shall be used subject to the provisions of
subdivision (d) of this section. Where the occupancy or use of a space
does not conform to any of those listed, the design load shall be
determined by the architect or engineer subject to approval by the
commissioner.
(b) Concentrated live loads.
(1) The building framing shall be capable of supporting the
concentrated live loads established in reference standard RS 9-2, placed
so as to produce maximum stress.
(2) Floors that support any items of machinery, electrical or
mechanical equipment, or other concentrated live load in excess of one
thousand pounds (including the weights of pads or bases) shall be
designed to support such weight as a concentrated load or group of
concentrated loads.
(c) Nonconcurrence.
(1) When a concentrated live load is present, the uniformly
distributed load may be considered to be omitted in the area occupied by
the concentrated load.
(2) Where reference standard RS 9-2 indicates that the concentrated
live load is nonconcurrent with the uniform live load, it may be assumed
that the total concentrated load is to be omitted when the uniform load
is present and that the total uniform load is to be omitted when the
concentrated load is present.
(d) Conformance. For purposes of determining that the magnitude of the
actual live load conforms to or is less than the minimum design live
load established in this section, the actual uniform live load shall be
approximated by averaging the total load actually applied over a
rectangular area of one hundred fifty square feet having no side less
than eight feet.
Section 27-558
§ 27-558 Live loads for sidewalks, driveways, and railings. (a)
Sidewalks and driveways.
(1) When supported on grade, all sidewalks for new buildings and
alterations shall be subject to inspection and acceptance by the
commissioner. Portions of such sidewalks that are located between the
curb line and the street line shall be constructed in compliance with
the specifications for concrete sidewalks of the department of
transportation.
(2) All sidewalks and driveways or portions thereof that are
structurally supported shall be designed for a live load of one hundred
psf uniformly distributed and in accordance with the provisions of
subchapter ten of this chapter. Where subject to intentionally or
accidentally imposed wheel loads of vehicles, such portions of sidewalks
and driveways shall be designed for a uniformly distributed load of six
hundred psf or for the maximum vehicular wheel load that could be
imposed thereon, whichever develops the greater stresses.
(3) Appurtenant components of sidewalks and driveways, including
manholes, manhole covers, vault covers, gratings, etc., shall be
designed for the loads prescribed in paragraph two of this subdivision,
or shall conform to the standards of the city agency having
jurisdiction.
(b) Railings and parapets.
(1) Railings and parapets around stairwells, balconies, areaways, and
roofs, and other railings in similar locations other than those for
places of assembly, shall be designed to resist the simultaneous
application of a lateral force of forty plf and a vertical load of fifty
plf, both applied to the top of the railing. For railings and parapets
at the front of theater balconies and in similar locations in places of
assembly, the lateral force shall be increased to fifty plf and the
vertical load to one hundred plf. An exception is made for railings in
one- and two-family dwellings, which shall be designed for a lateral
force of twenty plf plus a vertical load of twenty plf, both applied at
the top of the railing. The total lateral force and total vertical load
shall be at least two hundred pounds each.
(2) Intermediate and bottom rails, if provided, shall be designed for
the simultaneous application of forty plf applied horizontally and fifty
plf applied vertically; however, lateral and vertical design loads on
intermediate and bottom rails need not be considered in the design of
posts and anchorages. For railings having solid panels, the panels shall
be designed for a uniform lateral load of twenty psf.
(3) Where railings or parapets support fixtures, allowance shall be
made for the additional loads imposed thereby.
(4) Railings, bumpers, or similar devices used in parking areas to
resist the impact of moving vehicles shall be designed to resist a
lateral load of three hundred plf applied at least twenty-one inches
above the roadway; but in no case shall the load be less than
twenty-five hundred pounds per vehicle.
Section 27-559
§ 27-559 Columns in parking areas. Unless specially protected, columns
in parking areas subject to impact of moving vehicles shall be designed
to resist the lateral load due to impact and this load shall be
considered a load of infrequent occurrence. For passenger vehicles, this
lateral load shall be taken as a minimum of twenty-five hundred pounds
applied at least twenty-one inches above the roadway and acting
simultaneously with other design loads.
Section 27-560
§ 27-560 Stage areas using scenery or scenic elements. Scenery battens
and suspension systems shall be designed for a load of thirty pounds per
linear foot of batten length. Loft block and head block beams shall be
designed to support vertical and horizontal loads corresponding to a
four inch spacing of battens for the entire depth of the gridiron.
Direction and magnitude of total forces shall be determined from the
geometry of the rigging system including load concentrations from spot
line rigging. Locking rails shall be designed for a uniform uplift of
five hundred psf with a one thousand pound concentration. Impact factor
for batten design shall be seventy-five per cent and for loft and head
block beams shall be twenty-five per cent. A plan drawn to a scale not
less than one-quarter inch equals one foot shall be displayed in the
stage area indicating the framing plan of the rigging loft and the
design loads for all members used to support scenery or rigging.
Gridirons over stages shall be designed to support a uniformly
distributed live load of fifty psf in addition to the rigging loads
indicated.
Section 27-561
§ 27-561 Roof loads. Roofs and marquees shall be designed for wind,
live, and other loads as prescribed in subdivisions (a) through (d) of
this section. It may be assumed that maximum wind load occurs with zero
live load and that maximum live load occurs with zero wind load. For
dwellings an exception is made for awnings, canopies, and patio covers,
which may be designed for a live load of twenty psf of horizontal
projection.
(a) Live load. Minimum design live loads shall be as follows:
(1) For roofs with slopes up to and including twenty degrees from the
horizontal, thirty psf of horizontal projection.
(2) For roofs with slopes greater than twenty degrees from the
horizontal, thirty psf of horizontal projection, reduced by one psf for
each degree of slope in excess of twenty degrees.
(3) For valleys, live loadings shall be increased to provide for
accumulations of snow. The loading intensity shall be assumed to vary
from forty-five psf at the low point to fifteen psf at the ridge.
(4) For roofs having curved or pyramidal shapes, the proposed live
load shall be established by the architect or engineer, subject to
approval by the commissioner.
(b) Wind load. The provisions of section 27-569 of article five of
this subchapter shall apply.
(c) Concentrated loads. The provisions of subdivision (b) of section
27-557 of this article shall apply.
(d) Special loads.
(1) When used for purposes such as promenades, assembly areas, or roof
gardens, design shall be made for live loads corresponding to the
particular usage, as indicated in reference standard RS 9-2. Such loads
shall be considered as nonconcurrent with the wind load or with the live
load specified in subdivision (a) of this section. The design live and
wind loads for roofs, as specified elsewhere in this subchapter, shall
be deemed to provide for incidental use of the roof of a building by the
occupants thereof.
(2) Where roofs are intended for the ponding of water, the roof shall
be designed for the maximum possible depth of water which may be ponded
thereon as determined by the relative levels of roof deck and overflow
weirs or scuppers. Such load need not be considered as occurring
simultaneously with wind or live load.
(3) Girders and roof trusses (other than joists) over garage areas
regularly utilized for the repair of vehicles and over manufacturing
floors or storage floors used for commercical purposes shall be capable
of supporting, in addition to the specified live and wind loads, a
concentrated live load of two thousand pounds applied at any lower chord
panel point for trusses, and at any point of the lower flange for
girders.
(4) Where roofs are landscaped, the uniform design live load on the
landscaped portions shall be thirty psf. The weight of the landscaping
materials shall be considered as dead load and shall be computed on the
basis of saturation of the earth. The areas adjacant to the landscaped
portions shall be considered as assembly areas, unless specific
provision is made to prevent such use.
(5) Where equipment is placed on roofs, the design shall provide for
the support of such equipment.
Section 27-562
§ 27-562 Moving loads. Where applicable to the use or occupancy of the
building, the design shall consider the moving loads described below.
(a) General. The loads established in subdivisions (a) and (b) of
section 27-557 of this article shall be assumed to include allowance for
ordinary impact conditions.
(b) Passenger vehicles. Areas used for, and restricted by physical
limitations of clearance to, the transit or parking of passenger
vehicles shall be designed for the uniformly distributed and
concentrated loads for parking areas for such vehicles as provided in
reference standard RS 9-2, applied without impact. An exception is made
for members or constructions which, because of physical limitations,
cannot be subjected to direct load from the vehicle or from a jack or
hoist used to raise or suspend the vehicle. Such members or
constructions shall be designed for the loads corresponding to the
actual usage.
(c) Truck loads. Minimum loads (including vertical, lateral, and
longitudinal) and the distribution thereof shall meet the applicable
requirements of reference standard RS 9-3, except that impact shall be
taken as ten per cent of the vertical reaction.
(d) Railroad equipment. Minimum loads (including vertical, lateral,
longitudinal, and impact) and the distribution thereof shall meet the
applicable requirements of reference standard RS 9-4.
(e) Crane runways and supports.
(1) VERTICAL LOADS. Actual maximum wheel loads occurring when the
crane is lifting its capacity load shall be used. To allow for impact,
the lifted load shall be increased twenty-five per cent or the wheel
loads increased fifteen per cent whichever produces greater stress
condition.
(2) HORIZONTAL LOADS.
a. Lateral load (due to crane trolley travel) shall be twenty per cent
of the sum of the capacity load and the trolley weight, applied one-half
at the top of each rail and acting in either direction normal to the
runway rail.
b. Longitudinal load (due to crane travel) shall be twenty per cent of
the maximum total reaction (not including impact) on the rail being
considered, applied at the top of the rail and acting parallel to the
runway.
(f) Monorail beams and supports.
(1) Vertical loads shall be the sum of the capacity load and trolley
weight. To allow for impact, the lifted load shall be increased ten per
cent for hand-operated and twenty-five per cent electrically-operated
trolleys.
(2) Longitudinal loads shall be twenty per cent of the sum of the
capacity load and the weight of the trolley.
(3) Lateral load shall be twenty per cent of the sum of the capacity
load and the weight of the trolley.
(4) Centrifugal forces shall be considered for curved tracks.
(g) Loads on supports for elevators, dumbwaiters, and escalators. The
provisions of subchapter eighteen of this chapter shall apply.
(h) Loads on machinery supports. Unless machinery is isolated from the
support framing, the reactions of reciprocating or heavy powerdriven
units shall be increased at least fifty per cent and reactions of light
shaft- or motor driven units shall be increased at least twenty-five per
cent to provide for impact.
(i) Assembly structures. Seating areas in grandstands, stadiums, and
similar assembly structures shall be designed to resist the simultaneous
application of a horizontal swaying load of at least twenty-four plf of
seats applied in a direction parallel to the row of the seats, and of at
least ten plf of seats in a direction perpendicular to the row of the
seats. When this load is used in combination with wind for outdoor
structures, the wind load shall be one-half of the design wind load, and
the provisions of subchapter ten of this chapter relating to infrequent
stress conditions shall apply to this loading condition.
(j) Heliports and helistops.
(1) CONCENTRATED LOADS.
a. Landing area. Helicopter landing areas shall be designed for either
of the following vertical loads acting at any location:
1. A single concentrated load equal to three quarters of the gross
weight of the helicopter and acting on an area of one square foot.
2. Concentrated loads representing the gross wheel reactions of the
helicopter acting simultaneously and increased one-third for impact.
b. Taxiing area Helicopter taxiing areas shall be designed for
concentrated loads in accordance with clause two of this subparagraph.
(2) UNIFORM LIVE LOAD. The landing and taxiing areas shall be capable
of supporting a uniformly distributed live load of forty psf acting
nonconcurrently with the concentrated loads.
Section 27-563
§ 27-563 Partial loading conditions. (a) Uniformly distributed loads.
In continuous framing and cantilever construction, the design shall
consider live load on all spans and arrangements of partial live load
that will produce maximum stresses in the supporting members. The
simplifications given in paragraphs one through three of this
subdivision are permissible.
(1) FLOOR AND ROOF FRAMING.
a. For vertical live load applied to the level under consideration,
the far ends of the columns above and below that level may be assured as
fixed.
b. Combinations of live load may be limited to the following:
1. Live load placed on two adjacent spans.
2. Live load placed on alternate spans. The effects of live load on
spans more than two spans away from the span under consideration may be
neglected.
(2) ARCHES AND GABLED FRAMES.
a. Live load placed on 1/2 span adjacent to one support.
b. Live load placed on the center 1/4 span.
c. Live load placed on 3/8 the span adjacent to each support.
(3) COLUMNS. Moments due to vertical loads may be calculated from the
live load on the largest single adjacent span of the floor under
consideration. This moment shall be assumed to act concurrently with
live load on all other floors.
(b) Moving concentrated loads. Structural members supporting moving
concentrated loads shall be designed for only those loads that can
physically occur simultaneously and are arranged to produce maximum
stresses.
Section 27-564
§ 27-564 Floor loads to be posted. (a) Posting required. Posting
requirements shall conform to the requirements of section 27-225 of
article twenty-three of subchapter one of this chapter.
(b) Data required. The following floor load data shall be shown:
(1) The uniformly distributed design live load for each floor or part
thereof.
(2) The weight of any piece of machinery or equipment weighing more
than one thousand pounds, and its identifying description and location.
(3) The maximum design wheel load and total maximum weight of any
vehicle that may be brought into the building.
(4) The equivalent uniform partition loads or, in lieu of this, a
statement to the effect that the design was predicated on actual
partition loads.
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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