Impedance-based Identification of Strand Looseness in Multi-strand Anchorage under Temperature Effects

Abstract

Abstract In this study, strand looseness in a multi-strand anchorage is identified using measured impedance features of the PZT (Lead zirconate titanate) interface array under temperature effects. Firstly, a PZT-interface method for impedance monitoring in prestressed structures is briefly described. Secondly, a finite element model of multi-strand anchorage equipped with a PZT array is established to analyze the effects of prestress loss and temperature changes in impedance features. Thirdly, variations in simulated impedance signals are quantified using statistical damage metrics for damage detection in the analyzed structure. Last, a test on real-scale multi-strand anchorage is conducted to measure impedance signatures of the PZT interface under temperature fluctuation and prestress loss. The measured signals are then quantified using damage metrics for prestress looseness monitoring. The result reveals that environmental changes cause significant changes in PZT interfaces’ impedance features and affect strand looseness monitoring results.