Seismic Performance Analysis Of Steel Frame-Concrete Core Tube Structure

Hybrid structure is defined as frame-core tube structure that consists of reinforced concrete core tube and the outer steel reinforced concrete,concrete filled steel tube frame or steel frame,or is defined as tube in tube structure that consists of reinforced concrete core tube and the outer steel reinforced concrete,concrete filled steel tubular frame drum or steel frame tube.Steel and concrete hybrid structure system has the advantages of steel structure and concrete structure system that are convenient construction,low cost,wide lateral stiffness and more stronger deformation ability.At present,the seismic performance of this kind of structure system at home and abroad is still controversial and is one of the hot topic in academia and engineering.Seismic research status quo of hybrid structure has been introduced in this paper.According to the actual design construction drawing,considering the influence of the steel beam and concrete core tube connection,and by using large-scale finite element software ANSYS respectively by means of common nodes(rigid connectiont)and the way of node coupling connection(hinged connectiont),we established the rigid model and hinged model that was a super-high steel frame and concrete core tube hybrid structure finite element.The static analysis and modal analysis was discussed to verify the validity of the finite element model and get the natural vibration characteristics of the structure.On the basis of modal analysis and response spectrum analysis,the Elcentro,Taft waves were selected for time history analysis under the frequently occurred and the rarely met earthquake in seismic intensity of 7 degree.Under the action of earthquake,the acceleration,displacement,stress response and so o-n were listed,and the differences of two kinds of model calculation results were compared.Finally,in order to carry out the seismic performance evaluation of the office buildings,and we put forward corresponding measures including earthquake resistant structure and design suggestions.The results showed that the structure had a reasonable structure layout and interlayer displacement angle could meet the design requirements.At the layer 46-49,interlayer displacement angle was larger and these layers should be treated as the weak part,to which enough attention should be paid in the seismic design.The local stresses of the connections between steel frame beam and reinforced core concrete tube wall were so big that it was recommended to take some construction measures to strengthen.The core of the tube wall and the outer frame steel bar in the layer 3,stress was larger,to which enough attention should be paid in the actual design.Under gravity load representative value respectively with the frequently occurred and the rarely met earthquake,the steel frame of steel has not been entered a stage of yield,the structural seismic performance was well.Under the action of the same seismic wave,the top layer maximum horizontal displacement,acceleration and interlayer displacement angle of hinged model was larger than the corresponding maximum value of rigid model.In terms of the overall seismic performance,rigid model was superior to hinged model.Under the action of earthquake and gravity load representative value,the connection between the frame beam and the core tube of hinged model compared with rigid model,would lead to the internal force redistribution between outer frame and core tube that reduced the stress of the concrete core tube and increased the stress of the steel column,and could reduce the stress of the steel beam outside frame beam with the core tube connection node.