Structural monitoring of a bridge prestressed concrete beam under loading

The VIPP are simple span viaducts made of precast concrete girders prestressed by post-tension. This type of construction was largely developed after the second world war, thanks to its girders launching system which allowed the crossing of non classical obstacles with reasonable height. The many design and execution mistakes, and the absence of corrective maintenance actions to restore the defective waterproofing of these bridges, have led to several structural problems. It is in this context that the present study " Monitoring of the mechanical behavior of a VIPP beam under loading: the case of the Merlebach's VIPP " was initiated by the network of the Public Works Laboratories of the Ministry of Public Works. The principle of the study is to carry out a benchmark of various mechanical evaluations (acoustic emission, dynamic assessment, curvature measurements, displacements, gage measurements), some largely used nowadays, others being more innovative. This paper presents the principal results obtained from these diagnosis techniques. These investigations make it possible to appreciate the promising character of certain approaches within the framework of the performance assessment of prestressed concrete bridges