Electromechanical Impedance-based Health Diagnosis for Tendon and Anchorage Zone

The tendon and anchorage block are responsible to deliver high stress as key members of a prestressed structure. Thus, the deterioration of tendon in carrying tensile force or damages on the anchorage block may lead to failure of the structure so that they should be monitored continuously. In this paper, a simple impedance-based method was proposed to estimate the tensile force and monitor the condition of the anchorage zone. Experimental studies were carried out on two sizes of models of an anchorage system. The relationship between the impedance signature and the tensile force was first constructed for the tensile force estimation. Simultaneously, the damage diagnosis was performed using the relationship among impedance signatures of multiple sensors attached to the structure. When the loss of the tensile force occurred, the root mean square deviation (RMSD) index increased. Hence an empirical curve can be obtained for the estimation of tension loss based on the experimental data. On the other hand, when the structure got damaged, the RMSD index abruptly increased over this curve so that the status of the damage was able to be identified. The experimental results indicated a big potential of the proposed method for monitoring and diagnosis of the tendon and the anchorage zone.