Non-contact measurement method of beam vibration with laser stripe tracking based on tilt photography
Tong Wu, Liang Tang, Peng Du, Nian Liu, Zhixiang Zhou, Xiaolei Qi
Abstract
Aimed at the problems of strong dependence on target and light conditions in vision-based methods, a new method of analyzing bridge vibration by tracking a laser stripe is proposed. Specifically, the laser line is projected to the surface of the beam and continuous images are recorded. Through sub-pixel tracking of the laser stripe center-line position in the image, the bridge displacement time-history curve can be obtained, and then the dynamic parameters can be identified. A hammer impact test of a simply supported beam model was conducted in the laboratory. A Sony camera, a linear variable differential transformer displacement sensor, and seven accelerometers were used to collect data. The maximum error of displacement and maximum error of the first- and second-order frequencies obtained by the camera were 5.47% and 1.81%, respectively. Then, field tests of a track beam were conducted. This method provides a new non-contact technique for measuring bridge vibration.