A numerical investigation into the aerodynamic characteristics and aeroelastic stability of a footbridge

Taylor, Ian; Vezza, M.

doi:10.1016/j.jfluidstructs.2008.05.001

Cited by 26 publications

(9 citation statements)

References 19 publications

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“…The 2D vortex particle method has been extensively applied to bluffbody aerodynamics problems, specifically in bridge aerodynamics. Its success, besides a very low computational cost even for complex geometries, is due to generally good agreement with wind tunnel test results (Abbas et al, 2017;Farsani et al, 2014;Ge and Xiang, 2008;Larsen and Walther, 1997;Morgenthal and McRobie, 2002;Taylor and Vezza, 2009), which is mainly attributed to the conservation of the angular impulse and energy and insignificant numerical dissipation. The method is based on a discretization of the Navier-Stokes equations by vorticity-carrying particles and when the particle spacing reaches the Kolmogorov dissipation length it becomes a Direct Numerical Simulation (Fukuda and Kamemoto, 2004).…”

Section: Introductionmentioning

confidence: 85%

A synergistic study of a CFD and semi-analytical models for aeroelastic analysis of bridges in turbulent wind conditions

Kavrakov

Morgenthal

2018

Journal of Fluids and Structures

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Long-span bridges are prone to wind-induced vibrations. Therefore, a reliable representation of the aerodynamic forces acting on a bridge deck is of a major significance for the design of such structures. This paper presents a systematic study of the two-dimensional (2D) fluid-structure interaction of a bridge deck under smooth and turbulent wind conditions. Aerodynamic forces are modeled by two approaches: a computational fluid dynamics (CFD) model and six semianalytical models. The vortex particle method is utilized for the CFD model and the free-stream turbulence is introduced by seeding vortex particles upstream of the deck with prescribed spectral characteristics. The employed semi-analytical models are based on the quasi-steady and linear unsteady assumptions and aerodynamic coefficients obtained from CFD analyses. The underlying assumptions of the semi-analytical aerodynamic models are used to interpret the results of buffeting forces and aeroelastic response due to a free-stream turbulence in comparison with the CFD model. Extensive discussions are provided to analyze the effect of linear fluid memory and quasi-steady nonlinearity from a CFD perspective. The outcome of the analyses indicates that the fluid memory is a governing effect in the buffeting forces and aeroelastic response, while the effect of the nonlinearity is overestimated by the quasi-steady models. Finally, flutter analyses are performed and the obtained critical velocities are further compared with wind tunnel results, followed by a brief examination of the post-flutter behavior. The results of this study provide a deeper understanding of the extent of which the applied models are able to replicate the physical processes for fluid-structure interaction phenomena in bridge aerodynamics and aeroelasticity.

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Section: Introductionmentioning

confidence: 85%

A synergistic study of a CFD and semi-analytical models for aeroelastic analysis of bridges in turbulent wind conditions

Kavrakov

Morgenthal

2018

Journal of Fluids and Structures

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“…However, other dynamic influences were also discussed. In the work presented in [25], the authors delivered the results of the aerodynamic response of the footbridge. A seismic assessment of the cable-stayed footbridge was presented in [30].…”

Section: Related Workmentioning

confidence: 99%

“…Taking into consideration the primary function of the pedestrian bridges, the risk of the resonance phenomenon occurring has to be discussed for this type of structure [11][12][13][14][15][16][17][18][19][20][21][22][23][24]. In general, the estimation of the modal properties of footbridges is the main component of the general dynamic evaluation of these structures [25][26][27][28]. It must be pointed out that this part of the dynamic investigation has significant value for the design stage of construction as well as being required prior to approval of the structure for public usage, i.e., proof load testing (conduct in order to validate that a structure can carry the design loads) and acceptance tests (conducted before a bridge structure is accepted for exploitation).…”

Section: Introductionmentioning

confidence: 99%

Full-Scale Experimental and Numerical Investigations on the Modal Parameters of a Single-Span Steel-Frame Footbridge

Drygala

Dulińska

2019

Symmetry

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In this work, an examination on the modal properties of a single-span steel-frame footbridge is presented. The footbridge is situated in Jawornik (Lesser Poland). The footbridge is symmetrical since its main structure consists of two steel frames of the same shape. The boundary conditions for both frames are the same as well. The study was completed on the basis of numerical as well as experimental investigations. For finite element (FE) analysis, a 3-D model of the single-span steel-frame footbridge was created. For the experimental study, a research scheme for in situ tests was developed. Three kinds of excitation techniques were used during the in situ tests: shock excitation, operational vibration, and slow sine sweep testing. Different functions that estimate natural frequencies, i.e., the power spectral density function (PSD) and the frequency response function (FRF), were applied. The modal assurance criterion (MAC) was used as a mathematical tool for the verification of the mode shapes of natural vibrations obtained in experimental and numerical ways. Good compatibility was recognized between the results obtained for experimental and numerical procedures in terms of both the natural frequency and the mode of vibration. The identified and verified values of the five consecutive natural frequencies of the footbridge were smaller than 5 Hz, but they were recognized as being located outside the frequency range defined as having “maximum risk of resonance". The numerical and experimental modal analysis revealed that all modes corresponding to the natural frequencies from the 0–5 Hz range have both a symmetrical and an anti-symmetrical nature. In particular, the first vertical mode, which can play a central role from the serviceability of the footbridge point of view has a symmetrical shape. The results of the research might be applicable to the dynamic study of the structure type considered in the analysis, i.e., for the dynamic assessment of a single-span steel-frame footbridge with a relatively large mass as well as stiffness. The investigation proved that ambient vibration modal experiments are enough for the experimental investigation of the modal properties of the structure.

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“…e.g. [9,18,50]). Therefore, the application of the presented method could be directly extended to bridge decks including traffic barriers and other devices without any further modification.…”

Section: Reference Objectmentioning

confidence: 99%

“…In the VPM, the vorticity field is discretized by particles, carrying concentrated circulation. The VPM has been extensively utilized in bridge aerodynamics for the computation of the static wind coefficients and flutter derivatives [7][8][9], motion-induced indicial functions [10] and 2D vortex-induced vibrations [11].…”

Section: Introductionmentioning

confidence: 99%

Aeroelastic analyses of bridges using a Pseudo-3D vortex method and velocity-based synthetic turbulence generation

Kavrakov

Morgenthal

2018

Engineering Structures

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The accurate representation of aerodynamic forces is essential for a safe, yet reasonable design of long-span bridges subjected to wind effects. In this paper, a novel extension of the Pseudo-three-dimensional Vortex Particle Method (Pseudo-3D VPM) is presented for Computational Fluid Dynamics (CFD) buffeting analysis of line-like structures. This extension entails an introduction of free-stream turbulent fluctuations, based on the velocity-based turbulence generation. The aerodynamic response of a longspan bridge is obtained by subjecting the 3D dynamic representation of the structure to correlated free-stream turbulence in twodimensional (2D) fluid planes, which are positioned along the bridge deck. The span-wise correlation of the free-stream turbulence between the 2D fluid planes is established based on Taylor's hypothesis of frozen turbulence. Moreover, the application of the laminar Pseudo-3D VPM is extended to a multimode flutter analysis. Finally, the structural response from the Pseudo-3D flutter and buffeting analyses is verified with the response, computed using the semi-analytical linear unsteady model in the time-domain. Meaningful merits of the turbulent Pseudo-3D VPM with respect to the linear unsteady model are the consideration of the 2D aerodynamic nonlinearity, nonlinear fluid memory, vortex shedding and local non-stationary turbulence effects in the aerodynamic forces. The good agreement of the responses for the two models in the 3D analyses demonstrates the applicability of the Pseudo-3D VPM for aeroelastic analyses of line-like structures under turbulent and laminar free-stream conditions.

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A numerical investigation into the aerodynamic characteristics and aeroelastic stability of a footbridge

Cited by 26 publications

References 19 publications

A synergistic study of a CFD and semi-analytical models for aeroelastic analysis of bridges in turbulent wind conditions

A synergistic study of a CFD and semi-analytical models for aeroelastic analysis of bridges in turbulent wind conditions

Full-Scale Experimental and Numerical Investigations on the Modal Parameters of a Single-Span Steel-Frame Footbridge

Aeroelastic analyses of bridges using a Pseudo-3D vortex method and velocity-based synthetic turbulence generation

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