Wendong TANG and Hidekazu NISHIMURA To quantitatively evaluate the mechanical behavior related in damage of RC member by roadmap model, the static cyclic loading experiments were applied to the model beams. The load displacement relationships were obtained. The natural frequency taken for represent condition of soundness using the Impact Vibration Test (IVT), which measured the RC beam in each loading stage. Focusing on the natural frequency changes between the condition of soundness and the damages in each stage of loading, it confirmed that the decrease of bending stiffness can be reflected more accurately in higher-mode vibration. Furthermore, to examine the measured results of IVT, the eigenvalue analyses were conducted, where local reduction of bending stiffness to the beam can be taken into account rationally. In this way, a higher accuracy of analyses was achieved. Based on those results, the adequacy of natural damage estimation using natural frequency in RC member by roadmap model was verified.
