Free vibrations of continuous horizontally curved beams

Abstract This paper presents a closed form solution for the out-of-plane free vibration frequencies of a horizontally curved thin walled beam which is continuous over multiple supports. The bending and twisting of this beam is coupled in the mathematical model used. This coupled bending/twisting behavior causes two free vibration frequencies to be associated with each vibration mode shape. The solution is used to calculate the first six free vibration frequencies and the corresponding mode shapes for prismatic beams with three equal spans over a range of non-dimensional parameters representing variations in warping stiffness, torsional stiffness, radius of curvature, included angle of the curve and polar mass moment of intertia. The mathematical model and numerical results are presented in non-dimensional form. The results are applicable to the design of highway, rail, rapid transit and guideway structures.