Guidance on hidden defects in bridges in the UK and Ireland

There is a long history of failure or collapse of bridges in the UK and Ireland attributable to hidden defects. This paper summarises and discusses some of the guidance issued in the Ciria publication C764 Hidden Defects in Bridges - Guidance for Detection and Management. Some case studies of recent problems are included. The current standard practice of bridge inspection and associated management is compared to a proposed proactive approach, which includes targeted inspections and requires knowledge and understanding of the risks posed by types of defects. The question of what cannot be seen is raised. The importance and competence of the inspector, engineer and asset owner are emphasised. The types of defects that may be hidden are discussed and listed for each main element of bridges. The challenges to the industry arising from the recommendations are discussed; suggestions are made for further research and the recommended proactive methods are discussed.