Ultrasonic Guided Wave Inspection Technique in Anchorage Quality of Steel Bolt Embedded in Epoxy Base

Ultrasonic guided wave inspection technique in anchorage quality of steel bolt embedded in epoxy was investigated experimentally. According to dispersion curves derived from theoretical prediction, high-order longitudinal guided wave modes which were suitable for anchorage quality inspection of steel bolt embedded in epoxy and their excitation frequencies were chosen. In the experiments, a 22 mm diameter and 2 800 mm length steel bolt was embedded in epoxy layer with gradually increasing length. Based on pulse echo method, first end-reflected signals of high-order longitudinal guided wave modes were received in the anchorage structure under the condition of gradually increasing length of epoxy layer. Experimental results showed that there was an approximate linear decrease of the peak-to-peak amplitudes of received first end-reflected waves of high-order longitudinal guided wave modes with the increase of embedded length of the bolt.