PSI - Issue 38

B. Depale et al. / Procedia Structural Integrity 38 (2022) 317–330 "B. Depale-M. Bennebach" / Structural Integrity Procedia 00 (2021) 000 – 000

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- FEM Rules 1.001 (1998). After more than one year of work, the procedure described below was published at the beginning of 2003. The Recommendations also include guidance, comments and calculation examples. In this clause, we focus on the main steps of the procedure called “Special Evaluation” . The procedure of “Special Evaluation” shall be activated for at least one of the following criteria: - Increase in reports of accidents/incidents/inspections resulting from significant damage of the crane, - The crane is at least 19 years old (9 years for mobile cranes): see 4.2.3.1 below as background, - When the initial classification of the crane is known and 95 % of its working cycles have been completed, - Substantial modification of the use of the crane compared to the expected duty at initial design stage. If the crane manufacturer is not in charge of the “Special Evaluation”, a reconstitution of the history/duty of the crane is done as the first phase. All useful information shall be collected, such as crane configurations, number of working cycles, load spectra, incidents/accidents, and modifications of the crane. At this stage, it can be decided to take the crane out of service, for instance, for economic reasons. Otherwise, critical areas of the crane shall be identified and inspected next. If there is any doubt about the integrity of the structure or if the use of the crane has changed compared to original design assumptions, than the “Special Evaluation” shall be performed, consisting of: - Eventual instrumentation of areas judged to be critical, - Modelling (e.g. FEA) and calculations in accordance to FEM 1.001 Rules, including proof of fatigue strength, - Final identification of the critical areas, - Application of a Risk Based Inspection for the most critical constructional details. Then requirements for the future duty of the crane are developed by the design office, such as: - Parts to be replaced, - Parts to be repaired, - Parts to be inspected, with the relevant inspection period, - Duration until the next “Special Evaluation”, this period cannot be lower than 1 0 years. This phase should consider the future crane configurations and load spectrum, in agreement with the crane owner. In Italy, a Ministerial Decree of 11 th of April 2011 established that cranes older than 20 years should be submitted to an extra assessment of the structure the purposes of which is to: - Identify potential cracks, defects or anomalies; - Determine their residual life and compare it to the original classification provided by the crane manufacturers. The change introduced by this Decree is that such request for extra inspection should be addressed by the crane owner to the person in charge of the periodic inspections. Consequently, when a crane is 20 years old, the owner is expected to ask the Expert Engineer to carry out the assessment of the structure. We can see that, in Italy, even if this decree has not resulted in a specific methodology as in France for port cranes, the national authorities have decided on a special measure for old cranes, making the evaluation of their residual life mandatory. 4.2.2 Ministerial Decree for old cranes (Italy, 2011)