NOISE STUDIES FOR THE SAN ANTONIO "Y" PROJECT

Measurements were made in Austin, Texas, of highway traffic noise reflecting from the underside of an overhead roadway to diagnose these reflections and the resulting amplification to the side. Special care was taken to normalize all measurements to the actual emission level of each passing truck. It was determined that reflections from the precast I girders were scattered to the side rather than reflected specularly. An equation was developed that related this scattered sound to the relevant cross-sectional geometry at the two measurement sites. Subsequent measurements at two additional sites verified the scattering equations to within 1 dB, on average. For different cross-sectional geometries in San Antonio, where the proposed structure is a composite wing girder rather than a precast I girder, calculations were made of the sideline amplification caused by the expected specular reflections. Comparison of these calculated (specular) results with the measured (scattered) results in Austin indicates that the San Antonio amplification should be less than that measured in Austin, except when both of the following occur: (a) the receiver is within 50 to 60 ft of the edge of the elevated structure, and (b) the upper roadway curves away from the receiver.

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/trr/1984/983/983-001.pdf
• Summary URL:
  • https://scholar.google.com/scholar_lookup?title=NOISE+STUDIES+FOR+THE+SAN+ANTONIO+%22Y%22+PROJECT&author=G.+Anderson&publication_year=1984
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/03611981
• Supplemental Notes:
  • Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved. Publication of this paper sponsored by Committee on Transportation-Related Noise and Vibration.
• Authors:
  • Anderson, Grant S
• Publication Date: 1984

Media Info

• Media Type: Print
• Features: Figures; References;
• Pagination: pp 1-8
• Monograph Title: Issues in transportation noise mitigation: highway and railway studies
• Serial:
  • Transportation Research Record
  • Issue Number: 983
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Composite materials; Equations; Girders; I beams; Measurement; Overpasses; Reflection; Scattering; Traffic noise; Trucks
• Uncontrolled Terms: Amplification; Side
• Geographic Terms: San Antonio (Texas)
• Old TRIS Terms: Composite girders
• Subject Areas: Highways; Motor Carriers; Planning and Forecasting; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 00399853
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Feb 28 1986 12:00AM