Study On Application Of Y-shaped Frame Beam In Super High-rise Frame-Core Tube Structure

The frame-core tube structure,through the coordinated load-bearing of the outer frame and the inner core tube,has good seismic performance and is widely used in the super high-rise buildings.In most cases,the shear wall around the core tube is not aligned with the axis of the frame column.Generally,the oblique frame beam is placed to the corner of the core tube.At this time the beam will be exposed in the room.Sometimes the architect dosen't accept the oblique frame beam.The conventional way of treatment is to add an inner column,or to use a half frame beam to transfer forces to the core tube indirectly.The indirect force transferring is not appropriate,because the beam will be rigidly connected with the shear wall through non-planar joint,and the shear wall will be subjected to a larger non-planar bending moment.Adding inner columns will greatly reduce the vertical load of the shear wall,resulting in the greater degree of tensile stress of the shear wall,will reduce the anti overturning capability and the mechanical performance of the core tube,which is very unfavorable for the structure.In order to better meet the architectural requirements and structural load-bearing needs,it is necessary to adopt a more reasonable structural layout.The adoption of the Y-shaped frame beam is a good coping measure.However,the application of the Y-shaped frame beam is rarely seen in the frame-core tube structure and is only used in very few projects,and there are few studies on it.So it is of practical and important significance to study the load-bearing performance of the Y-shaped frame beam and the overall seismic performance of the frame-core tube with this kind of the beam.By means of the fine performance-based analysis of a specific project,the seismic performance of the frame-core tube with the Y-shaped frame beam can meet the current specifications and preset performance requirements.The Y-shaped frame beam can meet the strength requirements,and its yield and failure modes are in accordance with the conventional frame beams.The reinforcement arrangement of this kind of the beam is optimized.The finite element analysis of the beam joint is carried out by ABAQUS software.The results show that the stress of the steel bar can be effectively transmitted,the structure of the joint is reliable and the safety reserve is sufficient.In order to further verify the bearing capacity and seismic performance of the Y-shaped frame beam,the 1:3 scale model test was carried out.According to the internal forces of the beam under different performance levels in the actual structure,the scale model was loaded until it is destroyed.The test results show that the yield and failure condition of the Y-shaped frame beam is consistent with the result of the seismic performance analysis,and the beam can achieve the preset performance target.Therefore,the Y-shaped frame beam has no different performance in essence compared to normal frame beams and can be applied in similar structural system as needed.