Structural analysis of the Roman Bibei bridge (Spain) based on GPR data and numerical modelling

There are many ancient masonry arch bridges still in use within the actual transportation. Some of these bridges are in need of special attention because they are subject to potentially destructive conditions, such as increased traffic loads and intense vibrations produced by their new functions, and these stresses are compounded by their age. To preserve these functional structures, structural assessment is necessary or, at least, highly recommended. However, many of the details of these structures are underground and are therefore hidden from view. In recent decades, ground-penetrating radar (GPR) has shown potential for internal bridge evaluation. The Roman Bibei bridge (Spain) was surveyed with GPR to analyse its inner state of conservation. The GPR survey was conducted using 250 and 500 MHz antennas. The interpretation and analysis of the GPR data were supported by finite-difference time domain numerical modelling based on the precise external geometry provided by three-dimensional laser scanning methods. Both real and synthetic results reveal that GPR evaluation provides unknown structural details and possible modifications over time. The internal ring stone thickness was also measured, which represents valuable information for engineers to perform an exhaustive assessment of the load carrying capacity of the bridge. (C) 2011 Elsevier B.V. All rights reserved.