弦支穹顶强震后的预张力损失分析  

ANALYSIS OF THE PRETENSION LOSS OF SUSPENDOMES SUBJECTED TO STRONG EARTHQUAKES

作　　者：王琼[1,2] 邓华[1] 诸德熙[1] 

机构地区：[1]浙江大学空间结构研究中心,杭州310058 [2]中国建筑标准设计研究院,北京100048

出　　处：《工业建筑》2015年第8期14-19,66,共7页Industrial Construction

摘　　要：借助6个初始预张力、矢跨比、支座连接条件、下部结构对称性以及下部结构刚度不同的弦支穹顶结构模型,考察该类结构在强震作用后索杆系统的索力变化及相应的上部网壳残余变形情况。当各模型中网壳杆件截面分别满足7度多遇地震弹性、8度多遇地震弹性、8度设防烈度地震不屈服以及8度设防烈度地震弹性验算时,对结构在设防烈度地震与罕遇地震后的索力损失差异进行讨论。研究表明:强震作用后弦支穹顶结构的索杆系统一般会造成预张力损失,且多出现于内圈索;索力变化对下部结构对称性、支座连接方式及上部网壳矢跨比等结构参数较为敏感;设防烈度地震作用后环索索力变化相对较小,基本低于10%,而罕遇地震作用后环索索力变化明显,个别甚至出现松弛;采取设防烈度地震弹性设计的结构模型索力损失明显降低。Six suspendome models with different pretensions,rise-span ratios,bearing connections,symmetries and rigidity of substructures were employed to investigate the pretension changes in cable-strut system as well as the residual deformations of the upper reticulated shell of this kind of structure subjected to strong earthquakes. It was discussed the difference of structural pretension losses corresponding to four different checking criteria for the members of upper reticulated shell,i. e. elastic design under 7 degree frequently occurred earthquake,elastic design under 8 degree frequently occurred earthquake,unyielding design under 8 degree fortification intensity earthquake and elastic design under 8 degree fortification intensity earthquake,for each model respectively subjected to fortification intensity and rear earthquakes. The results revealed that there generally exists pretension loss in the cable-strut system of suspendome after the action of a strong earthquake,especially in the inner ring cables. The changes of cable’s internal forces are much more sensitive to the symmetry of substructure,the form of bearing connection and the rise-span ratio of upper reticulated shell. In case of suffering fortification intensity earthquakes,the internal forces of ring cables presented a lower change rate,basically less than 10%. However,their internal forces were significantly changed after the action of rare earthquakes,even totally loosed in some cables. The pretension loss was obviously decreased in those models adopting the elastic design under 8 degree fortification intensity earthquake.

关 键 词：弦支穹顶 抗震性能 索杆系统 预张力损失 残余变形 

分 类 号：TU399[建筑科学—结构工程]