Buckling Study Of In-service Storage Tanks Under The Combined Action Of Differential Settlement And Wind Load

As a core equipment of petroleum storage,large cylindrical steel storage tanks are widely used because of their small footprint,low consumables and low cost.In order to facilitate transportation,large-scale storage tanks are mostly built in soft soil areas along the river and the coast.The soil structure of these areas is complex,and the foundation of the storage tank is prone to settling and deformation.At the same time,in the summer,these areas also frequently encounter sudden disasters such as typhoons.In this paper,considering the influence of the combined action of differential settlement and wind load on the stability of the storage tank,the numerical simulation buckling method of large storage tank under the combined action of differential settlement and wind load is proposed.The behavior and the influence of differential settlement distribution on the wind stability of the tank were analyzed.Besides,the effects of liquid height and stiffening ring on the stability of the tank were studied.Based on the finite element analysis method proposed in this paper,the safety evaluation of the in-service settling tanks can be carried out to provide technical support for the tanks.The main work carried out is as follows:(1)A numerical simulation method for buckling of large storage tanks under the combined action of differential settlement and wind load is proposed.Considering the characteristics of static wind load and dynamic wind load,the influence of the differential settlement on the wind stability of fixed roof tank and floating roof tank is studied.The similarities and differences between static wind buckling and dynamic wind buckling of settlement tanks are compared.Studies have shown that differential settlement weakens the wind resistance of the tank,and the degree of weakening is related to the form of differential settlement.Wind-induced buckling occurs easily in the corresponding tank wall area where the foundation is lifted upwards;under the same conditions,the floating roof tank has better wind stability than the fixed roof tank.The dynamic wind load considers the influence of the action time on the buckling stability of the tank,which can make up for the shortcomings of the static buckling analysis.(2)The effect of the liquid storage height on the wind-induced buckling behavior of the settling tank was studied.Studies have shown that liquid storage can improve the wind stability of the tank.When the liquid storage height is less than 1/2 of the total height of the tank wall,the increase in the wind resistance stability of the tank is not significant.When the liquid storage height exceeds 3/5 of the total height of the tank wall,the pressure of the liquid can greatly increase the critical wind load of the storage tank.Accordingly,it is recommended to keep the liquid storage in the tank at a higher liquid level in the summer and autumn seasons when the typhoon frequently occurs.(3)Aiming at the decrease of wind resistance of in-service settling tanks,it is proposed to provide reinforcement measures such as stiffening ring on the tank wall,and the buckling numerical simulation method is used to verify the reinforcement effect.The number and position of the stiffening ring are studied.The reinforcement measures for the in-service settling tank are given.The results show that the stiffening ring is arranged at the buckling position of the storage tank,which has better reinforcement effect.And as the number of stiffening rings increases,the reinforcement effect becomes more apparent.