Conduct foundation investigations for high-mast illumination, radio towers, and overhead sign structures as close as feasibly possible when other borings are not located nearby.

The typical depth of the borings ranges from 30 to 70 ft. but depends on existing and proposed ground lines, soil strength, and structure loading.

Concrete sound (noise) walls require drilled shaft foundation design that results in shafts 20 to 30ft embedded and spaced 10 to 25ft center to center along the wall alignment. When adjacent structure borings are not present, place soundwall borings at maximum 200ft intervals and to a depth of 40 to 50ft depending on soil strength and anticipated planned height of soundwall.