Appendices to NCHRP Research Report 842 (2017) / Chapter Skim
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From page 48... ...
D1 APPENDIX D ADDITIONAL CONTOUR ANALYSIS FOR HEAVY TRUCKS TABLE OF CONTENTS HEAVY TRUCK NOISE CONTOUR DISCUSSION ...........................................................D2 Northern California Test Sites .........................................................................................D2
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From page 49... ...
D2 HEAVY TRUCK NOISE CONTOUR DISCUSSION Northern California Test Sites Lakeville Test Site. The typical vertical distributions at the Lakeville site reduce from the maximum profile level by 10 dBA at heights ranging from 5.3 to 8ft (1.6 to 2.4m)
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Fi Some sp Run 10, f indicates noise sou 9.8ft (2 t trucks of expanded band. In contribut axle tires somewha gure D1: Ov ecial-case ru or instance, the presenc rce levels.
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to note h most trai Another contours report. S but rathe the conto position contribut powertra from bot engine no and a so located a engine o testing.
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Figu Other sp 11.5ft (3 ground to have a se 4.5m) ab 82.3 dBA a source re D3: Over ecial-case ru .5m)
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This sou and abou contribut and 4,00 source re noted wi exhaust g without h levels are Figu rce region i t 3 dB lowe e much to th 0 Hz bands gions and p th respect t as at the ou aving a ma 14 dB lowe re D4: Ove s about 9 dB r than the m e overall le (not shown roduces max o Figure D1 tlet. For ru jor impact r than the m rall, 1,000, lower than aximum in vel, it is su )
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From page 54... ...
The two different the maxim until heig small dim and 400 H F)
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D8 For the truck from Run 45, the one-third octave bands from 400 to 630 Hz have the highest level and are about equal. The 315 Hz band is about 6 dB lower in level.
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Figur 505 SB1 contour r During th creating (1m) apa those of indicates However e D6: Over Test Site.
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D10 the overall A-weighted contours for Run 37 shown in Figure D8. In the 1,250 Hz band contours, engine noise from underneath the truck cab area is indicated, along with noise from the drive axle tires and trailer tires.
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Figure D7: Overall, 630, 800, and 3150 D11 Hz contours of truck pass-by Run 8 at 505 SB1
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Figure D8: Overall, 630, and 1250 Hz D12 contours of truck pass-by Run 37 a t 505 SB1
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Fi There we extended heavy-du truck fro overall A the 1,600 cab and display s gure D9: Ov re also sev to heights ty measurem m Run 9 ar -weighted c Hz band. extending to imilar chara erall, 800, a en heavy-du above 13ft ents, five e shown in ontours in th Additionally the front cteristics.
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Fi In two ru high leve the low f the 505 S affecting vehicles 505 SB2 at the La from trai case is s gure D10: O ns, the over ls stretching requency b B1 site, app the contou tested; and l Test Site. T keville site.
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From page 62... ...
indicated contours of contou this case powertra Fig around th do indicate rs for a tru , tire noise i in noise from ure D11: Ov e tractor. In some power ck represent s clearly in underneat erall, 630, a this case, train noise ed in Figur dicated for t h the tractor nd 1600 Hz D15 no elevate coming from e 30 of the he drive ax and noise fr contours of d sources beneath th main report les and the om elevated truck passare indicate e tractor.
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From page 63... ...
Fig Eleven o measurem site. In th reached t noise, wh contours the noise above the Lakeville noise lev ure D12: Ov f the heavy ents that y ese runs, n heir maxim ich is appro for Run 128 levels do n ground.
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D17 the 400 Hz frequency band (see Figure D13) , there were two distinct ovals of levels: one at the drive axle tires of 72 dBA; and one at the top of the exhaust stack of 71 dBA.
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Figur e D13: Overall, 400,500, and 630 H D18 z contours of truck pass-by Run 12 8 at 505 SB2
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Figure D14: Overall, 315, 800, and 1600 D19 Hz contours of truck pass-by Run 119 at 505 SB2
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D20 505 NB1 Test Site. Contours for one of the typical trucks (Run 62)
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Figure D15: Overall, 315, 800, and 1250 D21 Hz contours of truck pass-by Run 62 at 505 NB1
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Figu The seco at all fou around 1 that at 1 re D16: Ove nd example r Northern 1.5ft (3.5m)
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From page 70... ...
extremely of exhau drive axl the exhau and is on measured from a hi Figur low. The c st stack nois e tires and t st stack.
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