Study On The Behavior Of Beam-to-Column Minor Axis Connections In Steel Frames

In the past few centuries, the steel structure is developing rapidly. The research of steel structures is more and more important. At present, most of the research aims at the mechanical properties of the connections of the major axis. But there is seldom research for the mechanical properties of the connections of the minor axis. In order to research the mechanical properties of the connections of the minor axis, a kind of beam-to-column minor axis connections of steel frames was studied in this thesis. The mechanical properties of the steel frames were also studied in this thesis. The main works are as follows:1. The computational formula of the initial rotation stiffness of the connections was obtained by the virtual displacement method and the theory of elasticity. The effect of the initial rotation stiffness by changes in the parameters of the connections was studied. The second moment of area of the column and the floor height has a great influence on the initial rotation stiffness of beam-to-column minor axis connections.2. The mechanical properties of the connections of the minor axis were studied by the finite element method. The result of the finite element method agrees well with the result of the computational formula. The error does not exceed15%. It shows that the computational formula can be used in practical projects.3. A method to analyze beam-to-column minor axis connections was put forward in this thesis. It considers the second-order effects. Then a method to consider the influence of the initial defects was put forward. A SEASF program is compiled using the above theory by FORTRAN program.4. The mechanical properties of the steel frames were analyzed by the program. The results are as follows:â‘ Initial defects have great influence on the mechanical properties of the structure, at the same altitude conditions, with the increase of the number of spans, the effect also increases;â‘¡The mechanical properties of the connections of the minor axis have great influence on the mechanical properties of the structure. The effect should be considered.â‘¢The braced frame has a greater lateral displacement stiffness than the pure frame. The mechanical properties of the connections of the minor axis have less impact for the mechanical properties of the braced frame.