PERFORMANCE OF ARTICULATED VEHICLES AND ROAD TRAINS REGARDING ROAD DAMAGE AND LOAD CAPACITY

Transcription

1 PRFORMNC OF RTICLT VHICL N RO TRIN RGRING RO MG N LO CPCITY r. Glaeser is sine 980 researher at the Federal Highway Researh Institute (Bt) in Germany. He ahieved his degree as ipl.-ing. from the Tehnial niversity of Berlin in 979 and obtained r.-ing. from the Bergishe niversität Wupertal in 995. ine 99 he is head of the vehile/pavement interation setion at Bt. He was engaged in the uropean COT study on single vs. dual tyres and in the worldwide OC/JTRC study on truk freight transport. laus-peter Glaeser Federal Highway Researh Institute (Bt) Germany bstrat In the framework of the OC study Moving Freight with Better Truks - whih will be published at this onferene as well - several vehile ombinations whih are worldwide in operation were examined regarding different performane riteria. One riterion was the road wear performane of these artiulated vehiles. With given tyre and vehile data (mainly weights and axle loads) the road wear performane was alulated for eah vehile ombination. The method aording COT is presented and the vehile ombinations are ompared. ans le adre de l étude OC Moving Freight with Better Truks, des ombinaisons différentes de poids lourds étaient examinées par des ritères différents. L usure de haussée par des poids lourds était un des ritères examinés. n se fondant sur des dates des pneus et des véhiules, l usure de haussée étaient alulé par les résultats de COT. Par la ontribution présente, la méthode et les résultats seront présentés ainsi que les véhiules omparés. eywords Road wear performane, vehile ombinations, load apaity

2 . Introdution Besides safety performane, eonomi performane and environmental performane the road wear performane of truks and truk ombination plays a major role for road authorities and administrators. The soiety has to pay for the rutting damage aused by truk traffi. Road wear performane an be alulated and an be brought in relation to the payload moved. This is the topi of this paper. ifferent worldwide used truk ombinations were ompared.. Methode The most omprehensive study in reent years onerning the influene of tyres and axle loads in relation to pavement damage (rutting of asphalt roads in the primary road network) was the so alled COT tudy ffets of Wide ingle Tyres and ual Tyres published in 00. From extensive rutting tests performed in different uropean ountries with different tyres, tyre onfigurations, axle loads, inflation pressures, et. a so alled tyre onfiguration fator (TCF) was defined. The TCF value relates the pavement wear of a given tyre to the pavement wear of a referene tyre. Within different axle ategories (steered, driven or towed axle) there is a wide range of TCF values whih reflets the fat that there are more and less pavement damaging tyres and tyre onfigurations as options possible. Tyre assembly (single/dual), tyre width and tyre diameter are the most important fators whih influenes the TCF. The damage ontribution of a single passage of an axle is expressed by the so alled axle wear fator (WF). This WF is a dimensionless fator relating the damage ontribution of a speifi tyre at a given axle load to the damage ontribution of a single passage of the referene tyre(s) with a referene axle load. Referene for the WF means a passage of a 0 t axle equipped with 95/80R,5 tyres mounted as twin assembly. To adjust the axle load effet on pavement damage a load equivaleny fator (LF) was introdued by COT, too. If only primary asphalt roads are onsidered and only primary rutting as damage ause is taken into aount the pavement damage inreases with the power of by axle load. The sum of all axle wear fators are alled vehile wear fator (VWF). For equal TCF and LF the higher the number of axles the higher is the vehile wear fator, but on the other hand the higher the payload an be. For the same gross vehile weight the higher the number of axles the lower is the axle wear fator for eah axle and also the vehile wear fator as sum of all axles. The performane of a vehile regarding pavement wear an be alulated by relating the payload to the vehile wear fator. This performane indiator: VWF / Payload is abbreviated in the following as PR (vehile road wear performane). The following formulas have been used: Load quivalene Fator: LF= (axle load / 0)² Tyre Configuration Fator: (tyre width/70) -,65 x (tyre diameter /059) -, Calulated Tyre Configuration Fators: TCF: see Table.67 in the COT Report xle Wear Fator: WF=TCF x LF Vehile Wear Fator: VWF=M (WF) Vehile Road Wear Performane: PR: VWF / Payload

3 From the members of the OC working group the vehile data as gross vehile weight (GVW), payload, axle loads for 9 artiulated vehiles were provided and the data on tyre size and tyre assembly (single/dual) as well. The truk ombinations were divides in workhorse vehiles, vehiles mostly in operation today, high apaity vehiles up to 50 t GVW and 5 m length and very high apaity vehiles as road trains in operation in meria or ustralia with a length over 0 m. Table shows for alulation explanation a seleted workhorse vehile (urope ), whih has a share of > 50% on uropean roads. Table : eleted Workhorse Vehile: urope, Calulation Priniple Country of origin and vehile number: urope Vehile lassifiation: Workhorse vehile Payload (t): 6.0 ek spae (m ):. Total argo volume (m ): 87.6 FIFTH WHL L = LN (t) Tyres 95/80R,5 95/80R,5 85/65R,5 85/65R,5 85/65R,5 / axle load (t) 6,5,5 7, 7, 7, WF,,,,, VWF 6,8 PR : 6 = 0, s one an see, the steering axle is the most aggressive axle for the road surfae (WF), having in mind that the steering axle is loaded every time with the engine s weight but the other axles have less axle loads when the truk ombination is operated in empty ondition.. Results of Pavement Wear Performane Calulation Table shows the examined workhorse vehiles for this study. They are divided by ontinents: For outh frian, 8 merian, ustralian and 0 uropean truks the road wear performane was alulated with the formulas above (all with max. payload and given urb weight). The alulation results for VWF and PR an be found in the ppendix. The tyre data are based on the RRB tables for the alulation of the ustralian PB. The PR values are shown in Fig.. ome minor orretions were made, e.g. instead 95/75R.5 tyres 95/80R.5 tyres were used for alulation ( truks), no data on 95/75R.5 tyres available in the COT report.

4 Table : HGV-type: Workhorse Vehiles Vehile origin & identifiation number GCM (t) / Payload (t) Length (m) Vehile Classifiation hemati Vehile desription & vehile ode FRIC outh fria Z Workhorse Tb outh fria Z Workhorse Tb MRIC Canada C Workhorse Tb Canada C Workhorse Tb Mexio MX Workhorse Tb Mexio MX Workhorse Tb Mexio MX Workhorse Tb nited tates Workhorse Tb nited tates ).980 Workhorse Tbb nited tates Workhorse Tb TRLI ustralia Workhorse Tb ROP Belgium B Workhorse Tb enmark Workhorse Tb

5 enmark Workhorse Rigid truk Rab enmark Workhorse Tb urope Workhorse Tb urope Workhorse Tb urope Workhorse Truk Rab urope Workhorse Rigid truk with rigid drawbar Ra nited ingdom Workhorse Tb nited ingdom Workhorse Tb (overloaded?) axle Trator-emi (9t GVW) with 9t axle load on single tyres (steer and towed) and t on drive axle with twins (allowed,5t max!) Figure : Road Wear Performane Workhorses uropean workhorse truks have signifiant higher road wear ompared to the vehiles of other regions of the world. This is mainly beause the have single tyres on the towed axles of s and semi-s. In other ountries towed axles on truk units are equipped with twin tyres. The worst truk unit is the 9 t GVW vehile on axles (Belgium ) The twelve higher apaity vehiles are desribed in Table and the results are in Figure.

6 Table : HGV-type: Capaity Vehiles Vehile origin & identifiation number GCM (t) / Payload (t) Length (m) Vehile Classifiation FRIC hemati Vehile desription & vehile ode outh fria Z-h apaity Tbb outh fria Z-h apaity Tbb MRIC Canada C-h apaity Tbb nited tates -h apaity train double Tbab nited tates 5 5-h ) 5.0 apaity Tb TRLI ustralia -h apaity Tbb Belgium B-h enmark -h enmark 5 5-h Germany -h Netherlands NL-h Netherlands NL-h ROP apaity uropean modular vehile apaity uropean modular vehile apaity uropean modular vehile apaity uropean modular vehile apaity apaity uropean modular vehile with rigid drawbar Tba Truk Rab Tbb with rigid drawbar Tba Rigid truk with two rigid drawbar s Raa with rigid drawbar Tba Netherlands NL-h apaity Rigid truk Rab

7 Volume Capaity Related Vehiles Figure : Road Wear Performane of High Capaity Vehiles The omparison shows e.g. for the same 7 axle truk unit with 0t GVW (Germany ) or 60 t GVW (Netherland ) an inrease from 0,60 to 0,8 (+75%) or the omparison of truk units with the same GVW of 60 t on 8 axles (Belgium ) or on 7 axles (Netherland ): 0,6 vs. 0,8 (+ 5%). xept the volume oriented vehiles ( and NL ) the uropean units have a worse performane than the vehiles of the other states. The fife very high apaity vehiles (GVW 5 t - 90 t), oming only from meria and ustralia, are desribed in Table and the results are shown in Figure. Table : Very High Capaity Vehiles Vehile origin & identifyation number GCM (t) / Payload (t) Length (m) Vehile Classifiation hemati Vehile desripttion & vehile ode MRIC Canada C-v Very high apaity train double Tbab Mexio MX-v Very high apaity train double Tbab nited tates 6 6-v nited tates 7 7-v Very high apaity Very high apaity train triple Tbab ab train double Tbab TRLI ustralia -v Very high apaity B-triple Tbbb

8 Figure : Road Wear Performane of Very High Capaity Vehiles The very high apaity vehiles perform relatively well regarding pavement damage. The wear performane values are very low ompared to the other vehile lasses. The reason for this is that only the steering axle is equipped with single tyres, all other tyres (drive and towed) are twins. On the other hand this means higher rolling resistane values and worse eonomi (fuel onsumption) and environmental (CO ) performane. Figure shows the results of road wear performane for all kind of truk units at a glane. uropean Referene Vehile Figure : Road Wear Performane of HGV by tates and Continents

9 The volume related truk units have of ourse better road wear performane than the weight related units. In the distintion of payload apaity and volume apaity the determinant fator is the speifi weight or the so alled density of the load to be transported. Table 5 shows examples of the speifi gravity for different goods. The example truk urope, see table above, has 6 t payload apaity and 87.6 m³ volume apaity. This means the argo may have a density 0. kg/dm³ or less to avoid overloading. s one an see from table 5, empty beer bottles in boxes have just the density of 0. kg/m³. Table 5: peifi gravity of several goods (kg/dm³ = t/m³) Water, Milk, Beer, et. Fuel, Oil, thanol, et. arth and oil Conrete Briks lloy teel Wood (dry) Rubber Beer boxes with 0 empty bottles (0,mx0,mx0,m ) weigh 0 kg Beer boxes with 0 filled bottles (same size, but 0 kg) Refrigerators (white goods) Nine passenger ars,,5 t eah, on a 00m³ transporter ingle dispathed items (parels) tyropor kg / dm³ 0,6-0,8 kg /dm³, -,0 g / dm³, kg / dm³,9 kg / dm³,7 kg / dm³ 7,9 kg / dm³ 0,5-0,9 kg / dm³, kg / dm³ 0, kg / dm³ 0,6 kg / dm³ 0, kg / dm³ 0,5 kg / dm³ 0,5 kg/ dm³ 0,0 kg / dm³ Fluid and bulk transporters tend to be overloaded beause of the high speifi weight of the argo. The more argo spae is available the more the danger of overloading is given. WIM measurements from Germany ( measuring sites on highways) show that nearly one third of the heavy vehiles are overloaded. That is a strong argument for mandatory on board weigh (and axle load) measurements, see Figure 5. Figure 5: GVW measurement results for urope truk ombination in Germany at sites

10 Figure 6 shows the relation between payload and gross vehile weight. The differenes between workhorse and high or very high apaity vehiles are small. The payload share on the GVW is in almost all ases between 60% and 70%. n analogue performane ould be evaluated for argo volume. 0,800 0,700 better performane 0,600 0,500 0,00 0,00 0,00 0,00 0,000 h -v B B 5 L N L N L N 5 h -v 6 h -v 7 C C C h -v C X X X M M M h -v X M Z Z Z Z Figure 6: Load ffiieny (Payload/ GVW) of HGV by Continents This paper desribes only the performane of different truk units on pavement wear. The performane onerning bridge loads or turning ability and other impats on infrastruture are not examined. The topography and the existing road network in different ountries and regions in the world plays a major role in defining maximum weights or dimensions for artiulated vehiles. Referenes COT Report, 00, OC/JTRC Report: Moving Freight with Better Truks, 00 Bt WIM data unpublished Woodrooffe, J.: hapter evaluation of truk performane of OC Report RRB ontribution to OC Report

11 ppendix Vehile Vehile I Veh.Wear Fator VWF Payload [t] Wear Performane Payload/GWW Payload/GVW ustralia 5,86 9,0 0,0 9,0/6=0,67 0,67 ustralia -h 8,,5 0,89,5/68=0,65 0,65 ustralia -vh 0,96 60,0 0,8 60,0/9=0,66 0,66 Belgium B 7,,8 0,7 5,0/9=0,585 0,585 Belgium B-h 8,88 9, 0,6 9,/60=0,65 0,65 Canada C,6 5, 0,8 5,/0=0,60 0,60 Canada C 5,09, 0,6,/7=0,67 0,67 Canada C-h 6,8, 0,5,/6=0,677 0,677 Canada C-vh 5,79 7, 0,55 7,/6=0,597 0,597 enmark 7,75 0,0 0,58 0,0/=0,68 0,68 enmark 7,88,0 0,6,0/8=0,667 0,667 enmark 8,67, 0,68,/8=0,67 0,67 enmark -h 9,6 0,7 0,8 0,7/60=0,678 0,678 enmark 5 5-h 0,0 8,0 0,6 8,0/60=0,6 0,6 urope 5,,0 0,,0/8=0,6 0,6 urope Ref. 6,8 6,0 0,0 6,0/0=0,65 0,650 urope,9 7,0 0,8 7,0/0=0,675 0,675 urope 6, 5,0 0,58 5,0/0=0,65 0,65 Germany -h,8 5,0 0,60 5,0/0=0,65 0,65 Mexio MX 5,76 8,6 0,00 8,6/=0,650 0,650 Mexio MX 7,8, 0,5,/9=0,666 0,666 Mexio MX 5,76 8,6 0,00 8,6/=0,650 0,650 Mexio MX-vh 8,60,8 0,0,8/67=0,6 0,6 Netherlands NL-h,87, 0,6,/50=0,668 0,668 Netherlands NL-h 0,6 7,7 0,8 7,7/60=0,68 0,68 Netherlands NL-h 7, 9,7 0,79 9,7/60=0,66 0,66 outh fria Z 5,08 8, 0,80 8,/,5=0,66 0,66 outh fria Z 5,70,9 0,79,9/9=0,65 0,65 outh fria Z-h 6,,8 0,85,8/56=0,60 0,60 outh fria Z-h 6,, 0,79,/56=0,6 0,6 6,99 6, 0,68 9,/=0,59 0,59 6,99 8,0 0,50 8,0/=0,66 0,66 nited tates,, 0,57,/6=0,586 0,586 nited tates,, 0,,/6=0,650 0,650 nited tates,6 6,7 0,6 6,7/=0,66 0,66 nited tates -h,,6 0,,6/6=0,655 0,655 nited tates 5 5-h,9 8,9 0,6 8,9/=0,657 0,657 nited tates 6 6-vh,6 7, 0, 7,/5=0,69 0,69 nited tates 7 7-vh,0,8 0,,8/57=0,575 0,575 average 0,6