Haitao Bian

3D LiDAR Scans for Bridge Damage Evaluations

High resolution ground-based optical-photonic images generated from laser scans provide detailed geometric information about a structure and simple algorithms can be used to retrieve damage information from the geometric point cloud data. Also called terrestrial 3D LiDAR, the laser scanning technology has great potential for bridge condition assessment, in particular, for damage evaluations. This paper describes several studies on quantification of concrete material damages using 3D LiDAR including mass losses due to vehicle collisions, reinforcement corrosion and surface erosions. The computed information can provide engineers critical measurements for further damage analysis, which were not previously available using photogrammetry or plan photographic techniques.

LiDAR Scan for Blasting Impact Evaluation on a Culvert Structure

This paper summarizes a case study of using three-dimensional (3D) light detection and ranging (LiDAR) scanner technology in bridge postblast geometric assessments. Terrestrial 3D LiDAR scanners can generate dense point clouds of position information that can be used to establish baseline geometric information for structures and to establish critical dimensional footprints for before and after event comparisons. For close range blast effects, the preblast and postblast scans of a bridge are proposed to establish blasting induced effects and damage information. The Colony Road culvert bridge was monitored for a nearby construction blasting, where full-scale 3D scans of the bridge have been conducted before and after blasting. The critical sections and geometries are then compared to ensure the safety of the bridge.

Three-Dimensional Terrestrial LIDAR for Operational Bridge Clearance Measurements

AbstractThis paper reports the outcomes of a study of the vehicle crossing effects on a terrestrial light detection and ranging (LIDAR) scan on highway bridges for underclearance measurements. Ground-based or vehicle-mount terrestrial LIDAR scanners, which recreate the bridge structure as a three-dimensional point cloud of thousands of position data points, have been found to be ideal for bridge clearance measurements. To determine the effects of ambient overhead vehicle crossing and seasonal temperature variation on clearance measurements, periodic monitoring of the Harris Road Bridge has been conducted. A simplistic but practical correlation analysis is performed, which shows that operational LIDAR scanning is a viable technique for bridge clearance measurements.

Lidar based edge-detection for bridge defect identification

Previous visual damage detection on bridge structure based on eye-ball method is arbitrary and time-consuming for bridge management due to its heuristic nature. Commercial remote sensing (CRS), which has remarkable applications for geometric quantification, is suggested to supplement visual bridge inspection. Ground-based LIDAR is one of the remote sensing tools that have been successfully used in bridge evaluation. Most of the early measurement algorithms are developed based on the spatial information contained from the LIDAR data; this paper explores the potential of applying another important feature of the scan data: the reflectivity, to enhance the defect detection program. The addition of reflectivity in damage diagnostics is particularly useful for defect detection of curved surfaces. A damaged joint area and concrete beam were selected to verify the method. The study shows that the reflectivity of the LIDAR could be used to support the automatic defect detection in bridges by combining it with the current position-based only image processing algorithms.

3D terrestrial lidar for operational bridge clearance measurements

This paper reports the outcomes of a study of the vehicle crossing effects on terrestrial LiDAR scan on highway bridges for underclearance measurements. Ground-based or vehicle-mount terrestrial LiDAR scanners, which recreate the bridge structure as 3D point cloud of thousands of position data points, have been found to be ideal for bridge clearance measurements. To determine the effects of ambient overhead vehicle crossing and seasonal temperature variation on clearance measurements, periodic monitoring of the Harris Road Bridge has been conducted. A simplistic but practical correlation analysis is performed which shows that operational LiDAR scanning is a viable technique for bridge clearance measurements.

Study of a Skewed HPS Bridge and a Culvert Bridge Using LiDAR Scan

This paper summarizes two bridge studies: 1) testing and numerical modeling of a newly constructed skewed hybrid high-performance steel (HPS) bridge; and 2) testing of a culvert bridge near a rock blasting. The first study is for construction verification and the second study is for possible blast damage identification. In the first study, truck load tests were conducted on the first North Carolina HPS 100W girder bridge after construction completion. LiDAR scan technique was used to measure bridge displacements under truck loading. A detailed 3D finite element (FE) model of the bridge was established. Results obtained from numerical analyses were compared with static load tests. In the second study, 3D LiDAR scans of a culvert were performed before and after rock blasting. Possible bridge position changes and damages were investigated. This research demonstrates two applications of LiDAR scan for bridge condition assessment.

Bridge deck joints evaluation using lidar and aerial photography

Deck joint is important for a bridge - Any cost-effective evaluation methods that can help trace joint movements during frequent inspections will provide valuable data to bridge engineers. In this paper, 3D Terrestrial LiDAR and Aerial photography are being investigated as possible joint evaluation methods. The laser scanners record 3D positions of the surface points, generating high density point clouds. Aerial images taken by commercial DSLR cameras in a small airplane flying at 1000 feet, generates high resolution imagery. Both techniques have sub-inch pixel resolutions. Scanning results from bridges in both Florida and Alabama have shown that LiDAR and aerial imaging technologies are compatible techniques and can be applied in bridge deck joint performance evaluation. Moreover, both techniques have the potential to reduce the costs in bridge inspection.

Remote Sensing for Bridge Monitoring

Commercial remote sensing (CRS) as robust bridge health monitoring techniques offer unique features that are missing from current embedded structural health monitoring systems, including the ability to geo-reference bridge location, provide spatial views and high-resolution top views of bridges. Beginning in 2007, a research partnership (University of North Carolina at Charlotte, ImageCat Incorporated, Boyle Consulting, Charlotte Department of Transportation and North Carolina Department of Transportation) has completed a proof-of-concept project to develop ground-based LiDAR scan and sub-inch-resolution aerial photography into the IRSV (Integrated Remote Sensing and Visualization) bridge data diagnostic system. The IRSV system represents a critical juncture towards “Total View Total Integration (TVTI)” infrastructure monitoring concept and provides further incentive for CRS development. This paper presents a high-level discussion on the potentials of CRS tools to enhance bridge inspection and data management.