Research on seismic response of elevated silo by coupling discrete-finite element method

The interaction of the various components of the column-supported silo (CSS) is affected by the complex dynamic interaction between the ensiled particles and the silo wall, as well as particle-particle interactions. To evaluate the seismic response of the CSS in the foodstuff storage and dock project in Shanghai Waigaoqiao, the Discrete-Finite Element (DE-FE) coupled method, considering additional mass, was developed to address dynamic horizontal pressure, displacement, stress, and overpressure distribution along the silo wall. In the proposed method, the dynamic pressure generated by the grain particle motion is simplified by using the additional mass matrix of the silo wall. Kinetic equations of particle-structure coupled systems are derived according to the physical characteristics and coupling boundary conditions of the additional mass. Parameter studies and design cases were conducted under horizontal input excitations with different seismic waves and acceleration peaks. The dynamic mechanical behavior indicates that the DE-FE method can provide an effective path for the analysis of particle-structure coupling systems on a large computational scale. The structure dynamic responses from the numerical model agree well with shaking table test results for different acceleration peaks, which verifies the numerical solutions. Numerical results show that the overpressure first increases and then decreases along the silo wall height, exhibiting a non-linear change trend. This indicates that the horizontal seismic action may be far less than specified in European Specification 8 for the silo top. The suggested values of the dynamic overpressure coefficient for controlling the deformation and cracking of the column-supported bottom are tabulated to facilitate the engineering applications of CSS.