Florida Noise Barrier Evaluation and Computer Model Validation

Author(s):  
Roger Wayson ◽  
John MacDonald ◽  
Ahmed EI-Assar ◽  
Win Lindeman ◽  
Mariano Berrios

The results of a project that investigated the effectiveness of in situ noise barriers in Florida are presented. The prediction accuracy of the FHWA Traffic Noise Model (TNM) is compared with STAMINA 2.0 and 2.1 (Florida-specific). A total of 20 barrier sites were visited during a 3-year period that resulted in 844 discrete 20-min equivalent sound level (Leq) measurements behind the barriers. Barrier insertion loss was determined using the ANSI indirect barrier method. A methodology was developed to estimate shadow zone length created behind highway noise barriers. All of the barriers tested were effective (>5 dB:LAeq insertion loss at distances equivalent to the first row of homes, where LAeq is the A-weighted Leq) except one site because of marginal additional shielding from a berm–barrier combination. Only three sites had an insertion loss of less than 5 dB at distances representative of the second row of homes. Overall, measurements indicate that the barriers provide substantial sound level reduction for residents along the highway. TNM was the best prediction model when considering all test sites; however, the STAMINA models were more accurate at predicting source level. TNM predictions using the Average pavement input overpredicted the reference sound levels measured at these sites. TNM predictions using the OGAC (open-graded asphalt concrete) input were improved (under 2 dB:LAeq of error) over those using the Average pavement type input. This result is expected because Florida uses an open-graded asphalt friction mix.

Author(s):  
Sanghoon Suh ◽  
Vincent J. Badagnani ◽  
Luc Mongeau ◽  
J. Stuart Bolton

The installation of sound-absorptive materials near the edge of a noise barrier is known to increase its insertion loss. First, scale-model experiments were performed to compare the performance of barriers that have absorptive edge linings with that of linearly extended, rigid uniform barriers and T-shaped barriers. The issue of effective positioning of the sound-absorptive material was also addressed. It was found that in terms of material use, an absorptive treatment was the most effective treatment for reducing the sound level in the shadow zone for a given barrier height. It was concluded that absorptive edge treatments may offer the opportunity to design effective treatments that could be retrofitted to existing barrier installations to improve their effectiveness. Preliminary field measurements were performed near South Bend, Indiana. The performance of an existing barrier was evaluated. Predictions of its performance made using the FHWA Traffic Noise Model were verified. An acoustical treatment was added to one vertical edge of the highway noise barrier. The results for the performance of the acoustical treatment measured in the field confirmed the trends of the scale-model laboratory measurements.


2014 ◽  
Vol 584-586 ◽  
pp. 776-779
Author(s):  
Xian Feng Huang ◽  
Chen Hui Zhu ◽  
Quan Shi

By applying noise insertion loss predicting model of the noise barriers, influencing factors on insertion loss of the sound barrier are investigated for achieving the significant attenuation effects. In term of the infinite line sound source and the finite length of the barriers, the sound insertion losses with varying parameters are calculated and compared. Finally, the meaningful results indicate that the economic and reasonable height and length of the noise barrier are gained to be beneficial for barrier design.


Author(s):  
Jason C. Ross ◽  
Mark Arnoldy ◽  
Jonathan Evans

This paper presents the results of a statewide noise barrier study for the New Hampshire Department of Transportation (NHDOT). The feasibility and reasonableness of noise barriers throughout the state has been evaluated according to NHDOT acoustical and cost-effectiveness criteria. The study has provided the DOT with an estimate of the potential noise barrier material costs associated with a newly implemented Type II noise barrier program. The study also has identified municipalities that the DOT can coordinate with for enacting noise-compatible planning regulations. The paper describes the methodology used to develop the screening-level noise barrier evaluation. Highway noise levels throughout the state and the distances from the highway where noise levels exceed the noise abatement criteria were determined. A method to predict the noise reduction of barriers (insertion loss) based on a simple geometrical relationship of receptors and potential noise barriers was established and has been shown to correlate well to detailed traffic noise models using actual roadway and terrain geometry. The simplified prediction method was used to evaluate over 300 miles of highway, 300 candidate noise barrier study areas, and over 30,000 receptors. This screening-level modeling approach is critical to the practicality of using the Traffic Noise Model across the entire state given the significant number of receptors and noise barrier study areas. The results of the study including information about all 30,000 receptors and 300 noise barrier study areas were collected in Google Earth™ data files for easy access when the DOT responds to noise complaints from the public.


Author(s):  
Lloyd A. Herman ◽  
Michael A. Finney ◽  
Craig M. Clum ◽  
E.W. Pinckney

The completion of the largest Ohio Department of Transportation traffic noise abatement project in 1995 was met with public controversy over the effectiveness of the noise barriers. A public opinion survey was designed to obtain the perceptions of the residents in the project area. In a departure from most surveys of traffic noise barrier effectiveness, the coverage was not limited to the first or second row of houses, but was extended to 800 m on each side of the roadway. It was found that the larger survey area was needed to avoid misleading conclusions. Overall perceptions of noise barrier effectiveness were found to vary with distance from the roadway and with noise barrier configuration.


Author(s):  
Michael A. Staiano

Traffic noise exposures were measured at various locations adjacent to an Interstate highway and compared with sound levels predicted by the FHWA Traffic Noise Model (TNM). The prediction procedure underestimated the measured sound attenuation by 6 to 12 A-weighted decibels. Various TNM site model configurations were evaluated in an effort to improve agreement between measurements and predictions. For the site tested—a severe case with relatively distant receptors and extreme topography—variations in ground impedance (including a median ground zone) had little benefit or were counterproductive, while adding topographic detail via terrain lines helped somewhat. The best agreement resulted from the incorporation of a tree zone for the wooded site. However, this benefit is thought to be chance, because the site was not only relatively lightly wooded but also thinly foliaged at the time of the on-site measurements.


2000 ◽  
Vol 08 (03) ◽  
pp. 495-502 ◽  
Author(s):  
D. OUIS

This study is concerned with the theoretical solution to the problem of sound screening by simple hard barriers on the ground with special emphasis given to the type of wave incidence, namely a comparison between the use of either a spherical or a cylindrical sound source. For a receiver at the shadow of the noise source, the field may be assumed to be due to the edge wave and for this, exact solutions are used. Regarding the wave reflection on an impedance ground, exact formulations are also used, and finally, some calculations are made on the performance of a hard noise barrier on a two-impedance ground. As a conclusion, it is found that although the sound level at the receiver may show some small differences depending on the frequency and on the geometry of the problem, the overall insertion loss of the thin hard barrier is almost the same for the spherical and the line source, and the differences are found to amount to less than 1 dB for geometries of practical occurrence.


Author(s):  
Roger L. Wayson ◽  
John M. MacDonald ◽  
Ronald Eaglin ◽  
Barbara Wendling

Several models are available for predicting traffic noise levels. The FHWA-promulgated model, STAMINA 2.0, is the most widely used noise model in the United States and is used to model free-flow vehicular traffic. STAMINA 2.0 cannot directly model interrupted-flow traffic. Sound levels from interrupted-flow traffic can be approximated with STAMINA 2.0 using the method presented in NCHRP Report 311. This method is time-consuming and difficult to use. These limitations demonstrate the need for a traffic noise model that can model the acceleration and deceleration behavior of interrupted-flow traffic. The University of Central Florida has developed the American Automobile Manufacturers Association Community Noise Model (CNM). The CNM is a traffic simulation model that determines sound levels at receivers by modeling vehicles as discrete moving point sources. The vehicle energy is determined from acceleration, deceleration, idle, and cruise reference energy mean emission level curves. Sound energy attenuation is calculated from distance, ground absorption, and user input barriers. The model sums the energy at receivers from all vehicles and then calculates the Leq noise level at the receivers. It is demonstrated that the CNM predicts receiver Leq levels that are very close to STAMINA 2.0 results for constant-speed traffic. The CNM can also accurately predict sound levels at receivers located before and after intersections. In addition to the advantages of a real simulation model, the CNM is user friendly, allowing the user to place lanes and receivers using the mouse.


2014 ◽  
Vol 3 (1) ◽  
pp. 1-11
Author(s):  
Saša Ahac ◽  
Ivo Haladin ◽  
Stjepan Lakušić ◽  
Vesna Dragčević

Abstract The paper gives an overview of concrete noise barrier application in several EU countries and in Croatia. It describes a process of introducing different noise protection solutions on Croatian market in the phase of intensive motorway construction in recent years. Namely, an extensive motorway network has been constructed in Croatia in the last 10 years. Following the process of motorway construction, noise protection walls have also been erected. Usage of different building materials and installation processes as well as variations in building expenditures has led to a comparative analysis of several types of noise protection solutions (expanded clay, wood fibre) including a new eco-innovative product RUCONBAR, which incorporates rubber granules from recycled waste tyres to form a porous noise absorptive layer.


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