Analytical developments for the evaluation of the horizontal forces acting on the walls of flat-bottom silos containing grain-like material during earthquake

This paper proposes an innovative methodology for the seismic design of flat-bottom silos containing granular, grain-like material and presents analytical developments devoted to the evaluation of the effective behaviour of flat-bottom silos containing grain, as subjected to earthquake input. The analyses are developed by simulating the earthquake ground motion with constant vertical and horizontal accelerations (time-history dynamic analyses are not carried out) and lead to the subdivision of the ensiled material into three different portions (depending on the interaction with the container) by means of plain dynamic equilibrium considerations that take into consideration the specific mutual actions developing in the ensiled grain.. The findings indicate that, in the case of silos characterized by specific (but usual) height/diameter slenderness ratios, the portion of grain mass that interacts with the silo walls turns out to be noticeably lower than the total mass of the grain in the silo.