Vibrations of Axially Loaded Continuous Beams

The effect of a constant axial load either tensile or compressive on the natural frequencies of uniform multi-span beams is presented. The proposed solution is based on the exact dynamic stiffness matrix for the member, for any desired precision. The natural frequencies are found as the frequencies that cause the determinant of the stiffness matrix to become zero. The influence of the axial load and variation of span ratios on the vibration frequencies for beams with up to 4 spans are studied, and presented in graphical forms.