| With the continuous development of modern construction industry technology,concrete filled steel tube structures are widely used in building structures due to their good mechanical properties,and many landmark buildings have been established.With the continuous development of building modeling,space use functions and structural forms,the conventional joint form of the concrete-filled steel tube column-steel beam composite structure has been unable to meet the demand,and the unconventional joint form has become a development trend.At present,there are few studies on the mechanical properties of square steel tube concrete column-steel beam staggered joints,and lack of relevant experience accumulation.Therefore,it is necessary to carry out research on the mechanical properties of steel tube concrete column-steel beam staggered joints.The application of layer nodes in actual engineering plays a certain reference role.In this paper,the finite element analysis of the seismic behavior of the concrete-filled steel tube column-steel beam staggered joint is performed.The main work includes the following aspects:(1)Based on the test foundation of existing square steel tube concrete columnsteel beam staggered nodes under low-cycle reciprocating loads,a large-scale finite element analysis program Open Sees was used to establish a numerical model of the staggered node test specimens,and the results of the finite element analysis were analyzed.Compared with the test results,the reliability of the numerical model of the joint test piece is verified.(2)Based on this numerical model,related parameter analysis was performed on the opposite-layer concrete-filled steel tube column-steel beam nodes.By changing the axial compression ratio,concrete strength grade,steel beam strength grade,staggered height,square steel pipe width-thickness ratio,and beam The web height and width ratio and other parameters are studied.The effects of mechanical parameters such as the skeleton curve,bearing capacity,and ductility coefficient of the CFST column-steel beam staggered node on each parameter are studied.(3)Analysis of the stress characteristics of the opposite-layer concrete-filled steel tube column-steel beam staggered joints,and the formulas for calculating the shear forces of the three types of staggered joints;The strength and stability of concrete steel tube columns,steel beams and high-strength friction bolts of joint specimens.At the same time,suggestions are made on future research directions and issues that need to be resolved. |
