Bridges

Cover of Structural Assessment of Freight Bridges in Queensland
Structural Assessment of Freight Bridges in Queensland
  • Publication no: ABC-AAI101-14
  • Published: 22 October 2014

All road authorities have a range of bridges of varying ages and design classes, which have transitioned over time to carry modern heavy vehicles. This paper reports the structural assessment procedures adopted by the Queensland Department of Transport and Main Roads to undertake a structural assessment of over 2,000 bridges on its road train and B-double freight network, while maintaining safe access to the network for all road users.The bridge assessment criteria developed consider multi-combination vehicles, cranes and heavy load platforms for the spectrum of bridges currently in service. The criteria are based on the AS 5100 Bridge Design code with its simplifications that may be conservative for assessment and other limitations such as no consideration of cranes. The process consists of Tier 0 assessments based on the bridges’ original design class followed, where necessary, by a Tier 1 bridge assessment using traditional design-based methods but for assessment. Bridges identified as unsatisfactory for as-of-right loads are potentially subjected to more sophisticated assessment and inspection (Tier 2 assessments). Structure Management Plans are imposed on all bridges with substandard assessments in order to manage the ongoing risks.This paper provides the framework for the assessment process and discusses international approaches that accept higher short-term risk provided action is taken to upgrade the bridge in the short-term.