Stress Analysis And Strength Assessment Of Vertical Storage Tank Under Combined Loadings

With the construction of the National Petroleum Resources Strategic Base,vertical dome steel storage tanks are more and more needed.The vertical dome storage tanks are large in structure and acted by various loads.If damaged in service,it will result in huge economical loss and even claim human lives.In this thesis,finite element method is used to analyze the stress and deformation at the tank body and the reinforced concrete base of a vertical dome storage tank under combined loadings.The main contents and conclusions are as follows:(1)According to the GB50341 and related design conditions,the main structure of the storage tank were designed.The strength size of the tank body under the internal pressure and hydrostatic pressure were evaluated,which formed the basis for strength analysis of the tank under the combined loadings including wind and seismic loads.(2)The fluid-structure interaction finite element model for the modal analysis of the storage tank was established.Eleven vibration modes with natural frequencies for the tank with full medium were obtained.The height and density of the storage medium were investigated for their influences on the natural frequencies.(3)The equivalent seismic acceleration method,response spectrum method and time-history analysis method were adopted to analyze the seismic response of the storage tank.Results showed that equivalent seismic acceleration method is more conservative than response spectrum method for the storage tank studied here.(4)Stress and deformation analysis were performed for the tank body under the combined loadings including seismic load,wind load,hydrostatic pressure,internal pressure and other design loads.Strength assessment was conducted.Results show that the tank strength meets the strength requirements based on JB4732-1995.(5)The reinforced concrete ring beam foundation of the tank was designed and finite element model for the reinforced concrete ring beam foundation was established.Stress analysis and strength assessment were carried out for the ring beam under the horizontal shear force and bending moment.Results show that the reinforced concrete ring beam meets the strength requirement.Compared with the plain concrete ring beam,the reinforced concrete ring beam has a stronger tensile strength and is more capable to prevent the foundation from cracking.