NATURAL FREQUENCIES OF INITIALLY STRESSED ARCHES IN LATERAL VIBRATION

Under the natural coordinate system of arch axis, a variational formulation equation is established for arches with initial stress. The axial force, bending moment and shear force of plane arches in plane deformation that produced by initial loads are taken into account. An analytical relation between initial loads and the natural frequencies is presented, which shows that the natural frequencies in lateral vibration are reduced because of initial loads. The reduction of frequencies is of the same quantitative order as the sensitivity of frequency method in damage identification in structures.