ABSTRACT
Bridge assessments can often feel like a maze for asset owners with the wealth of information available internationally on approaches to determine the appropriate heavy vehicle access management strategy. Throughout the world, heavy vehicles are operating on bridges at levels that exceed the assessed load carrying capacities of the bridges determined using design based (“standard”) assessment procedures. The cost of strengthening these bridges is unpalatable and the consequences of restricting access are unacceptable. Inspections of these bridges in most cases indicate they are performing satisfactorily leading one to question the plausibility of the assessments. The key to unlocking the bridge assessment maze is to understand the inherent assumptions that underpin every form of assessment. An appreciation of the nature and type of assumptions then leads to a more informed position regarding actual risks, which ultimately provides the avenue to developed targeted management strategies for individual bridges and on a network-wide basis.
This paper aims to provide some guidance through the bridge assessment maze to empower the asset owner or manager to understand the requirements and outputs of bridge assessments. The paper begins by providing the distinction between design and assessment and then outlines current bridge assessment processes in Australia and selected international jurisdictions. A comparison of assessment assumptions is then presented to demonstrate the variability in assessment results that can in turn impact on the required management strategy and investment. The findings provide justification for the development of further guidance on the practical and reliable assessment of bridges.
