【摘要】 对54个双层球面网壳模型在罕遇地震下的弹塑性响应进行了计算。网壳模型中杆件截面按非地震工况下的满应力设计确定,并满足小震作用下的结构验算。计算时考虑网壳和下部结构的协同工作。杆单元采用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。根据计算结果,考察了网壳跨度、矢跨比、支座连接条件、下部结构形式以及地震波选取对结构塑性区域、塑性发展程度以及残余变形的影响。研究表明,罕遇地震下双层球面网壳的薄弱区域不全出现在临支座区域。当网壳受下部结构约束较强或跨度和矢跨比均较大时,发生残余塑性应变的杆件大多出现在网壳中间圈层区域。跨度、矢跨比和支座条件是影响塑性杆件分布和塑性应变大小的三个敏感因素。但所有模型并没有在罕遇地震下出现倒塌。更多还原

【Abstract】 The elasto-plastic responses of 54 double-layer spherical reticulated shell models were calculated.The cross-sectional size of members in those reticulated shell models was determined with the structural full-stress design under non-seismic load cases,and also satisfied the structural check under frequently occurred earthquake.The interaction between reticulated shells and their substructure was considered in numerical computation.An equivalent elasto-plastic hysteretic model was adopted to simultaneously deal with both tensile yielding and compressive buckling of bar element.The results of numerical computation showed that the effects of span of shell,rise-span ratio,connection condition of abutment,layout of substructure and choice of ground motion on structural plastic region,magnitude of plastic strain and residual deformation are analyzed;the weak regions of double-layer spherical reticulated shells under rare earthquake are not quite near the abutments;for those reticulated shells strongly constrained by substructure or with longer span and higher rise-span ratio,the members with residual plastic strain are mainly located in the inner annular region near the center of shells;span of shell,rise-span ratio and connection condition of abutment are three main sensitive parameters to the distribution of plastic members and the magnitudes of their plastic strains;however,no collapse occurs for all models under rare earthquake.更多还原