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Smart Structures and Systems
  Volume 9, Number 6, June 2012 , pages 489-504
DOI: https://doi.org/10.12989/sss.2012.9.6.489
 


Smart PZT-interface for wireless impedance-based prestress-loss monitoring in tendon-anchorage connection
Khac-Duy Nguyen and Jeong-Tae Kim

 
Abstract
    For the safety of prestressed structures such as cable-stayed bridges and prestressed concrete bridges, it is very important to ensure the prestress force of cable or tendon. The loss of prestress force could significantly reduce load carrying capacity of the structure and even result in structural collapse. The objective of this study is to present a smart PZT-interface for wireless impedance-based prestress-loss monitoring in tendon-anchorage connection. Firstly, a smart PZT-interface is newly designed for sensitively monitoring of electro-mechanical impedance changes in tendon-anchorage subsystem. To analyze the effect of prestress force, an analytical model of tendon-anchorage is described regarding to the relationship between prestress force and structural parameters of the anchorage contact region. Based on the analytical model, an impedance-based method for monitoring of prestress-loss is conducted using the impedance-sensitive PZT-interface. Secondly, wireless impedance sensor node working on Imote2 platforms, which is interacted with the smart PZTinterface, is outlined. Finally, experiment on a lab-scale tendon-anchorage of a prestressed concrete girder is conducted to evaluate the performance of the smart PZT-interface along with the wireless impedance sensor node on prestress-loss detection. Frequency shift and cross correlation deviation of impedance signature are utilized to estimate impedance variation due to prestress-loss.
 
Key Words
    prestress-loss; tendon-anchorage; electro-mechanical impedance; smart PZT-interface; wireless impedance sensor; structural health monitoring
 
Address
Khac-Duy Nguyen and Jeong-Tae Kim :Department of Ocean Engineering, Pukyong National University, Busan 608-737, Korea
 

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