Acquisition and Analysis of Dynamic Responses of a Historic Pedestrian Bridge using Video Image Processing

11th International Conference on Damage Assessment of Structures

物理学;材料科学

O'Byrne, Michael^1,4 ; Ghosh, Bidisha^1,4 ; Schoefs, Franck^2,3 ; O'Donnell, Deirdre^4 ; Wright, Robert^4 ; Pakrashi, Vikram^4

Department of Civil, Structural and Environmental Engineering, Trinity College, Dublin, Ireland^1

LUNAM Université, Université de Nantes-Ecole Centrale de Nantes, CNRS, GeM, Institute for Research in Civil and Mechanical Engineering, University of Nantes, Nantes, France^2

IXEAD/CAPACITES Society, Nantes, France^3

Dynamical Systems and Risk Laboratory, Civil and Environmental Engineering, School of Engineering, University College Cork, Ireland^4

关键词: Dynamic displacements;    Frequency domain response;    Historic structures;    Image processing technique;    Pedestrian movement;    Vertical deformation;    Video image processing;    Video-based tracking;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/628/1/012054/pdf
DOI  :  10.1088/1742-6596/628/1/012054

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Video based tracking is capable of analysing bridge vibrations that are characterised by large amplitudes and low frequencies. This paper presents the use of video images and associated image processing techniques to obtain the dynamic response of a pedestrian suspension bridge in Cork, Ireland. This historic structure is one of the four suspension bridges in Ireland and is notable for its dynamic nature. A video camera is mounted on the river-bank and the dynamic responses of the bridge have been measured from the video images. The dynamic response is assessed without the need of a reflector on the bridge and in the presence of various forms of luminous complexities in the video image scenes. Vertical deformations of the bridge were measured in this regard. The video image tracking for the measurement of dynamic responses of the bridge were based on correlating patches in time-lagged scenes in video images and utilising a zero mean normalised cross correlation (ZNCC) metric. The bridge was excited by designed pedestrian movement and by individual cyclists traversing the bridge. The time series data of dynamic displacement responses of the bridge were analysed to obtain the frequency domain response. Frequencies obtained from video analysis were checked against accelerometer data from the bridge obtained while carrying out the same set of experiments used for video image based recognition.