The masses, dimensions and numbers of heavy vehicles accessing the bridge network continues to grow and apply pressure to the bridge network. Consequently, asset managers are seeking to balance the increasing risks offailure to meet transport demand and sustainability objectives. AS 5104: 2017 General principles on reliability for structures, provides a risk-informed foundation for decision making concerning design and assessment of structures.
This presentation discusses the application of the principles of risk and reliability to support decisions related to the assessment of bridges, and access to them over their service lives. Three different but related approaches are discussed, namely, a risk-informed, a reliability-based, and a semi-probabilistic approach. AS 5100: 2017 Bridge Design is a semi-probabilistic, design standard and inadequate for the complex task of assessing existing bridges. Considering the over-arching risk-informed and reliability-based approaches, provides a more holistic approach to managing bridge access; particularly in cases where access would have been curtailed to meet the requirements of AS 5100 but the past performance is sound.
The presentation will provide some insights illustrated by case studies in the application of AS 5104 to bridge assessment and discuss the framework for making the transition from a semi-probabilistic standard such as AS 5100, to the more holistic and sustainable risk-informed and reliability-based approaches. This approach is lies at the core of the current development of an Austroads Guideline for Bridge Assessment.
