FPrimeC Solutions Inc. was engaged by the client to perform non-destructive testing and evaluation of a Concrete Mat Foundation at a Power Plant just outside of Taipei in Taiwan. The concrete foundation was 21 m x 7 m and had an average thickness of 1.2 m. The top surface of the mat foundation was accessible at the time of this inspection.

    Spectral Analysis of Surface Waves

    The Spectral Analysis of Surface Waves (SASW) was used to evaluate the uniformity, and structural integrity of concrete in the mat foundation. The technique utilizes the propagation of stress waves (shear waves) generated by a hammer impact to analyze the mechanical properties of concrete, evaluate the integrity and uniformity, and identify potential defects. 

    A hammer impact introduces a stress pulse into the test area. The pulse propagates into the material and is reflected by flaws or interfaces. The emitted impulse and reflected stress waves are monitored at the receiving accelerometers. The receiving waveforms are analyzed in the frequency domain to calculate the relationship between wavelengths and vibration frequencies of the test area.