Analysis And Research On The Optimization Design Of Large Scale Industrial Steel Silos

Steel silo is widely used in grain, coal, cement, electricity and chemical industry due to the superior structure property. However, the relevant theoretical study still lag behind the actual project, and the damage of it appeared more frequent. The main and difficult point of theoretical study for steel silo is the precise calculation of storing load, the effect of defect for stability and the impairment for seismic effect of the friction between storing particles. Meanwhile, exposed to the air cause the generating of non-uniform temperature effect of steel silo under the sun radiation which is harmful to the structures. Associate with the project, this paper analyzed the compression improvement caused by unloading, the sun radiation effect to structure property and the structure form of steel silo by numerical simulation. In the final, designed a large-scale cement steel silo and analyzed the stability of it by finite element software.The foreign code used the Janssen theory for all silos, compared with the foreign code, the code in China adopted Janssen theory for deep silos and Rankine theory for shallow silos. Meanwhile, the correction coefficient of the horizontal lateral pressure is larger than normal and the vertical friction correction coefficient is lower, the effect of storing decentration has not been considered as well. Particle flow analysis program PFC2 D was adopted to simulate the process of loading and unloading for large-scale ground supported steel silos, and the proposal value is given associated the Chinese and foreign code.The effect of radiation shadow was in consideration when analyzed the sun radiation, and propose the method of shadow calculation. Then analyzed the non-uniform temperature field for four working condition by ANSYS, and got the effect for structure property which caused by non-uniform temperature field. Found that considering the solar shadow, single side convection heat transfer condition effect structure obviously.Through extending the size of vertical columns and the surrounding beams and adopting reasonable arrangement, this paper proposed a silo structure form which resisted force mainly by columns and beams. Then 36 MIDAS models with different height-diameter ratios and diameter were analyzed and compared, from which the reasonable proposal for structure arrangement was gotten for the design of steel silo, such as the selection for structure forms, the changing section of vertical columns and the surrounding beams and the enhanced part. Beam-column structure is suitable for steel silo with large diameter(R>30m).At the end of the paper, a steel silo with the diameter of 23 m was designed, including the structure scheme, component arrangement, the calculation of load, model establishment, static and dynamic analyzed and the evaluation of the result. And the result show that the safety of the structure is adequate. Based on the design, analyzed the characteristic value buckling and the material and geometry nonlinear of the steel silo by ANSYS. The analysis for stability of empty and full silo show that the wind load effect to empty silo more obvious than the full. The horizontal inner compression effect the stability of silo significantly. The sensitive nonlinear characteristic of steel silo makes “elephant foot” damage occered.