Determination of the Noise Level Produced by Road Traffic

Transcription

1 Deermnaon of he Nose evel Produced by Road Traffc lna Mhaela RĂDO Unversy POTHNC of Buchares, Splaul ndependene 33, Romana, Ncolae NSCU Deparmen of Mechancs, Unversy POTHNC of Buchares, Splaul ndependene 33, Romana, oan MGHȚ Deparmen of Mechancs, Unversy POTHNC of Buchares, Splaul ndependene 33, Romana, bsrac: - Ths paper presens he NMPB-996 ( Nouvelle Méhode de Prévson du Bru ) mehod for deermnng he level of nose produced by road raffc wh he sofware Cadna. n mos of he cases, he modellng of he road s smply performed, hrough he fllng n of he number of vehcles / hour and he vehcle percenage. n he wor hereby, n he modellng of he road, here were used he daa, measuremens and he calculaons, n order o esablsh he level of acousc power per lengh un. n conclusons are presened he comparave analyss beween values of he nose n he wo cases. Keywords: - raffc nose, road vehcles, nose level, nose measuremens. NTRODUCTON 2. MTHODS Nose polluon creaes dscomfor and become annoyng and even harmful n some areas of Buchares, raffc areres, near he arpor, near sources of nose. Based on nose measuremens performed s esmaed ha raffc on he man roads, and especally wh heavy raffc nose polluon frequenly exceeds he level of 70 db (), consdered admssble. Combned wh gas polluon, nose polluon n some pons of nersecon of he srees n Buchares becomes unbearable. Share of major sources of nose polluon, besdes he fxed ndusral orgn, held n he case of large urban areas n 80% moble sources,.e. road raffc. n he U, he sandard approach for analyzng a raffc nose problem n an urban area s based on calculaons wh smple models. Frs nose levels n he area are calculaed wh an engneerng nose model and nex emprcal exposure-response relaons are appled o esmae he prevalence of annoyance and sleep dsurbance. The focus s ofen on annoyance a home, and herefore he nose levels are calculaed a he facades of dwellngs. n hs paper, nose levels values obaned by on se measuremens are compared wh values obaned by calculaon usng formulas and he values obaned by modelng he area wh specalzed sofware Cadna. 2. Nose measuremens on se n mporan elemen n performng accurae measuremens s he choce of measuremen pons. Fgure n pon was nsalled on a rpod a sound level meer - ype 2250 o monor he nose level for 24 hours (fgure). Pons 2, 3 and 4 were chosen o he dsance of 2 m from he hospal buldng facades. Pon 5 was chosen a he mdway beween he wo juncons a 2 m from he curb. Duraon of recordng he ousde nose level was 30 mnues for perods of he, evenng and ngh (5 mnues for each drecon of movemen). Hourly raffc flows were deermned esmavely by exrapolaon (mulplcaon wh 4) of drec RJV vol X ssue 2/ SSN

2 recordngs. When he vehcles are couned, mus be made a dfference beween he 2 ypes of vehcles (lgh and heavy). Şefan cel Mare Road presens 6 raffc lanes (3 raffc lanes for each drecon) and he coun of he vehcles was performed for he 2 raffc drecons. For emporary perods of ( 7-9 h), evenng ( 9-23 h), ngh ( 23-7 h) here were measured he wo generc caegores of vehcles (lgh: m < 3.5, cars, buses, slen rams, pc-up and heavy vehcles : m > 3.5, buses, coaches, rucs, moorcycles). Repeang he measuremen a all recever posons was necessary o ensure sascal relably of he resuls (hree repeons). The able shows he nose measuremens performed n he 5 pons and he number of lgh/ heavy vehcles durng measuremens. Table No eq eq evenng eq ngh Pon Pon Pon Pon Pon No Day venng Ngh gh veh/h Heavy veh/h The eq s he mos approprae nose descrpor o use when measurng nose mpacs. eq: - weghed equvalen connuous sound pressure level n db; eq : Day equvalen level: -weghed, equvalen connuous sound pressure level, measured over he 2-hour perod hours eq evenng: venng equvalen level: - weghed, equvalen connuous sound pressure level, measured over he 4-hour perod hours eq ngh: Ngh equvalen level: -weghed, equvalen connuous sound pressure level, measured over he 8- hour perod hours 2.2 Nose level calculaon wh formulas n he desgn and execuon gude of he urban areas from an acousc pon of vew, ndcave P6 (Consrucon Bullen NCRC), s presened he mehod of calculang he raffc nose level wh he equaon: ex n f 0. 0 lg db 0 () T where: ex. f s he equvalen nose level from raffc ousde, near he proeced funconal un; - s he nose level on he sragh secons of he raffc areres n whch he dsances beween he buldng frons (locaed face o face) are smaller or a leas equal o 75 m; s calculaed accordng o he ype of he nose sources wh he equaon: 0csczv lg d d d d d 0 d d D 2 d 0 db D d D D 2 d0 d 0 d0 n whch (2) s characersc nose of a source " passng hrough he measurng pon deermned a m from he lm of he source; D = he dsance beween he buldng frons (m) d = he dsance from he source o he measuremen pon; d 0 = m d = dsance from he source o he fron of he buldng =0 (coeffcen of drecvy of he source consdered on he normal drecon o he fron of he buldngs) =3 (coeffcen of drecvy of he refleced waves beween he frons of buldngs n case of 4-8 floors on one sde of he road and no more han 5 floors on he oher sde) =0.03 (sound absorpon coeffcen of buldng facades, where s he measurng pon s locaed ) 2 = 0.03 (sound absorpon coeffcen of buldng facades, he oppose sde) c s= land surface coeffcen, c zv = coeffcen of he green area, c s = 0.90 (asphal); c zv =.75 The calculaon of he me correspondng o he acon s performed, n he case of he raffc, wh relaon: = n (s), n whch n s he number of raffc vehcles of a parcular ype, ha flows n he characersc perod T, for whch he RJV vol X ssue 2/ SSN

3 equvalen nose level s deermned by measuremen or sascal calculaons. n pon 5, values for n were deermned by measurng : - cars ( 3400 veh/ h- ; 800 veh/ h evenng ; 650 veh/ h- ngh) - rams ( 30 veh/ h- ; 20 veh/ h- evenng; 0 veh/ h- ngh) - mnbuses/ pc-up ( 290 veh/ h- ; 220 veh/ h evenng; 90 veh/ h ngh) - moorcycles ( 20 veh/ h- ; 20 veh/ h- evenng; 0 veh/ h-ngh) - rucs ( 82 veh/ h- ; 28 veh/ h- evenng; 6 veh /h- ngh) - buses ( 60 veh/h-; 50 veh/h- evenng; 8 veh/hngh) The values for dfferen ypes of raffc sources are presened such : cars (.2 s), rams ( 2 s), mnbuses (.2 s), moorcycles (.8 s), rucs (.2 s), buses (.8 s), where s he me when he vehcle passes hrough a dsance = 20 m. On he paved srees are consdered he lgh vehcles: cars, mnbuses and slen rams. The remanng conveyances are he heavy vehcle raffc. Nose levels characersc o he sources consdered are rounded for he calculaon, n 5 classes of nose: 70, 75, 80, 85, 90 db (); n each class fs he vehcles whose characersc nose devaes more han ± 2 db () from he value of he class defnon. The values for lgh vehcles on paved srees are: = 70 db() (cars ); = 75 db() (mnbuses); = 80 db() (slen rams) The values for heavy vehcles on paved srees are: = 85 db() (moorcycles) ; = 90 db() (rucs) ; = 85 db() ( buses) The equvalen nose level ousde, s calculaed a a pon wh he equaon (2) for n dfferen nose sources : - for example, pon 5 ( d= 2 m) : 0.03 cars lg ( cars)= db(); ( rams) = db(); db() ( buses)= db() ( moorcycles)= ( mnbuses)= db(); db() ex ( rucs)= ,67 72, lg 3400, , 20 77,68 82,68 87,68 82, ,80 82,20 60,80 ex db() ; ex db() evenng; ex db() ngh The values and same for pons - 4. ex. f are calculaed he 2.3 The modellng of he area wh he Cadna sofware The mehod of calculaon for raffc wh he sofware Cadna s NMPB-996 ( Nouvelle Méhode de Prévson du Bru ). : For modelng he road, he raffc flow Q (n vehcle / hour) and he percenage of heavy vehcles p% mus be specfed. QP Q Q V Q P and p% Q QV - number of he lgh vehcles raffc (max.mass <3.5 ), n veh/ h QP - number of he heavy vehcles raffc, n vehcles / hour Q = 94( number veh./h for sens of movemen) (3) p% = 4.2 (4) Q =069 (number veh./h ) (5) p% = 4.6 evenng (6) Q =387 (number veh./h) (7) p% =4.4 ngh (8) The sree has 6 raffc lanes (3 raffc lanes for each drecon) and he numberng of he vehcles was done for he 2 raffc drecons. he numberng of he vehcles n he raffc, was made a dsncon beween he 2 ypes of vehcles (lgh and heavy). s consdered he speed lm of 50 m / h for lgh vehcles and 40 m / h for heavy vehcles. Of he four ypes of raffc flows, s chosen he pulse non-dfferenaed. Horzonal graden of he road for sree and raffc flow pulse s 2.%. Because of he fac ha on he chosen sree here crculae more han 300 vehcles / hour, s consdered he lnear source of nfne lengh. ll hese aspecs and he 3-8 relaons are flled n he dalogue box of he road n fgure 2. RJV vol X ssue 2/ SSN

4 QP - number of he heavy vehcles raffc, n vehcles / hour Correcon for operang me: D 0lg / B (0) Fgure 2. Nose level () = measurng me (h); B = reference me (2 h-, 4h-evenng; 8h-ngh) D 0lg / = 0 lg( 60/720)= () B D =0 lg(60/240)= - 6,02 (evenng); D =0 lg(60/480)= (ngh) Correcon due o dsance and ar absorpon: dv =20 lg(d/do)+ () do = m; d= source-recever dsance n Cadna, for he frequency of 500 Hz, he amospherc absorpon coeffcen s db/m. The sound power level per lengh un s calculaed usng he equaon (9) such: Fgure 3. Nose level (evenng) 67,67 72,68 77,68 V = lg = 78.5dB; 82,68 87,68 82,68 P = lg =89.2dB w, = 87.4 db (); w, = db (evenng) ; w, = 8.70 db (ngh) The values of he acousc power level, on lengh un, calculaed based on relaon (9), are flled n he dalogue box of he road for he modellng of he nose level (fgure 5). Fgure 4. Nose level (ngh) : f s no flled he number of vehcles / hour, hen s calculaed and compleed he dalog box of he road, he sound power level per lengh un: Q Q V 0 lg V /0 P 0 lg P /0 w, 0 lg 0 0 correcons (9) V V - sound power level of he lgh vehcles, n db () Q - number of he lgh vehcles raffc (max.mass < 3.5 ), n veh/ h P - sound power level of he heavy vehcles (m> 3.5 ), n db () Fgure 5. Nose level () RJV vol X ssue 2/ SSN

5 Table 2: Dfferences of db beween values of he nose n he wo cases No. Pon eve nng ngh eve nng ngh Pon Pon Fgure 6. Nose level (evenng) Pon Pon Fgure 7. Nose level (ngh) Fgure 8. Modelng area Cadna 3D Ngh 3.CONCUSONS The overall fndngs of hs nose sudy show ha he Cadna nose modellng pacage s as accurae and effecve as he nose measuremens n road raffc. Therefore boh models are consdered compeen, relable and generally accurae n modellng raffc nose. n conclusons are presened he comparave analyss beween values of he nose n he wo cases and (able 2). n he modellng of he road (case ), here were used he daa and measuremens from 2. and he calculaons from 2.2, n order o esablsh he level of acousc power per lengh un (rel.9). So, he resul of he modellng s beer because of he qualy of he enry daa. RFRNCS [] Consrucon Bullen, NCRC, Vol. 3 [2]. M. Salomons, S.. Janssen, H..M. Verhagen, P. W.Wessels, xpermenal sudy of raffc nose and human response n an urban area, ner.nose 204. [3] P.Karanons, T.Gowen, M. Smon, Furher Comparson of Traffc Nose Predcons Usng he Cadna and SoundPN Nose, Proceedngs of 20h nernaonal Congress on couscs, C 200. [4].K. Shula, S.S. Jan, M. Parda, J.B. Srvasava, Performance of FHW model for predcng raffc nose: case sudy of meropolan cy, ucnow (nda), Transpor, 2009, pp [5] M.J Crocer, Handboo of Nose and Vbraon Conrol, 2007, pp [6] C.H. Hansen, D.. Bes, ngneerng Nose Conrol: Theory and Pracce, Fourh don, 2009, CRC Press. [7] V.K. Kuraula, M. Kuffer, 3D Nose Modelng for Urban nvronmenal Planng and Managemen, Real Corp, 2008 Proceedngs. [8] DaaKus GmbH, Cadna Reference Manual, 202. [9] Klujver D.H., Soer J.: Nose mappng and GS: opmsng qualy and effcency of nose effec sudes, Compuers, nvromenal and Urban Sysems, RJV vol X ssue 2/ SSN