钢制储液罐的幂次失效模型及地震力折减

Power failure model and seismic force reduction of steel liquid storage tank

为了反映钢制储液罐的渐进失效趋势并合理地量化弹塑性地震力,采用流固耦合系统的单向动力推覆分析,建立反应谱层次的幂次失效模型.根据该模型构建等向强化的广义本构关系,在特定延性下迭代求解地震力折减系数Ry.结果表明,幂次失效模型下的地震力折减系数变异性较小,双线性滞回模型下的地震力折减系数会导致过于保守或偏于危险的地震力折减.选取40条最不利地震动并按场地分类,幂次失效模型下的地震力折减系数的均值略低于目标延性值,更符合长周期结构的等位移准则.GB50341与SH/T3026规定的地震力折减系数高于API650与EN1998-4,建议将地震力折减系数调整至2.0,应进一步细化边界条件的影响.

A power failure model in response spectrum format was conducted through unidirectional dynamic pushover analysis of fluid-solid coupled system in order to reflect the progressive failure trend of liquid storage tanks and rationally quantify the elastoplastic seismic force.Then generalized constitutive relations with isotropic hardening were established,and seismic force reduction factor Rywas iteratively solved under specific ductility values.Results show that seismic force reduction factor based on power failure model has slight variability,and seismic force reduction factor based on bilinear hysteretic model will cause overconservative or over-risky seismic force reduction.Forty severest ground motions were selected and classified by site types.The mean values of Rybased on power failure model were slightly lower than target ductility values,which is more in line with equal displacement rule of long-period structures.The specified seismic force reduction factor values in GB50341and SH/T3026are higher than those in API650and EN1998-4.The suggestion is that Ryshould be adjusted to 2.0and the effects of boundary conditions need to be further refined.