Assembled Frame Joints With Different Joint Connections Seismic Analysis And Optimum Design Of Structures

Nowadays,the country develops green industry,promotes the upgrading of the construction industry,and assembly building has gradually become a hot development project.Compared with traditional buildings,assembled buildings not only have the advantages of shortening construction period,noise reduction and pollution reduction.Some outdoor operations can also be transferred to factories and carried out indoors,which makes the quality of components more controllable,improves the maintenance conditions of components,and improves the working environment of workers.Research and development of assembly industry is helpful to promote the industrialization and digitization of the national construction industry,and to optimize the industrial structure,transformation and upgrading of the construction industry.The assembled structure has a variety of connection and combination forms,and its design is flexible and changeable.Research on assembly form and seismic performance of assembly structure can effectively promote the development of assembly industry.This paper mainly studies the seismic performance and joint construction of five different assemblies.Assembly form 1:cast-in-place beam-column prefabricated joints;assembly form 2:use composite beams and joints with U-shaped steel bars;assembly form 3:single-layer and double-layer column coupling;assembly form 4:beam-column connection through grouting sleeve,column dry connection at the bending point;assembly form 5:beam and column prefabrication,embedded steel members in beams and extended joints,cast-in-place joints.A three-storey three-span frame structure is built by ABAQUS software for quasi-static analysis.The seismic performance of assembled structure and cast-in-place structure is analyzed and compared.The concrete contents include bearing capacity,failure mode,hysteretic curve,skeleton curve,energy dissipation capacity,ductility and stiffness degradation.The influence of the fabricated joint construction measures on the seismic performance of the structure is also analyzed.The specific conclusions are as follows:(1)During the initial loading process,the yielding position of steel bars in cast-in-situ and assembled structures appears at the beam end,followed by the column foot.Until the structure is completely destroyed,the beam ends of each layer are seriously damaged,and the damage accumulates in the core area of the joints.The damage in the core area of the cast-in-situ joints is slightly lower than that of the assembled structure.(2)The hysteresis curve is linear in the initial stage,and the linear slope is larger.With the development of loading process,the slope of curve decreases,the area of hysteresis loop increases,the stiffness of structure decreases and the energy dissipation increases.The skeleton curves of each structure are S-shaped,and there is a tendency of stiffness degradation,and the stiffness of the assembled structure decreases more obviously than that of the cast-in-place structure.The ductility of sleeve,bolt,U-bar and section steel can be improved,and the ductility coefficient of fixed-assembly structure is higher than that of cast-in-place structure.Compared with the equivalent viscous damping coefficient and power ratio index of the structure,the energy dissipation performance of the cast-in-situ structure is better than that of the assembled structure.(3)Changing the section of embedded steel members has little effect on the bearing capacity,energy dissipation capacity and ductility coefficient of the structure.Additional stiffeners at the end of the beam can effectively improve the bearing capacity,energy dissipation capacity and ductility of the structure.The stirrup encrypting at the joints has a great influence on the energy dissipation capacity and ductility of the lifting structure.The speed of this kind of influence increases first and then decreases with the reduction of the stirrup encrypted spacing.Adding inclined bars to the joints of assembled structures can effectively improve the energy dissipation capacity and ductility of structures.The influence on the bearing capacity of the structure is not obvious.