Abstract
In this study, the authors propose a methodology for evaluating the risk of spatial illuminance decrease in the entire tunnel with a simulation based on (1) lighting failure and (2) luminous flux attenuation of lamps. The lighting failure is expressed by a Weibull deterioration hazard model, in which failure probability augments with time. The luminous flux attenuation of lamps is formulated with a spatial illuminance distribution model. Then, the authors propose a risk simulation model regarding the visibility inside the tunnel based on a Monte Carlo simulation. With this, it is possible to evaluate spatial illuminance risk, including the local illuminance decrease due to successive lighting failure, etc. Lastly, the effectiveness of the proposed method is empirically discussed through the analysis of the inspection data on actual tunnel lightings.
