Human-in-the-loop simulation for crane lift planning in modular construction on-site assembly

![CDATA[Modular construction has gained increasing popularity, to various extents, in both building and infrastructure projects with the merits of accelerated schedules, improved quality, and reduced cost and waste. The successful delivery of modular projects heavily relies on safe and efficient on-site assembly of prefabricated modules, and this job is primarily executed by tower or mobile cranes. Compared to loads present in typical on-site construction, prefabricated modules being lifted are likely more substantial in size, heavier in weight, and more expensive, and therefore more stringent requirements on lift safety and precision are expected. However, due to the lack of appropriate tools, it remains a challenging task for the lift team to recognise potential spatial constraints and safety risks associated with lift tasks on the dynamic and complex construction site. This study explores a human-in-the-loop simulation approach to facilitate the identification and mitigation of task-specific and human factor related safety risks in crane lift planning. This approach employs as-built 3D point cloud to simulate pre-existing spatial constraints in a lift task. In addition, it incorporates human factors in the simulation through an immersive user interface and collaborative virtual environment. The proposed approach was tested in a case study of a module lift task, and the results indicate its potential to improve crane lift safety by eliminating hazards that are difficult to be recognised in conventional planning practices.]]