Guideline for Monitoring of Prestressing Wire Breaks with Acoustic Emission Technique

The Guideline is published at the German Society of Nondestructive Testing (DGZfP) and can be purchased there [1]. An English version will be available soon. It is written by civil engineers, authorities having jurisdiction/ owners and Acoustic Emission Specialists. The Guideline describes the acoustic emission analysis method for detecting wire breaks in prestressed concrete bridges as part of a permanent monitoring. It provides information on the planning, installation and operation of monitoring systems for the detection of prestressing wire breaks with acoustic emission and for checking the function of installed systems. The main reason for publishing this guideline is that a lot of prestressed concrete bridges in Germany with an age of 50 years and more are showing more and more problems due to an unseen increase of heavy traffic and/ or insufficient construction. A few years ago, it was recognized and stated by the government in Germany, that some steel charges used for the tendons of older prestressed concrete bridges are prone to Stress Corrosion Cracking (SCC). Furthermore, there are structures in which the reinforcement is not sufficient for safe load transfer in the event of prestressing steel failure and therefore failure may occur without any prior notice.