Smart aggregate-enabled dual spatial domain health monitoring of concrete beams under loading conditions

Concrete beams are fundamental components in civil engineering, often subjected to various loads throughout their service life. Monitoring the health states of concrete beams under loading conditions is crucial for ensuring structural integrity and longevity. To the best of our knowledge, few studies have simultaneously investigated both global and local monitoring of concrete beams under external loads using smart aggregate (SA)-enabled active sensing technology. This paper proposes an SA-enabled dual spatial domain damage evaluation (SA-DSDDE) method to comprehensively investigate the damage evolution process of concrete beams under loading conditions. Specifically, the proposed SA-DSDDE method includes two primary damage evaluation functions: local spatial domain damage evaluation (LSDDE) and global spatial domain damage evaluation (GSDDE). The LSDDE function employs a parallel sensing mode of the embedded SA array to collect detection signals, utilizing the Hilbert-Huang transform (HHT) to define a sensitive index for assessing damage in the local monitoring zone. In contrast, the GSDDE function utilizes a cross sensing mode of the embedded SA array, alongside empirical mode decomposition (EMD), to construct a detection signal characteristic matrix and apply singular value decomposition (SVD) to establish a sensitive index for describing damage in the global monitoring zone. To validate the effectiveness of the proposed method, four-point loading tests of a concrete beam with embedded SA sensors are conducted. The results demonstrate that the proposed method can effectively reveal the damage evolution process of the monitored concrete beam under loading conditions both from local and global perspectives, displaying enormous engineering application prospects.