Damage Detection of Cyclically Loaded Concrete Shear Wall using EMI Technique

Abstract

Details of the investigations on an unexplored application of Electro Mechanical Impedance (EMI) technique using smart piezoelectric (PZT) sensors for damage detection of concrete shear wall structures under crack opening and closing is presented in this paper. The behavior and the ability of this method to detect damages, in a heterogeneous quasi-brittle material is studied for its effective utilization in structural health monitoring. The paper discusses the experimental investigations conducted on a concrete shear wall using PZT patches. Conductance data is acquired at different applied lateral displacements of shear wall. Damage index is calculated using Root Mean Square Deviation (RMSD), Mean Absolute Percentage Deviation (MAPD) and Correlation Coefficient (CC) computed between pristine and damaged states. It is found that compared to a metallic specimen, concrete specimens do not show a large variation in these damage metrics, due to reduced modal density and high damping. However, results and observations from these experimental case studies establish that EMI signature from surface bonded PZTs can identify damages even for a heterogeneous material like concrete, with improved and modified damage metrics.