Section 27-566. Floor live loads

The uniform live load to be used for design
  shall  be  the  basic  value  established  in  reference standard RS 9-2
  multiplied by the percentages given in subdivisions (a) through  (d)  of
  this section.
    (a)  Except  as  provided  in  subdivisions  (b),  (c),  and  (d), the
  percentages in table  9-1  shall  apply.  Contributory  areas  shall  be
  computed in accordance with section 27-567 of this article.
    (b)  No  live  load  reduction  shall  be permitted for the following:
  members  and  connections  (other  than  columns,  piers,   and   walls)
  supporting  floor  areas used for storage (including warehouses, library
  stacks, and record storage); areas used for  parking  of  vehicles;  and
  areas  used  as  place of assembly, for manufacturing, and for retail or
  wholesale sales. For columns, piers, and  walls  supporting  such  floor
  areas the maximum live load reduction shall be twenty per cent.
    (c)  No  live  load reduction shall be permitted for calculating shear
  stresses at the heads of column in flat slab or flat plate construction.
    (d) In lieu of the percentages given  in  table  9-1,  the  live  load
  reductions for columns, piers and walls may be taken as fifteen per cent
  of the live load on the top floor, increased successively at the rate of
  five  per  cent on each successive lower floor, with a maximum reduction
  of fifty per cent; and for girders supporting two hundred square feet or
  more of floor area, the live load reduction may be taken as fifteen  per
  cent.  The  limitations of subdivisions (b), (c) and (d) of this section
  shall apply.
 
                     TABLE 9-1  Percentage of Live Load*
  ========================================================================
                                        Ratio of Live Load to Dead Load*
          Contributory Area         0.625 or less        1       2 or More
  ------------------------------------------------------------------------
       149 or less                       100            100        100
       150-299                            80             85         85
       300-449                            60             70         75
       450-599                            50             60         70
       600 or more                        40             55         65
  ========================================================================
 
  Note:
    * For intermediate values  of  live  load/dead  load,  the  applicable
  percentages of live load may be interpolated.