超高层结构竖向变形与内力分析

Analysis of vertical deformation and internal force of super high-rise structure

超高层结构在施工及设计使用过程中的竖向变形对结构的安全性、适用性有重要影响。以一幢位于设防烈度为8度地区的超高层结构为例,在混凝土的收缩徐变作用下,分别考虑伸臂桁架与主体结构同时施工和后施工对结构竖向变形与内力的影响。该建筑总高度为270m,采用设置三道加强层的型钢框架-核心筒结构体系。基于MIDAS/Gen软件,对该结构进行数值模拟分析。研究表明:在竣工五年后,主体结构的变形主要以混凝土的收缩徐变为主,占结构总变形的50%以上;伸臂桁架采用后连接施工时,腹杆内产生的附加应力比同时连接减小为83%~107%;柱底轴力在主体结构的使用过程中逐渐增大,而剪力墙底部反力逐渐减小。超高层结构的施工过程中,构件应进行预抛高和预留下料长度处理。

The vertical deformation of super high-rise structure has an important impact on the safety and applicability of the structure during the construction and using process.Taking a super high-rise structure located in the area with fortification intensity of 8 as an example,under the action of concrete shrinkage and creep,the influence of simultaneous and post construction of outrigger truss on the vertical deformation and internal force of the structure is considered respectively.The total height of the structure including tower crown is 270 m.The steel frame core tube structure system with three strengthened stories is adopted.The structure is simulated and analyzed based on the MIDAS/Gen software.The results showed that the deformation of the main structure is mainly come from the shrinkage of concrete after five years,which accounts for more than 50%of the total deformation of the structure.When the cantilever truss adopts the posterior connection,the additional stress is less than 83%~107%of the simultaneous connection.The axial force at the bottom of the column gradually increases during the using process of the main structure,while the reaction force at the bottom of the shear wall gradually decreases.During the construction of the super high-rise structure,the pre throwing height and the reserved cutting length should be set.