Uplifting Resistance Study Based On Damage Performance For Stand Steel Storage Tanks

As one of the most important industry facilities in oil storage and transportation, stand steel storage tanks' volume is becoming larger and larger. Base floating (also as no anchor) has been the certain tendency in development. In practice,however,complete anchorage is not economical and may not be warranted at times.As a result, many tanks are either unanchored or only partially anchored at their bases. During highly-intensity ground shaking,these tanks tend to uplift and respond in a highly nonlinear manner. Researching the uplifting tanks' performance shows that these systems can be damaged easily. Nevertheless, traditional design against the earthquake mainly alters the rigidity and the intensity to ensure the tank system.The aseismic structure performance generally comprises elasticity performance and non-elasticity performance. Non-elasticity performance is also named the damage performance. The main goal of the aseismic design is to prevent structure from various degrees of the damages, so the aseismic structure performance is actually the damage performance.Decades' experience in earthquake disasters and the research of scholars of various countries show that earthquake is a to-and-fro action, and the duration of the earthquake movement is usually very short. Accordingly, the structure damage under earthquake is related to not only the maximal distortion, but also the accumulative damage caused by the effect of structure's low-cycle fatigue. The current criterion of aseismic design can not reflect the structure's low-cycle fatigue under the earthquake and quantificationally specific request for the structure damage performance. Thus, the more reasonable aseismic should be designed according to the allowable value of the structure's damage under the action of the coming earthquake, as a result,a new concept of designing based on the damage performance appears.This paper begins with the mechanism of dynamic uplifting .The appraisal method of the appraising the uplifting earthquake damage performance and the index system of the damage performance corresponding to the seismic damage grade is established.The main work and research achivement include: (l)Study of the mechanism of the dynamic uplifting for stand steel tanks;(2)Model based on earthquake damage performance for stand steel storage is established;(3)The damage index function based on the earthquake damage performance using base distortion and energy as parameter is established.A aseismic design theory methord is formed uplifting resistance effect with damage index as allowable value;(4) The damage index system appraising uplifting damage degree is set up and the numerical caculation of the typical engineering tanks is processed.