• Wind and Structures
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• v.20 no.2
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• pp.213-236
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• 2015

For high-speed railways (HSR) in wind prone regions, wind barriers are often installed on bridges to ensure the running safety of trains. This paper analyzes the effect of wind barriers on the running safety of a high-speed train to cross winds when it passes on a bridge. Two simply-supported (S-S) PC bridges in China, one with 32 m box beams and the other with 16 m trough beams, are selected to perform the dynamic analyses. The bridges are modeled by 3-D finite elements and each vehicle in a train by a multi-rigid-body system connected with suspension springs and dashpots. The wind excitations on the train vehicles and the bridges are numerically simulated, using the static tri-component coefficients obtained from a wind tunnel test, taking into account the effects of wind barriers, train speed and the spatial correlation with wind forces on the deck. The whole histories of a train passing over the two bridges under strong cross winds are simulated and compared, considering variations of wind velocities, train speeds and without or with wind barriers. The threshold curves of wind velocity for train running safety on the two bridges are compared, from which the windbreak effect of the wind barrier are evaluated, based on which a beam structure with better performance is recommended.

• Journal of Korean Society of Steel Construction
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• v.21 no.6
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• pp.553-561
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• 2009

Risk analysis of highway sign supporting structures and sound barriers was done. Stochastic wind load was modeled by using extreme value distribution from site measurement and the variability of structural parameters was considered. Limit state functions were defined to assess structural stability by wind and risk of highway facilities was analyzed by combining wind hazard. According to the numerical analysis results, sound barrier post shows significantly higher risk than highway sign supporting structures. This is caused by the fact that the design codes of the structures are different. To distribute wind induced risk in highway structures, unification and improvement of design codes are required based on risk assessment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.30-41
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• 2017

Types of noise barrier installed for noise attenuation are largely divided into noise-absorbing format and noise-proofing format. In these days, installation of transparent noise barrier is general trend to solve problems that hinder sunshine and landscape. Some kinds of transparent boards are used to one of components in noise barriers, but in some cases, less transparency and worse pollution due to yellowing phenomena, and severe material deformation are to harm the urban aesthetics Therefore laminated-tempered glass board in that yellowing phenomena does not occur can be replaced as a transparent one to secure those shortcomings. In this paper, the structural safety against train induced vibration and the resistibility to wind load are analyzed for laminated-tempered glass system as a component of noise barrier installed on Metro railway elevated bridges. Also the appropriateness is evaluated through flexural bending performance test, compressive strength test, modulus of elasticity tests, and impact test for the system or the glass material itself. All of these processes are intended to present the deployment of logic to evaluate the adequacy for the system.

• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.263-270
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• 2005

This paper presents a program for protecting vehicles against side winds on highways. The present study consists of three processes. The first one involves giving a guideline for evaluating driving safety in high winds. The second one involves making a guideline for determining the necessity of wind protection system for a certain road area. A reasonable procedure is suggested based on the probability model of wind data on weather stations and the correction of local topographical conditions. The third one involves design of wind barriers. Both CFD analyses and wind tunnel tests were performed to find the proper type of wind barrier considering vehicle controllability, structural safety, economical efficiency as well as driver's visibility. Performance of the designed wind fences was verified from field tests. The performance of the four different types of wind barrier installed at the elevated bridge were tested and some of the results were provided.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.115-119
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• 2011

Instead of very expensive sound record and professional measurement microphones the low cost Surface Mounted Device (SMD) microphones are proposed for practical barrier ANC system. FRF of the microphones and theirs sensitivity to the wind interferences are evaluated in semi anechoic chamber. The improvement of feedforward algorithm noise reduction index was evaluated based on measured coherence function between tested SMD and reference microphone. Test was performed at various wind speed from 1 m/s to 5 m/s.

• Journal of Environmental Science International
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• v.22 no.6
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• pp.717-721
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• 2013

In order to analyze the effect of environmental protection on wind energy dissemination quantitatively, the onshore wind resource potential is estimated using Environmental Conservation Value Assessment Map and Korea Wind Resource Map. The onshore wind resource potential of 11 GW is calculated if wind farm development is prohibited within Class 1 area of Environmental Conservation Value Assessment plus 500 m buffer area. Therefore it is worried that environmental protection would be a practical barrier of accomplishing 4,155 thousand TOE target of wind energy dissemination until 2030.

• Wind and Structures
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• v.31 no.1
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• pp.43-57
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• 2020

Considering the wind barriers induced aerodynamic characteristic variations of both bridge deck and trains, this paper studies the effects of wind barriers on the safety and stability of trains as they run through an urban rail transit cable-stayed bridge which tends to be more vulnerable to wind due to its relatively low stiffness and lightweight. For the bridge equipped with wind barriers of different characteristics, the aerodynamic coefficients of trains and bridge decks are obtained from wind tunnel test firstly. And then, the space vibration equations of the wind-train-bridge system are established using the experimentally obtained aerodynamic coefficients. Through solving the dynamic equations, one can calculate the dynamic responses both the trains and bridge. The results indicate that setting wind barriers can effectively reduce the dynamic responses of both the trains and bridge, even though more wind forces acting on the bridge are caused by wind barriers. In addition, for urban rail transit cable-stayed bridges located in strong wind environment, the wind barriers are recommended to be set with 20% porosity and 2.5 m height according to the calculation results of cases with wind barriers porosity and height varying in two wide ranges, i.e., 10% - 40% and 2.0 m to 4.0 m, respectively.

• Wind and Structures
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• v.17 no.2
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• pp.203-225
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• 2013

An analysis framework for vehicle-bridge dynamic interaction system under turbulent wind is proposed based on the relevant theory of wind engineering and dynamics. Considering the fluctuating properties of wind field, the stochastic wind velocity time history is simulated by the Auto-Regressive method in terms of power spectral density function of wind field. The bridge is represented by three-dimensional finite element model and the vehicle by a multi-rigid-body system connected by springs and dashpots. The detailed calculation formulas of unsteady aerodynamic forces on bridge and vehicle are derived. In addition, the form selection of wind barriers, which are applied as the windbreak measures of newly-built railways in northwest China, is studied based on the suggested evaluation index, and the suitable values about height and porosity rate of wind barriers are studied. By taking a multi-span simply-supported box-girder bridge as a case study, the dynamic response of the bridge and the running safety indices of the train traveling on the bridge with and without wind barriers are calculated. The limit values of train speed with respect to different wind velocities are proposed according to the allowance values in the design code.

• International Journal of Railway
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• v.5 no.2
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• pp.55-64
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• 2012

Subject of the paper is a particular configuration of overhead line, in which noise barrier structure is used as supports of the catenary instead of standard poles. This configuration is foreseen in case the noise barrier position is in conflict with the poles location. If the catenary is supported by the noise barrier, the motion that the latter undergo due to wave pressure associated to train transit is transmitted to the overhead line, so that potentially it influences the interaction between the catenary itself and the pantograph of the passing train. The paper focuses on the influence of such peculiar configuration on the quality of the current collection of high speed pantograph, for single and double current collection. The study has been carried out first with an experimental investigation on the pressure distribution on noise barrier, both in wind tunnel and with in-field tests. Subsequently a numerical analysis of the dynamics of the barrier subjected to the wave pressure due to train transit has been carried out, and the output of such analysis has been used as input data for the simulation of the pantograph-dynamic interaction at different speeds and with front or rear pantograph in operation. Consideration of structural modifications was then highlighted, in order to reduce the influence on the contact loss percentage.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.150-154
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• 2001

도로 및 철도에서 발생하는 소음을 저감시키기 위해 설치되는 방음벽은 흡음률, 투과손실 등과 같은 음향성능 외에도 태풍과 같은 강풍에 견딜 수 잇는 구조성능이 확보되어야 한다. 따라서, 본 논문에서는 지역별 특성 및 풍속을 고려한 풍압을 산정하는 방법을 소개하고, 풍압에 의한 방음판의 구조해석을 수행하였다. 또한, EN 1794-1의 규정에서 정하는 시험방법에 따른 방음판의 하중변형량 시험을 통하여 방음판의 구조성능을 평가하였다.