ABSTRACT
Current safety assessments of Australian bridges follows a deterministic method expressing safety as a subjective binary (yes/no) measure. The management of bridges deemed unsafe as per the deterministic method is outside the scope of the Australian standards. From international observations, the next tier in assessment, providing objective and quantifiable measures of safety on a continuum, is the use of probabilistic approaches such as structural reliability methods. This study aims to determine whether such approaches are of benefit for the Australian context. First, the implied safety levels of a selected subset of historical and contemporary bridge designs most prevalent in the Australian bridge inventory are obtained. Then, the current safety levels of the same historical and contemporary bridges under as-of-right road freight access is quantified. Ultimate bending and ultimate shear limit states for superstructures are considered. It is found a significant reserve in safety exists compared to deterministic measures for some bridge designs. This demonstrates the benefit of developing structural reliability-based frameworks as higher-order bridge safety assessments.
