CCTV新台址主楼钢结构施工变形预调值计算的分阶段综合迭代法

CCTV新台址主楼两塔楼双向倾斜6°,顶部通过"L"形大悬臂相连,整体结构形成一个不规则的"空间门式"结构体系,具有"塔楼倾斜"、"空间连体"及"大悬臂"的构成特点。主楼钢结构安装采用无支撑胎架的施工方案,悬臂段合拢前两塔楼不断地向倾斜方向内侧独立变形,合拢后二者相互支撑,协调变形。施工过程中必须对两塔楼及大悬臂结构和构件的安装位形设置预调值,使其施工完成后的结构位形满足设计位形或目标位形的要求,否则成型位形将不满足设计及施工要求,甚至会导致大悬臂结构无法顺利安装。针对CCTV新台址主楼,提出一种精确计算其钢结构施工变形预调值的分析方法———分阶段综合迭代法。分析给出了结构在施工过程中的变形预调值,作为实际结构施工及安装的重要定位依据。

ANALYSIS METHOD OF PRE-SET CONSTRUCTION DEFORMATION VALUES FOR THE NEW CCTV HEADQUARTERS

The new CCTV headquarters consists of two towers leaning 6° off vertical in both directions,a tremendous 14-story-high cantilever joining two leaning towers at the top and a 9-story-high podium at the bottom.Due to the continuously added gravity and additional bending moment conducted during the construction process,the variation of the structural deformation is very complicated.During the construction process of the structure,it may lead to a considerable deviation between the structural construction-completed configuration and the structural design configuration without taking the pre-set deformation value(PDV) for the structural members.It will be presented a computational method to determine PDVs for these inclined high-rise structures,i.e.stepped comprehensive iteration method.This analysis method has been conducted and directly applied in the determination of PDVs of structural members of the new CCTV headquarters.Lots of numerical results have been obtained and used as guidelines for the erection and construction of the new CCTV headquarters.