Automatic evaluation of rebar spacing and quality using LiDAR data: Field application for bridge structural assessment

This paper proposes a framework to automatically quantify the quality of rebar placement in the field to improve construction quality and long-term durability of the bridge structures. In this study, three-dimensional point clouds of a concrete bridge construction site were acquired using a mobile LiDAR scanner. Additionally, two algorithms, including projection algorithm and slicing algorithm, were developed to automatically extract the bridge rebar locations for layout quantification at the global level, bin level, and local level. Subsequently, LiDAR extracted rebar placement quality was compared to design drawings to investigate the effectiveness. This study also evaluated the quality of other concrete deck components, which include formwork panels and the contact surface between rebars and anchor bolts. The research revealed that the proposed framework can inform the rebar placement quality in the field prior to concrete pour, providing a permanent record of the bridge deck quality for future inspections and assessments.