Drilled Shaft Defects: NDT results

Conclusions- Down Hole Methods Conclusions- Surface Methods

Defects larget than 10% of cross-section were easily detected
Defect smaller than 5% of cross-section were not detected
Unable to locate defect outside cage, including soft bottoms
Soil inclusions were more dfficult to detect than voids
False positives were common

Better than previous studies
Able to locate voids down 6% of cross section
Able to locate soil inclusions down to 17% of cross section
Up to 3 defects were located per shaft
Difficult to detect soft bottom

Shaft 1

Shaft 2

Shaft 3

Shaft 4

Shaft 5

Shaft 6