Noise barriers

Italferr campaign (1999-2001)

Background

In the frame of the 1994-1997 Standard, Measurement and Testing program, the European Commission funded a research project, named Adrienne, to define new test methods for measuring the intrinsic characteristics of road traffic noise reducing devices in situ. The research team produced innovative methods for testing the sound reflection/absorption and the airborne sound insulation characteristics of noise barriers. These methods are now under consideration at CEN (European Committee for Standardization), to become European standards. The present work reports a detailed verification of the test method for sound reflection and airborne sound insulation over a selection of 42 noise barriers, representative of the Italian and European production.

RI measurement on a curved metallic barrier    RI measurement on a green wall barrier

Objectives

The work is divided in two parts.

The first part is a detailed verification of the Adrienne airborne sound insulation test method on a selection of 17 noise barriers (tested during 1999), plus other 13 barriers (tested during 2000) and other 12 barriers (tested during 2001), representative of the Italian and European market. The samples were tested both outdoors, using the new Adrienne method in controlled conditions, and in laboratory, following the EN 1793-2 standard. In both cases the single number rating for airborne sound insulation recommended by the European standard was calculated. The main aims of the work were at least three:
- to test the practicability and the reliability of the new Adrienne method for different kinds of barriers (composed mainly of concrete, metal, acrylic or wood; having a flat or non flat surface; having an absorbing or reflecting surface; etc.);
- to test the sensitivity of the new method to quality of workmanship, way of mounting and other details typical of real outdoor installations; these source of possible problems are present in real situations but are carefully eliminated when preparing laboratory specimens;
- to compare the outdoor and laboratory airborne sound insulation values obtained on the same set of barrier samples and to investigate their possible correlation, which would be useful for predicting the expected field performance from laboratory data.

The second part is a detailed verification of the Adrienne sound reflection test method on a selection of 17 noise barriers (tested during 1999), plus other 13 barriers (tested during 2000) and other 12 barriers (tested during 2001), representative of the Italian and European market. The samples were tested both outdoors, using the new Adrienne method in controlled conditions, and in laboratory, following the EN 1793-1 standard. In both cases a single number rating for sound absorption/reflection was calculated. The main aims of the work were at least three:
- to test the practicability and the reliability of the new Adrienne method for different kinds of barriers (composed mainly of concrete, metal, acrylic or wood; having a flat or non flat surface; having an absorbing or reflecting surface; etc.);
- to test the sensitivity of the new method to the shape and acoustic impedance of the barrier surface;
- to compare the outdoor and laboratory sound absorption/reflection values obtained on the same set of barrier samples and to investigate their possible correlation, which would be useful for predicting the expected field performance from laboratory data.

RI measurement on a barrier in light concrete blocks    SI measurement on a metallic barrier

Participating firms

RI measurement on a wooden barrier    SI measurement on a metal-PMMA barrier

Results

See the papers:

GARAI M., GUIDORZI P. (2000) Experimental verification of the European methodology for testing noise barriers in situ: sound reflection, Proc. Inter-Noise 2000 (invited paper), Nice. (PDF, 158 KB)

GARAI M., GUIDORZI P. (2000) Experimental verification of the European methodology for testing noise barriers in situ: airborne sound insulation, Proc. Inter-Noise 2000 (invited paper), Nice. (PDF, 99 KB)

GARAI M., GUIDORZI P. (2000) "European methodology for testing the airborne sound insulation characteristics of noise barriers in situ: Experimental verification and comparison with laboratory data", J. Acoust. Soc. Am., 108(3), 1054-1067. (PDF, 446 KB)

Acknowledgments

The measurements have been done in the years 1999, 2000 and 2001 by DIENCA under the scientific supervision of Prof. Massimo Garai for Italferr, the engineering company of Ferrovie dello Stato (Italian Railways) devoted to the technical supervision of the Italian high speed railway network. The laboratory tests were performed in the facilities of Istituto Giordano (Bellaria, Italy), in the frame of a contract with DIENCA.

Basic references

  1. GARAI M., GUIDORZI P. (1998) Caratterizzazione in situ delle proprietÓ riflettenti di barriere acustiche non piatte, Atti XXVI Convegno Nazionale AIA, Torino. (PDF, 35 KB)
  2. GARAI M., GUIDORZI P. (1999) Caratterizzazione in situ delle proprietÓ fonoisolanti di barriere acustiche, Atti XXVII Convegno Nazionale AIA, Genova. (PDF, 35 KB)
  3. GARAI M. (1999) Barriere antirumore: metodi di collaudo delle caratteristiche acustiche intrinseche, Atti Convegno "Le barriere acustiche: progettazione e rendimento", Alba.
  4. GARAI M., GUIDORZI P. (2000) Experimental verification of the European methodology for testing noise barriers in situ: sound reflection, Proc. Inter-Noise 2000 (invited paper), Nice. (PDF, 158 KB)
  5. GARAI M., GUIDORZI P. (2000) Experimental verification of the European methodology for testing noise barriers in situ: airborne sound insulation, Proc. Inter-Noise 2000 (invited paper), Nice. (PDF, 99 KB)
  6. GARAI M. (2000) Caratteristiche acustiche delle barriere, Atti Convegno "Traffico e Ambiente", Trento.
  7. GARAI M., GUIDORZI P. (2000) "European methodology for testing the airborne sound insulation characteristics of noise barriers in situ: Experimental verification and comparison with laboratory data", J. Acoust. Soc. Am., 108(3), 1054-1067.
  8. GARAI M. (2001) "Barriere acustiche", in: Manuale di acustica applicata, UTET Libreria, Torino.