Safety Assessment of Steel Bridges Damaged by Truck Strikes: Fid-Bau Portal

Safety Assessment of Steel Bridges Damaged by Truck Strikes

C. J. Earls / C. J. Stull

A comprehensive research effort was undertaken as a means for identifying a new and robust means for assessing damage and reserve capacity in slab-on-steel stringer bridges damaged by impacts with over-height trucks. The research program involved the use of two different terrestrial laser scanning technologies as a means for developing detailed point cloud maps of the damaged bridge geometry. Commercial image processing and registration software was employed as a means for generating well formed solid models from the large point cloud data sets emanating from the laser scanning activity. The commercially available nonlinear finite element software system ADINA was then used to map a mesh onto the solid geometry representing the damaged bridge. ADINA was subsequently used to perform a 'virtual load test' of the damaged bridge structure. Based on this research, it was observed that the subject bridge under study exhibited a significantly altered load-displacement response, as compared with modeling results considering its undamaged geometry. Indeed, the effect of the truck impact damage in the region of the exterior girder close to the interior support of the end-span precipitated a dramatic softening of the load-displacement response in the structure. Furthermore, the initial imperfection associated with the region of damage grew to become objectionable as large load levels were imposed on the bridge. This response was at variance with what was observed in the undamaged structure.