Downslope Gusty Wind Loading of Vehicles on Bridges

Kozmar, Hrvoje; Butler, Kyle; Kareem, Ahsan

doi:10.1061/(asce)be.1943-5592.0000748

Cited by 16 publications

(8 citation statements)

References 34 publications

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“…Generally, Bora is a very strong, commonly dry and always gusty wind, which significantly influences optimal functioning of transportation networks, the agriculture, local wind energy yield as well as the fatigue of energy structures (e.g. Kozmar et al 2012aKozmar et al , 2012bKozmar et al , 2014Kozmar et al , 2015. While previous geophysical and meteorological studies laid ground on the macro-and meso-scale features of the Bora, (Jurčec 1981, Smith 1987, Grubišić 2004, Grisogono and Belušić 2009, further work is necessary to fully elucidate Bora turbulence in a form usable for wind engineers.…”

Section: Introductionmentioning

confidence: 99%

Near-ground turbulence of the Bora wind in summertime

Lepri

Večenaj

Kozmar

et al. 2015

Journal of Wind Engineering and Industrial Aerodynamics

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Bora is a strong, temporally and spatially variable downslope wind that blows along the Eastern Adriatic Coast and many other dynamically similar places around the world. Bora mean velocity rarely exceeds 20 m/s, while its strong gusts create significant problems for engineering structures, traffic and agriculture. Previous meteorological and geophysical studies laid foundations on Bora large-and mesoscale motions, but further research is necessary to fully understand and resolve Bora turbulence in a form usable for engineers. In this study, unique high-frequency measurements, carried out simultaneously in three heights on a meteorological tower in the hinterland of the city of Split, Croatia, are analyzed for a single summertime Bora episode. Time histories and vertical profiles are studied for turbulence intensity, Reynolds shear stress and turbulence length scales in comparison with values recommended in major international wind engineering standards. Turbulence intensity and Reynolds shear stress proved to be not that sensitive to meandering of the mean wind velocity, as the observed values remain within the same range during the time record. This trend applies on mean wind velocities larger than 5 m/s, as for smaller velocities the spread of values increases considerably. Turbulence length scales are observed to increase with increasing mean wind velocity and vice versa. With increasing height from the ground, turbulence intensity and absolute Reynolds shear stress decrease, turbulence length scales increase, all in agreement with the atmospheric physics. However, while turbulence intensity, Reynolds shear stress and longitudinal turbulence length scales generally agree well with the values recommended in international standards for the respective terrain type,

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Section: Introductionmentioning

confidence: 99%

Near-ground turbulence of the Bora wind in summertime

Lepri

Večenaj

Kozmar

et al. 2015

Journal of Wind Engineering and Industrial Aerodynamics

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“…Based on previous studies, effects of excitation are researched, including seismic excitation, wind excitation, rain excitation, roughness excitation, and traffic flow excitation. e wind excitation is most widely concerned [24][25][26][27][28][29][30][31][32][33]. Dynamic analysis of the vehicle-bridge system is maturing, with a wealth of well-understood methods and algorithms, particularly in the wind-vehicle-bridge system.…”

Section: Introductionmentioning

confidence: 99%

Safety Prediction Using Vehicle Safety Evaluation Model Passing on Long‐Span Bridge with Fully Connected Neural Network

Yang

et al. 2019

Advances in Civil Engineering

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The safety condition of vehicles passing on long-span bridges has attracted more and more attention in recent years. Many research studies have been done to find convenience and efficiency measures. A vehicle safety evaluation model passing on a long-span bridge is presented in this paper based on fully connected neural network (FCN). The first step is to investigate the long-span bridge responses with wind excitation by using the wind tunnel test and finite element model. Subsequently, typical vehicle models are given and a vehicle-bridge system is established by considering weather conditions. Accident types of vehicles with severe weather are estimated. In particular, the input and output variables of the vehicle safety evaluation model are determined, and simultaneously training, validation, and testing data are achieved. Twenty-nine models have been compared and analyzed by using hidden layer, initial learning rate, batch size, activation function, and optimization method. It is found that the 4-15-15-4 model occupies a preferable prediction performance, and it can provide a kind of utility for traffic control and reduce the probability of vehicle accidents on the bridge.

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“…In the past, vehicle aerodynamics has been commonly studied for quasi-steady flow conditions. However, in case of transient flow conditions the vehicle aerodynamics can change dramatically, which is particularly exhibited when vehicles are passing viaduct and bridges (Kozmar et al, 2012(Kozmar et al, , 2015. The quasi-steady approach proved not to be completely adequate during an overtaking maneuver (Corin et al, 2008), as in this case the aerodynamic forces can be 400 % larger than calculated using the quasi-steady analysis, which can have significant effect on vehicle stability.…”

Section: Introductionmentioning

confidence: 98%

Automobile aerodynamics influenced by airfoil-shaped rear wing

Buljac

Džijan

Korade

et al. 2016

Int.J Automot. Technol.

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Computational model is developed to analyze aerodynamic loads and flow characteristics for an automobile, when the rear wing is placed above the trunk of the vehicle. The focus is on effects of the rear wing height that is investigated in four different positions. The relative wind incidence angle of the rear wing is equal in all configurations. Hence, the discrepancies in the results are only due to an influence of the rear wing position. Computations are performed by using the Reynolds-averaged Navier-Stokes equations along with the standard k-ε turbulence model and standard wall functions assuming the steady viscous fluid flow. While the lift force is positive (upforce) for the automobile without the rear wing, negative lift force (downforce) is obtained for all configurations with the rear wing in place. At the same time, the rear wing increases the automobile drag that is not favorable with respect to the automobile fuel consumption. However, this drawback is not that significant, as the rear wing considerably benefits the automobile traction and stability. An optimal automobile downforce-to-drag ratio is obtained for the rear wing placed at 39 % of the height between the upper surface of the automobile trunk and the automobile roof. Two characteristic large vortices develop in the automobile wake in configuration without the rear wing. They vanish with the rear wing placed close to the trunk, while they gradually restore with an increase in the wing mounting height.

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Downslope Gusty Wind Loading of Vehicles on Bridges

Cited by 16 publications

References 34 publications

Near-ground turbulence of the Bora wind in summertime

Near-ground turbulence of the Bora wind in summertime

Safety Prediction Using Vehicle Safety Evaluation Model Passing on Long‐Span Bridge with Fully Connected Neural Network

Automobile aerodynamics influenced by airfoil-shaped rear wing

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