Finite Element Analysis And Optimization Design Of The STCC Column-rc Ring Beam Joint

With China’s rapid economic development and the increasing population, availableplanning land decreases, as a result, a need for ultra high-rise buildings is increasingthroughout all regions in China. Concrete-filled steel tubular column, due to thesuperiority of its mechanical performance and economic benefits, is increasingly beingused in ultra high-rise buildings. A STCC beam needs to be intersected with several RCcantilever ring beams at the same height in engineering practices, and the way for theirintersection is being constantly renewed and refined, among which, concrete-filled steelring beam joint is being widely used because of its excellent mechanical performance aswell as its simple construction procedure.An ultra high-raise building construction program in Jiangbei District, ChongqingCity is taken as an example for discussion in this paper. The program is a civilconstruction with a seven-story-underground structure and a three-floor-podium with asingle tower structure upper portion of280meters high above ground, which falls underthe category of ultra high-rise building. Concrete-filled steel tubular columns andreinforced concrete shear walls are used as its vertical load component whilereinforced concrete podium beams and floors are used as its horizontal bearing load inthis program. In the bottom part of the podium, four RC cantilever ring beams arejointed with a STCC beam at the same height through ring beam joint. The papercomparatively analyzed distribution and change of stress under different ringreinforcement ratio of the joint on which the stirrups and diagonal reinforcement areadded. Mostly，the paper has:①introduced current studies of concrete-filled steel ring beam and its applicationin actual construction program while combining the design and construction situation ofa ultra high-rise building in Chongqing;②introduced finite element models and its computing method, and it also hassimulated the concrete-filled steel ring beam joint of the podium area at the bottom ofthe building by finite element program ABAQUS;③analyzed comparatively the stress evolving process of ring beamsteel reinforced cage under monotonic loading and the changeable tendency of eachsteel rebar&P-△curveunder different ring reinforcement ratio of ring beam joint;④compared the hysteretic behavior of the ring beam joint and the distribution of the yield area in different ring enforcement under reciprocating loading;⑤provided two optimal designs for ring beam joint and analyzed the performanceof stress&P-△c urveunder monotonic loading and the yield area of steel reinforcementunder reciprocating loading of the optimized joint.