Section 27-709. Cast-in-place concrete piles

(a) Description. Cast-in-place
  concrete piles shall be cast  in  shells  previously  installed  in  the
  ground  or,  with the limitations indicated in section 27-697 of article
  seven of this subchapter, may be cast in an uncased hole.  Cast-in-place
  piles  may  be  tapered  or cylindrical, or a combination of tapered and
  cylindrical shapes.
    (b) Materials. Concrete for cast-in-place concrete piles shall conform
  to the requirements of article five of subchapter ten of  this  chapter.
  Slump  shall be five inches plus or minus one inch. Where the pile shell
  is assumed to contribute to the capacity of the  pile  as  a  structural
  member,  the shell shall be of metal and shall conform to the provisions
  of article six of subchapter ten of this chapter or  section  27-712  of
  this  article.  Where the pile shell is not assumed to contribute to the
  capacity of the pile as a structural member, the shell  may  be  of  any
  material  that  will adequately resist the driving stresses and maintain
  an open well to receive the concrete. End closures for shells shall  not
  project more than one-half inch beyond the outer limits of the pile when
  bearing in soils of class 6-65 or lower.
    (c) Installation.
    (1)  After  installation to final depth and immediately before filling
  with concrete,  the  inside  of  the  tube,  shell,  or  bore  shall  be
  thoroughly  cleaned to the bottom and inspected by lowering a drop light
  or by means of a light beam. To be accepted: (a) the pile shall be  free
  of  collapsed  sections  of  shell and the pile shell shall not show any
  tears; (b) the pile shall be free of water except that a minor amount of
  water may be allowed to occur in the pile if it be absorbed by placing a
  suitable amount of dry cement-sand mixture in the tip end of  the  pile;
  and  (c)  the  alignment  of the pile shall conform to the provisions of
  section 27-691 of article seven of this subchapter. If the bottom of the
  casing is out of sight, the shape and alignment of the casing  shall  be
  surveyed with a suitable instrument, or the pile rejected.
    (2) Concrete shall be placed by such methods that the entire volume of
  the  tube,  shell,  or bore is filled and in a manner that will preclude
  separation of the ingredients.
    (3) No concrete shall be placed in  a  cast-in-place  pile  until  all
  piles  within  a radius of fifteen feet, or within the heave range, have
  been driven.
    (4) Rejected pile shells shall be filled with concrete or sand.
    (5) The concrete cap shall not be placed until at least one hour after
  all piles within the cap group are completely filled.