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In recent years an innovative beam-to-column connection type for steel moment resisting frames (MRFs) has been conceived. It deals with the Post-Tensioned Energy-Dissipating (PTED) connections, endowed with self-centering capability and energy dissipation capacity. A series of experimental studies has been carried out up to now and some simple numerical models have been set up. This paper shows an overview on the numerical activity ongoing at the University of Naples “Federico II”, aimed at setting up refined numerical models of PTED connections. The obtained results are illustrated. As planned activity, some basic aspects will be investigated, such as the connection behavior in presence of vertical and seismic loads and the comparison with the traditional welded nodes; furthermore, a more detailed study will focus on the evaluation of the influence of several geometric parameters.

In this paper, after a general presentation of the Submerged Floating Tunnel (SFT) as an attractive technical solution for waterway crossings, the SFT prototype to be built in Qiandao Lake (People's Republic of China) is introduced. The main peculiarities of such an innovative system are briefly summarized and the importance of realizing a SFT prototype is underlined. The types of action that the SFTs can be generally subjected to are illustrated and the specific load conditions for the SFT prototype in Qiandao Lake are presented. The numerical analyses carried out for investigating the system behaviour in presence of the environmental loads, such as waves, currents and earthquakes, are focused. Three cables configurations are considered for the hydrodynamic analyses, in order to select the most performing one, which is subsequently analyzed also under seismic loads. The model assumptions and the results of the performed analyses are shown and critically discussed. Finally, the displacement and strength safety checks are shown, which allow to state that the designed SFT prototype is able to withstand the environmental design actions in Qiandao Lake.