2006 New York Code - Short-span Concrete Floor And Roof Construction Supported On Steel Beams.

 
    §  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.