Fault-Tree Model for Risk Assessment of Bridge Failure: Case Study for Segmental Box Girder Bridges

Over the past few decades, the design capacity and service condition of many bridges, which are vital components of the surface transportation infrastructure reliability and functionality, have been challenged by rapid traffic growth and scarce maintenance funds. Numerous incidents of bridge collapse call for an urgent need to develop a systematic method of assessing the failure risks and identifying the initiating events that can lead to a bridge collapse. This paper presents a process of bridge failure risk analysis through fault-tree modeling for a common type of bridge known as segmental concrete box girder bridge. The process was applied to a segmental box girder bridge in South Carolina and was found to effectively identify causal factors of bridge failure and estimate overall failure risk. However, to comprehensively assess the probability of bridge failure, fault-tree analysis can best be used in combination with current risk assessment methods, such as visual inspections and structural health monitoring sensors.