Dissipative properties of a structural system are difficult to be characterized in real structure. Nevertheless, damping features may be dominant in several operating conditions of railway bridges influencing fatigue life or passenger comfort during train passage. Observations treating real data acquired in operational condition on steel and concrete railway bridges belonging to the Italian network permits to highlight dissipative sources and features. Consequently, linearized modal damping ratios are evaluated through a recursive process on the acceleration signals acquired before, during and after train passages and/or in environmental conditions. Stochastic Subspace Identification has been used to identify state-space dynamical models able to reproduce the vibrations. Through these models, characterized by an increasing number of state-space variables, it is possible to extract modal damping ratios. A mechanical interpretation of damping characteristics is pursued through the evaluation of the differences with respect to a classical Rayleigh proportional damping matrix of the viscous matrix belonging to the identified state-space models determined through the system spectral features. A non-proportional damping index is presented as a basis to determine the influence of different sources of non-proportionality in the damping matrix (as the ballast layer under the track) and to justify the high value of damping observed in specific experimental campaigns.

Measured properties of structural damping in railway bridges / Gattulli, V.; Lofrano, E.; Paolone, A.; Potenza, F.. - In: JOURNAL OF CIVIL STRUCTURAL HEALTH MONITORING. - ISSN 2190-5452. - 9:5(2019), pp. 639-653. [10.1007/s13349-019-00358-3]

Measured properties of structural damping in railway bridges

Gattulli V.;Lofrano E.;Paolone A.;
2019

Abstract

Dissipative properties of a structural system are difficult to be characterized in real structure. Nevertheless, damping features may be dominant in several operating conditions of railway bridges influencing fatigue life or passenger comfort during train passage. Observations treating real data acquired in operational condition on steel and concrete railway bridges belonging to the Italian network permits to highlight dissipative sources and features. Consequently, linearized modal damping ratios are evaluated through a recursive process on the acceleration signals acquired before, during and after train passages and/or in environmental conditions. Stochastic Subspace Identification has been used to identify state-space dynamical models able to reproduce the vibrations. Through these models, characterized by an increasing number of state-space variables, it is possible to extract modal damping ratios. A mechanical interpretation of damping characteristics is pursued through the evaluation of the differences with respect to a classical Rayleigh proportional damping matrix of the viscous matrix belonging to the identified state-space models determined through the system spectral features. A non-proportional damping index is presented as a basis to determine the influence of different sources of non-proportionality in the damping matrix (as the ballast layer under the track) and to justify the high value of damping observed in specific experimental campaigns.
2019
Beam bridges; Dynamic identification; Experimental results; Non-proportional damping; Railway bridges; Structural damping
01 Pubblicazione su rivista::01a Articolo in rivista
Measured properties of structural damping in railway bridges / Gattulli, V.; Lofrano, E.; Paolone, A.; Potenza, F.. - In: JOURNAL OF CIVIL STRUCTURAL HEALTH MONITORING. - ISSN 2190-5452. - 9:5(2019), pp. 639-653. [10.1007/s13349-019-00358-3]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1337320
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