Hibrid Approach of Cameras and GPS for Displacement Measurements of Super Long-Sapn Bridges

In a recent decade, the GPS has been introduced to directly measure the displacements of super long-span bridges. However, due to its high cost, it is not appropriate to apply a number of GPS receivers in a super-long span bridge in order to measure the displacements through the overall bridge. From the limited point-based measurements of the displacement, a mode shape model for the bridge maintenance gets more complicated and includes errors due to the assumption in the displacements other than the measured points. This study considers digital cameras as the supplementary approach for the displacement measurements to address the limitation of GPS receivers. The objective of this study is to theoretically investigate the feasibility to use digital cameras with GPS receivers to develop a more compelling mode shape model for the super long-span bridge maintenance. From a case study, it was found that digital cameras can provide a sufficient measuring width with a moderate resolution to measure the displacements of a super long-span bridge.