Fatigue strength of high-strength steel linings with different types of grouting opening

Owing to the increased use of high-strength steel (HSS) grades for steel linings in pressure shafts, the fatigue check becomes more and more critical for the proper design of such components. Eurocode 3, AD 2000 and IIW Recommendations do not consider the specific needs of liners with grouting openings (also called nipples) in combination with the higher steel grades. Therefore, a three-year research project of the Austrian Research Promotion Agency (FFG) was conducted to focus on investigating the fatigue strength of grouting nipples. This project saw a new design concept for steel linings with nipples established which takes into consideration the design concept of the Eurocode. The new findings regarding the fatigue strength of nipples were embedded in this concept.