Sound and vibration measurements for pipe wall condition assessment of concrete pressure pipes

Abstract

The condition of buried watermains and similar pipelines can be assessed by non-intrusive means. To this end certain features of sound propagation in the water column within the main are measured. Most applications use the Korteweg-Lamb correction to estimate the average wall thickness for homogeneous pipes. For complex composite structures such as concrete pressure pipes, condition assessment is presently based on a great deal of empiricism. This can now be replaced with proper physical models based on measurements conducted on a 25 m long test pipe. Using controlled sound sources, hydrophones and surface mounted accelerometers, features of the acoustic waves inside the water column and the associated wall vibrations were deduced from two-point space-time correlations. The data permits the determination of the complex-valued wavenumbers as well as the dynamic coupling of the liquid column and the pipe wall from which certain properties of the pipe wall can be characterized to ascertain if the pipe is fit for purpose.