NONLINEAR ANALYSIS OF SILO/MATERIAL INTERACTION UNDER LATERAL LOAD

The response of a filled silo to external lateral loads involves both the silo structure and the stored material. Due to the great difference between the mechanical properties of the silo wall and the stored material and the possibility of slip of the stored material along its contact surface with the silo wall, the composite action of the silo wall and the stored material to external load effects was quite questionable.;Results of analysis showed that a silo filled with granular material tended to deflect more in the direction of external lateral loading comparing to the same silo subjected to the same external lateral loading when it was empty. This is equivalent to that the stored granular contributes 'negative' stiffness to the silo structure. As a result of larger bending, the longitudinal and hoop stresses in the silo wall increased in regions perpendicular to the direction of external lateral loading and decreased in regions parallel to the direction of lateral loading as compared to the linear superposition of effects due to internal radial pressures resulting from the stored granular material without external disturbance and that the same silo subjected to the same external loading when it was empty. The final internal radial pressures also increased and decreased following the same pattern and became no longer axisymmetric.;It was thus concluded that a filled silo was more vulnerable to external lateral loading than the same silo subjected to the same external loading when it was empty.;Nonlinear finite element analysis accounting for material nonlinearity as well as possible large strains in the stored granular media was performed to investigate the silo/material interaction under quasi-static lateral loading. Very large bulk modulus, incompressible comparing to that of the stored material, was assigned to 16-node 3/D continuum elements to simulate the interface action between the silo wall and the stored material in the analysis.