Experimental Study on Active Interface Debonding Detection for Rectangular Concrete-Filled Steel Tubes with Surface...

Area of Science:

• Structural Engineering
• Materials Science
• Non-Destructive Testing

Background:

• Concrete-filled steel tube (CFST) members are crucial in construction, relying on the bond between steel and concrete.
• Interface debonding defects can compromise the structural integrity and confinement effect in CFSTs.
• Effective detection methods for these internal defects are essential for structural health monitoring.

Purpose of the Study:

• To propose and validate an active interface debonding detection approach for CFST members.
• To investigate the influence of interface debonding defects on surface wave measurements.
• To develop a damage index for quantifying debonding severity.

Main Methods:

• Utilizing piezoelectric lead zirconate titanate (PZT) patches as both sensors and actuators on the CFST outer surface.
• Employing a pitch-and-catch pattern for surface stress wave propagation and measurement along the steel tube.
• Experimentally studying two rectangular CFST specimens with varying degrees of internal interface debonding.

Main Results:

• Surface-mounted PZT sensors successfully detected the presence of interface debonding defects.
• Interface debonding was found to increase the voltage amplitude of the measured surface waves.
• A defined damage index demonstrated a linear correlation with the height of the interface debonding defects.

Conclusions:

• The proposed surface wave measurement technique is a feasible and effective method for detecting interface debonding in CFST members.
• External PZT sensor placement avoids the need for embedded sensors, simplifying the detection process.
• The developed damage index provides a quantitative measure for assessing the severity of interface debonding defects.