活塞对大型储气柜柜体抗震性能的影响分析

Study of damping effect of piston on seismic performance of large-scale gasholder

现行气柜结构抗震设计的地震反应计算模型中,将活塞质量计入质点,把活塞作为柜体结构抗震性能的不利因素。实际储气柜结构中的活塞受所储气体压力作用,呈悬浮状态,活塞周边与柜体之间采用弹簧和油封,并不直接刚性接触。文章依此实际状态,提出将活塞视为以悬浮质量块阻尼器(suspended mass damper,简称SMD)建立气柜结构的SMD计算模型,推导了活塞结构的刚度系数的计算公式;以某30×104m3正多边形气柜为例,选择3条地震波,应用状态空间分析法,利用Matlab软件实现2种计算模型的地震反应分析;计算结果对比分析表明活塞对柜体抗震具有显著的减震效果,属于有利影响;研究成果可以为气柜结构抗震设计和在役气柜的安全评估提供参考。

Current calculation model of seismic response in the seismic design for gasholder takes the mass of piston into the main mass, and regards the piston as the negative factors on the seismic performance of gasholder. Bearing the gas pressure, the piston actually suspends in gasholder, and there are no direct rigid contact between the two because springs and oil sealing are adopted between the piston side and gasholder body. In this paper, based on the actual construction features of gasholder, and taking the piston as suspended mass damper（SMD）, the SMD calculation model for the gasholder is established. The formula of stiffness coefficient of the piston is also deduced. Taking a regular polygon gasholder of 30× 10^4m3 as an example and selecting three earthquake waves, the seismic responses of two models are calculated by applying state-space analysis method and the software Matlab. The calculation results show that the piston has a remarkable positive damping effect on the seismic performance of the gasholder. The study result can be referred in the seismic design of gasholders and the safety assessment of in-service gasholders.