ground attenuation, barriers and distant receivers
DESCRIPTION
Ground Attenuation, Barriers and Distant Receivers. Lloyd Herman Ohio University. Distant receivers. Location: 0.4 – 3.2 km (¼ to 2 mi) from highway Problem: complaints of increased noise levels after barrier construction. California experience. Hendriks and Hecker 1989 - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/1.jpg)
Ground Attenuation, Barriers and Distant Receivers
Lloyd Herman
Ohio University
![Page 2: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/2.jpg)
Distant receivers
Location: 0.4 – 3.2 km (¼ to 2 mi) from highway
Problem: complaints of increased noiselevels after barrier construction
![Page 3: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/3.jpg)
California experience
• Hendriks and Hecker 1989•I-405 in LA•Receivers: 0.3 – 0.6 km (0.2 – 0.4 mi)
•Woodward-Clyde & Illingworth and Rodkin•1994•I-680 in SF Bay area•Receivers: 0.4 – 1 km (0.25 – 0.67 mi)
![Page 4: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/4.jpg)
Ohio experience
• I-71 in southern Ohio• Receivers 0.2 – 0.5 km (0.1 – 0.33 mi)
• SR8 in northern Ohio• Receivers 0.2 – 0.8 km (0.15 – 0.5 mi)
![Page 5: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/5.jpg)
Survey of 1200 residents
• 35% said noise levels increased
• The most complaints:• 0.2 – 0.3 km (0.15 – 0.2 mi)• located in parallel barrier sections
![Page 6: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/6.jpg)
Source
Receivers
a
b
cd
Barrier attenuation and path length difference
![Page 7: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/7.jpg)
Sound path
![Page 8: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/8.jpg)
SourceLevel Geo Sprd
AtmBarrier
GroundMeas. Level
Attenuation Mechanisms
![Page 9: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/9.jpg)
Ground Attenuation
SR
• Path length difference
• Air to ground impedance ratio
• Angle of incidence
![Page 10: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/10.jpg)
Ground effect
Source: Piercy and Embleton, JASA 61 1403-1418
![Page 11: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/11.jpg)
Before barrier construction
Geo Sprd
AtmBarrier
GroundMeas. Level
SourceLevel
![Page 12: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/12.jpg)
After barrier construction
Geo Sprd
AtmBarrier
Ground Meas. Level
SourceLevel
![Page 13: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/13.jpg)
High and Low source levels
40
45
50
55
60
65
70
75
80
180 210 240 270 300 330 360Distance from Barrier (m)
dBA
H
L
Site: Cinderella
![Page 14: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/14.jpg)
High and Low source levels
40
45
50
55
60
65
70
75
80
180 210 240 270 300 330 360Distance from Barrier (m)
dBA
H
L
Site: Kenwood Meadows
![Page 15: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/15.jpg)
High and Low source levels
40
45
50
55
60
65
70
75
80
180 200 250 300 360 420 480
Distance from Barrier (m)
dbA
H
L
Site: Glenover
![Page 16: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/16.jpg)
40
45
50
55
60
65
70
75
80
180 210 240 270 300 330 360
Distance from Barrier (m)
dBA
H
L
High and Low source levels
Site: Delray
![Page 17: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/17.jpg)
High and Low source levels
40
45
50
55
60
65
70
75
80
180 210 240 270 300 330 360Distance from Barrier (m)
dBA
H
L
Site: Cooperwood 1
![Page 18: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/18.jpg)
High and Low source levels
40
45
50
55
60
65
70
75
80
180 210 240 270 300 330 360
Distance from Barrier (m)
dBA
H
L
Site: Cooperwood 2
![Page 19: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/19.jpg)
After barrier construction
Geo Sprd
AtmBarrier
Ground Meas. Level
SourceLevel
![Page 20: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/20.jpg)
Parallel barrier degradation
0
0.5
1
1.5
2
2.5
3
3.5
4
0 30 60 120 180 240 300 420
Microphone Distance From Barrier (m)
Pa
rall
el B
arr
ier
Deg
rad
ati
on
(d
B)
Cooperwood
Jolain
Baywind
Glenover
Delray
Castleford
![Page 21: Ground Attenuation, Barriers and Distant Receivers](https://reader036.vdocument.in/reader036/viewer/2022062304/568142ba550346895daefb7b/html5/thumbnails/21.jpg)
Ideas, Thoughts, Comments, Questions?
…no conclusions!