engleski

Application of a 3D terrestrial laser scanner in a survey of a railway bridge "Sava Jakuševac"

The railway bridge "Sava Jakuševac", was built in 1968. It is located on a relation Velika Gorica – Sesvete. The bridge was used for transportation of cargo between The Railroad Terminal and Sesvete train station. On 30th March 2009, a freight train containing a 26 cart composition stopped on the bridge because the engineer noticed irregularities of the track. There was a significant, uneven settlement of a load-bearing column in the river bed. Consequently, a deformation of a span structure occurred, which is why traffic across the bridge had to be stopped. Independent experts were hired to determine the reasons of the settlement and the scale of the consequent deformations. An investigation had to be performed in order to determine the cause of the deformation, and to design a bridge reconstruction project. Experts from the University of Zagreb, Faculty of Geodesy were hired in order to conduct measurement and create an accurate model of the bridge which is to be used for deformation determination and as a base for reconstruction project. The investigation, which the Faculty of Geodesy preformed, included the hydrographic survey of an area under the bridge, and measuring the span structure with special focus on the area of greatest deformation. Since the lower part of the span structure is inaccessible to conventional methods, the survey of the structure was conducted using a terrestrial laser scanning method, which today represents the most advanced method of surveying. Terrestrial laser scanners provide a contactless method of survey and a high data acquisition rate. They make the collection of thousands of points per second possible. The Faculty has in its possession a terrestrial laser scanner Trimble GX Advanced, which was used for the survey. The paper shows the entire workflow of survey and processing of measured data, and gives insight into new survey technology that is used in infrastructure projects.

Railway; bridge; terrestrial laser 3D scanning; contactless measuring

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