新型型钢混凝土框架-四角筒-双向钢桁架混合结构弹塑性地震反应分析

Seismic analysis for a new-type hybrid structure of steel reinforced concrete frame-four corner tubes-bidirectional steel truss

中海油(深圳)大厦裙房是总高度为24.5m的大跨结构,位于两栋超高层塔楼之间。为满足市政规划及建筑功能提出的结构内部需具备33.6m无柱空间、结构周边双向需分别提供50.4m及27.6m大跨空间的要求,结构设计时提出了一种新型结构体系:型钢混凝土框架-四角筒-双向钢桁架混合结构体系,其中剪力墙筒体和型钢混凝土框架柱作为竖向抗侧力构件,跨层钢桁架实现了竖向抗侧力构件之间的水平力传递,并为梁、楼板的合理布置提供了条件。采用有限元分析方法对此结构进行了罕遇地震作用下的弹塑性时程反应分析,计算结果表明,新型型钢混凝土框架-四角筒-双向钢桁架混合结构体系的结构位移满足规范限值要求,四角筒的损伤主要集中在连梁处,大跨桁架保持不屈服,混凝土梁及钢梁的损坏有效耗散了地震输入能量,证明了此结构布置的合理性。

The podium of CNOOC Shenzhen Building is a four-story large-span structure with 24. 5 meters height,and situated between two super high-rise towers. To fulfill the requirements of the local municipal planning and architecture functions,the interior of the podium should supply 33. 6 meters astylar space and the perimeter of the structure should supply 50. 4 meters and 27. 6 meters large-span space in two directions,a new-type structure was proposed for the podium,named as steel reinforced concrete( SRC) frame-four corner tubes-bidirectional steel truss hybrid structural system. The shear wall tube and SRC columns worked as vertical lateral force resisting components,while the cross-layer steel trusses could realize the internal force transmission between lateral force resistance components and supply the conditions for reasonable layout of beam and floor members. Elasto-plastic time-history analysis for the structure under the rare earthquake was carried out by using the finite element method. The analysis results indicate that the displacement of the new-type structure can satisfy the seismic design requirements of Chinese codes. The damages of the four corner tubes focus on coupling beams. Large-span steel trusses keep non-yielding state. The damages on RC beams and steel beams can dissipate some dynamic energy. Therefore the rationality of the structural arrangement is verified.