§ 27-691 Tolerance and modification of design due to field conditions.
AC § 27-691
(a)Tolerance in alignment of the pile axis. If the axis of any pile is installed out of plumb or deviates from the specified batter by more than four per cent of the pile length, the design of the foundation shall be modified as may be necessary to resist the resulting vertical and lateral forces. In types of piles for which subsurface inspection is not possible, this determination shall be made on the exposed section of the pile, which section, at the time of checking axial alignment, shall not be less than two feet. In piles which can be checked for axial alignment below the ground surface, the sweep of the pile axis shall not exceed four per cent of the embedded length.
(b)Tolerance in location of the head of the pile. A tolerance of three inches from the designed location shall be permitted in the installation of each pile, without reduction in load capacity of the pile group. Where piles are installed out of position in excess of this amount, the true loading on such piles shall be analytically determined from a survey which defines the actual location of the piles as driven, and using the actual eccentricity in the pile group with respect to the line of action of the applied load. If the total load on any pile, so determined, is in excess of one hundred ten per cent of the allowable load bearing capacity, correction shall be made by installing additional piles or by other methods of load distribution, as required to reduce the maximum pile load to one hundred ten per cent of the capacity.
(c)Bent piles. Where piles have been bent during installation, and the amount of the bend exceeds the allowable tolerance for alignment of the pile axis in subdivision (a) of this section, the condition shall be investigated and, where required, correction made by the installation of additional piles, by strengthening the bent piles, by reduction in capacity or other means acceptable to the commissioner.
