某总部大楼扭转体型结构设计分析

Design and Analysis for Twisted Structure of a Headquarters Building

某总部大楼采用扭转体型的框架-核心筒结构,外框钢柱均绕塔楼中心沿逆时针方向倾斜。在竖向荷载作用下,扭转体型结构受力方式与常规结构不同,竖向荷载作用分解为沿斜柱的轴向力和水平分力,斜柱水平合力形成对结构的整体扭矩。通过竖向荷载作用下结构整体和构件两个层次的分析,楼板采用弹性板假定,并考虑重力荷载下的P-Δ效应,反映扭转体型结构的实际受力情况,重点分析扭转体型结构在竖向荷载下的外框斜柱内力、楼板面内剪力、底层墙剪力和层间位移角。分析结果表明,扭转体型结构与非扭转体型结构在竖向荷载下结构整体和构件受力显著不同。在竖向荷载作用下,核心筒翼墙的剪力与多遇地震下的剪力相当,角柱的剪力为多遇地震下剪力的4~6倍,应引起设计重视。

A headquarters building is a twisted frame-core tube structure,and the outer frame steel columns are inclined counterclockwise around the centre of the building.When bearing the vertical load,the forcebearing mode of the twisted structure is quite different from that of a conventional building structure.The vertical load is decomposed into the horizontal force and axial force along the inclined column,and the horizontal forces are combined to form the overall torque to the structure.The overall structure and members under vertical loads were analyzed.The floor slab is assumed as an elastic plate,and the P-Δ effect under gravity load is also considered,which can better reflect the actual stress of the twisted structure,with a focus on analyzing the internal force of the outer frame inclined column,the in-plane shear force of the floor.The calculation results indicate that there are significant differences in the overall and member forces under vertical loads between twisted and non-twisted structures.The shear force of the core tube wing wall under vertical load is equivalent to that under frequent earthquake action,and the shear force of the corner column is about 4~6 times of that under frequent earthquake action,which should be paid attention to in design.