This paper reviews the use of reliability techniques for assessing the structural adequacy of bridges and highlights how the output of such an analysis can both inform and guide the user in their investigation of a structure. Three different ways of interpreting the value of reliability indices are identified and the feasibility of using each of these to prioritise repair and strengthening works is examined. An average acceptable value (AAV) of reliability index for different bridge types and failure modes is proposed and it is shown that in some cases priorities can be identified directly by comparing reliability indices, sometimes a measure of the significance of the reliability index is needed, while in other cases priorities are still not obvious and further investigation is required. To achieve this, the principles of risk management are explored and it is shown that where two or more structures have similar reliabilities, consideration of risk does represent a feasible approach.
Robert J. Lark, BSc(Eng), PhD, CEng, MICE
Cardiff School of Engineering, Cardiff University, UK
Dipl.-Ing Katja D. Flaig, PhD
Allianz, Munich, Germany