Tire Configurations Research Articles

Investigation of impact of wheel wander on pavement performance

The procedures in Mechanistic-Empirical Pavement Design Guide (MEPDG) and Caltrans software program using Mechanistic-Empirical (CalME) methodologies to address wheel wander are relatively simple and based on dividing the wheel wander distribution into a number of segments (say five) of equal areas. Such approaches suffer from a major limitation that the selection of equal segments is arbitrary, and can, therefore, lead to biased results relative to realistic transverse wheel wander distribution. The proposed Monte-Carlo simulation scheme provided cumulative distribution functions for all the critical responses and they in turn were used to estimate pavement performance (or life). The investigation covered a variety of pavement factors that significantly affect pavement performance or life. The factors included are: (1) pavement layer configuration (thin and thick); (2) pavement material properties (unmodified and polymer-modified asphalt mixture); and (3) tyre configurations (dual and wide-base). In this paper, the focus has been on the description of the proposed approach and its application in two of the important modes of failure in asphalt concrete pavements: fatigue cracking (top-down and bottom-up) and rutting. The required traffic-induced pavement strain database needed in the pavement performance investigations was developed using the 3D-Move analysis software. The proposed approach is more appealing than current procedures (e.g. MEPDG and CalME) since the pavement response distributions were derived statistically. The pavement design information presented are in the form of data sets that the pavement engineers and researchers can readily use to assess the impact of wheel wander in terms of many important factors such as pavement layer configuration, non-uniform tyre contact distribution, vehicle speed, etc., that affect long-term pavement performance.

Modelling of Plastic Culvert and Road Embankment Interaction in 3D

A series of 3D Finite Element simulations was performed to investigate the effect of different factors influencing the distortions undergone by a plastic culvert tube while subject to external loading from a heavy truck. The applied simulation model was verified by full-scale loading tests carried out on a number of actual culvert installation sites. Based on the results of the study, it can be concluded that both installation depth and quality of the material surrounding the culvert have a dominant effect on culvert distortions while the effects of material quality above the culvert and the type of tyre configuration transmitting the wheel load are much less pronounced.

Tire choices in Roman chariot racing

Formal chariot racing was a sophisticated and popular sport for over 1800 years, from Etruria in the 6th c. B.C. down to the fall of Constantinople, and the races held in a large number of circuses and hippodromes imply that huge numbers of racing chariots were made over the course of those centuries. It may therefore be thought surprising that no racing machine has been found, but the dearth of such hardware is plausible given the perishable wood and leather components of the lightweight vehicles and the desirability of recycling the metal parts. In this situation a particular artifact must be accorded special significance. It is a hand-sized bronze model of a Roman racing biga, known as the Tiber model because found in the river. Dated to the 1st-2nd c. A.D., it is now on display in the British Museum (GR 1894.10-30.1, Bronze 2694). With this model as our guide, all the major dimensions of Roman racing chariots have been reasonably well determined; further, several technical aspects (some obvious, others quite subtle) of actual racing chariots can be established from it. Among the subtle details of the model, one feature is especially intriguing in view of the remarkably realistic work of its maker, who was clearly knowledgeable in matters large and small of vehicular racing. As first mentioned to me by J. Swaddling of the British Museum during our latest study of the model (November 2014), an unusual tire configuration is apparently represented on this all-bronze model: the right wheel has a slightly raised rim, as if to indicate a thin iron tire, but the left wheel lacks this feature (fig. 1). This asymmetrical arrangement is not only curious, it also implies extra work and expense. What, then, could be the reason for it?One possibility for having apparently only one tire on the Tiber model — which was probably a toy for a rich individual; the emperor Nero, an avid racer, was said to play with toy chariots — is that two different castings were used in the toy's production, and either one could have been used in the assembly, in random selection from a box.

Influence of tyre inflation pressure on measured pavement strain responses and predicted distresses

The Federal Highway Administration conducted controlled loading tests on the US Route 23 Test Road under hot weather conditions in 1998. The testing was conducted using three tyre inflation pressures (TIPs) for four tyre types in two configurations on two asphalt concrete pavement sections. The pavement response data were collected from strain rosette sensors glued to the existing surface pavement layer and were adjusted to common temperature, lateral offset distance and speed for comparison purposes. The comparisons of the adjusted strain responses revealed the impact of the TIP on pavement strain responses and distress prediction. Mechanistic-Empirical Pavement Design Guide fatigue cracking and rutting models were used to predict the damage influenced by TIPs to the experimental pavement sections. The most road-friendly inflation pressure is recommended for each tyre configuration based on the resulting pavement service life, with pavement thickness influencing distress predictions. The two pavement sections with different thicknesses are compared based on their predicted performance as an additional study.

Combining performance based lab tests and finite element modeling to predict life-time of bituminous bound pavements

As roads are subjected to high traffic loads due to the strong growth in heavy vehicle traffic and new trends in the automotive and tire industries, the traditional asphalt mix tests are often inadequate for a reliable prediction of the in-service performance of flexible road pavements. With performance-based test methods (PBT) at hand, the thermo-rheological properties of hot mix asphalt can be obtained. This paper presents results of a research project where 4-point bending beam (4-PBB)-tests are carried out on different AC mixes for base layers at various temperatures and frequencies to obtain stiffness and fatigue behavior. At the same time, linear elastic finite element simulations are performed with input data for the materials different from the 4-PBB. These simulations are carried out on two different pavement structures, different tire types (twin-tires and wide base super-single tires) and wheel configurations (tire load and pressure). Loading data for the tires are obtained from stress-in-motion measurements using the Vehicle–Road Surface Pressure Transducer Array (VRSPTA). The strain at the bottom of the bituminous bound layers are taken from the simulations and used in combination with the fatigue functions to evaluate the life-time in permissible load cycles for different tire configurations. The main findings are that super-single tires lead to significantly lower pavement life-times than the standard twin-tire configuration and that the relative difference increases with decreasing thickness of the pavement structure. Also, the tire pressure has a strong impact on the pavement life-time; an increase in tire pressure by 60% decreases the life-time by 25–52% (super-single) and 15–38% (twin-tire) respectively.

Effect of Tire Configuration on the Performance of a Low-Volume Road Exposed to Heavy Axle Loads

A series of response measurements was conducted at an instrumented low-volume road test site to determine the effects of different tire con-figurations of a heavy vehicle on the performance of the road structure. After the measurements were made, a true three-dimensional finite element model was developed with PLAXIS 3D 2012 software. The aim of the modeling was to find explanatory factors between the measured stress–strain relationships and confirmed permanent deformations, rutting in particular, at test site conditions. A model was created with reasonable material parameters. The model produced stress levels and road surface deflections that are comparable with the measured values. The mobilizing levels of shear strains seem to explain the notable permanent deformation at the test site despite the relatively low amount of heavy traffic. The shear strain levels can also be used as an efficient tool in evaluating the effects of other variables, such as road structural layers, construction materials, and environmental conditions, on the risk that structural deterioration of roads may occur when the intensity of loading increases.

Effect of Tire Configuration on the Performance of a Low-Volume Road Exposed to Heavy Axle Loads

A series of response measurements was conducted at an instrumented low-volume road test site to determine the effects of different tire con-figurations of a heavy vehicle on the performance of the road structure. The test site road had a thin asphalt concrete surface, and the total thickness of its structural layers was about half a meter; the road rested on a silty subgrade. The response measurements with two axle loads, 80 kN and 100 kN, included recording of road surface deflection and vertical stresses at three depths below the road surface. The results indicated that the stresses inside the road structure were up to 30% higher when narrow types of single tires were used instead of normal dual tires. According to the employed distress models, this means a threefold to fourfold difference in the service life of the road.

Influence of tyre configuration on pavement response and predicted distress

The Federal Highway Administration conducted controlled loading tests on the U.S. Route 23 Test Road in hot weather conditions in Ohio, including two dual and two wide-base configurations. This paper is to reveal the influence of tyre configuration on pavement and provide some suggestions on tyre configuration from the perspective of reducing pavement damage. The raw strains were adjusted to common temperature, lateral offset distance and nominal speed for consistent comparison. MEPDG fatigue cracking and rutting models were used to predict damage brought by different tyres to pavement sections. The results indicate that newer generation of wide-based tyres with wider interface with pavement could be road-friendly, inducing similar or even less damage than the conventional dual tyres. At the same time, certain conventional dual tyres, which are commonly used in the current market, might cause larger damage to the pavement than other tyres in certain environmental and loading conditions.

Heavy Truck Driver Workload Investigation

ABSTRACT Driver workload is of growing interest in the automotive society, since the number of in-vehicle technologies and vehicles on the road grows. Operational and environmental factors impact the driver's ability to negotiate a chosen course and place heavy demands on the driver in terms of mental and physical capacity. A key component of the driver's operating environment is the vehicle. In this research, the impact of various tire configurations, for example, dual and wide based, for a Class 8 tractor–semitrailer combination vehicle on driver workload performance is presented. Driver workload performance is assessed during four maneuvers: 60 m radius steady state circle, 120 m radius steady state circle, road course, and North Atlantic Treaty Organization emergency lane change maneuver. Surface electromyography (sEMG) electrodes were placed on the left and right wrist flexors (flexor carpi ulnaris) and right wrist extensors (extensor carpi ulnaris) in order to capture muscle activity during all maneuvers. Peak and integrated values of sEMG are calculated to obtain metrics of driver workload. Results of the study show distinct separation of muscle activity for each tire configuration. Differences in driving techniques were also identified based on the dominant hand of the driver and orientation of the maneuver, that is, clockwise or counterclockwise.

타이어 종류 (Wide Base Tire and Dual Tire Assembly)에 따른 아스팔트 포장 반응 평가

PURPOSES : The first generation of wide base tires introduced in the early 1980s was found to cause a significant increase in pavement damage compared to dual-tire assemblies. However, wide base tires have evolved considerably, and a new generation of wide base tire is thought to be comparable to conventional dual tires for pavement damage. A challenge associated with using wide base tires is the accurate quantification of pavement damage induced by these tires. The objective of this study was to investigate the responses of flexible pavement to continuously moving vehicular loading under various tire configurations. METHODS : The comparison of the strain/stress responses of full-depth pavement caused by conventional dual tire assembly and new generation of wide-base tires was performed. The FE model incorporates linear viscoelasticity of asphalt material and continuous moving load using implicit dynamic analysis. RESULTS AND CONCLUSIONS : The result demonstrates that the new wide-base tires caused slightly more fatigue damage and less primary rutting damage in HMA layer than a dual-tire assembly, but caused more secondary rutting damage in subgrade than a dual tire assembly.

Objective Analysis of the Stability of an Extralegal Weight Tractor-Trailer Combination during a Rapid Air Loss Event

ABSTRACT In the California Transportation Permits Manual, the minimum overall tire-to-tire axle width (overall width) of a vehicle in the extralegal weight configuration is 2.44 m. Commercial truck tractor and trailer tandem 1.82-m-wide axles fitted with new-generation wide base single (NGWBS) tires measure 2.34 m in overall axle width; thus, they are not compliant with the current California Department of Transportation requirement. Because of the growing application of NGWBS tires in the market, it is important to understand the vehicle stability characteristics of a tractor-semitrailer fitted with both dual and NGWBS tire configurations. In this research, a comparison of dual to NGWBS with both a 50.8-m outset wheel and a 25.4-mm outset wheel is presented. A rapid air loss (RAL) event was initiated to represent a severe scenario in each of the three following maneuvers: straight line, steady-state curve, and lane change. The data were evaluated, and differences between NGWBS and dual tire–fitted vehicles were compared. While a tire RAL event can be perceived as a dramatic event, previous studies and driver-training events have shown that such an RAL event is manageable. The conclusion of this work is that an RAL event with NGWBS tires is as manageable as a dual tire–fitted vehicle and does not make the system unstable.

Soil Displacement and Soil Bulk Density Changes as Affected by Tire Size

<abstract><title><italic>Abstract.</italic></title> The selection of the appropriate tire size and inflation pressure for a particular load and soil condition is a critical consideration to ensure that the effects of vehicle traffic on soil compaction are minimized and that agricultural soils are managed in a sustainable manner. This study investigated the changes in soil bulk density from soil displacement data produced by a range of combine harvester tires (680/85R32, 800/65R32, and 900/60R32) with vertical load of 10.5 t and inflation pressures in the range of 0.19 to 0.25 MPa to provide a valuable indicator for tire selection. The study was conducted in a soil bin facility using a sandy loam soil (Cottenham series) maintained at 10% (w w^-1) moisture content. Results showed that the initial density (γ) was the main factor influencing soil displacement and soil bulk density changes beneath the tires. Increased tire size and low inflation pressure reduced soil displacement and the resultant increase in soil bulk density. After a single pass of the tires over the soil, these increases were approximately 26% for a low (γ = 1.20 g cm^-3), 17% for a medium (γ = 1.40 g cm^-3), and 4% for a high (γ = 1.60 g cm^-3) initial bulk density soil, respectively. The advantages of increasing tire size and lowering inflation pressure were also reflected in the results obtained from the cone penetrometer resistance data. The tire with the highest inflation pressure (0.25 MPa) produced a significantly (p < 0.05) higher increase in soil cone index (0 to 700 mm depth range) compared with the tires with lower inflation pressures (0.19 and 0.22 MPa, respectively), particularly at the centerline of the wheeling. Linear relationships (R² ≥ 0.98) between drop cone penetration and rut depth were established; these data were subsequently related to the calculated increase in soil bulk density determined from soil displacement data. The increase in soil bulk density resulting from a single pass of a tire over the soil can be determined for a range of tire configurations and initial soil conditions with the data produced by this study.

Stress-In-Motion (SIM) system for capturing tri-axial tyre–road interaction in the contact patch

A unique measuring system for the quantification of tri-axial (3-D) tyre contact force (or stress) distributions was designed, developed and used in several studies since 1994. The uniqueness of the system is defined by a textured measuring surface in order to represent a typical “textured” road surface. The system is referred to as the Stress-In-Motion (SIM) system. A single SIM measuring pad testing area comprises a total of 1020 supporting pins and a transverse array of 21 sensing elements, covering the entire tyre contact patch with in a single run. The SIM pad measuring system is modular in concept, allowing multiple SIM measuring pads to be used for e.g. wide base truck tyres, or a dual tyre configuration, or full axle measurements – using a quad SIM pad measuring system configuration. Tyre contact force (or stress) distributions are simultaneously captured in the three orthogonal directions X, Y and Z for a single, dual or full axle truck tyre configuration. Each of the sensing elements has a 9.7mm diameter circular contact surface area (∼73.9mm2) and is dimensionally optimised, allowing measurements in various tyre rolling conditions on a textured measuring surface. The textured surface induces some pre-conditioning of tyre–road contact properties, as it has small gaps around all supporting and measuring pins. The system is installed flush with the road surface, preferably on a rigid support base, and can be used for real tyre (or truck) rolling conditions. A single SIM measuring pad contains 63 strain measuring channels (3×21) for the sensing elements. Aspects such as SIM system design, sensing element calibration, system usage and outputs of specially developed software are illustrated. Several results of tri-axial road contact stress distributions are also presented.

Full-depth flexible pavement responses to different truck tyre geometry configurations

Pavement stresses and strain responses due to tyre loading are essential data for design and performance analysis. The magnitude and distribution of these responses are primarily affected by the tyres configuration geometry. This study investigates the longitudinal strain responses at the bottom of a hot-mix asphalt layer for full-depth medium-volume flexible pavement under different truck tyres design. Pavement testing was carried out with a user-control accelerated pavement facility at various speeds and tyre inflation pressures and loading. Three truck tyre configurations: dual-tyre (11R22.5) and two wide-base tyres (425/65R22.5 and 455/55R22.5) widely used in the truck industry were examined. A 3D finite element model was developed to quantify surface stresses to loading at various critical locations in the pavement after being calibrated with the field-measured strains. Field measurements showed that the 455 wide-base tyres yield 7% more longitudinal strain than a dual-tyre assembly at the same tyre pressure.

Whole-body vibration in heavy equipment operators of a front-end loader: Role of task exposure and tire configuration with and without traction chains

IntroductionThis study measured whole-body vibration (WBV) exposures in front-end loader operators, and evaluated the effects of traction chains and work tasks on their WBV exposures. MethodWBV exposures were measured and compared across three different front-end loader tire configurations: (a) stock rubber tires, (b) rubber tires with ladder chains, and (c) rubber tires with basket chains. The operators completed three distinct standardized tasks: driving on a city street, simulated plowing, and a simulated scooping and dumping task. A portable data acquisition system collected tri-axial time weighted and raw WBV data per ISO 2631-1 and 2631-5 standards. In addition, Global Positioning System (GPS) data were collected in order to compare loader speeds across tire conditions and the standardized tasks. ResultsRelative to the stock rubber tires, both types of tire chains significantly increased WBV exposures with the ladder chains having substantially higher WBV exposures compared to basket chains. Additionally, there were task dependent differences in WBV exposures. During the driving task, the z-axis (up and down) was the predominant exposure; the plowing task had a more even distribution of exposure across all three axes; while during scooping and dumping task, the x-axis (fore and aft) had the highest WBV exposures. The GPS data indicated that there were significant speed differences across tasks but not between the basket and ladder chain conditions. ConclusionsTires with ladder chains increased the front-end loader operators' exposure to WBV above the ISO 2631-1 recommended eight hour action limit increasing risk for adverse health effects. Although more expensive, basket chains are recommended over ladder chains since they substantially lowered the front-end loader operator's exposures and may ultimately reduce vibration related wear and tear on the vehicle. Impact on IndustryIn order to reduce a heavy equipment vehicle (HEV) operator’s chances for developing low back pain, this study provides information that health and safety professionals can use to reduce whole-body vibration (WBV) exposures when operating front-end wheel loaders with traction chains.

Characterisation of interface bonding between hot-mix asphalt overlay and concrete pavements: modelling and in-situ response to accelerated loading

This study investigates the effects of pavement interface conditions on hot-mix asphalt (HMA) overlay response using the laboratory and field measurements accompanied by a numerical analysis. A laboratory and accelerated testing programme were conducted as part of a comprehensive study to determine the optimum tack coat application rate for HMA–Portland cement concrete (PCC) composite pavements by Leng et al. (2008, Transportation Research Record: Journal of the Transportation Research Board, 2057, 46–53; 2009, Transportation Research Record: Journal of the Transportation Research Board, 2127, 20–28). This study synthesises the accelerated and laboratory test results with a 3D finite element (FE) model to evaluate the effects of various bonding conditions on the overlay response as well as the interface behaviour. The model outcome was validated using the laboratory and field results. The FE model was utilised to extend the findings of this study to different temperatures, tyre configurations and loading conditions. Pavement interface was modelled using a hyperbolic Mohr–Coulomb friction model, whereas HMA overlay was modelled as a viscoelastic material. A moving load was applied and implicit dynamic analysis was carried out. Field and laboratory experiments along with the numerical analysis proved the importance of achieving good bonding at the pavement interface for HMA overlay. This study found that as pavement temperature increases, the interface bonding effects on the overlay response are amplified. This could be the main contributing factor to overlay rutting. The influence of interface condition on the HMA surface and bottom strains was evaluated using a numerical model supported by full-scale accelerated pavement testing results. The effects of varying interface properties such as stiffness and strength on the HMA overlay response were investigated. The numerical model provided a range of expected HMA critical strains under realistic interface conditions ranging from full bonded to debonded conditions. This study clearly shows the significance of tack coat type and application rate effects on pavement critical responses through laboratory, in-situ response and advanced modelling.

Impact of Wide-Base Tires on Pavements: Results from Instrumentation Measurements and Modeling Analysis

Wide-base tire technology can reduce vehicle fuel consumption and greenhouse gas emissions because there is less rolling resistance at the tire–pavement interface. This study investigated the impact of wide-base tires on two typical flexible pavement structures—full-depth and thin asphalt pavements—through accelerated pavement testing and advanced finite element modeling. Three tire configurations (dual, the first-generation 425, and the new generation 455 wide-base tires) and various pavement sections with different asphalt layer and granular base layer thicknesses were considered. In particular, the advanced modeling simulated realistic tire–pavement interaction and considered appropriate material properties for each pavement layer. It was evident from this study that, of the three possibilities, the wide-base 425 tire configuration caused the greatest pavement damage. The wide-base 455 tire was found to cause greater bottom-up fatigue cracking and increased potential for subgrade rutting than the dual-tire assembly on most tested sections except the thin pavement section with the thickest granular base layer. However, the impact of wide-base tires on fatigue cracking and subgrade rutting potential became less significant with a stronger pavement structure. The finite element modeling results indicated that, compared with the dual-tire assembly, the wide-base 455 tire resulted in similar or less primary rutting potential in thin asphalt pavements and less near-surface cracking potential in thick asphalt pavements.

Evaluation of tractive performance of four agricultural tractors in laterally inclined terrain

The present work aimed to evaluate the tractive performance of four agricultural tractors with auxiliary front traction in function of six lateral inclinations in a lateral track of trials, which belongs to the Agronomic Sciences Faculty from the São Paulo State University, Campus of Botucatu. The lateral inclinations were 0; 5; 10; 15; 20 and 25 degrees. In all of these situations, the tractors operated with predetermined load of an imposed traction to the pulled tractor of 40 kN in the inclination of 0 degrees. Hence a delineation in random blocks was used, considering six inclinations and four tractors, and with three repetitions for each treatment. The analyzed variables were slippage, tractive force, hourly fuel consumption, and speed. It was concluded that the pneumatic tire configurations influenced in the tractive performance of the tractors, as they increased the lateral inclinations of the terrain.

A three-dimensional generalised finite element analysis for the near-surface cracking problem in flexible pavements

Near-surface cracking is one of the major distress types which results in reducing pavement service life. Heavy traffic loads, construction deficiencies, and surface mixture characteristics are among the predominant factors contributing to near-surface cracking. In addition, non-uniform tire-pavement contact stresses have a potential to generate extremely complex stress states near the surface. Prediction of crack initiation under these conditions requires high accuracy in the computation of state variables in pavement structure such as stresses, strains and displacements in the pavement. The generalised finite element method (GFEM) provides a computational framework in which arbitrary orientation of cracks in a finite element mesh is possible when using an enrichment strategy. The enrichment strategy in the GFEM can also increase the accuracy of the solution using higher-order polynomial approximations. A 3D analysis of near-surface cracking is performed using the GFEM. A 3D large-scale model of a long-lasting pavement is built, and cracks at various locations near the surface are introduced. Numerical experiments of a long-lasting pavement structure with defects at the aggregate scale illustrate the complex fracture conditions on and near the surface in the vicinity of a dual tire configuration.

Geogrid mechanism in low-volume flexible pavements: accelerated testing of full-scale heavily instrumented pavement sections

This study uses full-scale accelerated testing to provide new insight into the effectiveness of geogrids on the performance of low-volume flexible pavements. Although several previous studies reported that geogrids improve pavement performance by enhancing its structural capacity and reducing distress potential, this study goes further to quantify the effectiveness of geogrids, specify the mechanism of the reinforcement they provide and identify the optimum placement of geogrid in low-volume flexible pavements. Full-scale, low-volume flexible pavement sections were constructed on weak subgrade (California bearing ratio = 4%) and heavily instrumented with 170 sensors. The pavement was divided into three cells with each cell having three sections. The granular base and hot-mix asphalt layer thicknesses varied, and each cell had at least one control and one geogrid-reinforced pavement section. The instruments were embedded to measure stress, strain, deflection, moisture, pore-water pressure and temperature and were used to monitor pavement response to a moving load using the Accelerated Transportation Loading ASsembly (ATLAS). The testing programme was divided into two parts: response testing and performance testing. The response testing considered tyre configuration, loading, inflation pressure, speed and travelling offset. The performance testing considered number of passes to failure. This paper presents the various pavement responses to different loading configurations and pavement performances when a repetitive moving dual-tyre assembly at 8 km/h and 44 kN was applied. Based on the performance testing and visual observation of the pavement cross sections after excavation, the reinforced sections showed reduced rutting and delayed surface cracking compared to the control sections. Specifically, the pavements' measured response showed that geogrid-reinforced pavement sections exhibited less vertical pressure and less vertical deflection in the subgrade when tested at a low speed. Therefore, the study's most notable conclusion is that geogrid reinforcement reduces the horizontal movement of the granular material, especially in the longitudinal direction. The study also concludes the following about geogrid placement: (1) for a relatively thick granular base layer, placing the geogrid in the upper one-third of the base reduces the shear strains in the longitudinal and transverse directions. (2) For weaker pavements, the geogrid reinforcement at the base–subgrade interface reduces the vertical deflection. In the second case, the effectiveness of geogrid shall be compared to the increase in pavement structure or using other geosynthetic materials such as geotextiles.