SEISMIC BEHAVIOR OF SILOS WITH DIFFERENT HEIGHT TO DIAMETER RATIOS CONSIDERING GRANULAR MATERIAL-STRUCTURE INTERACTION

Abstract

Silos are structures that are used for storing different types of granular material. Dynamic behavior of silos under seismic loads is very complex. In this paper seismic behavior of steel silos with different height to diameter ratios is investigated by considering granular material-structure interaction using ABAQUS finite element package. Silo wall is modeled by shell elements and its behavior is considered elastic, seismic behavior of granular material inside silo is highly nonlinear and requires a complex nonlinear description of the granular material. The hypoplasticity theory describes the stress rate as a function of stress, strain rate and void ratio. The granular material is modeled by solid elements and its behavior is considered with a hypoplastic constitutive model, for modeling of interaction between silo wall and granular material, surface to surface contact with coulomb friction law is considered between silo wall and granular material. The results show that the seismic behavior of silos is dependent on the height to diameter ratio of the silo. While considering a constant value for the distribution of acceleration in the height of silo leads to conservative design pressures for a squat silo based on Eurocode 8, this assumption is not conservative for a slender silo.