Showing papers on "Noise barrier published in 1982"

Noise barrier cost reduction procedure stamina 2.0/optima: user's manual

Abstract: This manual presents the operation of the Barrier Cost Reduction (BCR) Procedure. The FHWA Level 2 Noise Prediction Model (STAMINA 1.0) has been modified to calculate the sound energy passing over several barrier segment heights in one run. The information is then used in an interactive program (OPTIMA) which can guide the user to the most efficient noise barrier design. The user is shown, step-by-step, how to input information and to interpret the output results for both STAMINA and OPTIMA.

Handbook of Urban Rail Noise and Vibration Control

Abstract: This handbook is a guide to the prediction and control of all types of urban rail transit noise, ranging from train noise heard by the community at large to noise in maintenance shops heard only by transit employees. The topics covered include: acceptability criteria for transit related noise and vibration; the general characteristics of urban rail noise and vibration; techniques and equipment for measurement of noise and vibration; control of transit vehicle noise and vibration; control of community noise from surface tracks and aerial structures; prediction and control of groundborne noise and vibration; control of noise in transit stations; control of noise from station ancillary equipment such as air-conditioning systems and fan and vent shafts; control of noise around yards and shops; control of wheel squeal noise; and control of pressure transients in subway tunnels. The handbook is primarily intended for transit engineers, although it should also be useful for transit system executives and transit system acoustical consultants. Extensive bibliographic information is provided for readers looking for more detailed information. Also, for those interested in a general overview of urban rail noise and vibration, the executive digest of this handbook is available as a separate document. (a) (Author/TRRL)

Are earth berms acoustically better than thin-wall barriers

Abstract: The two most common highway noise barrier structures are earth berms and thin-walls. Yet the relative acoustical performance of these barriers is not well understood. Previous analytic, scale-model, and full-scale studies, comparing the acoustical effectiveness of thin-walls with that of berms and wedges, are reviewed. Additional data obtained by full-scale measurements, and in particular by a 1:16 scale-model study, are presented. The source-barrier-receiver geometry and model materials used were selected to simulate typical highway situations. Preliminary results indicate that, contrary to a recommendation in the Federal Highway Administration Highway Traffic Noise Prediction Model, thin-wall barriers and earth berms of the same height are about equally effective in reducing noise. In addition, the acoustical effectiveness of combining a wall with an earth berm was found to be quite similar to that of using thin-wall barriers alone. The practice of erecting relatively low walls on top of earth berms was found to be acoustically sound. (Author)

Transparent noise barriers along i-95 in baltimore city, maryland

Abstract: The Archbishop Keough Noise Barrier Project is classified as a category 2 experimental project by the Federal Highway Administration because of the barrier material (Lexan) used in the project. Lexan, a clear plastic panel system, has never been used as a noise-abatement measure in this area and its inclusion in this project provides cost and performance information for future project comparisons. Lexan was chosen for this project because of its effectiveness in attenuating highway noise levels while at the same time not interfering with the natural, scenic vista from a highway. It was incorporated into the system of noise barriers along Interstate 95 and protects Archbishop Keough High School from elevated noise levels due to the highway. The Keough noise barrier consists of 58 transparent panels, each 10 ft high by 0.25 in thick, supported at a 7.5-ft on-center width. The panels are held in place by steel posts that are attached to a concrete footing that runs the entire 435-ft length of the project. The project was built at a cost of $151,770. The cost of the barrier itself was $87,000. Delays in the delivery of materials and our underestimation in the number of working days were not totally unexpected due to the experimental nature of the project. (Authors)

Determination of effectiveness of noise barriers along i-285, atlanta

Abstract: A study was conducted to compare the field insertion loss with the calculated insertion loss of four noise barriers along Interstate 285 in Atlanta, Georgia. Field insertion loss was determined in accordance with the latest guidelines promulgated by the Federal Highway Administration (FHWA). The calculated insertion loss was obtained through the use of STAMINA 1.0, the level-2 computer model based on the FHWA highway traffic noise prediction model. The study indicates a high level of confidence in the accuracy of the computer model. Also included are the results of a survey administered to the affected population behind each noise barrier. Results of this survey indicate general public support for a noise-abatement program and the need for more public involvement prior to the construction of a noise barrier. (Author)

Comparison of aircraft and ground vehicle noise levels in front and backyards of residences

Abstract: Investigation of aircraft overflight and ground vehicle noise around a general aviation airport provided the opportunity to measure the frontyard to backyard noise reduction afforded by residential structures for these two types of noise sources. The measured average noise reduction for two residences using passing street vehicles as noise sources was found to be 17 and 21 dBA. For aircraft overflights using identical measurement instrumentation and microphone locations, as were used for the street traffic noise, the average measured noise reduction (i.e., difference between frontyard and backyard noise levels) was found to be 0.2 and 0.4 dBA. The results of the measurements show that acoustical factors around residences are such as to generally cause substantial frontyard to backyard noise reduction for street traffic noise, but not for the noise from aircraft overflights.

Mathematical modeling of complex noise barriers

Abstract: Mathematical modeling of the noise reduction efficiency of highway noise barriers depends on the shape and absorptivity of the barrier, the influence of the impedance of the ground under the receiver, the atmospheric conditions as well as traffic details. The mathematical model for a barrier's noise reduction requires the knowledge of point-to-point acoustic diffraction models. In many instances, the shape of the barrier is simple; such as thin wall (edge), sharp wedge, and cylindrically topped berms. However, new designs of more efficient barriers have been investigated recently.

Tyre/road interaction. a source of traffic noise

Abstract: This report deals with the noise caused by the rolling of tyres on road surfaces. Information regarding tyre/road noise must however be placed in its context. For this reason other sources of traffic noise are included as well. The current Swedish recommendations regarding outdoor and indoor noise are presented. The generation of noise and its impact on people are also dealt with. In order to reduce traffic noise, measures like reduction of engine and transmission noise, changes in tyre design, choice of road surfacings and design of embankments and barriers are discussed. Finally, the cost of these traffic noise reductions is calculated. (TRRL)

Prediction modeling for the assessment and abatement of highway traffic and construction noise

Abstract: Noise models described have been designed to assess noise propagation over asymmetric barriers and nonuniform ground cover, noise generated by stop-and-go traffic in urban settings, and construction noise impacts.

Highway construction noise modeling

Abstract: A model and interactive computer program for predicting highway construction noise levels have been developed and evaluated for the Federal Highway Administration (FHWA), as part of its on-going efforts to provide state-of-the-art tools for highway-noise analysis. The model addresses noise sources as points, lines, or areas and has a built-in data base for 53 different sources. Noise barrier attenuation may also be analyzed. The results of the calculations are the total 8-h equivalent sound levels (L sub eq (8h)) at noise receptor as well as the individual contributions from each source. Use of the model will not be required by FHWA; however, the model can serve as a useful tool for meeting the requirements of the FHWA noise standards for impacted areas and for evaluating abatement measures. It may also be used during construction as a diagnostic tool for investigating citizen complaints and for designing mitigation strategies, if necessary. (Authors)