• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.374.2-374
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• 2002

This paper investigates the insertion loss of nosie barrier with a intereference device. The efficiency of the conventional intereference-type noise barrier depends on specific frequency. Thus this study is performed to improve the efficiency of the rosie barrier in the range of broadband frequency, by changing the shape of intereference device and adding the channel with various depths. The boundary element method (BEM) is used to predict the insertion loss of noise barrier. (omitted)

• Environmental Engineering Research
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• v.20 no.4
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• pp.383-391
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• 2015

Transparent type noise barrier is a desirable facility since it provides a secure view to drivers and passengers. However, reflection from this type of barrier could annoy dwellers on the sides of the road. To reduce reflection noise by transparent type barrier, modification can be made to the shapes on the front side and hence get effects by distortion of sound transmission. To achieve this, we have conducted simulation by which the effects of patterned screens of noise barrier on high-ways were investigated. The reduction effects of reflected sounds were evaluated for swelling, swelling with curved, rectangular and V-shaped screen type barriers, compared to the planar panel. The emitting noise was generated by 6-lane road and the patterned noise barriers had shown the reduction effects, especially in swelling and swelling with curved type for middle height dwellers, and the V-shaped screen type for higher elevation dweller. The swelling-type showed a decrease of 0.7~1.2 dB, performing the best diminution effect among the tested noise barriers.

• Journal of KSNVE
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• v.10 no.3
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• pp.517-522
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• 2000

This study is concerned with the acoustic characteristics for recently developed interference-type noise barrier (T-shaped). To modify the previous shape more conveniently the T-shaped noise barrier with tuning partitions was examined in detail by varying the number and the hight of tuning partitions. The 2-D boundary element method(BEM) analysis were compared with the experimental results of 1/10 reduced scale model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.388-391
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• 2006

The use of noise barrier is being increased to reduce the environmental noise in these days. Also, many noise reducers installed at the top of noise barrier are developed for improving the performance of noise reduction. So we evaluate the performance of the noise reducers and compare the results. Results of the field tests show that the insertion loss due to the noise reducers is up to 10.6 dB.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.12
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• pp.1139-1144
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• 2007

The use of noise barrier is being increased to reduce the environmental noise in these days. Also, many noise reducers installed at the top of noise barrier are developed for improving the efficiency of noise reduction. So we evaluate the performance of the noise reducers and compare the results among the others. Results of field tests show that the insertion loss due to the noise reducers is up to 10.6 dB.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.570-574
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• 2013

The use of noise barrier is being increased to reduce the environmental noise in these days. Also, many noise reducers installed at the top of noise barrier are developed for improving the efficiency of noise reduction. So we evaluate the performance of the noise reducers and compare the results among the others. Results of field tests show that the insertion loss due to the noise reducers is up to 10.6 dB.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.849-854
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• 2001

A study on performance of the sound absorbing noise barrier is presented. Noise barrier of sound absorbing type is composed of the front panel, sound absorbing material, and back panel. For allowing sound path, front panel is usually perforated. The performance of the noise barrier is governed by the opening ratio of the perforated panel, sound absorption coefficient of the sound absorbing material. In this study, the effects of the opening ratio, diameter of the hole, thickness of the sound absorbing material are investigated. It is found that the thickness of the sound absorbing material must be at least 50 mm to ensure the required minimum NRC value 0.70, and the opening ratio is greater than 0.2. It is shown that the thickness of the back panel is crucial in providing required STL (Sound Transmission Loss) value. The performance of the developed noise barrier is measured, where its sound absorbing coefficient and sound transmission loss satisfy the criteria.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1125-1128
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• 2007

In order to improve the acoustic performance of a noise barrier without increasing its height, various type of acoustic devices are suggested but, there is no proper method to estimate the performance in Korea. For this, an outdoor test facility was established in Expressway and Transportation Technology Institute(ETTI) of Korea Expressway Corporation for testing the acoustical performance of noise reducing devices installed on the top of a noise barrier. Noise measurements before and after installation of the noise reducing devices were carried out by using sound pressure level for long distance range from the barrier, from 10m to 40m. For considering the directivity effects of noise reducing devices, multivariate regression analysis was attempted.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.4
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• pp.232-238
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• 2012

In this study, the noise mapping simulation is executed to design an effective barrier reducing noise levels of a school site. The geographical features of the ambient site and the school buildings are modelled in detail in order to consider sound propagation, deflection, and absorption phenomena etc. The main sound source, sound power level of expressway, is estimated on the basis of measured noise levels at several points of the site. The noise mapping simulation is performed by using ENPro, environmental noise prediction program based on ISO 9613 to analysis the effectiveness of noise barrier. Consequently, the noise barrier is designed to meet an environmental noise standard and satisfy low cost and safety conditions.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.584-589
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• 2002

Recently, in various industrial field standardization and performance improvement are actively on going. Noise barrier is generally used to reduce railway noise. But the effectiveness of its use is low because of low level of technology development. In this basic study, test item and its specification are suggested for standardization of railway noise barrier.