The perceptible vibration of concrete box girders under traffic loads is an important topic in existing bridges, on which vehicle movement often cause vibrations too strong from the viewpoints of travellers. In this paper the results of an extensive program of full-scale ambient vibration tests involving a 380 m concrete box girder bridge, the Cannavino bridge in Italy, are presented. The human safety assessment procedure of the bridge includes ambient vibration testing, identification of modal parameters from ambient vibration data, comparison with a detailed finite element modelling as validation of experimental measurements, comparison of peak accelerations to reference values from technical standards/literature in order to estimate the vibration level, evaluation of safety by the use of histograms. A total of nine modal frequencies are identified for the deck structure within the frequency range of 0-10 Hz. The experimental data clearly indicate the occurrence of many closely spaced modal frequencies. For each direction the results of the ambient vibration survey are compared to modal frequencies computed by a detailed three-dimensional finite element model of the bridge, obtaining a very good match between experimental and theoretical modal parameters. The findings of this first investigation show that a linear finite element model appears to be capable of capturing the dynamic behaviour of concrete box girder bridges with very good accuracy. For each direction, experimental peak accelerations are compared to acceptable human levels available in technical standards/literature. It emerges that traffic loads mainly induce a vertical component of vibration in the bridge's deck, probably due to the structural shape of prestressed concrete girders which are wide but shallow in depth. Finally the elaboration of histograms allows to assess that the bridge is mainly exposed to clearly perceptible vertical vibrations, requiring the adoption of suitable vibration reduction devices. © 2014 Taylor & Francis Group.
Monitoring of traffic induced vibrations on concrete bridges: A case study / Fiore, A.; Marano, G. C.; Monaco, P.. - (2014), pp. 695-702. (Intervento presentato al convegno 7th International Conference on Bridge Maintenance, Safety and Management, IABMAS 2014 tenutosi a Shanghai, China nel July 7-11, 2014).
Monitoring of traffic induced vibrations on concrete bridges: A case study
Fiore, A.;Marano, G. C.
;Monaco, P.
2014-01-01
Abstract
The perceptible vibration of concrete box girders under traffic loads is an important topic in existing bridges, on which vehicle movement often cause vibrations too strong from the viewpoints of travellers. In this paper the results of an extensive program of full-scale ambient vibration tests involving a 380 m concrete box girder bridge, the Cannavino bridge in Italy, are presented. The human safety assessment procedure of the bridge includes ambient vibration testing, identification of modal parameters from ambient vibration data, comparison with a detailed finite element modelling as validation of experimental measurements, comparison of peak accelerations to reference values from technical standards/literature in order to estimate the vibration level, evaluation of safety by the use of histograms. A total of nine modal frequencies are identified for the deck structure within the frequency range of 0-10 Hz. The experimental data clearly indicate the occurrence of many closely spaced modal frequencies. For each direction the results of the ambient vibration survey are compared to modal frequencies computed by a detailed three-dimensional finite element model of the bridge, obtaining a very good match between experimental and theoretical modal parameters. The findings of this first investigation show that a linear finite element model appears to be capable of capturing the dynamic behaviour of concrete box girder bridges with very good accuracy. For each direction, experimental peak accelerations are compared to acceptable human levels available in technical standards/literature. It emerges that traffic loads mainly induce a vertical component of vibration in the bridge's deck, probably due to the structural shape of prestressed concrete girders which are wide but shallow in depth. Finally the elaboration of histograms allows to assess that the bridge is mainly exposed to clearly perceptible vertical vibrations, requiring the adoption of suitable vibration reduction devices. © 2014 Taylor & Francis Group.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
