Nonlinear vibration analysis of steel frames with semirigid connections

To obtain an accurate insight into the behavior of most realistic steel frames, joint flexibility should be allowed for in the analysis. So far, most research work is concentrated on the linear and nonlinear static analysis of steel frames with flexible connections. Very few papers were contributed to the dynamic and vibration analysis of these types of frames. This paper proposes a numerical method for linear and nonlinear vibration analysis of frames with semirigid connections. The special features about this method are the derivation and the use of a shape function with end springs to formulate the element matrices. The effects of initial stress and of the change of joint stiffness due to the applied load are accounted for in the suggested method, which is believed to be more general than the existing methods for vibration analysis of flexibly connected steel frames.