Research On The Seismic Behavior Of The Concrete-filled Steel Tubular Frame Structures

Concrete-filled steel tube (CFST) structures have been developed rapidly and appliedwidely in engineering field. Especially earthquake disaster happens frequently in recent years.It is severely significant to further the research on the seismic behavior of CFST structureafter exposure to earthquake.In this paper, numerical simulation is performed to research the seismic behaviors ofmulti-layer and high-rise CFST structure. The following aspects of the works have been done:(1) Considering the reanonable material and geometric nonlinear, the software ABAQUSwas used to analyze multi-story CFST frame and the elastic-plastic analysis was based on thethree-dimension finite element method. The bond-slip behaviors between the tube andconcrete were considered and reasonable material constitutive model and element type wasselected. The numerical simulation of1-span1-story circular section and square section CFSTcolumns and steel beam planar frames has been performed to verify the validation modelingmethod.(2) Based on the modeling process, finite element analysis models (FEAM) in ABAQUShave been established to simulate2-span3-story circular section and square section CFSTcolumns and steel beam planar frames. The load-displacement (P-Δ) curves obtained from theFEAM under monotonic loading were verified against the experimental results. Mechanicalbehavior, ductility, and failure mechanism of the frame models under monotonic loading arestudied systematically.(3) The theoretical basis of dynamic behavior analysis and dynamical time-historyanalysis about high-rise CFST frames is introduced in detail. Some critical issues to build theFEAM with ABAQUS were discussed. With the numerical simulation of shaking table testingcompleted by other scholars, model response and displacement response were obtained. Inorder to verify the rationality of the analysis model, the results of ABAQUS were comparedwith the experimental results.(4) A13-layer square section concrete-filled steel tubular frames (S-CFST) structure wasdesigned, and the elastic time history analysis in frequent earthquakes was carried out.Displacement responses and acceleration responses of S-CFST structure in frequentearthquakes were discussed. The CFST columns were processed in two methods includinguniform type and separated type, and the results calculated with these two methods werecompared. With the same bearing capacity and close steel ratio, a13-layer concrete-filledcircular steel tubular frame (C-CFST) structure was designed according to the S-CFST structure. With the elastic-plastic time history analysis of the C-CFST structure and theS-CFST structure in rare earthquakes, the displacement responses and acceleration responseswere compared.