Abstract
Concrete-filled steel tube (CFST) members have been widely employed as major structural members carrying axial or vertical loads and the interface bond condition between steel tube and concrete core plays key roles in ensuring the confinement effect of steel tube on concrete core. An effective interface debonding defect detection approach for CFSTs is critical. In this paper, an active interface debonding detection approach using surface wave measurement with a piezoelectric lead zirconate titanate (PZT) patch as sensor mounted on the outer surface of the CFST member excited with a PZT actuator mounted on the identical surface is proposed in order to avoid embedding PZT-based smart aggregates (SAs) in concrete core. In order to validate the feasibility of the proposed approach and to investigate the effect of interface debonding defect on the surface wave measurement, two rectangular CFST specimens with different degrees of interface debonding defects on three internal surfaces are designed and experimentally studied. Surface stress waves excited by the PZT actuator and propagating along the steel tube of the specimens are measured by the PZT sensors with a pitch and catch pattern. Results show that the surface-mounted PZT sensor measurement is sensitive to the existence of interface debonding defect and the interface debonding defect leads to the increase in the voltage amplitude of surface wave measurement. A damage index defined with the surface wave measurement has a linear relationship with the heights of the interface debonding defects.
Highlights
With advanced structural performance including high load-carrying capacity, good ductility and energy dissipation capability under strong dynamic excitations, convenience and economy in construction, concrete-filled steel tubes (CFSTs) have been extensively employed as major vertical and/or axial load-carrying structural members in civil infrastructure such as long-span bridges, super high-rise buildings and off-shore platforms in harsh environments [1]
Xue et al investigated the effect of interface debonding on the mechanical behavior of circular CFST columns subjected to axial load and eccentric load with results indicating that the interface debonding leads to serious local buckling of steel tube and decrease in the ultimate load-carrying capacity when compared with that of specimens without interface debonding defects [3]
For the interface debonding detection of CFSTs, Xu et al firstly proposed a novel piezoelectric lead zirconate titanate (PZT) based active approach, where PZT patches mounted on the outer surface of the steel tube or embedded in concrete core are used as actuator or sensors and the changes in the wavelet energy and wavelet energy spectrum of the PZT sensor measurements are employed to detect the interface debonding defects, and the feasibility of the proposed approaches was validated experimentally and numerically considering the piezoelectric effect of PZT materials and the coupling effect between PZT patches and CFST members [33,34,35,36,37]
Summary
Detection for Rectangular Concrete-Filled Steel Tubes with Surface Wave Measurement. Bin Xu 1,2,† , Lele Luan 3,† , Hongbing Chen 4, *, Jiang Wang 1, * and Wenting Zheng 1. Key Laboratory for Intelligent Infrastructure and Monitoring of Fujian Province (Huaqiao University), Xiamen 361021, China.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
