Terrestrial Laser Scanning-Based Bridge Structural Condition Assessment : Tech Transfer Summaries

PDFTech ReportStructural health monitoringLasersBridgesOptical scannersIowaIowa State University. Institute for TransportationTurkan, YeldaLaflamme, SimonTan, LiangyuIowa State University. Institute for TransportationMidwest Transportation CenterUS Transportation CollectionProblem StatementWhile several state departments of transportation (DOTs) have usedterrestrial laser scanning (TLS) in the project planning phase, limitedresearch has been conducted on employing laser scanners to detectcracks for bridge condition assessment.BackgroundMost bridge condition assessments in the US currently require trainedinspectors to conduct complex and time-consuming visual inspections.TLS is a promising alternative method for documenting infrastructurecondition. This advanced imaging technology rapidly measures thethree-dimensional (3D) coordinates of densely scanned points withina scene to produce 3D point clouds, which are then analyzed usingcomputer vision algorithms to assess structural conditions.This technology has been shown to effectively identify structuralcondition indicators, such as cracks, displacements, and deflectedshapes, and is able to provide high coverage and accuracy at long ranges.However, large-scale, high-resolution scanning requires a significantamount of time on site, and data file sizes are typically very largeand require extensive computational resources. Therefore, advancedalgorithms are needed that would enable automated 3D shape detectionfrom low-resolution point clouds during data collection.Project Objectives\ue2\u20ac\ua2 Measure the performance of TLS for the automatic detection of cracksfor bridge structural condition assessment\ue2\u20ac\ua2 Develop adaptive wavelet neural network (WNN) algorithms fordetecting cracks from laser scan point clouds based on state-of-the-artcondition assessment codes and standardsLaser scanning a concrete cylinderMTCIowa State University2711 S. Loop Drive, Suite 4700Ames, IA 50010-8664515-294-8103The Midwest Transportation Center (MTC) isa regional University Transportation Center(UTC). Iowa State University, through itsInstitute for Transportation (InTrans), is theMTC lead institution.MTC\ue2\u20ac\u2122s research focus area is State of GoodRepair, a key program under the 2012 federaltransportation bill, the Moving Ahead forProgress in the 21st Century Act (MAP-21).MTC research focuses on data-drivenperformance measures of transportationinfrastructure, traffic safety, and projectconstruction.The opinions, findings, and conclusionsexpressed in this publication are those of theauthors and not necessarily those of the projectsponsors.Using computer vision algorithms to process laser scannerpoint cloud data would allow a bridge\ue2\u20ac\u2122s condition to be assessedautomatically and remotely, which would ultimately help improveinfrastructure management