Underwater Tests on Corroded Steel Piles With the Thickness Measurement by Beam Alignment System

Abstract

An ultrasonic thickness measurement by beam alignment (TMBA) system developed by Southwest Research Institute was tested on underwater corroded steel piles at the Port Hueneme Harbor near Los Angeles, California. This ultrasonic system measures the thickness of steel piles by alignment of a focused ultrasonic transducer over a pit formed on the pile by corrosion. Tests conducted at the harbor demonstrated the ability of the system to measure the thickness of corrosion-pitted piles underwater at depths ranging from 0.3 m to 2.2 m (1 to 7 ft) below the water level. The tests also demonstrated that the system was successful in measuring the thickness of rough piles—that is, those with less corrosion—as well as pitted piles. Thus, the TMBA system is feasible as an overall approach to thickness measurement.