Instrumentations traditionnelles et innovantes d'un essai de flexion à rupture sur une poutre précontrainte de pont
Résumé
Cerema in France has set up an experimental project about a prestressed concrete bridge beam recovered during the demolition of a bridge. Before testing, an accurate diagnosis of the beam has been achieved. Three series of tests were carried out in 2014: bending tests before reinforcement, after a first phase of reinforcement bonded composite materials, and finally after a second and final phase of reinforcement bonded composite materials. This final test was gradually led to a complete break of the beam. Traditional instrumentations were installed on the beam: 187 measuring points were monitored at a frequency of 10 Hz by twenty five PEGASE WiFi connected sensors. Innovative instrumentations were also used and compared with the traditional ones. This experience on a precast, prestressed concrete bridge beam reinforced with FRP allows us to deliver some first lessons. The real break of the beam was held to a force of about 61 tonnes, corresponding to a bending at mid-span to about 20 cm. Thereafter, the effort has been decreasing. The complete shearing by delamination of the bonded composite reinforcements (which have thus accompanied the beam to maximum effort of loading), was held to a force of about 59 tonnes, corresponding to a bending to about 27 cm. The complete break in bending in a controlled section (cracking up in the upper table) was obtained for an imposed displacement of more than 40 cm.
Domaines
Sciences de l'ingénieur [physics]
Origine : Fichiers produits par l'(les) auteur(s)