Abstract
Accelerometers, easy to install and inexpensive, could play an important role in status monitoring of civil engineering structure. When they are installed on a bridge, the dynamic displacement response under live load can be found by double integration of the acceleration time history observed by the sensor installed, which helps us to estimate the local damage and cause of the damage. However, as acceleration time histories are integrated to the response, measurement error of accelerometer has an large negative effect on the result. Moreover, it is very difficult to determine the boundary condition because bridge under live load vibrates at all times.
In this study, firstly, the effect of measurement error of accelerometer on the accuracy was mathematically revealed. Secondly, we proposed “FREE VIBRATION METHOD”. Assuming bridge is vibrating with its natural vibration before and after vehicular pass, displacement and velocity can be calculated. The velocity and displacement while vehicular is passing on the bridge are calculated by using initial and terminal conditions estimated above. Finally, we conducted the measurement on an actual bridge to examine the effectivity of the proposed method.
