Static And Dynamic Monitoring New Methods Of Highway Material And Bridge Deformation

Highway material or bridge deformation measurement is an important module of Structural Health Monitoring(SHM)program which is accomplished in different ways.Generally,highway material or bridge deformation measurement methods are divided into two types: contact-based and non-contact-based techniques,each of which has its own advantages and disadvantages.In this study,considering the capabilities of non-contact optical sensing methods,two innovative methods of 2D and 3D optical deformation measurement were developed to measure the static and dynamic deformation of asphalt mixture and bridge structure.These methods utilize a robust image processing and analysis algorithm to detect and track either artificial or natural targets and subsequently calculate the asphalt mixture and bridge deformation in a convenient,cost-effective and time-saving manner by following the general steps of installation of equipment,image data acquisition,camera calibration,image undistortion(2D)or rectification(3D),image processing and analysis,and structure deformation measurement.Then 2D image-based motion correction methodology was proposed to recover the real bridge deformation in presence of camera motion.This methodology is a combination of image motion correction algorithm and 2D image-based deformation measurement technique.The image motion parameters are estimated by defining a region of interest within the image and using Iterative Affine Motion Estimator and subsequently the vibrated images are corrected and finally the real deformation is calculated.Several experiments in the lab and in the real field were conducted to verify and investigate the accuracy and reliability of the proposed methodologies.First,two asphalt experiments were established to verify 2D and 3D optical deformation measurement methods by measuring the vertical and radial deformation of asphalt mixture.Then 2D image-based motion correction methodology was validated through the results of asphalt Uniaxial Compression test.Following these tests,a concrete beam which was a part of the slab track was tested in the lab to measure the static vertical deformation by applying 2D and 3D optical deformation measurement methods and the results were compared with those obtained through MTS machine sensors.In addition,the accuracy of 2D and 3D optical deformation measurement methods were compared through conducting an arch bridge model experiment in the lab for dynamic deformation measurement.Then,a real bridge experiment was conducted to investigate the reliability of 2D optical deformation measurement method for bridge static deformation measurement.Finally,another real bridge in China was tested under dynamic loading condition to measure the real deformation of bridge structure in presence of camera motion.The results of all experiments in the lab and in the field showed the accuracy and efficiency of the proposed methodologies for asphalt mixture and bridge deformation measurement.Based on the obtained results of conducted experiments,other issues were also investigated and addressed including the comparison of accuracy and efficiency of 2D and 3D optical deformation measurement methods,evaluating the effect of different camera types and their capabilities,providing conditions to reduce the time and cost of deformation measurement procedure,and the possibility of detecting and tracking any number of targets on the asphalt or bridge structure.