The Seismic Behavior Analysis Of Concrete-filled Square Steel Tubular Composite Frame Structure

Concrete-filled square steel tube has superior mechanical properties, along with the rapid development of our country economy and the cause of construct, therefore has been applied more and more widely in high-rise and ultra-high buildings. In general, concrete-filled square steel tube forms composite structures with steel or reinforced concrete. In view of that China is located in Earthquake-prone areas, it is particularly important to understand and master seismic behaviors of the concrete-filled square steel tubular composite structure. However, the studies on seismic behaviors of concrete-filled square steel tubular composite structure need be further thorough, for this structure is a new type.In order to investigate seismic behaviors of concrete-filled square steel tubular composite structure, a ten-storey concrete-filled square steel tubular composite frame structure is selected in this paper, and A three-dimensional finite element analysis model of this structure is established based on Sap2000, then three aspects is studied as follow:(1) Modal analysis for this model is conducted to get the dynamic characteristics and the analysis shows that integral performance of this structure is well.(2) Static elastic-plastic analysis for this frame structure is carried out to analyze seismic behaviors of the structure, considering the P-Δ effect in the process of Pushover analysis to investigate the influence of the P-Δ effect on seismic behaviors of this structure. The analysis shows that the P-Δ effect have adverse effects on mechanical behavior of the structure, increase lateral displacement and the effect is more and more significant accompany with structural height increase. Whether considering the P-Δ effect or not, the maximum inter-story drift satisfy the requirements of the Seismic Codes, and also the structure can satisfy the request of "No Collapsing With Strong Earthquake".(3) Dynamic elastic-plastic time history analysis for this frame structure is carried out to analyze seismic behaviors of the structure under frequent earthquakes and rare earthquakes. The analysis shows that, the structure meets the code of strong column and weak beam, the structure in elastic stage can satisfy the request of "No damage With minor Earthquake" under frequent earthquake of8degree, as well as the structure in elastic-plastic stage can satisfy the request of "No collapsing With strong Earthquake" under rare earthquake of8degree, structural displacement response is less than displacement limit, and also the seismic resistance of the structure is well.