Third Bosporus Bridge Aerodynamics: Sectional and Full-Aeroelastic Model Testing

Zasso, Alberto; Belloli, Marco; Argentini, Tommaso; Flamand, Olivier; Knapp, Gunnar; Grillaud, Gérard; Klein, J-F; Virlogeux, Michel; Ville, Vincent De

doi:10.1007/978-3-319-19785-2_11

Cited by 3 publications

(2 citation statements)

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“…Comparative studies of the performance of the approaches have been presented by Scanlan et al (1997) and Wardlaw (1980). Section models are the most widely used (Diana et al, 2013;Ge and Xiang, 2008;Zasso et al, 2014) because the tests can be performed in reasonably sized wind tunnels and because it is possible to perform the tests at a larger scale (Matsuda et al, 2001;West and Apelt, 1982;Zasso et al, 2014). However, taut strip and full bridge models are commonly used to evaluate the overall performance of new bridge concepts, stretching the present state of the art, because it is possible to include several vibration modes in the modeling.…”

Section: Introductionmentioning

confidence: 99%

An enhanced forced vibration rig for wind tunnel testing of bridge deck section models in arbitrary motion

Siedziako

Øiseth

Rönnquist

2017

Journal of Wind Engineering and Industrial Aerodynamics

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This paper presents a new experimental setup for the aerodynamic section model testing of bridge decks. The rig is designed to move a section model in arbitrary motion in a wind tunnel to imitate the motions of such scaled real bridge motion, step motion or random motion histories to be close to white noise. The proposed setup enables the forces acting on the section model to be measured directly while considering motions that resemble actual bridge motion and still fully utilizing the benefits of the forced vibration testing technique. The excellent performance of the system and testing procedure is proved by performing state-of-the-art forced vibration tests to extract 18 flutter derivatives of the Hardanger Bridge cross-section. The new experimental setup is further used to simulate a three-degree-of-freedom dynamic system driven by white noise to investigate whether the estimates of the aerodynamic derivatives are sensitive to the motion considered. The experimental results demonstrate that the estimates of the aerodynamic derivatives are not sensitive to the motion considered; these results indicate that the principle of superposition is fully applicable for the cross section as long as the motions are within the range considered.

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Section: Introductionmentioning

confidence: 99%

An enhanced forced vibration rig for wind tunnel testing of bridge deck section models in arbitrary motion

Siedziako

Øiseth

Rönnquist

2017

Journal of Wind Engineering and Industrial Aerodynamics

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“…Wind tunnel tests are therefore commonly carried out in the design process. Currently, sectional model tests, where only a part of the bridge deck is considered, are the most commonly used [1][2][3]. Compared to other available testing techniques, sectional models are low cost, easy to build and are suitable for relatively small wind tunnels.…”

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confidence: 99%

Identification of Aerodynamic Properties of Bridge Decks in Arbitrary Motion

Siedziako

Øiseth

Rønnquist

2016

Special Topics in Structural Dynamics, Volume 6

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Flutter, buffeting response and vortex shedding are crucial factors when designing long-span bridges. An analysis of these phenomena requires experimental data, which can be provided by wind tunnel tests. The forced vibration method is chosen in this study because it is considered to be more reliable and better suited to provide data at high velocities, large amplitudes and more intense turbulence. The models currently used to describe self-excited forces in bridge engineering are linear. However, it is a well-known fact that the principle of superposition does not hold in fluid dynamics. Several case studies have shown that it is a fair approximation when predicting wind-induced dynamic response of bridges if the response is dominated by one vibration mode in each direction. Yet, it is uncertain how well the current models will be able to predict the self-excited forces for a more complicated motion. Currently developing experimental setup will enable the performance of forced vibration tests by applying an arbitrary motion. This paper focuses on extending three identification methods developed for single harmonic motion such that they can be applied in more complex motion patterns. Numerical simulations of forced vibration tests were performed to test the performance of those extended methods. Keywords Forced vibration test • Arbitrary motion • Aerodynamics • Bridges • System identification IntroductionThe aerodynamic properties of the bridge deck play an important role in long span bridge design. Wind tunnel tests are therefore commonly carried out in the design process. Currently, sectional model tests, where only a part of the bridge deck is considered, are the most commonly used [1][2][3]. Compared to other available testing techniques, sectional models are low cost, easy to build and are suitable for relatively small wind tunnels. Moreover, details of the bridge deck known to have significant impact on aerodynamic performance, such as handrails, can be easily reproduced. The main outputs from the tests are static force coefficients and aerodynamic derivatives, which define the self-excited and static wind forces and characterize the overall aerodynamic behavior of the bridge deck.There exist two main types of sectional model tests. Either the bridge deck is suspended in springs in a free vibration test or it is forced in an oscillatory motion in a forced vibration test. The free vibration method has been the most common method in the past. However, in recent years this trend seems to be changing. Data from forced vibration test are by some researchers considered to be much more reliable and repeatable, [4]. In particular, the forced vibration test outperforms the free vibration test when considering large reduced velocities, large motion amplitudes, high turbulence intensities and cross sections sensitive to vortex shedding [5,6].The load models most commonly used in bridge aerodynamics are linear engineering approximations. It has been shown in several case studies that the models are working wel...

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Static and Seismic Characteristics of Cable-Stayed Bridges with New Stay Systems

Samim

Nakamura

2015

IABSE Reports

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<p>This paper presents static and seismic structural behaviours of cable-stayed bridges with two new cable systems: the overlapping stay system and the hybrid cable system. First, static analysis is carried out for four cable-stayed bridge models with three different patterns of live load consisting</p><p>/of the train and vehicle loads. The live load distributed in the mid-span gives larger deflection for all four models. The overlapping stay system and the hybrid cable system can significantly reduce the displacements of the girder and bending moment of the towers due to live loads. The deflection of the girder with the overlapping stay system due to the train loads decreases by 9.5% and the hybrid cable system decreases by 10% in comparison with the conventional cable system. The deflection of the new cable systems are within the allowable value specified for the Japanese bullet train, confirming that serviceability limit is satisfied. Second, seismic response of the four cable-stayed bridge models was investigated for the ultra-large seismic waves. The longitudinal displacement of the girder and the tower top and bending moment at the tower base was smallest for the overlapping stay system among the four bridge models, showing better seismic performance than the conventional cable-stayed bridge. In conclusion, the cable-stayed bridges with the overlapping stay system and that with the hybrid cable system provide better serviceability and better seismic performance as well, which validates the superiority of these structures.</p>

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Third Bosporus Bridge Aerodynamics: Sectional and Full-Aeroelastic Model Testing

Cited by 3 publications

References 12 publications

An enhanced forced vibration rig for wind tunnel testing of bridge deck section models in arbitrary motion

An enhanced forced vibration rig for wind tunnel testing of bridge deck section models in arbitrary motion

Identification of Aerodynamic Properties of Bridge Decks in Arbitrary Motion

Static and Seismic Characteristics of Cable-Stayed Bridges with New Stay Systems

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