Embedded Interface Debonding Detection for an Irregular Complex Multi-chamber Steel Reinforced Concrete Column with PZT Impedance

Abstract

Due to the excellent mechanical performance including high load-carrying capability, good ductility and energy assumption capability under strong dynamic excitations including earthquakes, complex steel reinforced concrete (SRC) columns have been extensively employed as vertical load-carrying components in super highrise buildings. With the increase in cross section area of SRC members, steel plates in two directions and the steel horizontal diaphragm usually form independent chambers in a single column. The interface condition between concrete core and embedded steel plates is of significant concern because of the possible shrinkage of mass concrete after curing and concrete defect under horizontal diaphragms. The interfacial condition monitoring and debonding defect detection is still a challenging task because traditional ultrasonic method does not work. In this study, an embedded PZT based interface debonding defect detection approach for multi-chamber SRC columns is proposed with the electro-mechanical impedance (EMI) measurement of both PZT patches surface-bonded on steel plate and embedded piezo-based functional elements (EPFEs) for an irregular complex multi-chamber SRC column specimen with artificially mimicked interface debonding. The EMI results of both PZT patches and EPFEs are measured at different frequency regions with an impedance analyzer and are employed to detect the interface debonding defect. By taking the root mean square deviation (RMSD) of the measured EMI as a damage index, results show that the defined damage index is sensitive to the existence of interface debonding defects. The proposed approach provides a useful way for the interface debonding defect detection of large-scale multi-chamber SRC columns. doi: 10.12783/SHM2015/42