Wednesday, 26 September 2018
Austroads has published a report documenting the options and methodologies available to conduct higher order assessments of existing bridges which are encouraged by but not currently defined by Australian Standard AS 5100.7.
In Australia, there is a continued push to improve productivity by making the freight task more efficient.
Key mechanisms to achieve this include increasing freight vehicle masses and allowing flexibility in truck configurations.
Increasing bridge load limits is seen as an important aspect of productivity improvements but this objective is tempered by an aging infrastructure system that was not designed for the current or proposed loads of the future.
As a result, there is increasing focus on the management of aging bridge infrastructure both nationally and internationally and, in particular, determining ways to get more out of the existing bridge stock.
The project investigated international and local practice and developed a framework to provide guidance on when and where higher order assessments are appropriate and their relative benefits and costs.
The proposed framework focusses on three tiers of assessment with a specific flow chart to assist with the decision-making process to elevate to successively higher tiers of assessment.
The focus on deterministic approaches to bridge assessment in Australia represents a significant gap in Australian practice.
A key recommendation of this study is to further investigate the usefulness of probabilistic and reliability assessment with a focus on both code calibration and Tier 3 site‑specific evaluations. Several other recommendations are made around improving Tier 3 investigations, the most significant being the development of an Australian guide to bridge assessment.
Report link: Higher Order Bridge Assessment in Australia