Hinterrhein-Bridge

The tests were performed in two phases. In the first phase, two locomotives were placed at three different specific positions representing where the behavior of the bridge could be captured with measurable deformations. The deck was observed with precise levelling by Schneider Ingenieure AG and GSEG captured the bottom surface of the structure using three 3D scanners. This allowed determining the areal deformation under all three load situations and get a large-scale picture of the bridge behavior. A comparison of the levelling results and the analysis based on TLS shows excellent agreement of the two methods with deviations on the order of 1.4 mm (rms). In contrast to the traditional levelling, which only allows analyzing for vertical deformation of the deck, the TLS data facilitate a variety of analyses showing 3d deformations of various parts of the bridge. In particular, we could perform an analysis of the twist of the deck, of crossbeam deformations and of deformations of the pillars. All this supports a more comprehensive assessment of the structural stiffness.

 

In the second phase, quasi-static tests were carried out with one locomotive moving over the entire bridge at walking pace. While Schneider Ingenieure AG monitored the displacement of two prisms continuously tracked using two total stations, we captured the temporal evolution of the deformation along an entire longitudinal profile of the bridge by observing three consecutive runs of the locomotive with one laser scanner operating in 2D profile mode. The captured time series could be analyzed with respect to the approximately known positions of the moving locomotive allowing to study the response of the bridge to the spatially and temporally varying load situation.