Abstract
The original purpose of this study is to develop an evaluation system of corrosion level in the inner surface of galvanized steel tubular sections as a maintenance engineering for steel structures. As the first step of this study, the application of ultrasonic testing is attempted to the thicness measurement of galvanized steel plate elements, which is not yet authorized as a practical measure. In a preliminary study, it was clarified that the application of the speed of longitudinal ultrasonic wave in zinc to the layers composed of zinc and several alloys of iron and zinc results in a conspicuous underestimation of the thickness of galvanized steel plate, and in the present sudy, the speed of longitudinal ultrasonic wave in the specimen's steel plate is applied to the whole specimen of galvanized steel plate. This result is compareed with the thickness obtained by the different devices.
