Post-tensioned structures - improved standards

Between 1979 and 1992 the UK Standing Committee on Structural Safety published annual reports which included reports on suspected deficiencies of grouting of post-tensioning tendons; then in 1992 the UK Department of Transport banned ducted grouted post-tensioning in bridges. This marked the beginning of a process of investigation and review of standards and procedures which led over 20 years to national and international bodies introducing improvements to help ensure the safety and reliability of post-tensioned structures. This is a prime example of where industry had to learn from the past, and has used that knowledge to introduce improvements, culminating in the publication of new ISO standards. This paper describes significant lessons to learn from this process for structural designers, material scientists and owners of structures, both for new designs and for asset maintenance.