Comparison of vibration analysis for a bridge using accelerometers and a piezoelectric cable sensor

Reinforced concrete bridges occasionally became structurally unstable because of its deterioration and damages due to strong earthquakes. In case of an earthquake disaster some restrictions are impose on road operation to ensure safety. Then to permit a quick recovery of road operation it is necessary to monitor structural components before and after the earthquake. This paper presents a novel piezoelectric cable vibration sensor prototype for use in a monitoring system that can easily evaluate the structural integrity of a reinforced concrete bridge quantitatively. In addition to measurements to obtain the natural vibration characteristics of a target bridge, forced vibration due to moving loads were performed using a truck running on the bridge. Results from proposed sensor are compared with results obtained with accelerometers and in general natural frequencies of vibrations estimated from both procedures are in good agreement. However, additional investigation is required to improve accuracy and reliability of proposed sensor. As described herein, an outline of proposed system with emphasis on upgrading of its function and principal specifications of the developed system for monitoring reinforced concrete bridge stability.