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  • SIMPLIFIED NUMERICAL MODELING OF ELEVATED SILOS FOR NONLINEAR DYNAMIC ANALYSIS

    Silos are industrial facilities used for storing a huge range of different materials. They should be designed to resist several loading conditions, and their seismic behaviour strongly depends on the geometrical and mechanical behaviour of their supporting frame, and the nonlinear behaviour of the content (e.g. friction, content-silo wall interaction). Nonlinear dynamic simulation of such systems can be very time-consuming, and most of the time unfeasible. This study compares a finite element model made of bricks elements and a simpler model with distributed masses on the silo walls. While simplified models were not suitable to simulate local behaviour of the silo wall, they reasonably predicted the global response of the elevated silo system. Yet, the accuracy strongly depended on the rigidity of the supporting structure, and this should be investigated carefully during the calibration phase.

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  • Underground tunnels in seismic areas

    Analytical and numerical models of the structural safety of an underground tunnel under seismic ac- tions are discussed. Three procedures are compared: the first is analytical, in two versions (Penzien-Wu 1998 and Penzien 2000), and the others are numerical, referring to the computer codes Flush and Flac, in two-dimension space. The analytical procedure considers the soil as homogeneous. The tunnel cross-section is circular and this allows an application to the underground railway of Naples, which has effectively this structural cross-section. When conditions are equal, the three procedures offer similar results in terms of maximum values of internal force components and in fair agreement as distribution along the wall. However important effects are highlighted next to soil discontinuities, in particular in seismic conditions.

    The complete paper is available in Italian only.