Augmented reality-based safety inspection framework for safety management in railway bridge and tunnel projects

The need for advanced and modem approaches for onsite safely inspection has increased in tandem with a growing concern over construction safely issues. Railway construction inspection, in particular, occurs in proximity to existing facilities in urban areas, and is thus performed under severe spatial and temporal constraints. However, current inspection methods are conducted mainly with the naked eye and conventional tools, limiting their effectiveness. This study aimed to formalize a framework specialized for railway site safety inspection by utilizing smart technologies, namely Augmented Reality (AR) and BIM . AR is posited to be suitable for safety inspection as it allows the projection of 3D models and relevant information directly onsite. The major functions of AR are investigated together with railway safety accident data to identify potentially hazardous conditions. Legal inspection mandates are also evaluated followed by interviews with safety experts to verify the findings. As a result, a formal procedure is established for AR based site inspection and six detailed techniques are implemented for its operations. Unlike existing studies, this system is not limited to simple model projections, but enables the projection of BIM models that reflect the results of initial safety checks performed on site. Furthermore, remote inspection is implemented to enable precise safety checks that can be performed in a stable indoor environment free from unfavorable weather conditions and time constraints. Both features are developed with the intention of using AR as a medium for sharing and communicating inspection results for project participants in the field.