Cable–deck dynamic interactions at the International Guadiana Bridge: On-site measurements and finite element modelling

Abstract

The International Guadiana Bridge is a cable-stayed bridge crossing the Guadiana River, which marks the southern border between Portugal and Spain. The bridge has a central span of 324 m and a total length of 666 m and was open to traffic in 1991. Despite the globally satisfying behaviour under the common environmental loads, which largely ensures the bridge serviceability, frequent episodes of cable vibration have been observed since completion of the construction. In this paper, the bridge modal properties and dynamic behaviour, identified from repeated campaigns of vibration data acquisitions, are compared with the response of a three-dimensional finite element model, including the description of the cable transversal motion. The model, after minor updating, furnishes a realistic reproduction of the current bridge dynamic behaviour. Then different possible justifications of the local vibrations are evaluated, briefly scanning the known sources of large amplitude cable oscillations both in the linear and the nonlinear field. In particular, the occurrence of different internal resonance conditions is deeply discussed, in order to verify whether the experimental observations could be really justified by a cable-deck dynamic interaction mechanism. Among different possibilities, a beating phenomenon between two resonant modes, amplified by the lower damping and inertial characteristics of the local mode with respect to the global one, is selected as the most critical cable excitation source. Since the cable vibrations are proved to persist for different wind conditions, the heavy traffic load on the bridge deck is investigated as one possible source of the global mode direct excitation. On this respect, the model response to random load and moving forces acting on the bridge deck is numerically evaluated evidencing how some particular features of the real bridge behaviour can be qualitatively reproduced.

Finite Element Analysis of Cable-Stayed Bridges with Appropriate Initial Shapes Under Seismic Excitations Focusing on Deck-Stay Interaction

“…In parallel to the previous work [11,16], the authors of the present paper also studied the deck-stay interaction of cable-stayed bridges based on the analytical and numerical methods as well as the long-term comprehensive full-scale measurements [17]. The measurement data indicated that the deck oscillations of small to moderate amplitudes are coupled with the large-amplitude stay cable vibrations due to the linear coupling between these two components.…”

“…Two types of simplified models: the single cable with moving anchorage [5][6][7] and the cable-supported cantilever beam [3,4,[8][9][10][11], have been presented to theoretically investigate the deck-stay interaction. To extend the results of the simplified models, the OECS and MECS models of full cable-stayed bridges based on the finite element method have been widely used to explore such coupled phenomena of real structures [1,[11][12][13][14][15][16]. By focusing on the analytical and numerical study of the linear coupling, the localization factor was introduced to reveal the frequency veering phenomenon and to evaluate the mode hybridization level of a cable-stayed bridge [11].…”

“…It was suggested that the nonlinear coupling is not consistent with the measurement data. In contrast, the linear coupling is recognized as the critical excitation source of the coupled modes [16].…”

Control of dynamic stability of stays using passive viscous dampers

“…The value r≈1 defines the region where global modes may provide external excitation. Subharmonic (r≈0.5) and superharmonic (r≈2) resonance conditions bound two nonlinear interaction regions, where global modes may provide parametric and angle variation excitation of local modes respectively [8,9]. The excitation from angle variation between cable tension and bridge girder is a phenomenon detailed by Gattulli and Lepidi and Gattulli et al [9,10].…”

Non-linear interactions in the flexible multi-body dynamics of cable-supported bridge cross-sections

“…According to this well-established literature, high-amplitude cable oscillations can be determined by either linear or non-linear excitation mechanisms, generally regulated by commensurable frequencies of global and local modes. Consequently, global-local interactions have been invoked as physical explanation for the frequent reports of unacceptable levels of cable vibration in real long-span bridges [23,24]. From the engineering viewpoint, the matter tends to increase in relevance for the newest structural realizations.…”