• Wind and Structures
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• v.20 no.5
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• pp.643-660
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• 2015

The wind tunnel test of large-scale sectional model and computational fluid dynamics (CFD) are employed for the purpose of studying the aerodynamic appendices and mechanism on suppression for the vortex-induced vibration (VIV). This paper takes the HongKong-Zhuhai-Macao Bridge as an example to conduct the wind tunnel test of large-scale sectional model. The results of wind tunnel test show that it is the crash barrier that induces the vertical VIV. CFD numerical simulation results show that the distance between the curb and crash barrier is not long enough to accelerate the flow velocity between them, resulting in an approximate stagnation region forming behind those two, where the continuous vortex-shedding occurs, giving rise to the vertical VIV in the end. According to the above, 3 types of wind fairing (trapezoidal, airfoil and smaller airfoil) are proposed to accelerate the flow velocity between the crash barrier and curb in order to avoid the continuous vortex-shedding. Both of the CFD numerical simulation and the velocity field measurement show that the flow velocity of all the measuring points in case of the section with airfoil wind fairing, can be increased greatly compared to the results of original section, and the energy is reduced considerably at the natural frequency, indicating that the wind fairing do accelerate the flow velocity behind the crash barrier. Wind tunnel tests in case of the sections with three different countermeasures mentioned above are conducted and the results compared with the original section show that all the three different countermeasures can be used to control VIV to varying degrees.

• Interaction and multiscale mechanics
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• v.3 no.4
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• pp.405-414
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• 2010

The performance of full-scale steel and composite bridge safety barriers under vehicle crash is evaluated by using the nonlinear explicit finite element code LS-DYNA. Two types of vehicles used in this study are passenger car and truck, and the performance criteria considered include structural strength and deformation, occupant protection, and post-crash vehicle behavior. It can be concluded that the composite safety barrier satisfies all performance criteria of vehicle crash. Although the steel safety barrier satisfies the performance criteria of occupant protection and post-crash vehicle behavior, it fails to satisfy the performance criterion of deformation. In all performance evaluations, the composite safety barrier exhibits a superior performance in comparing with the steel safety barrier.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.5
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• pp.627-634
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• 2018

In the study, computational fluid dynamics analysis was performed to estimate wind force coefficients for a box-type concrete girder bridge under the influence of wind. The drag, lift and pitching moment coefficients were obtained for the bridge section without noise barrier and compared with those of the bridge section with noise barriers of various heights. The shear stress transport $k-{\omega}$ turbulence model was employed to estimate the wind force coefficients, and the contribution of the friction drag force to the total drag force was investigated. It was found from the study that the drag force coefficients increased as the height of noise barrier increased when a wind blew horizontally, and that the contribution of the friction drag force was highest for the bridge section without noise barrier. It is concluded that the impact of the height of noise barriers should be considered in the design of bridges, and the friction force played an important role in evaluating wind forces on bridges.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.2
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• pp.49-57
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• 2012

Recently, in field of bridge construction, modular technology has been studied to reduce construction period. However, main stream of the study is limited to the pier, girder and deck of bridge, which are huge or main members. Studies on incidental facilities like concrete barrier is out of sight. Thus, in this study, connection system of concrete barrier was developed to apply to modular bridges and static experiment was performed in order to verify structural capability of proposed system. Variables of experiment are composed of bolt direction such as vertical and horizontal. The experimentation due to the designed variables was conducted by comparison with a standard concrete barrier, which is a traditional barrier. As a result, vertical joint way of the bolt showed nearly identical structural performance and healthy to standard specimen's. it can be applied to modular bridges.

• Wind and Structures
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• v.20 no.2
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• pp.237-247
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• 2015

Wind tunnel experiments are used to investigate the aerodynamic interactions between vehicles and wind barriers on a railway bridge. Wind barriers with four different heights (1.72 m, 2.05 m, 2.5 m and 2.95 m, full-scale) and three different porosities (0%, 30% and 40%) are studied to yield the aerodynamic coefficients of the vehicle and the wind barriers. The effects of the wind barriers on the aerodynamic coefficients of the vehicle are analyzed as well as the effects of the vehicle on the aerodynamic coefficients of the wind barriers. Finally, the relationship between the drag forces on the wind barriers and the aerodynamic coefficients of the vehicle are discussed. The results show that the wind barriers can significantly reduce the drag coefficients of the vehicle, but that porous wind barriers increase the lift forces on the vehicle. The windward vehicle will significantly reduce the drag coefficients of the porous wind barriers, but the windward and leeward vehicle will increase the drag coefficients of the solid wind barrier. The overturning moment coefficient is a linear function of the drag forces on the wind barriers if the full-scale height of the wind barriers $h{\leq}2.5m$ and the overturning moment coefficients $C_O{\geq}0$.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.45-52
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• 1999

In this study, a new bridge rail system is proposed to prevent large vehicles from running off the bridge edge. The crush model has accounted for the effects of both curbs and bridge rails which are simulated by Highway Vehicle Object Simulation Model(HVOSM) and BARRIER VII. Vehicle sizes ranged from minicars weighing 1800kg to large vehicles weighing 14000kg, and impact angles ranged from 15$^{\circ}$ to 25$^{\circ}$.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.490-494
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• 2008

U-Channel Bridge is effective bridge type, because its edge beam performs role of barrier and enables to reduce additional dead loads. Although it is effective to reduce additional dead loads, there is possibility of bridge collapse under impact load due to car crash. Also, edge beam must have ability to induce safe driving and prevent falling accidents. Therefore, it requires behavior analysis and property investigation through the vehicle impact crashing edge beam. This study presents method of structural analysis of U-channel bridge and investigates design specifications for the effect of the edge beam under the vehicle impact. Also, it carries out stability investigation of behavior of edge beam and slab, based on Korean Highway Bridge Design Specifications and AASHTO LRFD Bridge Design Specification.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.4
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• pp.11-18
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• 2011

In this study, the performance of a steel-FRP composite bridge safety barrier was evaluated through vehicle crash simulation. Surface veil, DB and Roving fibers were used for FRP. The MAT58 material model provided by LS-DYNA software was used to model FRP material. Spot weld option was used for modeling contact between steel and FRP beam. The structural strength performance, the passenger protection performance, and the vehicle behavior after crash were evaluated corresponding to the vehicle crash manual. As the result, A steel-FRP composite safety barrier was satisfied with the required performance.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.4 s.74
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• pp.325-335
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• 2006

In this paper, flexural test, girder-connection test and barrier-connection test for the pultruded composite bridge deck of hollow section, were carried out and its structural characteristics were evaluated. In the flexural test specimen, deflection was measured at center of the span and strains were measured at various locations to see the structural behavior up to the failure. In addition, finite element analysis was performed for the flexural test specimen and the results were compared with experiments, and load carrying capacity was evaluated. Also, field load test was conducted for the demonstration plate girder bridge and other field applications were described.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.333-336
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• 2008

U-Channel Bridge is effective bridge type, because its edge beam performs role of barrier and enables to reduce additional dead loads. Nevertheless, there is possibility of bridge collapse under impact load due to car crash. Also, edge beam must have ability to induce safe driving and prevent falling accidents. Therefore, this study carries out analysis of behavior of edge beam and slab and evaluation of structural stability under impact loads, based on Korean Highway Bridge Design Specifications and AASHTO LRFD Bridge Design Specification. According to analysis result, the maximum stress of edge beam and slab satisfies specification of allowable stress.