武汉绿地中心主塔楼外框巨柱设计研究

Design research on outer mega column of Wuhan Greenland Center main tower

武汉绿地中心主塔楼建筑高度475m,采用了12根巨柱+核心筒+9道环带桁架+3道伸臂桁架+角部巨柱间支撑的抗侧力体系,其中巨柱外框结构是塔楼抗侧力体系及重力体系的重要组成部分。分析了塔楼体型在低区向外倾斜对巨柱设计的不利影响,给出了结构加强对策;开展了巨柱屈曲分析,得到了巨柱的计算长度,基于巨柱性能目标及计算长度进行了巨柱构件验算,验算结果可以满足规范要求;计算了巨柱考虑高强混凝土爆裂的耐火极限时间,耐火极限在7h以上;论述了综合考虑建筑利用率和结构抗侧效率最大化的巨柱定位设计方法;介绍了巨柱关键节点设计构造,ANSYS分析结果表明,关键节点的强度满足要求;对罕遇地震作用下巨柱损伤进行了动力弹塑性时程分析,研究表明型钢混凝土巨柱满足IO(立即入住)的性能目标。目前项目主体结构已经封顶,证明了上述分析、研究及设计对策保障了外框巨柱及整个结构的安全性。

The height of Wuhan Greenland Center main tower is 475 m. Its lateral force resistance system is 12 mega columns + core tube + 9 belt trusses + 3 outriggers + braces between mage columns in the corner, among them, the outer frame structure of the mega column is an important part of the lateral force resistance system and the gravity system of the tower. Adverse effect of outward inclination of the tower’s shape in the low zone on the design of mega columns was analyzed, and then the structural strengthening countermeasures was given. Buckling analysis of the mega column was carried out, calculated length of the mega columns was got. Based on performance objective and calculated length of mega columns, checking calculation of mega columns was carried. The checking results meet the requirements of the specification. Fire resistance limit time of the mega column considering the burst of high-strength concrete was calculated, resistance limit time is above 7 h. The positioning design method of the mega column that comprehensively considers the building utilization rate and the maximization of the lateral resistance efficiency of the structure was discussed. Design and construction of key joints of the mega column were introduced, ANSYS analysis results show that the strength of key joints meet the requirements. Dynamic elastic-plastic time-history analysis of the damage of mega column under rare earthquake was carried out, the research shows that the mega columns meet the IO(immediate occupancy) performance target. At present, the main structure of the project has been capped, which proves that the above analysis, research and design countermeasures ensure the safety of outer mega column and whole structure.