Shaking Table Test On Seismic Performance Of Column-supported Silos In Line

Silo is an important storage facility for bulk materials in life Line engineering,which is widely used in grain,metallurgy,chemical and other warehousing and logistics industries.China is a country with frequent earthquakes,and the phenomenon of silo damage still exists in the earthquake.The safety of silo structure,especially how to ensure its good seismic performance in the event of earthquake disaster,is a key problem to be solved in the field of storage structure construction.The column-supported silos in line is a group of silos which take the column as the lower supporting system and are arranged in parallel according to the single line of the single silo.The stiffness of the lower supporting column is much smaller than that of the upper silo.There is a sudden change in stiffness at the connection between the two,which is prone to earthquake damage.The column-supported silos in line structure is different from the single silo,and its dynamic effect is more complex.It is blindness and irrationality to simply apply the seismic design results of the single silo directly to the silo without checking it as a whole.Therefore,it is necessary to make an in-depth and systematic study on the seismic performance of column-supported silos in line,reveal its seismic response mechanism,and provide reference and basis for the seismic design of column-supported group silos in line,which has important theoretical value and engineering practical significance.In this paper,taking the column-supported silos in line as the research object,the seismic simulation shaking table test of the silo model with geometric scale of 1:25 is carried out,combined with test,finite Element simulation and theoretical analysis.The dynamic response and seismic performance of bunker structures on two spindle directions under different working conditions are studied.The main research contents and conclusions are as follows:(1)The shaking table test of the column-supported silos in line silo model is carried out,and the dynamic characteristics and dynamic responses of the silo structure in two spindle directions are obtained and compared with the single silo.The results show that: 1)the natural frequency of the warehouse structure in the Y direction is close to that of the single warehouse,but the difference between the two principal axes is increased,which shows that the stiffness of the warehouse structure in the Y direction is close to that of the single warehouse and both of them are less than the X direction.2)there are differences in the acceleration response of the single warehouse in different positions,and the acceleration magnification coefficient of No.2 warehouse is generally larger than that of No.1warehouse under different working conditions.On the whole,the acceleration amplification factor of the bunker structure is smaller than that of the single silo.3)the displacement response of the bunker in the two principal axis directions is quite different,and the maximum relative displacement in the X direction is generally smaller than that in the single silo,and the maximum relative displacement in the Y direction is larger than that in the Y direction.From the point of view of the dynamic characteristics and dynamic response of the warehouse-row structure in the two principal axis directions,only the single warehouse can not fully reflect the seismic response characteristics of the warehouse-row structure.The seismic design of the warehouse-row structure should be considered according to the different positions of the warehouse and the direction of seismic action.(2)The distribution law of dynamic lateral pressure of silo wall along the height of silo wall under earthquake is revealed.The distribution law of the dynamic lateral pressure increment is correlated with the location of the measuring point and the position of the warehouse body.The dynamic lateral pressure increment of the No.1 warehouse is generally larger than that of the No.2 warehouse,and the values of both at the top of the warehouse body are larger than that of the single warehouse.Within the range of 1 stroke 3 in the upper part of the silo body,the over-pressure coefficient of silo 1 is greater than that of silo 2,both of which are greater than the coefficient 2.0 specified in the code,indicating that the storage over-pressure caused by earthquake can not be ignored,and the comprehensive correction coefficient adopted in the current code is too small.the internal force of the silo wall should be calculated according to the position of each silo body in the silo.(3)The finite Element model of column-supported silos in line is established,and the finite Element numerical calculation under earthquake is carried out,and the dynamic characteristics and dynamic response of the silo structure in two spindle directions are obtained.The results show that: 1)the first two modes of the model are translation along Y direction and X direction respectively,while the third mode is the torsion of the whole bunker;the natural frequency of the simulated bunker structure is close to the experimental results,and the establishment of the finite Element model is reasonable.2)the finite Element results of acceleration response,displacement response and dynamic lateral pressure of silo wall are similar to the experimental results,and the finite Element value of dynamic response is close to the experimental value.the finite Element value of dynamic lateral pressure is larger than the experimental value,which shows that there are some limitations in using D-P model to simulate the stored material in the warehouse.(4)Based on the mode decomposition response spectrum method,the horizontal seismic action of the bunker structure in two principal axes is analyzed by using the dynamic calculation model of multi-degree-of-freedom in series with three particles.The results show that: 1)the first-order natural frequency calculated by the dynamic calculation model is close to the experimental value,and the establishment of the calculation model is reasonable;2)the base shear distribution coefficient of each single warehouse in the X direction is relatively close;the difference of the base shear distribution coefficient of each single warehouse in the Y direction is large,and the base shear distribution coefficient of No.1warehouse is 0.324,and the base shear distribution coefficient of No.2 warehouse is 0.351.3)in the row structure,the base shear force of each single warehouse is larger than that of single warehouse.In the X direction,the ratio coefficients of No.1 warehouse and single warehouse under different storage conditions are 1.12,1.01 and 1.18 respectively.The ratio coefficients of No.2 warehouse and single warehouse are 1.13,1.06 and 1.20,respectively.In the Y direction,the ratio coefficients of No.1 warehouse to single warehouse were 1.22,1.08 and 1.14 respectively.The ratio coefficients of No.2 warehouse and single warehouse in Y direction were 1.41,1.12 and 1.20,respectively.The test results show that there is a certain irrationality in using the deformation and force of the single warehouse to speculate the seismic response of the warehouse,and the seismic design should be carried out according to the location of the warehouse body and the direction of seismic action.The research results can provide reference and basis for the seismic design of column-supported group silos.