| This thesis deals with vibration frequency evaluation using non-destructive modal testing of beam-type structures. The current state of Canada's bridges is reviewed for its present condition and urgent needs. The basic modes of deterioration in concrete bridges, namely, corrosion of reinforcing steel and freezing and thawing cycles were also reviewed. Bridge inspection fundamentals are discussed summarily. In addition, a summary of the available research on modal testing is presented.;Five reinforced concrete beams were tested in this preliminary research program to study the effect of progressive cracking at increasing load levels on the changes in their natural frequencies. Analysis of the results shows that the natural frequency is related to the changes in the structural stiffness of the beam, and the level of damage. The results from this preliminary investigation show that vibration testing is a useful tool for studying the existing health of a structural system. |
