Frame model for outrigger truss-core wall joint in super high-rise buildings

Due to the importance of the outrigger truss-wall joint in the structural system of frame with huge columnsoutrigger truss-core tube which was commonly used in super high-rise buildings,a simplified frame model and design method were proposed for the joint with outside steel plates,where the web members of the truss were directly connected to the outside steel plates of the wall.Numerical simulations were conducted for the joint,using the finite element program MSC.MARC(2010) and the boundary ranges of the model were analyzed and determined.Then a frame model considering the cracking of concrete was proposed and verified by the numerical models.Besides,the effect of the openings on the joint was studied and a simplified design method for the joint was finally presented.It is demonstrated that the joint becomes more dangerous subjected to tensile force,which is the control load case in design.The development of the stresses on the outside steel plates can be predicted accurately by numerical models.The simplified model is easy to conduct with proper accuracy,which can estimate the stiffness and internal forces of the joint precisely at high loading levels and give a safe result at low loading levels.The axial force shared by the coupling beams is mainly affected by the height of the openings with an approximate linear relationship.Conclusions drawn in this paper are helpful for the application of the outrigger truss-wall joint in super high-rise buildings.