Automatic Evaluation of Rebar Spacing Using LiDAR Data

When constructing Reinforced Concrete (RC) components, rebar spacing must be inspected in the field before pouring concrete. The traditional inspection of rebar spacing: (1) depends on the experience of the individual inspector; (2) is limited to a pass/fail outcome; and (3) is in general conducted with limited time. This paper presents a recognition algorithm that automatically identifies the rebar position using LiDAR. The result is an automatic Rebar Layout Quality Index (RLQI). Researchers collected LiDAR data from a real rebar mat, compared it with the design drawings, and obtained the RLQI for both top and bottom rebar mats. The authors also quantified the quality of the structural construction with a new flexural relative moment strength index. This methodology has the potential to reduce inspection time and increase the reliability of inspections through an objective assessment of rebar spacing, by creating an as-built record of actual rebar location in the structure.