Application of 3D LIDAR Scan of a Bridge under Static Load Testing

The size and complexity of bridges make the analysis of such structures difficult. Load testing is a useful technique to test the performance of bridges and assess the presence of damage. Traditional techniques for measuring the response of bridges during load testing often necessitate physical contact with the bridge and thus restrict measurements to only the contact area. A 3D terrestrial light detection and ranging (LIDAR) scanner can provide highly accurate, noncontact measurements of bridge surface points. The scanner can obtain the geometric information of the entire bridge surface area within its scanning range, making it a powerful tool for bridge load test measurements. In this paper, the 3D scanner capability was demonstrated through the testing of a high-performance steel girder bridge in Iredell County, North Carolina. By comparing the changes of bridge surface scan data before and after a static load test, displacements of surface points were calculated. Also, the accuracy of the deflection measurement and a strain calculation technique using LIDAR scan data are discussed.