| Based on many problems faced by the existing prefabricated concrete frames,a new type of prefabricated frame structure system is proposed in this paper,which uses the I-shaped honeycombed columns with rectangular concrete-filled steel tube flanges as the frame columns and the I-shaped honeycombed beams with rectangular concrete-filled steel tube flanges as the frame beams.The frame columns and frame beams are reliably connected by engineered cementitious composites(ECC)integral joints.This kind of composite frames is suitable for the application to the tall buildings in the complex environment such as seismic zones.Given that there are few researches on this kind of frames at home and abroad,technical support for the writing of relevant specifications and practical engineering application is provided by this paper,and the following four aspects of work are carried out.1.By finite element software ABAQUS,appropriate steel constitutive model,constrained concrete nonlinear constitutive model and ECC constitutive model are selected.Considering the interface contact between steel tube and concrete,a three-dimensional finite element model of single-layer and single-span concrete-filled steel tube honeycombed beam-column-ECC reinforced joints frames(PCFHWF)is established.Based on the existing experiments,the numerical simulations of the rectangular concrete-filled steel tube flanges-honeycombed steel web composite columns(STHCC),ECC columns and bolted RC frame prefabricated joints are carried out,and the rationality of the finite element modeling is verified by comparing the simulation results with the experimental results.2.Taking the axial compression ratio,the steel strength of beam,the steel strength of column,the concrete strength of beam,the concrete strength of column and the concrete of joint as the main parameters,a total of 17 full-scale single-layer and single-span prefabricated steel tube concrete flanges-honeycombed steel web composite frames(PCFHWF)are designed.Based on the reasonable finite element model,the static analysis of PCFHWF under monotonic horizontal load with different parameters are carried out,and the influences of different parameters on the ultimate bearing capacity,ductility and stiffness of the frames are investigated.3.Through the static analysis for full-scale single-layer and single-span PCFHWF,the failure mode of the frames is obtained,and the hinge law of the frames can be attained.Based on the plastic hinge length formula of the frame proposed by the previous authors,the plastic hinge length formula of the new kind of full-scale single-layer and single-span PCFHWF is fitted and regressed by 1stopt software.4.Taking the axial compression ratio,the steel strength of beam,the steel strength of column,the concrete strength of beam,the concrete strength of column and the concrete of joint as the main parameters,the seismic performance numerical simulation analysis of 17 prefabricated steel tube concrete flanges-honeycombed steel web composite frames(PCFHWF)under the combined action of axial force and low-cycle reciprocating horizontal load are carried out.The hysteretic curves and skeleton curves of the frame are obtained.The seismic indexes such as energy dissipation capacity and stiffness degradation of the composite frames are investigated.The influences of different parameters on the seismic performance of the novel frames are obtained,and the failure mode of the composite frames is attained.Moreover,the skeleton curve models of the composite frames are concisely regressed by 1st Opt software.Through the numerical simulation analysis for the seismic performance of this kind of composite frames,the seismic performance of the new frames can be more comprehensively understood and mastered,which can lay a solid foundation for the application of this kind of frames in practical engineering. |
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