Structure Analysis And Design Research Of Vierendeel Truss Strengthened Story In High-rise Building

For controlling the lateral displacement in the design of high-rise or super high-rise frame-core tube structure,we often add some outriggers between core tube and framework columns to advance the lateral stiffness of the structure.Horizontal outriggers was often placed in the space of the facility or refuge story.Although it is an effective way to reduce the lateral displacement,it will cause the sudden variation of structural stiffness and internal force and easy to come into being weal story.The yield mechanism of"story column,weak beam"and"strong in resistance of shear force,weak in resistance of bending moment"will be presented difficultly.Presently,we often use high section solid concrete beam as the outriggers in the design of high-rise or super high-rise frame-core tube structure,so the reinforcement concrete Vierendeel truss was little used in the horizontal strengthened story and also lacks systematic research.A typical frame-core tube structure model as an example was used in this thesis.The trusses was placed in the middle story and top story of the structure.This form was used by the advice of Technical specification for concrete structures of tall building.By applying the FEA analysis software SAP2000,in setting four kinds of models with different space among rods in the belly of the truss.and adopting dynamical time history analytic method to make elastic time history analysis on the models,this thesis gets the best form is the bigger space in the middle and equal space at the both sides of the truss if we consider the performance of the frame-core tuber and the trusses which was influenced by the forms of the Vierendeel truss.In addition,adopting response spectrum analytic method to analyze and compare the structure with different outrigger(beam,Vierendeel truss and no outrigger),this thesis find out outrigger with truss relieves the sudden variation of structural stiffness and internal force by a large margin,so the Vierendeel truss is better than high section solid beam in the performance of resisting seismic effect.Owing to the great axial pull stresses by adopting truss in the horizontal seismic effect.,the common reinforcement concrete truss satisfies the request very difficultly,so the structure must be adopted pre-stress concrete truss..This thesis compared the internal force of the truss between the top story and middle story when the structure was impacted by earthquake.It find out the internal force of the truss in the middle story which is more than the truss in the top story.lastly,this thesis analyzed the internal force of the truss with pre-stress and find out the performance of the truss was improved much more.