Investigation of a new experimental method for damage assessment of RC beams failing in shear using piezoelectric transducers

• Tests of 5 shear-critical RC beams with smart aggregates and externally bonded PZTs.
• Portable real-time Wireless impedance/Admittance Monitoring System (WiAMS) is used.
• WiAMS utilizes an alternative consideration of electromechanical impedance method.
• PZT signal curves, RMSD indices, beams’ response & cracking patterns are presented.
• Results showed cogent evidence of damage & predicted the forthcoming shear failure.

The ability of a new portable real-time Wireless impedance/Admittance Monitoring System (WiAMS) in damage diagnosis of shear-critical RC beams is experimentally studied. This system is based on the electromechanical impedance concept integrating piezoelectric transducers in reinforced concrete structural elements. The proposed monitoring method uses WiAMS devices and an array of embedded “smart aggregates” and externally bonded piezoelectric transducers. Five shear-critical beams are tested in order to evaluate the ability of the proposed methodology in damage detection and assessment. Voltage signatures of the piezoelectric transducers have been measured at the healthy state and at different damage levels of the beams. Quantitative assessment of the damage using values of statistical damage index is also presented and discussed. Test results showed that transducers close to the diagonal cracking provided sound and gradual differences between the signatures at the healthy state and each damage level. Voltage responses and index values of the transducers located on the shear span where the critical crack formed provided cogent evidence of damage and their gradual character revealed the magnitude of damage. Promising results concerning the prediction of the forthcoming final shear failure at earlier damage stages such the onset of diagonal cracking have also been derived.