School of Urban Construction, Yangtze University, Jingzhou 434000, China.
Department of Mechanical Engineering, University of Houston, Houston, TX 77204, USA.
Sensors (Basel). 2018 Jul 6;18(7):2171. doi: 10.3390/s18072171.
L-shaped concrete filled steel tube (L-CFST) columns are used frequently in civil engineering, and the concrete damage inside the L-CFST column is difficult to monitor. This research aims to develop a new method to monitor the internal concrete damage in the L-CFST column by using embedded piezoceramic smart aggregates (SAs) under low frequency cyclic loading. The SA enabled active method is used to monitor the concrete damages near the bottom of the L-CFST columns, and the wavelet packet analysis is used to establish a damage index, which is used to analyze the acquired data. During the experiment, three L-CFST columns with different wall thickness of the steel tube were tested. The experimental results find that the structural damage indices under the low-frequency cyclic loading are basically consistent with the results of the hysteretic curves and the skeleton curve of the specimens, and are in good agreement with the experimental phenomena. We conclude that the use of smart aggregate can directly and clearly reflect the damage process of the concrete core, demonstrating the feasibility of using piezoceramic smart aggregates to monitor the internal concrete damage of the L-CFST column.
L 形钢管混凝土(L-CFST)柱在土木工程中被广泛应用,但 L-CFST 柱内部混凝土的损伤难以监测。本研究旨在开发一种新方法,通过在低频循环荷载下使用嵌入式压电阻智能骨料(SA)监测 L-CFST 柱内部的混凝土损伤。使用 SA 激活法监测 L-CFST 柱底部附近的混凝土损伤,并使用小波包分析建立损伤指标,用于分析采集到的数据。在实验中,测试了三根具有不同钢管壁厚的 L-CFST 柱。实验结果表明,低频循环荷载下的结构损伤指标基本与试件的滞回曲线和骨架曲线的结果一致,与实验现象吻合较好。我们得出结论,智能骨料的使用可以直接清晰地反映混凝土芯的损伤过程,证明了使用压电阻智能骨料监测 L-CFST 柱内部混凝土损伤的可行性。