Measurement and Analysis of PCCP Wire Breaks, Slips, and Delaminations

Monitoring and condition assessments methods have struggled with discerning the differences between various degradation activities on Prestressed Concrete Cylinder Pipe (PCCP). The accumulated damage due to wire breaks can be estimated and assessed using electromagnetic methods. Wire break activity can be monitored using acoustic methods. Previous work with acoustic methods indicates that it may be possible to determine post wire break, slips and mortar delaminations from acoustic dataⁱ. Recent workⁱ indicates that it may be possible to harvest condition assessment information from acoustic data. In this work, above grade sections of PCCP are instrumented and wires systematically cut while acoustic and mechanical distortion data were collected. Instantaneous changes along with relatively long term relaxation of the pipe were monitored. Advance acoustic data process were applied and results correlated with mechanical measurements and observations including, wire breaks (WB), apparent wire slips (WS) and delaminations (DLAM) of the mortar coating. Results of the testing on an instrumented aboveground 48-inch lined cylinder PCCP show that WBs can be distinguished from other mechanical/structural degradation activity including WSs and DLAMs based on the amplitude, time domain characteristics and frequency spectra. The conclusion is therefore that by using acoustic monitoring detections of the early, intermediate and advanced stages of PCCP degradation leading up to failure can be measured, discriminated and acted upon.