Investigating the relationship between the extent of failure resulting from cyclic loading and changes in the dynamic properties of reinforced concrete beams

Over the past few years, vibration monitoring of construction structures has found considerable importance, which is due to simplicity of equipment and the novel and powerful fault detection system. Failure assessment involves the ability of establishing a logical relationship between dynamic properties and the failure pattern of structures. In this paper, the experimental results obtained from the output of the monitoring system for the status of construction structures were presented in terms of changes in their dynamic properties. In this research, reinforced concrete columns were subjected to cyclic loading, and after each state of loading, to obtain the dynamic properties they were stimulated by modal hammer and with processing the frequency responses through ANSYS software, the natural frequencies, damping ratio, and shape of corresponding modes of the column were also determined. The concrete beams with modal hammer were stimulated within the frequency range of 0-4000 Hz. The frequency response functions were obtained through OROS 8 -channle vibration dynamic analyzer. The frequency response function, by employing vibration analyzer and with considerable reduction in natural frequencies, resulted in enhanced structural damping.

Keywords:

frequency response function , damping , mode shape , fatigue , natural frequency