| The concrete-filled steel tubular structure has the characteristics of high bearing capacity and good ductility.To expand the application of laced columns in low-rise,assembly buildings in villages and towns,this paper choose the loop-four-legged concrete-filled steel tubular laced columns(The loop-four-legged CFST laced columns)as research objects,which is easy to assembly.This paper,considering the relative slip between the loop with column limbs,the relative rotation from the bars and slenderness ratio as the experimental variables,designs some loop-four-legged CFST laced columns as specimens to deeply study the mechanical behavior on axial pressure.The main research work completed in this paper is displayed as the following:After introducing the excellent characteristics of the composite components of round CFST,summarizing the research progress and finite element analysis of the composite members of CFST and describing the development history and domestic status of assembly structures,this paper suggest it is feasible and necessary to figure out the mechanical behavior of the loop-four-legged CFST laced columns on axial pressure.The paper details the preliminary preparations for the test and the production process of 10 specimens.About the test,the phenomena during the entire test process and the damage patterns of the test pieces are described.The test data is analyzed to obtain the the load-strain curve and load-displacement curve of each specimen.Finally,the calculation formula for the carrying capacity of the new type of loop laced columns is suggested by comparing the bearing capacity of specimens with the value calculated on standard.The ABAQUS software was used to establish a finite element nonlinear analysis model for some specimens of the loop-four-legged CFST laced columns.The stress cloud diagram,load-strain curve and bearing capacity from the numerical analysis results are compared with the test results.A loop-bolt connection node of the loop laced column is also established the finite element mode by ABAQUS.At last,a method for checking the bearing capacity of the loop-bolt joint is proposed.Using the same modeling method,the main influencing parameters of the bearing capacity of the loop-four-legged CFST laced columns are analyzed by numerical simulation,such as the concrete strength in tubular,the strength and thickness of the cylindrical steel pipe,the thickness and strength of the bars,the hoop index and the slenderness ratio,etc.And this paper obtains the influence of various parameters on the bearing capacity of the loop-four-legged concrete filledsteel tubular laced column. |
