ABSTRACT: Modal analysis is a popular non destructive method for evaluating the health of structural systems. Damaged as well as intact structures are being used as validation tools. A test program on reinforced concrete beams is set up. Beams are gradually damaged and the changes of the dynamic parameters monitored from the initial to the failure state. A total of 8 reinforced concrete beams with similar dimensions were made using concrete with two different compressive strengths and reinforcement ratios. Static loading was performed with four-pointbending setup in order to generate different damage levels in specimens while dynamic testing was conducted to monitor the changes in dynamic characteristics of the samples. By increasing the damage level in specimens, frequencies of the beams were decreased. Damping prosperities behave in the opposite direction and grew as damage level increased. Modal curvatures turned out to be a good damage indicator.The intensity of the damage level in each specimen affects the shape of its mode as well. Fixed points and curvature of the beams tends to move toward the location of the damage.

Keywords