§ 27-666 Probings and geophysical explorations.
AC § 27-666
(a)Footings, pier or wall designs. Where the foundations for a proposed building consist of footings or foundation piers or walls bearing on rock of class 1-65, 2-65 or 3-65, the use of probings, auger borings or geophysical methods, made without the recovery of soil samples or rock cores, may (except as hereafter specified) be substituted for up to one-half of the number of borings required by the provisions of subdivision (a) of section 27-663 of this article, provided that such probings, borings, etc. are carried to adequate depth and are of a nature that will reasonably define the surface contours of the rock. The accuracy of such surface contour definition shall be confirmed by recovering rock cores at the locations of at least one-fifth of the probings or auger borings or, in the case where geophysical methods are used, those borings which are made shall be so distributed as to permit confirmation of the accuracy of the geophysical investigations. The provisions of paragraph two of subdivision (a) of section 27-663 of this article, shall not apply where the provisions of this section are invoked.
(b)Pile support. Where the foundation for the proposed building consists of piling bearing on rock of class 1-65, 2-65 or 3-65, the provisions of subdivision (a) of this section shall apply, provided that the borings consistently show that the soil overlying the rock consists solely of deposits of class 6-65 through 11-65 and is free of boulders or other obstructions.
(c)Geophysical methods. Geophysical investigations shall be conducted by experienced and qualified personnel acceptable to the commissioner who may reject the results and require additional exploration by borings if the results of the geophysical explorations cannot be satisfactorily correlated to the logs of the borings.
