创新组合伸臂系统在重庆来福士广场北塔楼中的应用

Application of innovative hybrid outrigger system in north towers of Raffles City in Chongqing

对于高356m且长细比高达9.4的重庆来福士广场北塔楼,其抗侧设计为塔楼结构设计的重难点。本项目在塔楼角部引入巨柱,并采用伸臂连接核心筒角部和巨柱,以最高限度地提高结构抗侧刚度。作为主要抗侧构件的伸臂,在传统钢伸臂或混凝土伸臂的基础上,创新性地引入组合伸臂系统,该系统包括连接于巨柱上的软钢剪切耗能件、从核心筒角部延伸出的钢筋混凝土伸臂墙、连接剪切耗能件和混凝土伸臂墙的钢支撑以及围绕核心筒一周的钢筋混凝土环梁(保护核心筒)。该系统利用混凝土伸臂墙刚度较大的特点以提高结构的整体刚度,同时通过系统构件合理屈服顺序的设计,使得剪切耗能件在大震情形下屈服,起到保险丝的作用,利用其屈服后的延性和耗能能力保护混凝土伸臂墙和核心筒。采用弹塑性有限元分析和实验室节点试验对该系统进行分析计算和对比验证,结果表明计算分析和试验结果较为吻合,且符合设计要求和预期。

For north towers of Raffles City in Chongqing with height of 356 m and slenderness ratio of 9. 4,the lateral design is important and difficult in the structural design of the towers. In the project,mega columns are set in the corners of towers,and the outriggers are used to connect corewall corners and mega columns,to maximally improve the structural lateral stiffness. Outriggers are the main lateral components,and the innovative hybrid outrigger system is introduced into the project based on the traditional steel outriggers or concrete outriggers. The system includes mild steel shear energy dissipation element connected on mega columns,reinforced concrete cantilever walls extending from the corners of the corewall,steel braces connecting shear energy dissipation element and concrete cantilever walls,and reinforced concrete ring beams around the corewall to protect the corewall. The system takes advantages of large stiffness of the concrete cantilever wall to raise the stiffness of the whole structure. At the same time,through the reasonable yield sequence design of component system,the shear energy dissipation element is designed to act as fuse in yield under the rare earthquake,in which the ductility and energy dissipation capacity after the yield can be used to protect concrete cantilever wall and corewall. Calculation and comparison analysis were carried out on the system using the elasto-plastic finite element analysis and laboratory joint test. The results show that the calculated results are in good agreement with the experimental results,which fulfills design requirements and expectations.