Internal Parametric Resonance and Aeroelastic Effects for Long-Span Suspension Bridges

Abstract

The potential occurrence of internal parametric resonance phenomena has been recently indicated as a possible cause of failure for long-span suspension bridges. At the same time, suspension bridges, in view of their flexibility, are prone to aeroelasticity driven response, such as vortex shedding, torsional divergence and flutter. In this paper, a nonlinear dynamic model of a suspension bridge is devised, with the purpose of providing a unified framework for the study of aeroelastic and internal resonance instabilities. Inspired by the pioneering work of Herrmann and Hauger, the analyses have been based on a linearized formulation that is able to represent the main structural non-linear effects and the coupling given by aerodynamic forces. The results confirm that the interaction between aeroelastic effects and non-linear internal resonance leads to unstable phenomena for wind speeds which are by far lower than the critical threshold for standard aeroelasticity.

Stability of dynamic response of suspension bridges

“…Recently, Arioli and Gazzola [24], trying to explain why torsional oscillations suddenly appeared before the Tacoma Narrows collapse, found out that, also in isolated systems, vertical oscillations may switch to torsional ones, as long as they become large enough. The problem was already tackled by other authors [25][26][27][28][29] but it seems that there is still an open issue regarding the complete explanation of the sudden appearance of large oscillations which led to collapse. Hence, they paved the way for future works concerning the interaction between internal resonance and aeroelastic phenomena, as the present paper wants to do.…”

“…Hence, they paved the way for future works concerning the interaction between internal resonance and aeroelastic phenomena, as the present paper wants to do. Indeed, the present article intends to study the stability of a suspension bridge model, following the preliminary attempt described in [27]. The analysis will exploit the continuum formulation of Abdel-Ghaffar [11], enriched by the aeroelastic actions coming from Theodorsen [16] indicial formulation for the wind-structure interaction.…”