Research On The Selection And Analysis Of Super High-rise Building Frame Core Tube Structural Floor System

Frame-core tube structure is a structural form of frame system formed by beams and columns,which uses the space of elevator shaft,stairwell and so on in the building to establish the central core tube.The structural characteristic of frame-core tube structure is that it can form the core tube and frame as a whole.The spatial effect of the core tube and frame makes the lateral stiffness of the building far exceed that of the ordinary frame-shear wall structure.Therefore,this structure has the advantages of large stiffness,good integrity,small lateral deformation and excellent seismic performance.Floor is one of the important components of the structure.The selection and layout of floor is an important factor affecting the safety and economy of the building.In the design of super high-rise structures,special attention should be paid to the reasonable selection of floor structure forms.Based on this,the main research work and conclusions of this paper are as follows:According to the characteristics of frame-core tube structure,the mechanical properties and material consumption indexes of floor systems of different forms such as unidirectional slab-ribbed beam floor,bidirectional slab-ribbed beam floor,well-shaped floor,multi-ribbed floor and beam-free floor are analyzed.The results show that ribbed-beam floor has good seismic performance,high safety and affluence,less material consumption,and high space utilization ratio of beamless floor,which can effectively improve the net floor height.Elastic time history analysis is carried out for ribbed and non-girder floor structures respectively,and the results are compared with those calculated by mode decomposition response spectrum method.Considering the influence factors of seismic response of ribbed and non-girdered floor,the distribution law of shear curve along the floor is analyzed.It is found that the ribbed beam floor system has better seismic performance than the non-beam floor system.Elasto-plastic static push-over analysis of ribbed and non-girdered floor structures under rare earthquakes is carried out respectively.Elasto-plastic deformation of the whole structure is calculated,weak parts and weak members are identified,and the order and distribution of plastic hinges are determined.Define the failure modes of ribbed and non-girder floor structures,and give corresponding design suggestions.It is found that the beam-less floor system can not make the core tube shear wall and the outer frame column work together.The seismic resistance of frame-core tube structure with ribbed beams is stronger than that of frame-core tube structure without beams.When different floor systems are used in the local floors of frame-core tube structure of beamless floor,the shear stress of the floors with different floor systems will change abruptly.The performance analysis of structural members of ribbed and non-girder floor systems is carried out respectively,and the variation law of the axial compression ratio of shear walls and frame columns is analyzed.The bearing capacity of key components is reviewed and the performance objectives of the two floor systems are analyzed.The stiffness effects of ribbed and non-girdered floor on the whole system and the stiffness and shear distribution of frame and core tube are systematically analyzed.It is found that under the representative value of gravity load,the axial compression ratio of wall limbs may not meet the requirements of the code.Under the seismic action of fortification intensity,the stiffness of the external frame of the girderless floor system is less than that of the ribbed floor system,and the core tube of the shear wall shares more seismic force.The local wall limbs of frame-core tube structure of beamless floor are close to the limit of the code,and appropriate strengthening measures are suggested.