上海中银金融中心双塔结构关键问题研究

Study on the key problems of the twin tower structure of BOC Shanghai International Financial Center

上海中银金融中心采用巨型支撑-框架-核心筒结构体系,南、北塔楼平面均为狭长的平行四边形,弱轴方向的刚度与强轴方向的相差悬殊;塔楼上部单侧悬挑长度27 m,结构存在偏心;双塔距离较小,对风荷载取值影响显著。通过静力分析与动力弹塑性分析研究单侧悬挑塔楼结构的力学特性,其中双塔风荷载体型系数与风振加速度由风洞试验确定。分析结果表明:立面巨型支撑可以显著提高结构的侧向刚度,明显减小层间位移角和扭转位移比;塔楼悬挑锥体一侧的弹塑性变形显著大于另外一侧的,故非对称结构需要在正、负两个方向进行地震激励;通过对南、北塔楼进行罕遇地震作用下的相对位移分析,最终确定悬挑锥体尖点之间的距离为1.5 m;南、北塔风荷载互相影响,对于狭长平面的塔楼,当长边为迎风面时,风荷载与顺风向风振响应均较大,背风侧塔楼风荷载效应显著减小;当短边方向为迎风面时,横向风振效应较为显著;提出的筏板双向多排钢筋与钢管混凝土钢柱的连接构造以及巨型支撑-角柱节点,两连接形式传力可靠,适用性强。

BOC Shanghai International Financial Center adopts a mega bracing frame-core tube structure system.The plane of the south and north towers are long and narrow parallelograms,and the stiffness in the weak axis direction differs greatly from that in the strong axis direction.The cantilever length of the upper part of the tower is 27 m on one side,and the structure is eccentric.The distance between the two towers is small,which has a significant impact on the value of wind load.In this paper,the mechanic performance of the single side cantilevered tower was studied by static and dynamic elastic-plastic analysis,and the wind load shape factor and wind vibration acceleration of the twin towers were determined through wind tunnel test.The analytical results show that the mega bracing on facade can significantly improve the lateral stiffness of the structure,and significantly reduce the inter story drift ratio and torsional displacement ratio.The elastic-plastic deformation of one side of the cantilever quadrangular pyramid of the tower is significantly greater than that of the other side,so the asymmetric structure requires seismic excitation in both positive and negative directions.By analyzing the relative displacement of the south and north towers under rare earthquakes,the distance between the cantilevered cone tips is finally designated as 1.5 m.The wind loads of the south and north towers affect each other.For narrow and flat tower,when the long side is the windward side,the wind load and windward vibration response are both greater,while the wind load effect on the leeward side of the tower is significantly reduced;when the short side direction is on the windward side,the lateral wind-induced vibration effect is more significant.The proposed connection details between the raft two-way multi row reinforcement and the concrete-filled steel tube column,as well as the mega bracing-corner column joint,have reliable force transmission mechanism and strong applicability.