| As the composite concrete-filled steel tube (CFST) has the advantages of high bearingcapacity, good ductility, strong earthquake resistance, high fire resistance and convenientconstruction, it has a good prospect of application. However, the researches on theconnections of CFST are still not deep enough at present, not to mention the frame ofmultibarrel tube-confined concrete column with steel beam. Therefore, quasi-static cyclic teston the connections of multibarrel tube-confined concrete column with steel beam areconducted and the results are analyzed in this paper. Additionally, the mechanical property forthe frame of the multibarrel tube-confined concrete column with steel beam is discussed in thepaper. The main work in this paper is as followed:(1) Quasi-static cyclic tests on6connection specimens of multibarrel tube-confinedconcrete column with steel beam and1connection specimen of square CFST column withsteel beam are carried out in this paper. In these tests, the protruding length of vertical rib, therib on anchorage web and the axial compression ratio are the main parameters underconsideration. The test results show that the hysteretic curves of the connections ofmultibarrel tube-confined concrete column with steel beam are all in spindle shape, and thecurves are full without reduced pinch phenomenon. It indicates that the new type ofconnection performs well in ductility and energy dissipation, which proves the rationality ofthe new joint form. In addition, such mechanical properties as skeleton curve, ultimate load,ductility, energy dissipation, strength degeneration and rigidity degeneration are alsoanalyzed.(2) Through using finite element analysis software ANSYS, the finite element models forconnections of the multibarrel tube-confined concrete column with steel beam are establishedwith solid element. The double nonlinear finite element analysis of the whole stressingprocesses is carried out, the mechanics mechanism, the failure mode and the energydissipation are researched and the influence character of parameters including the axialcompression ratio and the thickness of pipe wall are analyzed. The result shows that thehysteretic curves of the connections got by numerical analysis are full without reduced pinchphenomenon. and it matches well with that got by tests. On the basis of the study, theinfluence character of parameters including the axial compression ratio and the thickness ofpipe wall are studied.(3) Through using finite element analysis software ANSYS, the finite element model forthe frame of multibarrel tube-confined concrete column with steel beam are established with beam element. The double nonlinear finite element analysis of the whole stressing processesis carried out, the mechanics mechanism, the failure mode and the seismic behavior areresearched and the influence character of parameters including axial compression ratio andslenderness ratio are analyzed. The result shows that the hysteretic curve of the frame is fullwithout reduced pinch phenomenon. It indicates that the frame has good anti-seismicperformance. |
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