Minimizing noise from metro viaduct railway lines by means of elastic mats and fully closed noise barriers

2018 ◽  
Vol 232 (6) ◽  
pp. 1828-1836 ◽  
Author(s):  
Caiyou Zhao ◽  
Wang Ping
Keyword(s):  
Noise Reduction ◽  
Vibration Energy ◽  
Rail Transit ◽  
In Situ Experiment ◽  
Noise Barriers ◽  
Transit Systems ◽  
Slab Track ◽  
Noise Barrier ◽  
Reduction Effect

An adverse effect of urban elevated rail transit systems is the associated noise, which has become a source of environmental complaints. In order to effectively address this problem, an in situ experiment has been conducted on the elevated sections of Hangzhou Metro Line 1 involving three cases: a 2.2 m vertical noise barrier with integrated bed track, a 2.2 m vertical noise barrier with an elastic mat floating slab track, and a 5.1 m fully enclosed noise barrier with an elastic mat floating slab track. The noise reduction effects of the elastic mats and the two kinds of noise barriers for metro viaduct railway lines were evaluated, and the mechanisms of these countermeasures were analysed. The results show that elastic mats can effectively reduce the transmission of wheel–rail vibration energy into the bridge, thus decreasing bridge-borne noise; meanwhile, the elastic mats could lead to an increase in wheel–rail noise. An excellent noise reduction effect was achieved in the area below and near the bottom of the bridge, while an increased noise effect was observed close to the area above and near the rail surface. The fully enclosed noise barrier controlled the propagation of wheel–rail noise more effectively than the vertical noise barriers, but no difference was found between these two kinds of noise barriers in controlling bridge-borne noise.

scholarly journals Operational Noise Assessment in an Open Cycle Power Plant: Study on the Existing Acoustical Performance.

2018 ◽  
Vol 7 (4.35) ◽  
pp. 11 ◽  
Author(s):  
Helmi A Halim ◽  
Gasim Hayder
Keyword(s):  
Power Plant ◽  
Noise Level ◽  
Performance Study ◽  
Noise Barriers ◽  
Noise Assessment ◽  
Noise Barrier ◽  
Open Cycle ◽  
Gas Turbine Power Plant ◽  
The Impact

This research is an acoustical performance study in an open cycle peaking gas turbine power plant located at the southern coast of Peninsula Malaysia. Referring to its location at the middle of residence and tourism area, throughout its operation years, several complains from public has been lodged about the excessive operational noise at the perimeter of the plant and statistically from the last decade, twenty-four (24) noise related public complains were recorded. This issue has initiated a study to determine the current operational noise level as well as the effectiveness of the existing noise barriers. Based on EIA approval, the boundary noise for the operation should be limited to 55 dB(A) at any time. The field measurement of noise level at two (2) different locations are assessed in-situ and continuously noise monitoring covering all the plant’s operational regime and at different plant operational pattern. These results are compared with the initial noise report during its early year of operation in 1999. Finally the hypotheses then compared with the referenced legislations. Results from all the methodologies show the current operational noise level of the plant are within the permissible limit, however the overall operational noise of the plant is increasing compared with 1999 report due to the increasing of surrounding activities as well as deteriorating of current engineering and natural noise barrier arrangement. Mitigation plans has been recommended to the management to minimize the impact of the excessive noise to surrounding residence and to the plant workers. On top of that, the theoretical and commercial implication of the research is also discussed.

scholarly journals Noise Reduction Effect of Noise Barrier for Shinkansen Based on Y-shaped Structure

2006 ◽  
Vol 47 (3) ◽  
pp. 162-168 ◽  
Author(s):  
Kaoru MURATA ◽  
Kiyoshi NAGAKURA ◽  
Toshiki KITAGAWA ◽  
Shin-ichiro TANAKA
Keyword(s):  
Noise Reduction ◽  
Noise Barrier ◽  
Reduction Effect

scholarly journals Examination of Rail Dampers with Respect to Noise and Vibration Mitigation

2020 ◽  
Author(s):  
Gabriella Csortos ◽  
Fülöp Augusztinovicz ◽  
László Kazinczy
Keyword(s):  
Noise Reduction ◽  
Field Measurements ◽  
Vibration Damping ◽  
Mode Shapes ◽  
Vibration Energy ◽  
Test Results ◽  
Railway Transport ◽  
Noise And Vibration ◽  
Reduction Effect ◽  
Rolling Noise

Nowadays there are more and more possibilities to mitigate noise and vibration emitted by railway transport to the lower levels. Among them, rail dampers with highly viscous properties placed on the rail web, fixed with adhesives or other methods, appeared as a new element in the railway superstructure. The elements are applied to reduce noise and vibration by transforming the vibration energy of the rail web into heat, through their large internal friction. Many companies produce rail web elements and apply them with success abroad. Domestic manufacturers have already appeared in Hungary; however, the installation of these elements is still very limited. This publication is intended to introduce the rail dampers and to demonstrate their efficiency through laboratory and field measurements. Experimental modal analysis was used during the laboratory test to determine the eigenfrequencies, the damping factors and the mode shapes of an experimental rail section, thus analyzing the vibration damping and noise reduction effect of the elements. Field measurements were also carried out at a segment installed with rail web elements in Hungary and its vicinity, under standardized conditions. By averaging measured noise level values for various types of trains, comparable noise reduction of the investigated rail web element can be achieved. The laboratory and field test results confirmed that the rail web elements can be suitable for rolling noise reduction and vibration damping in most of the cases. The results of the measurements provide guidance and information for future development of the elements.

Influence of static preload on vibration reduction effect of floating slab tracks

2018 ◽  
Vol 25 (6) ◽  
pp. 1148-1163 ◽  
Author(s):  
Minghang Li ◽  
Meng Ma ◽  
Weining Liu ◽  
Bolong Jiang
Keyword(s):  
Vibration Reduction ◽  
Coupled Model ◽  
Mitigation Measures ◽  
Vehicle Body ◽  
Reference Case ◽  
Slab Track ◽  
Vibration Responses ◽  
Reduction Effect ◽  
Impact Vibration

To effectively reduce the railway vibration and its environmental impact, vibration mitigation measures are increasingly used. The vibration reduction effect of railway tracks is described quantitatively by insertion loss (IL). ILs obtained from in situ measurements under moving train loads and laboratory tests under artificial excitation differ significantly due to the different track loading state between these two methods. The differences of track loading state are induced by the moving effect of train passages and the preloads effect of vehicle masses, the latter of which is a significant factor to discuss in this paper. In order to study the static preload by vehicle masses influence on the vibration reduction effect in isolated tracks, the steel spring floating slab track and regular slab track, as a reference case, were compared. First, a theoretical simplified model was constructed, following which a finite–infinite element coupled model was built, which was calibrated by experimental test results. Impact loads were applied to both tracks with preloads using unsprung wheelsets or sprung vehicle-body masses, with the total mass varying from 0 t to 30 t. The results demonstrate that the increase in preload of unsprung mass makes the natural frequencies further reduced, and the peak IL value increased from 39 dB to 48 dB. The increase in preload has a significant effect on vibration responses below 5 Hz, and the application of the preload has different effects on the reduction effect in different frequency ranges.

An experimental study of vibration reduction of a ballasted ladder track

2016 ◽  
Vol 231 (9) ◽  
pp. 1035-1047 ◽  
Author(s):  
Meng Ma ◽  
Weining Liu ◽  
Yulu Li ◽  
Weifeng Liu
Keyword(s):  
Laboratory Test ◽  
Vibration Reduction ◽  
Potential Effect ◽  
In Situ Experiment ◽  
Low Frequencies ◽  
Environmental Vibration ◽  
New Type ◽  
Reduction Effect ◽  
The Time Domain

The ballasted ladder track is a new type of longitudinal track. In this paper, to investigate its vibration reduction effect, both a laboratory test and in situ experiment were conducted. As the vibration sources, a newly designed drop weight impulse setup was employed in the laboratory test, and moving metro trains were employed in the in situ measurement. The vibration reduction effects of the ballasted track with ladder sleepers and regular concrete sleepers were compared. The results show that the ballasted ladder track can effectively decrease the peak value in the time domain and has the potential effect to control the environmental vibration in low frequencies. The shape of the sleeper can induce changes in the vibration field of the ballast.

Research on Effect of Noise Emission from Railway Viaduct on Noise Reduction of Noise Barriers

2012 ◽  
Vol 433-440 ◽  
pp. 1852-1856
Author(s):  
Lei Ming Song ◽  
Shou Guang Sun ◽  
Xin Hua Zhang
Keyword(s):  
Noise Reduction ◽  
Microphone Array ◽  
Field Testing ◽  
Vibration Testing ◽  
Noise Emission ◽  
Noise Sources ◽  
Noise Barriers ◽  
Sources Identification ◽  
Array Technology ◽  
Noise Barrier

Noise sources identification based on microphone array theory was firstly introduced, A method was derived, which can be used to analyze effect of noise emission from railway viaduct to noise reduction of noise barriers. Vibration and noise emission of railway viaduct and noise barrier were studied using field testing with microphone array technology and vibration testing. The results concluded that noise emission from the viaduct has remarkable effects on noise reduction of noise barriers compared with the effects of noise emission from the noise barriers themselves, which is neglectable.

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