Blast events and scenarios, as known, represent extreme phenomena that may result in catastrophic consequences, both for humans and structures. Accordingly, for engineering applications, the reliable description of expected blast waves is a crucial step of the overall design process. Compared to ideal theoretical formulations, however, real explosive events can be strongly sensitive to a multitude of parameters and first of all to the basic features (size, type, shape, etc.) of the charge. In this regard, several advanced computer codes can be used in support of design and research developments. Besides, the input parameters and solving assumptions of refined numerical methods are often available and calibrated in the literature for specific configurations only. In this paper, with the support of the ANSYS Autodyn program, special care is dedicated to the numerical analysis of the blast wave propagation in the air due to several charges. Five different explosives are taken into account in this study, including RDX, DAP-2, DAP-E, Polonit-V, and homemade ANFO. The effects of different mixtures are thus emphasized in terms of the predicted blast wave, as a function of a given control point, direction, explosive mass, and composition. As shown, relatively scattered peak pressure estimates are collected for a given explosive. Comparative results are hence proposed towards selected experimental data of the literature, as well as based on simple analytical predictions. The collected overpressure peak values are thus discussed for the selected explosive charges.

Offshore structures are complex facilities whose malfunction can lead to serious impacts and losses, such as human lives, environmental disasters and the complete loss of the structure. Additionally, the cost associated to their construction and maintenance is very high, so it is crucial to keep them fully operational throughout their entire service life. Standby periods in offshore platforms generate large financial losses for their owners. The most devastating effects on offshore platforms are often the result of incidents which eventually lead to accidental actions. Hence it is very important to develop measures which limit the effects of accidental actions on the overall performance of these facilities. In this paper the most likely accidental scenarios and the strategies currently used to mitigate their devastating effects were analysed. Accidental scenarios were discussed based on the available historical data of incidents on offshore platforms, and classified according to the type of offshore platform or the type of structural elements affected. Furthermore, the most frequent hazards were used to introduce specific accidental actions which will then be the subject of a study for comparing the approaches proposed by different technical standards. The strategies currently used for mitigating the effect of accidental actions, both non-structural and structural, were classified according to the materials used and the structural typology adopted. The objective of this study was to identify new opportunities for the development of innovative mitigation strategies for the devastating effects associated to accidental actions in offshore platforms, considering the most recent developments in terms of innovative materials and of structural analysis approaches. In this context, this paper discusses the current trends in research and the future challenges related to this issue. This will serve to identify the possible methods for improvement of the existing structural mitigation measures.

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The response of the bulkhead type of blast wall under deflagration blast pulse was studied using finite element modelling software. The behavior of unstiffened and stiffened panels was analyzed. The study aimed at determining the effect of plate and stiffener thicknesses on energy dissipation and distribution of reaction forces. This was carried out in order to optimize the response of the primary steelwork through typological and geometrical modifications of the local element. Furthermore, novel strategies for the improvement of the blast response were introduced with a focus to use alternative materials and innovative connections. The latter was assessed numerically using a simplified model and its benefits were analyzed by comparing with the traditional approach.