Study on the application of TLS for bridge deflection inspection in Vietnam

Abstract

Inspecting defects, geometric size discrepancies compared to the design profile, and displacement under theload of the bridge structure aims to gather information and current data before putting the bridge into operation. However, the quality of inspection on the structure size performed by traditional methods usually takes time consuming and potentially unsafe due to difficulties in accessing because the bridge dimension is high and the rugged terrain is challenging, especially with bridges crossing rivers, deep valleys, etc. Therefore, applying modern, effective, and reliable inspection methods is essentially required. The Terrestrial Laser Scanner (TLS) is a technique to quickly and accurately gather topographic data points of objects’ surfaces. TLS is applied in many survey fields, including surveying the structure of bridge engineering. To evaluate the effectiveness of applying TLS, the research conducted a determination of the main span P61-62’s deflection of the balance casting bridge crossing the Vong intersection of the urban traffic bridge project Ring Road 2, Hanoi city during static load testing. Three methods to determine the deflection of the bridge span structure were implemented (1) Using dial indicators; (2) Using a total station to measure points reflecting attached to the structure of the bridge girder; (3) Applying TLS to inspect the structure at the time of no load and load. The results led to the conclusion that TLS methodology facilitates the determination of the bridge deflection with acceptable accuracy.