Section 27-639. Design

The following design requirements shall supplement
  the applicable provisions of this subchapter.
    (a) Flexibility. Suspenders, unless  encased,  may  be  considered  as
  perfectly flexible.
    (b)  Elastic  stretch.  The elastic stretch of the suspenders shall be
  considered.
    (c) Displacement. Displacement resulting from changes in magnitude and
  position of load and its affects on stress shall be considered.
    (d) Other considerations. Consideration shall be given to the  effects
  of  temperature  variations,  partial  and reversible wind loadings, and
  vibration.
    (e) Allowable working load. The allowable working load  in  suspenders
  formed  from bridge wire cable shall be computed on the basis of factors
  equal to one and one-half times dead load plus two  and  one-half  times
  live load or one and two-tenths times dead load plus two times live load
  plus  two  times  wind load, applied to the specified, minimum, ultimate
  strength of the suspender. The  allowable  working  load  in  suspenders
  conforming   to   the  materials  specifications  or  several  reference
  standards of this code shall  be  the  allowable  working  stresses  for
  tension  members  as prescribed in the applicable reference standard or,
  for those materials where allowable stresses for tension members are not
  prescribed, on factors of one and one-half  times  dead  load  plus  two
  times  live  load  or  one  and  two-tenths times dead load plus one and
  one-half times live load, plus one and one-half times  wind  load,  also
  applied to the specified minimum, ultimate strength of the suspender. In
  no case, however, shall the factor, applied to the yield strength of the
  material  or  to the prestretching or prestressing force, exceed one and
  one-tenth times dead load plus one and one-quarter times live load.