超高层钢管混凝土重力柱-混凝土核心筒结构振动台试验研究

Shaking table test of super-high-rise concrete-filled steel tube gravity column-concrete core tube structure

提出一种新型的钢管混凝土重力柱-核心筒结构体系,通过地震模拟振动台试验验证其抗震性能。以实际超高层钢管混凝土柱框架-混凝土核心筒建筑结构为参考,将钢框架梁与柱或核心筒的刚性节点改为螺栓连接的铰接节点,简化结构并制作1/40的缩尺结构模型,采用4条地震动记录进行不同工况的振动台试验,分析结构的震损特点、动力特性、侧向位移、层间位移角、扭转角、地震惯性力、楼层剪力和倾覆弯矩等。结果表明:震损主要出现在下部楼层的混凝土楼板与柱连接、楼板与核心筒连接、楼板与钢梁连接、核心筒角部等部位;基本自振周期和阻尼比随震损增加而增大,动力放大效应减小,长周期地震动反应显著,侧向变形和层间位移显著增大;外排架柱的层间位移主要为不产生内力的刚体转动,核心筒层间位移角达1/26,超过规范JGJ 3-2010中规定的框架-核心筒结构体系不倒塌限值的3.85倍而未出现倒塌;外排架抗扭刚度小,结构扭转反应由核心筒主导;地震惯性力和楼层剪力受地震长周期分量的影响小,随结构损伤增大楼层内力增加幅度减小。

A new type of concrete-filled steel tube(CFST)gravity column-reinforced concrete(RC)core-tube structure system was proposed.The shaking table test was performed to verify its seismic behavior.Taking an actual super-high-rise CFST column frame-concrete core tube structure as a reference,a CFST gravity column-core tube prototype structure was designed with simplifying the steel beam to column joints and steel beam to RC core joints to bolted joints.An 1/40 scaled model structure was constructed and the shaking table tests considering four seismic waves under different test conditions were conducted.The damage phenomena,dynamic characteristics,lateral displacement,inter-story drift ratio,torsion angle,seismic inertial force,story shear force and overturning moment of the structure were studied.The experimental results show that the damage mainly occurs at the connections between the concrete slab and the column on the lower stories,the connections between the concrete slab and the core wall,the connections between the concrete slab and the steel beam,and the corner concrete of the core walls.With the increasing seismic damage,the natural vibration periods and damping ratios increase,resulting in the decrease in the dynamic amplification effect.The long-period ground motion response is more significant.The lateral deformation and inter-story drift are significantly increased.The inter-story drift of the peripheral column is mainly the harmless drift caused by the rigid body rotation.The maximum inter-story drift ratio of the RC core is 1/26,which exceeds 3.85 times of the no-collapse threshold for the frame-core wall structure system in the Chinese code JGJ 3-2010.However,collapse of the CFST gravity column-core tube model structure is not found.The torsion stiffness of the outer bent component is small.The structural torsion response is dominated by the core walls.The earthquake inertia force and story shear force are slightly affected by the long-period motion components.Thus,the amplitude of the increased story internal force decreases with the increase of the structural damage.