八点弹性不均匀支承的类椭圆形弦支穹顶结构设计与分析研究

Study of structural design and analysis of ellipse⁃like suspended dome with eight⁃point elastic heterogeneous support

随着结构造型及功能的日益复杂,异形壳面、不均匀弹性支承、荷载不均匀分布等复杂条件下弦支穹顶结构的设计是一个值得深入研究的问题。以大沙河文体中心项目会议厅八点弹性不均匀支承异形壳面屋盖为例,采用肋环型单层网壳+Giger型索系组成的类椭圆形弦支穹顶,剖析其结构设计思路及特点,对其弹性支承条件的影响进行对比研究,并结合基于刚性索法和改进PGSA算法的预应力优化方法,对不同布索形式下的弦支穹顶结构进行静力及稳定性能的对比分析。研究表明,弹性不均匀支承条件对弦支穹顶结构的变形、索力分布、单元应力均有较大影响,结构计算分析中需充分考虑其影响;在最终被采用的撑杆杆底等标高的布索形式下,结构受力及变形分布更为均匀,静力及稳定性能相对较好,且有效避免了双向弯曲对环向索索体的不利影响。

With the more and more complicated structural modeling and function,the design of suspended dome under complex condition such as heteromorphic shell surface,elastic heterogeneous support,uneven load distribution and so on,is a problem that need to be further studied.Taken the heteromorphic shell surface roof of conference hall in Dashahe Stylistic Center with eight-point elastic heterogeneous support for example,ellipse-like suspended dome consist of ribbed-type single-layer latticed shell and Giger-type cable strut was applied.The structural design idea and characteristic were discussed,and the influence of elastic supporting condition was also compared and studied.Combining prestress optimization method based on rigid-cable method and improved PGSA method,the static and stable performance of suspended dome under various type of cable strut arrangement was analyzed.The results show that elastic heterogeneous supporting condition has a relatively great effect on deformation,cable force distribution and element stress of suspended dome,and is necessary to be taken into consideration during the structural calculation and analysis.The cable strut arrangement with the same bottom elevation of the same circle brace rod,which is finally applied,can lead to more average bearing and deformation distribution,and relatively satisfied static and stable performance,and can effectively avoid the adverse effect of bidirectional bending on ring loop cables.