Section 27-705. Procedures

(a)  Continuous  Driving.  Driving  of  piles
  preliminary to  final  seating  shall  be  continuous  for  an  interval
  adequate to break or prevent the development of freeze. The hammer shall
  be operated at its rated speed during this interval.
    (b)  Jetting.  Jetting,  augering  and other methods of pre-excavation
  shall not be used unless  permitted  in  writing  by  the  architect  or
  engineer.    When  permitted,  such procedures shall be carried out in a
  manner which will not impair the carrying capacity of the piles  already
  in  place  or  the  safety  of  existing adjacent structures. Jetting or
  augering shall be stopped at least three feet above the  final  expected
  pile-tip  elevation  and  at least three feet above the tip elevation of
  any pile previously driven within six feet of the jet or  auger,  except
  that  where  piles  are to be end bearing on rock or hardpan, jetting or
  augering may be carried to the surface of the  rock  or  hardpan.  Piles
  shall  be  carried  down  beyond the depth of jetting, augering or other
  pre-excavation until the required resistance is obtained.  If  there  is
  evidence   that   jetting   or   other  procedures  have  disturbed  the
  load-bearing capacities of previously installed piles, those piles  that
  have  been  disturbed  shall  be  restored  to  conditions  meeting  the
  requirements of this article by redriving or by other methods acceptable
  to the architect or engineer.   Redriving  or  other  remedial  measures
  shall  be  instituted  after the jetting or other operations in the area
  have been completed.
    (c) Sequence of installation. Individual piles and pile  groups  shall
  be  installed  in  such  sequence  that:  (1)  the  carrying capacity of
  previously installed piles is not reduced; (2) the soil surrounding  the
  piles  is  not  compacted  to  the  extent that other piles in the group
  cannot be installed properly; and (3) ground movement that would  damage
  adjacent  buildings or utilities is prevented. In general, in any group,
  driving shall start from one side and proceed progressively  toward  the
  other  side  of  the  group  or  shall start from the middle and proceed
  toward the edges of the group.
    (d) Heaved piles. In soils in which the installation of  piles  causes
  previously  installed  piles to heave, accurate level marks shall be put
  on all piles immediately after installation, and  all  piles  that  have
  been  heaved  by  an amount in excess of one-quarter of an inch shall be
  redriven to the required resistance.
    (e) Penetration measurements. Penetration measurements  made  for  the
  purpose of determining resistance to driving shall not be made when pile
  heads are damaged to an extent that may affect measured penetration, nor
  shall  they  be  made  immediately  after fresh cushion blocks have been
  inserted under the striking part of the hammer.