Research On The Seismic Behavior Of Mega RC Column,Steel Truss Beam Mix Frame Structures

Mega-frame structure is a new high-rise structural system which has greater stability and high-performance through the main structure made up by several large-scale structure units work together with the minor structure made up by other structure units. Mega-Frame structures are such large and complex structures which are more complicated than normal frame structure on mechanical behaviors, the seismic failure mechanism, the mechanics analysis and the structure design. Based on shaking table test of model and finite element analysis, seismic behavior of mega-frame structures are studied deeply in this thesis.According to geometric similar of 1:35 with the Chong Qing Xi Yong building and the require of lateral stiffness similitude, the similitude relationships on model design of seismic simulation shaking table test were established. The steel structure model is made by galvanized-iron instead of steel. By inputting seismic waves of different intensity, the experimental studies on failure mechanism of model structure, the elastic and elastic-plastic seismic response are finished. The test results show that the ground floor is the weakness of the structure and the connecting part of the steel truss and the shear wall has some failure under great earthquake. But the whole structure has a good seismic performance and can satisfy the seismic requirements.The numerical model of shaking table test was established in FEM software, then the modal analysis, the elastic and elastic-plastic time-history analysis were calculated. Comparing the results of shaking table test with the FEM calculation, it indicates that FEM analysis simulations in the structural dynamic response is feasible.The mechanical performance of the steel truss transfer story is related to the stiffness of mega beam and column. The analysis results showed that the larger the stiffness of mega column is, the larger the force of the truss is. Changing of the stiffness of the truss chords has obvious influence on the force of the steel trusses, but the changing of the stiffness of the webs has little influence on the force of the steel trusses. And the higher the story height of the truss is, the smaller the forces of the steel trusses are. The influence of the stiffness of the upper beam of the truss and the web type on mechanical performance of steel truss are been researched. Herringbone web suffers more stress than intersecting web, and there is little influence on mechanical performance of the whole truss when taking off the vertical webs. If we increase the stiffness of the upper beam of the truss, the force of the steel element will also increase. Therefore the stiffness of the upper beam of the truss should be under control so that it will not have a greater impact on mechanical performance of the truss.