self-anchoring suspension bridges;  Free vibration;  functional variation;  Frequency formula

The self-vibration characteristic analysis of suspension bridge is the basis for studying the wind, seismic and other dynamic effects of suspension bridge. Considering the bending effect of the stiffener beam, taking into account the influence of the inclination angle and longitudinal displacement of the large cable, based on the functional analysis of incomplete generalized potential energy of large displacement, the differential equation of free vibration of the stiffener beam of the two-tower three-span continuous self-anchored suspension bridge is derived by using the variational principle, and the longitudinal and vertical frequency calculation formulas of the self-anchored suspension bridge are obtained according to the simplified differential equation, and finally the formula is basically reasonable through two examples.