This article gives a rough overview about a research project FOSTA P778 “Design of components for crane structures made of high-strength fine grain steels under fatigue load” . This research was on fatigue resistances of specific crane notch details made of high-strength steels of crane and mobile crane structures. Besides the three universities RWTH Aachen, KIT Karlsruhe and HM München also crane manufacturers actively carried out parts of the research as there were Liebherr Ehingen, Liebherr Biberach and Gottwald Port Technology Düsseldorf. All results are published in a comprehensive research report which consists of three main parts.
Part I deals with the basics of the assessment methods for steel members subjected to fatigue loading, in particular details of crane engineering. For this purpose, miscellaneous standards and guidelines are available. However, the practical implementation of these basics partially shows elementary differences between these documents regarding the methodology, time exposure and results obtained for fatigue verification. Furthermore, some selected standards are directly compared.
In part II, the ... mehr results of numerous fatigue tests on different specific crane details are presented, including low-cycle fatigue tests and steel grades S690QL, S960QL and S1100QL. These investigations are verified by numerical simulations on some selected structural details. Test results support also the present classification of these welded details for high-strength steels. The presented results facilitate an efficient use of high-strength steels and allow an increase of capacity while reducing the constructional weight at the same time.
Within the scope of part III, measurements on various tower cranes in use on different construction sites have been taken to determine their load spectra. Detailed knowledge of working conditions and operational behavior of cranes is of high importance to get accurate calculation results. The recorded rated load and load moment spectra allow an insight in the actual loading situation of tower cranes on current construction sites. The analysis of the series of measurements allows a first comparison of normative classification of these cranes according to national and international standards.