外框支框筒内核心筒钢管混凝土组合筒体结构拟动力试验研究

Pseudo-dynamic experimental study on framed tube supported on frame-core tube structure of concrete filled steel tube(CFST)

进行了1个钢管混凝土组合筒体结构模型的拟动力试验。模型为比例1∶10的13层钢管混凝土组合筒体结构,外筒为钢管混凝土框支框筒结构,内筒为钢筋混凝土核心筒结构。将模型等效为两自由度体系,分别进行了地震波加速度为0.22g、0.40g、0.62g和1.0g共4种工况的拟动力试验,通过对位移时程、作用力时程、应变状态、开裂状况等参数的测试,研究了结构在地震作用下的耗能机制、破坏特征与破坏机理,以及结构的弹塑性性能。研究表明,核心筒是抵抗水平剪力的重要构件,承担了结构大部分剪力,先于其它构件开裂,但核心筒底层的破坏程度比2层要轻;连梁是核心筒受力最集中、破坏最明显的部位,应重视连梁的延性设计;钢管混凝土角柱的强度高、变形性能好,分担了外框筒的主要轴向力,对其它翼缘混凝土柱起到了卸载保护作用,另外,钢管混凝土柱与梁的环形节点构造在复杂的节点内力联合作用下受力是可靠的。试验证明了钢管混凝土组合筒体结构是一种具有良好抗震性能的结构体系。

The pseudo-dynamic test of the model CFST tube structure has been conducted.The CFST tube structure model with 13 floors and a scale of 1∶10 consists of an outer-tube and an inner-tube.The former is a framed tube supported on CFST frames and the latter is an RC tube.A series of pseudo-dynamic tests on acceleration earthquake waves in four cases(0.22g,0.4g,0.62g and 1.0g) have been fulfilled by taking the model as two degrees of freedom system.The energy dissipation,failure mechanism and elasto-plastic behavior of model are studied under earthquake by testing the factors,such as displacement time-history cure,force time-history cure,strain state and cracking state.The experiment shows that the core-tube bears a greater part of the shear force and cracks earlier than other elements,but the failure of the 2nd floor is more serious than the ground floor.Because of concentrate force and obvious failure,great attention has to be paid to the design of connecting beam's ductility.As for higher strength and superior deformation property,CFST columns bear the main axial force of outer framed-tube and protect other RC columns of flag frame.The ring joint of CFST column and RC beam is rather reliable by bearing flex force in node zone.The experiment has illustrated that the CFST tube structure is an outstanding structural style with excellent seismic behavior.