BIM-supported tunnel light environment evaluation: a case study on Shanghai Chenxiang road tunnel project

The design of tunnel light is of significant importance for road safety and should take into account a number of factors such as the "black hole effect" at the entrance, the "glaring effect" at the exit, and sufficient reaction time/stopping distance when a hazard is identified. As project scale increases and many projects can be rendered as "fast-track" projects, a quality design of tunnel illumination keeping abreast of the times requires the designer applying more efficient design approaches to handle growing workload and project complexity. The conventional tunnel illumination design process is recognised as highly reliant on both prescriptive rules of technical standards and two-dimensional (2D) CAD design systems. This approach is becoming limited because it is time-consuming for the designer to query design specifications and make relevant adjustments in case of project change. Meanwhile, a CAD-based design, although being able to yield light parameters for the different segments of a tunnel, does not allow light designers to review the light conditions throughout the entire tunnel. To address these challenges, this article proposes an innovative Building Information Modeling (BIM) supported design approach, which incorporates three-level tasks: inputting geographical and meteorological conditions, simulating tunnel lighting and solar access, and evaluating simulation results. According to Shanghai Chenxiang Road Tunnel Project, this paper demonstrates how BIM technology could efficiently and comprehensively be applied in real case tunnel light design process, for instance, mitigating the design errors, verifying the alternative design schemes and assisting with the fast-tracking design making process.