Axle Configurations Research Articles

Dynamic load responses of perpetual pavement test roads on U.S. 23: Full-scale instrumentation and evaluation

Perpetual pavement experimental roads of varying asphalt concrete thicknesses (28 cm, 33 cm & 38 cm) were constructed and instrumented on U.S. Route 23 in Delaware County, Ohio. Controlled Vehicle Load (CVL) testing was performed to obtain dynamic load responses under vehicular load and to evaluate influence of vehicle speed, tire pressure and axle configuration. CVL tests were conducted in November 2012 and July 2013 to evaluate temperature effects on pavement responses. A linear elastic finite element model program, OpenPave was used to obtain layered elastic solutions of load responses with time history to validate measured results. Paired t-tests were performed to compare mean difference between measured and calculated strain responses. Factorial ANOVA test was performed to evaluate significance of truck speed and tire pressure on measured strain responses. It was found that the calculated strain responses were overall in good agreement with the measure values. A uniquely designed strain gage rosette was installed to obtain vertical strain in the pavement and was found to be effective. However, significant differences existed between measured and calculated strain responses in summer test due to unaccountability of the FE program for viscoelasticity of asphalt concrete materials. 33 cm section with stabilized subgrade performed the best with lowest strain responses. Tandem axle truck produced strains lower than single axle truck even though total weight was heavier. Transverse strain tends to increase as lateral wheel offset increases.

FEM based parametric analysis for investigating effect of wheel base characteristics and axle configurations on flexural stresses in rigid pavements

The main advantages of rigid pavements are their durability and ability to hold their shapes when subject to heavy traffic and extreme weather conditions. Different vehicles have different wheel base characteristics and axle load configurations, due to which the above conditions structurally affect the performance of the rigid pavements in different ways. One of the main causes of critical defects in the rigid pavement is the development of flexural stress exceeding the critical level under different conditions. In rigid pavements the critical stresses are generated with the combination of wheel load stresses and curling stresses. In this paper, the investigation of the variation of flexural stress developed in jointed plain concrete pavements under different axle load configuration and wheelbase characteristics was done using FEM (Finite Element Method). In this paper, the modelling of the rigid pavement was carried out using KENPAVE software. In modelling, effect of both axle load and temperature difference is considered. For loading effect, axle configuration of SASW (Single Axle Single Wheel), SADW (Single Axle Dual Wheel), Tandem and Tridem axle was considered in modelling. To include the combined effect of base and subgrade an equivalent modulus of subgrade reaction was considered as per the IRC-58 code provisions. Parameters related to rigid pavement were taken according to the provisions of IRC code for modelling of base case. Parameters of pavement like thickness of pavement slab, equivalent modulus of subgrade reaction, temperature difference, modulus of elasticity and location of wheel load were changed from the base case and maximum tensile stress was calculated for each axle configurations. Based on the analysis of results for different thickness of pavement slab, equivalent modulus of subgrade reaction, temperature difference, modulus of elasticity and location of wheel load, the variation of magnitude and location of maximum tensile stress was reported for given properties of subgrade, base and axle configuration.

Fatigue life analysis of bituminous pavement for different material properties and axle configurations

Fatigue and rutting are the major distress in the flexible pavement that occur when the strains at the bottom of the asphalt layer and top of the subgrade layer exceeds the allowable value. It becomes important for the pavement design engineers to perform analysis on the pavement structure in the fatigue and rutting distresses. There are many factors influences the distress in the pavement structure and few are traffic characteristics, material properties, and environmental conditions. The influence of material properties and temperature becomes major area of interest on the behaviour of pavement structure. This project attempts to study the influence of material properties and axle configurations in the temperature range of fatigue regime (-10 °C to 20 °C) on the behaviour of different pavement cross section. It also aims to investigate the fatigue life of pavement structure on the varying parameters.In this study, the pavement cross section is considered for three different CBR (California Bearing Ratio) values and the horizontal tensile strain is determined by using Pavement analysis software. The influence of material properties such as modulus of elasticity, Poisson's ratio of bituminous mixture is analysed. The effect of single axle and tandem axle configurations at low and high fatigue temperatures were investigated. Further the efficacy of pavement structure was evaluated for varying material properties and axle configuration in the low and high fatigue temperatures. This study will further help in optimizing the pavement structure for different site conditions.

Effects of Axle Configuration on Third Type of Rolling Contact Fatigue of Wheels of High-power AC Locomotives

Effects of Axle Configuration on Third Type of Rolling Contact Fatigue of Wheels of High-power AC Locomotives

Assessment Of Factors Affecting Road Pavement Design And Remedial Actions

Many factors such as number of vehicles, speed, climatic conditions and other factors affect are to be considered for the design of pavement. In this article we will discuss about the factors influencing pavement design. Pavements are engineered structures which are used as roads, runways, parking areas, etc. Ground or surface transportation is the most widely used transportation in the world. So, construction of pavements should be done as it is strong and durable for their design life. There are so many factors which influencing the pavement design. The factors may be of loading, environment, materials used etc. Which are as follows Wheel load, Axle configuration, Contact pressure, Vehicle speed, Repetition of loads, Subgrade type, Temperature and Precipitation. This paper aims to present a review on the performance, problems and possible remedial measures practices for roads constructed on these problematic soils in the country. Finally, emphasis should be given to the importance in construction in this kind of soil of strictly applying engineered design of geometric, drainage, pavement thickness, material selection and proportioning. Thus, those concerned bodies shall decide to accept and control the risk associated with construction on this soil or not, or to decide that more detail study is required to allow for extra design and construction preemptive measures once the potential problem has been identified and the end user convinced of the cost-savings in adopting a pro-active approach.

Research of multi-axles effects on the flexible pavement based on the viscoelastic continuum damage model

Damages caused by the multi-axles load on the pavement are more complex, due to the interaction between axles. To investigate influences of the multi-axles load on the bottom-up crack of the flexible pavement, the equivalent factor (EF) that represents damage ratios of multi-axles to single-axle based on the viscoelastic continuum damage model was proposed. Through the finite element method, influences of temperature, pavement thickness, and axle configuration on the EF were analyzed. Results suggest that the asphalt mixture with smaller m-value is more likely to have smaller EF. With the increase of temperature and asphalt layer thickness, EF of dual-axles load increases but EF of triple-axles load decreases. Besides, the wheelbase is the only factor of the axle configuration that has remarkable impacts on the EF. Making the distance between the maximum compressive and tensile stress close to the wheelbase can reduce the damage of multi-axle load.

Probability-based static truck loading model for rural bridges in Saskatchewan

A study was conducted to establish a new truck load model intended for the evaluation and design of bridges with simple spans of 20 m or less located on rural roads in Saskatchewan. Monte Carlo simulation was used to generate truck data sets based on site-specific traffic conditions determined from a traffic count program conducted between 2008 and 2012 across all 296 rural municipalities, and data collected from six weigh-in-motion stations in the province from January to December 2013. All axle weights and spacings were modelled as probabilistic parameters. The critical truck configuration featured a truck tractor with a steering axle and tandem axle group, and a truck trailer with a tridem axle group. Truck models with a common axle configuration but varying weights were developed for various reference periods that reliably reproduced extreme nominal load effects over those periods. The use of other data sets may lead to different results.

Axle Configuration and Weight Sensing for Moving Vehicles on Bridges Based on the Clustering and Gradient Method

Traffic information, including vehicle weight and axle spacing, is vital for bridge safety. The bridge weigh-in-motion (BWIM) system remotely estimates the axle weights of moving vehicles using the response measured from instrumented bridges. It has been proved more accurate and durable than the traditional pavement-based method. However, the main drawback of conventional BWIM algorithms is that they can only identify the axle weight and the information of axle configuration (the number of axles and axle spacing) is required to be determined using an extra device in advance of the weight identification procedure. Namely, dedicated sensors (pressure-sensitive sensors placed on the deck surface or under the soffit of a bridge) in addition to weighing sensors must be adopted for identifying the axle configuration, which significantly decreases the utility, feasibility, and economic efficiency of BWIM technology. In this study, a new iterative procedure simultaneously identifying axle spacing as well as axle weights and gross weights of vehicles is proposed. The novel method is based on k-means clustering and the gradient descent method. In this method, both the axle weight and the axle location are obtained by using the same global response of bridges; thus the axle detectors are no longer required, which makes it economical and easier to be implemented. Furthermore, the proposed optimization method has good computational efficiency and thus is practical for real-time application. Comprehensive numerical simulations and laboratory experiments based on scaled vehicle and bridge models were conducted to verify the proposed method. The identification results show that the proposed method has good accuracy and high computational efficiency in axle spacing and axle weight identification.

An investigation of bridge influence line identification using time-domain and frequency-domain methods

The method to obtain an accurate influence line (IL) from the direct measurement is an important research topic for structural condition assessment, model correction and bridge weigh-in-motion (BWIM) system. The two most common approaches used for the identification of IL are the time-domain (TD) method and the frequency-domain (FD) method. Despite having a similar mathematical framework, the TD and the FD methods are treated as two different methods by the researchers working on this field. This paper presents a detailed theoretical demonstration to show that the two methods discussed above are nothing but the same. The two methods were compared experimentally by using field measurement data on an existing steel girder bridge which were obtained by using three calibration trucks (CTs) with different axle weights and axle configurations. Although the ILs identified by the two methods were apparently different, but a theoretical insight into the frameworks revealed that the TD and FD methods are basically the same and a seeming difference between the two methods is due to the inherent assumptions involved in the discrete Fourier transform (DFT) such as the assumption of cyclic nature of analysis interval. Finally, a method to obtain an accurate influence line has been outlined.

Advanced full-scale laboratory dynamic load testing of a ballasted high-speed railway track

Understanding ballast layer dynamic response and long-term behavior under moving train loads is necessary for optimization of railway track performance. This paper discussed an advanced testing effort undertaken in a controlled laboratory environment for the measurement of dynamic load responses via multitude of installed sensors and the development of validated computer models and simulation tools suitable for analyzing full-scale ballasted track under dynamic loading. Constructed in a large rectangular metal frame, the laboratory model consisted of a full-scale track with eight ties, ballast, subballast, and embankment. Three different speeds and axle load configurations were applied sequentially onto the full-scale ballasted track using eight actuators, which realistically captured both slow moving freight and high-speed passenger train loads. Vibration velocities were captured at different locations on ballast surfaces and ties. Dynamic soil stresses were recorded at the bottom of the ballast and subballast layers. Both transient and permanent deformations due to repeated dynamic loads were measured in the track substructure layers and for all eight ties. “SmartRock” advanced sensors were used for the first time to track ballast particle movements under dynamic loading. Further, the test data from the experiments were compared with preliminary Discrete Element Method (DEM) simulations.

Feasibility study of low density polyethylene modified bituminous mix in DBM layer of flexible pavement

An efficient and adequate system of transportation is inevitable for the development of any country. A high traffic intensity in terms of overloaded commercial vehicle, introduction of new axle configuration, significant variations of daily and seasonal temperature of the pavement are significant factors contributing to early development of distress symptoms like ravelling, rutting, cracking, bleeding, shoving and pot holing of bituminous surfacing, which demand a proper strengthening of pavements. The early development of distress in the pavement with the conventional mixes revealed the need of design specification based on performance tests. To overcome such kind of distress, properties of bitumen and bituminous mixes can be improved to meet the requirement of pavement with the incorporation of certain modifiers. The present study evaluates the Low-Density polyethylene (waste milk pouches) modified bituminous mix properties corresponding to the optimum binder content by conducting different performance test. Experimental studies demonstrated that waste milk pouches (6% by weight of the binder) modified bituminous mix gives the best result in terms of stability and durability. Experimental results indicated that using the waste milk pouches in bitumen is not only a cost-effective mix but also a very good solution in terms of improving bitumen pavement mix properties. The present paper aims to highlight the change in properties by addition of modifiers in bitumen and develop a procedure to estimate the reliability of a particular mix design. By considering these aspects, statistically it has been proved that the bituminous mix obtained experimentally, is also reliable to be used in real life scenario.

Impact of pavement roughness and suspension systems on vehicle dynamic loads on flexible pavements

Several mechanistic-empirical software packages have been developed in the last two decades to address the impact of axle load and axle configuration on pavement responses and their performance. These software packages generally do not consider the vehicle pavement interaction. The interaction of truck suspension system with the roughness of the road surface may exert additional forces to the pavement.A process to quantify the impact of truck suspension systems and road surface condition on the damage exerted to the pavement is presented in this paper. The International Roughness Index (IRI) was used to simulate the road roughness. The truck-pavement interaction was then modeled to estimate the dynamic load applied to the pavement. The process followed to develop the algorithms is discussed, followed by a parametric study to demonstrate the interaction among the suspension properties, road roughness and vehicle speed. The impact of dynamic load on the pavement distresses and the progress of deterioration is also discussed.

Axle Weights in combined Vehicle Routing and Container Loading Problems

Overloaded axles not only lead to increased erosion on the road surface, but also to an increased braking distance and more serious accidents due to higher impact energy. Therefore, the load on axles should be already considered during the planning phase and thus before loading the truck in order to prevent overloading. Hereby, a detailed 2D or 3D planning of the vehicle cargo space is required. We model the Axle Weight Constraint for trucks with and without trailers based on the Science of Statics and provide flexible formulas for different axle configurations of trucks. We include the Axle Weight Constraint into the combined Vehicle Routing and Container Loading Problem (“2L-CVRP” and “3L-CVRP”). A hybrid heuristic approach is used where an outer Adaptive Large Neighbourhood Search tackles the routing problem and an inner Deepest-Bottom-Left-Fill algorithm solves the packing problem. Moreover, to ensure feasibility, we show that the Axle Weight Constraint must be checked after each placement of an item. The impact of the Axle Weight Constraint is also evaluated.

Influence of Commercial Vehicle Characteristics on the Magnitude of Dynamic Wheel Loads Over Asphalt Pavement Profiles with Different Roughness

The magnitude of commercial vehicle wheel loads applied on the pavement plays a crucial role in pavement performance. To avoid premature failure in the asphalt pavements, an insight into the factors influencing the magnitude of wheel loads is required. The objective of this study is to evaluate the influence of vehicle characteristics such as speed, magnitude of payload, and distribution of payload over the loading platform of a truck on the magnitude of dynamic wheel loads. For this purpose, commercial vehicle models were simulated using TruckMaker software, and the magnitude of wheel loads generated was measured. Three vehicle classes consisting of different axle configurations were considered in this study, and their movement was simulated over the pavement profiles generated according to the guidelines of ISO 8608: 2016. Dynamic wheel loads quantified in terms of dynamic load coefficient are found to be significantly affected by the above three parameters, and the effect of these three parameters is inseparable. Due to the effect of these parameters, the commercial vehicles operating under different conditions can produce dynamic loads, which are 4–60% higher than their static loads. The average load applied by the axles of a truck on the pavement is found to be sensitive to the distribution of payload over the loading platform of the truck. The trucks when loaded to the maximum legal load limit, and only when the load is located between one-third and two-third part of the loading platform, the average load applied by all the axles is found to be within the legal axle load limit.

Flexible Pavement Response Analysis under Dynamic Loading at Different Vehicle Speeds and Pavement Surface Roughness Conditions

AbstractPavement responses are affected by the magnitude and frequency of dynamic loads generated by vehicles, which are significantly dependent on axle configuration, pavement surface roughness, a...

A Universal and Reconfigurable Stability Control Methodology for Articulated Vehicles With Any Configurations

To meet with many different transportation needs, it comes in a rich diversity and variety of articulated vehicles. Vehicle combinations are seen in different axle configurations, number of articulations, powertrain, active actuation systems, etc. This research is, therefore, motivated to develop a model-based control system in a universal and reconfigurable fashion to any articulated vehicles stability control. To achieve its universality and reconfigurability, we introduce a hierarchical (two-layer) control system. Namely, the high layer formulates a model predictive control (MPC) tracking problem to generate corrective Center of Gravity (C.G.) forces/moment. The lower-level controller is formulated as Control Allocation (CA) algorithm to regulate steering or torque (brake) at each wheel optimally and reconfigurable as to meet high-level calculations. Real-time constraints, i.e. actuator limits, tire capacity, and actuator failure are discussed. Diverse applications are presented that the universal and reconfigurable methodology is handy, capable and effective on stability control while applying to various vehicle configurations and objectives.

Gaussian Mixture Model to Characterize Payload Distributions for Predominant Truck Configurations and Body Types

AbstractThis article develops and applies a Gaussian mixture modeling approach to characterize payload distributions and calculate mean payloads for the 14 predominant axle configuration–body type ...

Modelling and parametric study of a gasketed bell and spigot joint in a buried high density polyethylene pipeline

The performance of joints in gravity flow pipelines has recently been investigated since these elements influence the longevity of the pipeline system. A variety of pipe materials and joint configurations are available for gravity applications; for lined corrugated High Density Polyethylene (HDPE) pipelines, gasketed bell and spigot joints are the commonest configuration employed in North America. The purpose of the present research study is to develop a numerical model of this joint configuration that helps improve the understanding of its behavior by capturing the kinematics of the system while buried and subjected to surface load. The model provided estimates of springline rotation within 9% of the observed angle, and vertical displacement at the joint in the crown region within 8% of the experimental data from a previous research study. Other objectives include a parametric study to assess the influence of various factors that control joint performance such as surface load position and configuration, soil properties around the pipe, and the presence of pavement. The results from the parametric study indicated that the size difference of the loading pads employed in North America had little influence on the response of the jointed pipeline. It also confirmed that the single wheel pair configuration produces some of the largest demands across the joint compared to single and tandem axle configurations. The results demonstrated the significant influence that the soil and pavement have on the kinematics demands that develop across the joint due to surface loads.

Analyzing Deterioration on Arterial Roads Caused by Overloaded Business Vehicles

The many business vehicles performing important roles in the distribution of goods and services cause flexible pavement to experience overloading, which will eventually result in diminished pavement quality and durability. Roads need to be maintained periodically to maintain a high level of service. This research aims to discover the pattern of weight increments on overloaded business vehicles with the highest potential for road deterioration; analyze the relationships between said patterns and types of heavy vehicles; and determine what steps and relevant maintenance methods need to be taken. Research is performed on type 6a through 7c3 vehicles weighing 12 to 45 metric tons with various axle configurations, during both peak and off-peak hours on both workdays and holidays, to calculate the Average Daily Traffic in vehicle/day. Load on the road is then calculated to discover load value measured in Equivalent Single Axle Load (ESAL). Load is simulated up to 125 per cent heavier than total permitted weight according to data from Weight in Motion devices installed on certain arterial roads. Remaining pavement life is then calculated with the AASHTO 1993 method in accordance with its planned lifespan. Analysis shows that single-axle vehicles with double rear wheels weighing sixteen metric tons dominate national arterial roads and possess the highest potential to cause deterioration. Road deterioration, most of which consists of various forms of cracks, is accordingly determined using the Binamarga method. Relevant maintenance courses are thus formulated, comprising the forms of routine maintenance, periodical maintenance, and improvements to the roads in question.

Geodynamics of very high speed transport systems

This work reveals the existence of a new dynamic load amplification mechanism due to ground surface loads. It is caused by the interaction between a moving vehicle's axle configuration and the vibration characteristics of the underlying soil-guideway system. It is more dominant than the traditionally considered ‘critical velocity’ dynamic amplification mechanism of the guideway-ground structure, and is of relevance to very high speed transport systems such as high speed rail.To demonstrate the new amplification mechanism, first a numerical model is developed, capable of simulating ground-wave propagation in the presence of a series of discrete high speed loads moving on a soil-guideway system. The model couples analytical equations for the transportation system guideway with the thin-layer element method for ground simulation. As a practical example, it is validated using high speed railroad field data and then used to analyse the response of a generalised single moving load at high speed. Next the effect of multiple discrete vehicle-guideway contact points is studied and it is shown that dynamic amplification is highly sensitive to load spacing when the speed is greater than the critical velocity. In particular, large resonant effects occur when the axle/magnet loading frequency and the propagating wave vibration frequency of the soil-guideway structure are equivalent. As an example, it is shown that for an individual case, although critical velocity might increase displacements by 50–100%, for the same scenario, axle configuration can increase displacements by 400%. It is also shown that resonance is sensitive to the total number of loading points and the individual frequencies excited by various spacings. The findings are important for current (e.g. high speed railway) and potential future (e.g. hyperloop) transport systems required to operate at speeds either close-to, or greater than the critical velocity of their supporting guideway-soil structure. In such situations, it is important to design the vehicle and supporting structure(s) as a combined system, rather than in isolation.