FINITE ELEMENT ANALYSIS OF SEMI-RIGID COMPOSITE FRAMES UNDER VERTICAL LOADS
To study the effects of moment-rotation characteristics of connections and load magnitude on the behavior of composite frames, nonlinear finite element method is presented considering the effects of the moment-rotation characteristics of beam-to-column connections, composite action of slab and geometric nonlinearity. The stiffness matrixes of structures and fixed-end forces of members are modified by introducing an end-fixing factor. The results indicate that the moment-rotation characteristics of connections affect the forces and deformations of the composite frames, while the load magnitude has no significant effect in the range of 0.143 r00.727. In addition, the effects of semi-rigid connection and composite action of slab on the behavior of steel frames must be properly considered in design. The proposed finite element method can be used in practice.