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Abstract:This paper reports on the results of soil-foundation numerical modelling and the seismic response of a cooling tower founded on piles of a petrochemical facility located in the city of Augusta (Sicily, Italy). The city was affected in the past by some destructive earthquakes (1693, 1848, and 1990) that damaged a large territory of Southeastern Sicily, which was characterized by a very high seismic hazard. With this aim, the paper reports the FEM modelling of the seismic behaviour of the coupled soil-structure system. To determine the soil profile and the geotechnical characteristics, laboratory and in situ investigations were carried out in the studied area. The seismic event occurred in January 1693 and has been chosen as a scenario earthquake. Moreover, a parametric study with different input motions has also been carried out. A Mohr-Coulomb model has been adopted for the soil, and structural elements have been simulated by means of an elastic constitutive model. Two different vertical alignments have been analysed, considering both the free-field condition and the soil-structure interaction. The dynamic response has been investigated in terms of accelerations, response spectra, and amplification functions. The results have also been compared with those provided by Italian technical regulations. Finally, the seismic response of the coupled soil-structure system has been further examined in terms of peak bending moments along the pile foundation, emphasizing the possibility of a kinematic interaction on piles induced by the seismic action.Keywords: petrochemical equipment; geotechnical characterization; coupled soil-structure system; FEM 3D analysis
plaxis 3d foundation 2.2 178
The transmission of a train load through the rail structure and the subsequent response of the individual track components are dependent on important elements, i.e., subballast, subgrade, and soil properties [28, 29]. The dynamic response of a rail track is also strongly associated with the material characteristics that define the stiffness of its constituents. As train-induced vibrations become more prominent, a larger settlement is expected in track structures with ballast or subballast made of low-stiffness materials [18, 30]. Subgrade has been responsible for many past cases of track failures, as little can be done to improve the subgrade during maintenance operations [29]. Moreover, when the track embankment is constructed on soft subsoil, the possibility of differential settlement and dynamic response amplification may lead to bearing capacity failure and potentially put the safety of the track at risk [24, 31] (see also Figure 1). Soil structure also affects lateral deformation [32]. Delayed lateral deformations can be significant for clay foundations [33], as 20% of the total settlements have been reported to be due to lateral deformations [34]. Most related studies observed the lateral deformations of road embankments [33, 35, 36] but did not examine the lateral deformation or strain distribution of the soft subsoil of railway embankments under dynamic train loads.