The objective of this work is to analyse the influence of corrosion cleaning employing sandblasting, sand-paper cleaning, high-pressure-fresh-water-cleaning and corrosion cleaning by hammering on the mechanical properties of aged steel specimens. Tensile tests of cleaned corroded specimens are carried out. The specimens were cut from steel box girders, corroded in open sea water. The material properties of five groups of corroded specimens are experimentally estimated including the modulus of elasticity, yield stress, tensile strength and total uniform elongation. The trend of mechanical properties is analysed as a function of the degree of degradation and cleaning procedure, identifying that the cleaning treatment of the corroded surface significantly influences the mechanical properties and stress–strain relationships. A multi-criteria decision technique is employed to identify the most suitable cleaning technique accounting for the efficiency of the cleaning process and reducing the scatter in the mechanical properties of the cleaned corroded specimens.

Analyse des vibrations propres des risers tendus par la méthode de segmentation-Dans le but de l'évaluation des vibrations des risers induites par vortex (VIV), les vibrations modales d'un riser uniforme tendu en eau profonde sont considérées. Du fait de la faible rigidité des risers, les vibrations du type câble et poutre sont analysées. Les solutions exactes et asymptotiques de l'équation différentielle de câble sont présentées. Les vibrations de la poutre sont déterminées en modifiant la solution câble pour chaque demi-longueur d'onde du mode propre. La procédure analytique simplifiée est vérifiée par la méthode des éléments finis. Les conclusions utiles sur le comportement dynamique des risers dans le domaine des hautes et basses fréquences sont présentées.

Studies on the extrapolation of extreme significant wave height, based on long-term databases, are extensively covered in literature. An engineer, working in the field of naval architecture, marine engineering, or maritime operation planning, when tackling the problem of extreme wave prediction, would typically follow relevant codes and standards. Currently, authorities in the field of offshore operation within its guidelines propose several methods: the initial-distribution, extreme value, and peak-over threshold approaches. Furthermore, for each proposed method, different mathematical fitting techniques are applicable to optimize the candidate distribution parameters: the least-square method, the method of moments, and the maximum likelihood method. A comprehensive analysis was done to determine the difference in the results depending on the choice of method and fitting technique. All combinations were tested on a long-term database for a location in the Adriatic Sea. The variability of the results and trends of extreme wave height estimates for long return periods are presented, and the limitations of certain methods and techniques are noted.