A Methodology for Detecting Loss of Support Under PCC Pavement Based on Real-Time Structural Acceleration Response

Loss of support is a concealed distress in PCC pavements, weakening the support condition under PCC slabs and causing other distresses such as cracks, which accelerate the pavement deterioration. Currently, the traditional loss of support detection method uses the falling weight deflectometer (FWD) to obtain maximum deflection response, which requires traffic closure and makes it impossible to conduct real-time monitoring. To realize real-time dynamic health monitoring of PCC pavement, this study proposes a methodology for detecting loss of support under PCC pavement based on real-time structural acceleration response. Specifically, this study constructed PCC pavements without loss of support, with loss of support at the slab edge, and with loss of support at the slab center. The slab corner and center were loaded and monitored, where loss of support easily occurs. Acceleration signals were collected using self-developed MEMS acceleration sensors suitable for monitoring PCC pavements. Analysis of the time-domain signals and frequency spectrums shows that both the maximum acceleration response and the main frequency at the loss of support region would significantly increase when the loss of support region is loaded. Two critical values are proposed, including the amplitude ratio of acceleration signals at the slab corner and center [Formula: see text] and the ratio of signal energy within the high-frequency range to that within the low-frequency range (ER). The results indicate that by deploying sensors at the slab corner and center, the loss of support condition can be evaluated based on [Formula: see text] and ER when the slab corner is loaded. Compared to traditional deflection detection methods, the proposed methodology offers a better integral structural monitoring for detecting loss of support. The findings can be used for future detection of support loss under PCC pavements subjected to traffic load, enabling real-time monitoring and maintenance guidance for PCC pavements that have been open to traffic.