【摘要】 借助25个不同跨度、不同矢跨比、不同下部结构、不同支座连接条件的结构模型,考察双层球面网壳在设防烈度地震下的弹塑性动力响应性能.该25个模型的网壳杆件截面均根据非抗震设计工况的满应力优化设计确定,并满足多遇地震作用的验算.所有模型的结构分析均考虑上下部结构的共同工作,网壳杆单元采用了能够同时考虑受拉屈服和受压屈曲的等效弹塑性滞回模型.设防烈度地震下结构的弹塑性动力响应采用非线性时程法计算,地震波采用由规范反应谱生成的三向人工波.根据计算结果,统计了25个模型在7度、8度设防烈度地震下网壳塑性变形杆件的分布、塑性应变大小和结构残余变形,并对主要的影响因素进行了分析.研究表明,中小跨度双层球面网壳在7、8度中震作用下均未出现塑性变形杆件;大跨度双层球面网壳在中震作用下会出现一定数量的塑性变形杆件,其分布区域与下部结构刚度有关,但大多出现在中间圈层;矢跨比和下部结构的对称性是影响塑性变形杆件数量和塑性应变大小的两个主要因素.更多还原

【Abstract】 By means of analysing 25 structural models with different span,different rise-span ratio,different connection condition of abutment and layout of substructure,elasto-plastic dynamic response behavior of double-layer spherical reticulated shells under fortification intensity earthquake is investigated.The cross-sectional size of members in those 25 shell models is determined by the structural full-stress design under non-seismic load cases,and also satisfied by the check of frequently occurred earthquake.The interaction between reticulated shell and its substructure is considered in structural analysis of all models.An equivalent elasto-plastic hysteretic model,which can simultaneously deal with both the tensile yielding and the compressive buckling of bar element,is adopted.Structural elasto-plastic dynamic responses under fortification intensity earthquake are analyzed by nonlinear time-history method.A three-direction artificial earthquake wave generated by code response spectrum is adopted.According to calculation results of 25 models,the distribution of plastic members,magnitude of plastic strain and structural residual deformation of reticulated shell are analyzed respectively for 7 and 8 degree fortification intensity earthquake,and their effecting factors are investigated.The results reveal that plastic members do not occur in small-and medium-span double-layer spherical reticulated shells under 7 and 8 degree fortification intensity earthquake.A certain amount of plastic members exist in large-span reticulated shells under fortification intensity earthquake.The distribution of plastic members is closely related to the stiffness of substructure,and mainly in the inner annular region near the center of shell.Rise-span ratio and symmetry of substructure are two major factors influencing the quantity of plastic members and magnitude of plastic strain.更多还原