Abstract (EN):
This study intends to provide an insight on the possibilities of detecting structural damage through the analysis of the measured structural response of a cable-stayed bridge to daily and seasonal temperature variations. The Corgo Bridge, where a continuous monitoring system has been installed and is acquiring data for more than one year, is selected as case study. The characterization of the thermal action in its three components (uniform, linear and non-linear) is performed using a finite element thermal analysis in which the boundary conditions are defined using the measured wind velocity, radiation, ambient temperature and air temperature inside the box-girder. Once the calculated concrete temperatures fit well those measured by the embedded temperature sensors, the corresponding time histories of the uniform and differential temperature components are applied to a mechanical finite element model to obtain the structural response of the bridge. The results of the numerical simulations are compared with one year and half of experimental measurements and reasonable agreement is found. Finally, two damage scenarios are simulated involving small decreases in stiffness of the stay cables. The ability of detecting damage using the structural response to thermal loads is evaluated applying Multilinear Regression Analysis (MLR) and Principal Component Analysis (PCA) to the simulated data sets. Finally, some conclusions are put forward regarding the feasibility of early damage detection in the selected cable-stayed bridge using the adopted methodology and the installed monitoring system.
Language:
English
Type (Professor's evaluation):
Scientific