Analysis Of Earthquake Time History Response And Dynamic Buckling Of 15X10~4m~3 Self-anchored Oil Storage Tanks

The large self-anchored storage tanks are the key equipment of Strategic Oil Storage Base in china. Under the effect of the earthquake disaster, the dynamic response of tanks is very complex. Since 1930's, scholars have been taking a lot of research on oil storage tanks of dynamic response and positive corresponding criterions too. However, the oil storage tanks that designed by the criterion are also destroyed in the seismic disaster sometimes. That indicates further study of seismic behavior and dynamic response of oil storage tank is still necessary.The dynamic response analysis of 15×104m3 oil storage tank has been carried out, also the "elephant foot" buckling failure behavior and the effect of hoop stress generated by hydrodynamic pressure on the "elephant foot" buckling are studied in this paper. The main research work in the study is concluded as follows:(1) Comparative analysis of the earthquake force and "elephant foot" buckling of American, Japan and Chinese seismic design codes on oil storage tanks; Take 15×104m3 oil storage tank as an example, compare the calculation results of these three seismic design codes by using dimensionless method.(2)Taking into account the material nonlinear, geometric nonlinearity and contact state nonlinear of model for dynamic response analysis. Study the distribution of stress along the tank wall; sloshing wave height, uplift, and acceleration amplification, obtained the relationship between the uplift, sloshing wave height and axial compressive stress. Besides, compare the difference of seismic response between one thickness and variable thickness model.(3) Discusses the "elephant foot" buckling failure behavior by using one thickness model and harmonic load. The results are as follows:the "elephant foot" buckling is one kind of plastic local buckling, which results from the effect of hoop stress and axial compress stress. The occurring condition of "elephant foot" buckling is axial compress stress exceeds the critical stress and hoop stress is near or more than the yield stress, when "elephant foot" buckling occurres, the tank wall deformation is too large to make the bottom plate deform, so that the bottom plate may occur plastic yield damage.(4) Study the effect of hoop stress on the "elephant foot" buckling. The results: Only the hoop stress is near or more than the material yield stress, the tank will occur "elephant foot" buckling. The greater hoop stress is, the easier the tank is to occur "elephant foot" buckling. When hoop stress is low, even great axial stress is also less prone to "elephant foot" buckling. And study the effect of hoop stress generated by hydrodynamic pressure on the "elephant foot" buckling from the liquid level, the characteristic period, type and direction of load.