| The fly ash concrete filled steel tube structure is characteristic of good bearing capacity, ductility, anti-seismic capability and easy construction, currently which is widely used in the engineering construction. The creep of core concrete can make the concrete filled steel tube’s deformation increases and the cross section’ internal force redistributes, which can lead to the structural’ ultimate bearing capacity change and security reduce. Consequently, the study on creep effect on bearing capacity of concrete filled steel tube structure is necessary.This paper combines the theoretical analysis and experiment. In the aspect of theory, this paper establishes a Drucker-prager-type of core concrete plasticity constitutive model considering the influences of creep, bringing which into ANSYS finite element software. Analysis results show that, for the axial compression member, the creep does not much affect the bearing capacity of the CFST, but for the compress ion-bend ing member, the creep have great influence on the bearing capacity of the CFST.Experimentally, our group conducted the contrast experiment of bearing capacity of the CFST. The bearing capacity reduction coefficient of the axial compression member of20%fly ash and40%fly ash is0.99and0.98respectively, which shows that the creep does not much affect the bearing capacity of the ACFST. The bearing capacity reduction coefficient of the axial compression member of10%fly ash and30%fly ash is0.83and0.88respectively, which illustrates that the creep have great influence on the bearing capacity of the CCFST. The results of experiment tally well with that of theoretical analysis, which verifies feasibility of the plasticity constitutive model.Finally, our group develops a table about the bearing capacity reduction coefficient taking into account strength grade of core concrete, strength class of steel, steel ratio, load eccentricity ratio and axial compression ratio. |
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