Xu Bin, Luan Lele, Chen Hongbing, Wang Jiang, Zheng Wenting
College of Civil Engineering, Huaqiao University, Xiamen 361021, China.
Key Laboratory for Intelligent Infrastructure and Monitoring of Fujian Province (Huaqiao University), Xiamen 361021, China.
Sensors (Basel). 2019 Jul 24;19(15):3248. doi: 10.3390/s19153248.
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.
钢管混凝土（CFST）构件已被广泛用作承受轴向或垂直荷载的主要结构构件，钢管与混凝土核心之间的界面粘结状况对于确保钢管对混凝土核心的约束效果起着关键作用。一种有效的CFST界面脱粘缺陷检测方法至关重要。本文提出了一种主动界面脱粘检测方法，该方法利用安装在CFST构件外表面的压电锆钛酸铅（PZT）贴片作为传感器进行表面波测量，并通过安装在同一表面的PZT驱动器进行激励，以避免在混凝土核心中嵌入基于PZT的智能骨料（SA）。为了验证所提方法的可行性，并研究界面脱粘缺陷对表面波测量的影响，设计并试验研究了两个在三个内表面具有不同程度界面脱粘缺陷的矩形CFST试件。由PZT驱动器激发并沿试件钢管传播的表面应力波由PZT传感器采用一发一收模式进行测量。结果表明，表面安装的PZT传感器测量对界面脱粘缺陷的存在敏感，且界面脱粘缺陷导致表面波测量电压幅值增大。用表面波测量定义的损伤指标与界面脱粘缺陷高度呈线性关系。
