ABSTRACT
Recent catastrophic or unexpected structural failures in road and rail bridges (such as Stewarton rail bridge, Ayrshire, De la Concorde bridge in Canada and more recently the Italian concrete bridge near Lecco) have, in part or full, been attributed to concealed deterioration or deficiencies in one or many components. Defects are usually identified in the course of regular visual inspections carried out by a competent inspector, making an assessment on the condition of the visible components, with reference to appropriate guidelines provided in standard inspection manuals. Hidden defects present unknown risks to the overall integrity of the structure if not identified and rectified.
In recognition of these risks, members of the Bridge Owner’s Forum in the UK initiated a project to develop a guide that provides recommendations for identifying, inspecting, designing and maintaining bridges with hidden components. Recently published by CIRIA, Arup and AECOM have collaboratively developed this guide, which the current paper provides a summary of findings from the guide. Translated into an Australian context, key concepts are discussed, such as defects in typical hidden components, proposed risk assessment techniques for management, and recommendations for the development of more targeted inspection and maintenance regimes (that may include health monitoring techniques) to critical areas. The paper also provides various design and planning recommendations for consideration in the preliminary evaluation phase.
