Analysis Of Plane Frames With Generalized Semi-rigid Connections

Steel frame system has been applied extensively in practice. Multi-layer steelframe structure housing has become one of the10construction technology which arewidely promoted. Research on the semi-rigid joint of beam-to-column connections isthe most important and critical part. At present, the study of semi-rigid connections isa series of explorations about rotational semi-rigid characteristic, while the influenceof the axial and transverse direction is rarely involved. There is an urgent need toform the integrated theoretic system. Whole purpose is to give a mechanical modeland analytical method which can be used to consider the axial, the shearing and thebending semi-rigid characteristics.On the base of comparatively analysis about various design method to semi-rigidconnections, the three-spring mechanical model about the axial, transverse androtational semi-rigid characteristic is proposed. The model is composed of a barelement and three springs at each end. In this paper, the matrix displacement methodis used to analyze mechanism of the model, including element analysis and structuralanalysis. The model has an advantage that the element number of structure does notincrease. The stiffness matrix of the element is derived. Some reaction forces at theend of the element are obtained when it is subjected to eight kinds of different loadsrespectively. The relation of displacement between the bar element end and the jointis also derived. The entire balance equations of frames composed by this kind ofelement are presented.The example is calculated and analyzed using the both programs VB and Matlab,and through the analysis result, the correctness of the programs is verified.Displacements of nodes and the composing elements, as well as the force vectors ofthese elements are derived for different connection stiffness. Exponential function andpolynomial function curve are used in the nonlinear analysis. Compared thecalculation results of the both forms of the same example, it can be seen that thetranseverse force-transeverse displacemnt and the moment-rotation relationships of joint can greatly affect the behavior of the structure except the axial force-axialdisplacement. And the influence of the relation curves about internalforce-deformation is obvious. This paper will further promote the development of thetheory about semi-rigid joints.