Wheel Load Research Articles

Numerical and experimental study of a segmentally prefabricated orthotropic steel–ultra-high-performance concrete composite deck for long-span cable-stayed bridges

Utilizing the high strengths, toughness, and durability of ultra-high-performance concrete (UHPC), a segmentally prefabricated orthotropic steel–UHPC composite deck (POSUCD) system has been developed for long-span cable-stayed bridges. The deck system combines an orthotropic steel deck (OSD) with a reinforced UHPC layer using notched perfobond strips (NPBLs). The UHPC layer is prefabricated onto the OSD of the girder segment in the factory to form the POSUCD. After the precast UHPC layer is cured, the girder segments are transported to the bridge site and assembled. The precast UHPC layers are then connected via transverse wet joints before tensioning stay cables. Against the background of the Danjiangkou Reservoir Bridge with a main span of 760 m, finite element (FE) analysis was conducted to examine the stress state and flexural tests were carried out on local full-scale models to verify the feasibility of POSUCD. The results show that the prefabricated UHPC layer reduces the maximum static compressive stress of the steel deck in the girder system by 21%, and the stress ranges at fatigue-prone details of the steel deck are decreased by 28%–90% compared to traditional OSDs with asphalt overlay. Since the prefabricated UHPC layer helps withstand dead axial load in the main girder, the high compressive strengths of UHPC can be utilized more effectively than in deck systems with UHPC only used as a cast-in-situ overlay to resist vehicular wheel loads. The transverse wet joint interfaces were identified as the weakest aspect of the POSUCD, whether under tension or compression; however, their nominal flexural strengths along the longitudinal direction meet the required design standards. The shear resistance of NPBLs was also well confirmed by the minimal interfacial slip on the specimen when it reached the ultimate capacity under positive bending moment.

Comparison of the Structural Performance of Ballasted and Non-Ballasted Pavement of the Railway with the Help of Beam Models on Elastic Bed and Finite Element Model

Today, many countries are opting for ballast less paving of railways using concrete line slabs as an alternative. Ballast paving is particularly prevalent in high-speed lines, urban railways, as well as bridges and tunnels designed for high loads and speeds. The priority lies in ensuring that these lines are paved with proper structural performance, especially considering the mechanics of the line and the choice between ballast pavement and line slabs. This article delves into the structural modeling and analysis process of ballast and slabs for railway lines. Models for both ballast and slab lines under passage have been developed. The study investigates the train wheel load and the impact of bed conditions. Theoretical solutions, including the beam model on an elastic bed for ballast lines and the two-beam model for line slabs, have been presented. Multiple finite element models were explored using ABAQUS software, confirming the accuracy of the theoretical results with acceptable precision. This work establishes a suitable model for calculating the effects of vertical force on the line pavement structure and provides applications for comparing design performance between ballast and slab lines. The results highlight the optimal performance of the modeling and the superiority of the line slabs.

Effect of Ceramic Waste Powder on Rutting and Dynamic Modulus of Asphalt Mixture

Abstract: Aggregates, asphalt binder, and mineral filler are blended in appropriate proportions to guarantee the desired characteristics of asphalt. Besides from aggregates and bitumen, the role of filler material in HMA is critical since it affects the mechanical characteristics and serviceability particularly when subjected to wheel load. The current research investigated the effect of Ceramic Waste Powder (CWP) used as filler in terms of rutting, and dynamic modulus of asphalt mixtures when used in different proportions 20%, 40%, 60%, 80% and 100% by weight of Marshall Specimen, and the results were compared to conventional mixture employing stone dust as a filler. The performance testing revealed that the rut resistance increases with the increase in CWP content from 40 % to 60 % in asphalt mixtures and showed 21 %, and 58 % decrease in rut depth value to that of conventional asphalt mixture at 55 ℃ respectively. While dynamic modulus increases as the frequency of the applied load increases from 0.1 Hz to 25 Hz and it decreases when the temperature of the dynamic modulus test increases from 4.4 °C to 54 °C. Higher values of Dynamic Modulus are observed at 21.1°C and 37.8 °C temperature for all frequencies. Therefore, using CWP as filler in asphalt not only increases the mechanical properties of HMA but also be a suitable approach towards reducing ceramic waste pollution.

The effect of 3D printing parameters on the tensile strength of acrylonitrile butadiene styrene filament for designing CNC router machine gears

Print parameters are factors that influence the mechanical strength of 3D printed objects. Based on a literature review, the parameters of layer thickness, printing speed, and fill geometry percentage value influence the mechanical strength of 3D printed objects. This study focuses on a combination of robust 3D printing parameters for designing CNC router machine gears. The purpose of this research was to determine the effect of printing parameters on the mechanical strength of tensile loads on 3D printed objects. From the experimental results, it was found that by providing a combination of layer thickness parameters, printing speed parameters, and fill percentage parameters, it has an effect on the mechanical strength resistance of 3D printed objects to accept tensile loads. From the research it was found that the ideal layer thickness parameter of 0.1 to 0.2 mm does not exceed half the size of the nozzle diameter of 0.4 mm to produce fine raster fibers. From the research it was found that the ideal speed parameter for printing gears with ABS filament material is at speed 30 mm/s to 50 mm/s to produce a stable raster fiber size and the percentage parameter of a good fill for printing gears is at a value of 20% to 40%. The results of the research found the best printing parameters for printing gears with a print parameter formula with a 3D print parameter formula layer height 0.15mm, gyroid infill 20%, with a speed of 30mm/s maximum tensile strength reaching 30.7 MPa with the results of wheel loading simulation analysis gear is able to withstand a maximum workload of 85 Kg

Assessing Vehicle Wandering Effects on the Accuracy of Weigh-in-Motion Measurement Based on In-Pavement Fiber Bragg Sensors through a Hybrid Sensor-Camera System.

Weigh-in-motion (WIM) systems are essential for efficient transportation and monitoring parameters such as vehicle number, speed, and weight to ensure regulatory compliance and enhance road safety. Recently, WIM measurements using the Glass Fiber Reinforced Polymer Fiber Bragg Grating (GFRP-FBG) sensors have shown robustness and effectiveness. However, the accuracy of weight evaluation using the WIM systems based on GFRP-FBG sensors can be significantly influenced by the vehicle-wandering effect, which introduces uncertainties in wheel position determination and weight calculations. This paper assessed the impact of vehicle wandering on the accuracy of a WIM measurement system based on GFRP-FBG sensors by utilizing a new hybrid sensor-camera system that integrates roadside cameras and in-pavement GFRP-FBG sensors. The detailed methodology and framework of the developed hybrid system are introduced, followed by field testing on Highway I-94 in the United States. The field testing results indicate that by using the hybrid system, the wheel load detection accuracy of the WIM system based on GFRP-FBG sensors can be controlled to be a Type I or Type III WIM according to the ASTM 1318E-09 standard, with an average accuracy ranging from 87.83% to 94.65%. At the same time, when the wander distance is less than or equal to 9 cm, the developed WIM system proves to be very cost-effective as it only comprises two GFRP-FBG sensors, one temperature FBG sensor, and one camera. These findings indicate the practical potential to enhance the accuracy of WIM systems based on GFRP-FBG sensors designed for highways for low-coast, reliable, and accurate measurements by addressing vehicle wandering effects.

Effective Notch-Stress-Based Stress Concentration Factors of the Rib-Deck Weld in Orthotropic Steel Decks Considering the Effect of Asphalt Surfacing.

Effective notch stress (ENS) approaches have many application prospects in fatigue damage assessments; however, an ENS can only be obtained by conducting complex and time-consuming numerical analyses, deterring many engineers from applying such an approach. In terms of the rib-deck weld in orthotropic steel decks (OSDs), predictive formulae for determining the ENS concentration factors (ENS-based SCFs) have been proposed; however, the effect of asphalt surfacing is not involved, which limits their applications in practical engineering. In the present study, refined finite element (FE) models, including asphalt surfacing, were developed to obtain the ENS-based SCFs which could be applied to practical engineering. Parametric analyses were conducted to investigate the effect of the transverse loading position, the combined effect of the transverse loading position and asphalt surfacing, and the effect of the temperature of the asphalt surfacing. The amplification coefficients (kSCF, kSCF1, and kSCF2) were introduced to determine the ENS-based SCFs on the basis of the predictive formulae without considering the effect of asphalt surfacing. Results show that the ENS-based SCFs of the rib-deck weld is considerably affected by the transverse position of wheel loading and the asphalt surfacing. The cubic polynomial function could be employed to fit the numerical results of the ENS-based SCFs and amplification coefficients (kSCF, kSCF1, and kSCF2) with high fitting precision. Predictive formulae for determining the ENS-based SCFs corresponding to arbitrary transverse loading position and temperature of asphalt surfacing are proposed. The validation investigation turns out that the relative error of the proposed formulae is within 10%, indicating the feasibility of using this approach for engineering applications.

Cover crops and soil loosening are key components for managing P and C stocks in agricultural soils

AbstractAgricultural soils have accumulated phosphorus (P) and lost carbon (C) in the recent decades. Simultaneously, soil structure has been degraded by the large increase in machinery weight. High wheel loads compact the subsoil, resulting in reduced root growth, decreased yields, and hence decreased C inputs and P removals. To reduce the accumulated excess P stock, the P balance should be kept strongly negative for decades, which requires high biomass production. P accumulation in poorly yielding field parts has created local hotspots, often characterized by soil compaction and poor drainage. They may be only 1%–6% of the agricultural landscape area but present a high risk for waterbodies. Identifying and targeting these hotspots for P removal can be a key strategy for mitigating P emissions. Achieving the P removal is most likely to require soil loosening to repair the damage caused by compaction and use of cover crops to mine out the accumulated P. This soil improvement strategy can also be beneficial for C sequestration and crop productivity. This commentary highlights the current status and recent developments in the interactions between compaction, cover crops and P loss to provide a research basis for developing landscape‐level strategies.

Research, analysis and optimization of the drive characteristics of the drive wheel of the machine tiller based on SPH method

Abstract The boat tiller (machine tiller) uses the floating working principle to make the hull and drive wheel bear the general tractor drive wheel load and drive two functions, respectively, so that it has good applicability in the operation of deep muddy foot water field, which greatly improves the tillage efficiency of China’s water field farming. The drive wheel is an important component of the machine tillage boat; its structural parameters have a significant impact on the driving performance and efficiency of the machine tillage boat. In this paper, combined with the kinetic analysis of the drive wheel, a single-wheel leaf-soil smooth particle hydrodynamic model of the drive wheel is constructed based on the SPH method, and the influence of the parameters of the wheel spurs of the drive wheel unit group on the driving performance is analyzed, and the drive wheel mechanism parameters with the best driving efficiency are finally obtained through simulation analysis. The research results show that the maximum propulsive force of the optimized single-wheel blade structure increases by 35.8% compared with that before optimization, the slip rate decreases by 3.9% compared with that before optimization, and the driving efficiency increases by 14.4% compared with that before optimization. The structural design and parameter selection of the drive wheel of the research results of this paper provides a certain theoretical basis, which is of great significance to the later improvement of the drive efficiency and performance of the drive wheel of the machine tiller in paddy soil.

An exploratory framework for accelerated airport pavement testing using the geotechnical centrifuge

ABSTRACT Full-scale Accelerated Pavement testing (APT) has been regarded as an essential step to bridge the gap between research and practice for pavement design because it can fully mimic a large number of heavy wheel loading on pavements. Despite being able to test pavements in an accelerated manner compared to Long-term Performance Monitoring (LTPM), conducting one full-scale APT experiment is still demanding in terms of monetary cost, space, time, etc., and the accessibility to APT facilities is only available in a few countries nowadays. In this study, an exploratory APT study with a down-scaled pavement model in a high-g environment created by geotechnical centrifuge was performed with up to half a million simulated aircraft load repetitions. Through this test, it was proved that the centrifuge APT can reproduce the full-scale airfield pavement responses, including rutting, cracking, material fatigue, etc. The transient and permanent deflection of the pavement surface, variations in stress and strain states within the pavement structure over its lifespan can be well captured for analysis. This framework of centrifuge APT provides a new methodology for pavement testing and can significantly save the current cost and time of full-scale APT.

Research on the permanent deformation mechanism and dynamic meso-mechanical response of porous asphalt mixture composite structure using the discrete element method

This study proposed a heterogeneous 3D virtual rutting model to investigate the rutting evolution mechanism and the dynamic meso-mechanical response of a porous asphalt mixture composite structure. The 3D virtual rutting test model incorporated a three-phase asphalt mastic-aggregate-airvoids system with grain size distribution and genuine aggregate morphology. Innovative algorithms were developed for cyclic rolling loading to reflect repetitive wheel loading. In contrast to the indoor rutting tests, the 3D virtual rutting tests exhibited greater rutting deformation and weaker dynamic stability in the range of 3.16%–10.17% and 2.65%–11.77%, respectively. Shear forces were predominant in the virtual rutting tests. As the porous asphalt mixture composite structure's surface layer thickness increased, the shear contact force increased and the maximum parallel-bond (PB) contact force diminished. The 3D virtual rutting test model was demonstrated to be feasible for simulating rutting deformation and dynamic meso-structural responses in porous asphalt mixtures with cyclic rolling loading algorithms.

Influence of Nonlinear Analysis Technology on Damage Analysis of Asphalt Pavement Structure

As a means of predicting the damage pattern and design life of asphalt pavement structures, the reliability of damage analysis is highly dependent on the calculation accuracy of the pavement mechanical responses under wheel load. The nonlinear analysis, on its part, can practically describe the stress dependence of the modulus of granular materials and fine-grained soils, so that the mechanical responses of the wheel-loaded asphalt pavement structure can be obtained more accurately. Therefore, the correct application of nonlinear analysis technology is essential to obtain reliable damage analysis results. For this reason, computer program KENLAYER was utilized to explore the effects of stress adjustment methods and core parameters of nonlinear iterative analysis on the damage analysis results. According to the calculation results, this paper explains the reasons why the stress adjustment Methods 2 and 3 are not applicable to the structural analysis of pavements containing nonlinear granular materials in the case of thin surface layers, illustrates the effects of improper selection of the adjustment methods and each iteration parameter on the dominant damage pattern, finds out the reasons for unreliable calculation results due to improper selection of the iteration parameters, and makes corresponding suggestions for carrying out damage analysis accurately.

Predictive Modeling for Highway Pavement Rutting: A Comparative Analysis of Auto-Machine Learning and Structural Equation Models

Highway pavements deteriorate over time as successive wheel loads cause rutting, cracking, texture loss, and so forth. Design standards and pavement performance models account for some of the known contributory factors, such as levels of traffic and vehicle composition. However, such models are limited in their predictive power, and highway authorities must conduct regular pavement condition surveys rather than relying on the standard deterioration models alone. The ways in which multiple factors affect pavement deterioration, including rutting, are complex and are believed to include feedback loops where rutting then influences driving position, exacerbating the rutting levels. Standard regression models are not well suited to representing such complex causal mechanisms. This paper compares two alternative modeling approaches, structural equation models and auto-machine learning, and evaluates the predictive ability and practicalities of each. The findings indicate that auto-machine learning (AutoML) may be superior in its predictive ability. However, the “black box” nature of AutoML results makes them potentially less useful to practitioners. A process of using machine learning to help inform a structural equation model is proposed.

Evaluating the dynamic behavior of railway-bridge transition zone: numerical and field measurements

Short-span bridges are one of the most frequent infrastructures along railway tracks where railway track stiffness suddenly changes. The sudden variation in the vertical stiffness of railway tracks increases dynamic loads and causes numerous defects in ballasted railroads. Therefore, improving the dynamic performance of railway tracks can be conducted by constructing countermeasures along the transition zone. In this regard, the approach slab is a practical technique used in railway-bridge transition zones. As the dimensional shape of the approach slab plays a significant role in the dynamic response of transition zones, this study evaluated the effects of its main geometric parameters. A three-dimensional model of the railway portal bridge, including the approach slab, was built using the finite element method and analyzed by imposing moving wheel loads as a series of acting force points along rail elements. The model was validated with field-obtained results acquired through a laser/camera-based measuring technique. Then, some sensitivity analyses were performed to find optimized geometric dimensions of approach slabs to improve the dynamic behavior of railway-bridge transition zones. Obtained results of the geometrical sensitivity analysis show that when the geometrically optimized approach slab is used along the railway-bridge transition zone, the displacements of rail and ballast are decreased by 24% and 18%, respectively.

Dynamic Analysis of Train–Bridge Coupling System for a Long-Span Railway Suspension Bridge Subjected to Strike–Slip Fault

Long-span railway bridges crossing active faults are more vulnerable owing to the joint combination of pulse ground motions and surface dislocation. To study the dynamic effects resulting from the coupling of long-span railway suspension bridges crossing strike–slip fault and trains, a nonlinear model in which wheel–rail contact was established based on Hertz’s nonlinear theory and Kalker creep theory. To generate the ground motions across strike–slip fault, an artificial synthetic method, which considers both the fling-step effect with a single pulse and the directivity effect with multiple pulses, is employed. The effects of fault-crossing angles (FCAs) and permanent ground rupture displacements (PGRDs) are systematically investigated based on wheel–rail dynamic (derailment coefficient, lateral wheel–rail force, and wheel–load reduction rate). Conclusions are drawn and can be applied in the practical seismic design and train running safety assessment of long-span railway suspension bridges crossing strike–slip fault.

Mechanical properties of polypropylene fibre reinforced recycled concrete aggregate for sustainable road base and subbase applications

There is limited research on the dynamic behaviour of soils reinforced with polypropylene (PP) fibres and a scarcity of literature on using PP fibres to improve the mechanical properties of recycled construction and demolition (C&D) waste subjected to dynamic wheel loads. To fill these research gaps, this study introduces varying proportions of PP fibres (0%, 0.1%, 0.2%, and 0.3% by dry weight of recycled concrete aggregate (RCA)) to enhance unbound granular RCA for pavement base/subbase applications. Incorporating PP fibres resulted in increased unconfined compressive strength, primarily attributed to the reinforcement effect of the fibres, which improved the tensile strength and resistance to stretching between aggregates and hindered the development of tension cracks through a bridging mechanism. Moreover, the enhanced stretching resistance between RCA particles, achieved by incorporating PP fibres, led to a 7% increase in Mr when the PP content was increased from 0 to 0.1%. Incorporating PP fibres into RCA also reduced permanent deformation and permanent strain rates. Notably, adding 0.1% PP fibres yielded the most favourable outcome in terms of permanent deformation response, transforming the behaviour of RCA from “Incremental Collapse” to “Plastic Creep.” This distinctive characteristic makes the blend of RCA with 0.1% PP fibres suitable for application as base and subbase layers.

Response of Strain-Gauge-Based Tie Reaction Measurement Circuits under Dynamic Loading and Variable Support Conditions

Strain gauges are often used to measure vertical wheel loads in a railroad track. This approach is based on the concept of differential-shear-strain (DSS) measurement: The difference in vertical shear force between two points along a beam equals the magnitude of the resultant of applied vertical forces in between. With a slight modification to the strain-gauge positions and installation of an additional set of strain gauges, this concept can be extended to measure the vertical rail–tie interface reaction forces, thus assessing the tie support conditions. Although the application of DSS measurements for vertical-wheel-load quantification is widely prevalent in the railroad community, the validity of this approach for tie reaction measurement has been relatively unexplored. Conceptually, the approach is similar to the vertical-wheel-load measurement system, with the only difference being the placement of the strain gauges along the rail. Nevertheless, several questions have been raised about how different track and loading configurations can affect the accuracy of such a measurement system. To address some of these concerns and establish this approach as a viable method for tie support condition assessment, a field-validation effort was undertaken. Under the scope of this research effort, the strain-gauge-based DSS measurement system for rail–tie interface reaction-force measurement was evaluated in the field under static as well as dynamic loading. The study showed that the strain-gauge-based measurement approach is as accurate as other conventional methods of tie reaction-force measurement.

Analysis of soil compaction under different wheel applications using a dynamical cone penetrometer

Soil compaction is one of the major problems in modern agriculture. Thus, the workability of a soil reflects to its ability to accept the traffic of agricultural machinery and implements. Water content and compaction are factors that influence the rheological behavior of the soil. the representation of soil shows limitations regarding the behavior of the tire-soil interface and its resistance to deformation is both influenced by the different forms of loading application along a tire path on a soil particle. This paper presents a study of the impact of multiple wheel passage, the wheel velocity, and the weight applied to the wheel on the agricultural soil represented by the cone index. To do this, we were inspired to launch an investigation for soil compaction determination at three levels of wheel load, three levels of velocity and at tillage, first, second and third passages of wheel with three replications on clayey sandy mixed grain soil. The results of this study shows that the greatest soil compaction occurred at the highest wheel load (1000 N), the lowest speed (0.1 m/s) and the highest number of passes (third pass), this leads to minimize multiple passes and or follow the same path, also, keeping the load on the ground as low as possible (weight of the machines), and working at high speed in agricultural fields.

Impacts of vehicle light-weighting on wheel wear and RCF and a novel ultralight vehicle design

Vehicle light-weighting is a critical design target for rail vehicles, as it reduces energy consumption and enhances the vehicle capacity and dynamic performance, making the railway system more attractive in addressing the rising environmental challenges and increasing demand in transportation. This paper presents a quantitative analysis of the impact of vehicle light-weighting on wheel wear and rolling contact fatigue (RCF), using the USFD wear law, the shakedown map and the Tγ approach. A conventional metro vehicle is utilized as a baseline model, and the mass reductions from different vehicle components (i.e., car-body, bogie frame and wheelset) are implemented for the simulation considering various running scenarios. The effect of mass reduction on wheel wear can be divided into two aspects: quasi-static wheel load and wheel-rail dynamic interaction. In short-radius curves, the change in static axle-load predominantly determines wheel wear, whereas in large-radius curves and tangent track, the wheel-rail dynamic interaction plays an important role, thus showing different rates of wear reduction when mass reduction is achieved respectively from car-body, bogie frames and wheelsets. Reducing vehicle mass can significantly reduce wheel damage of RCF on short-radius curves with curve radii above 400 m, while there is a risk of increasing RCF on tight curve R250, due to the impaired function of wear to counteract the crack propagation. This work also exhibits a specific innovative ultralight vehicle design, where the linear synchronous motor technology is applied to reduce substantially the mass of the vehicle without impairing the capability to provide the required amount of tractive effort. The proposed ultralight vehicle can reduce the wheel wear by approximately 40% and shows substantial benefit for preventing RCF damage, compared to a conventional vehicle.

Reducing Wheel Loading in the Grinding of Titanium Alloys through Ultrasonic-Assisted Plasma Oxidation Modification

To reduce wheel loading caused by chip adhesion in the grinding of titanium alloys, a new method named ultrasonic-assisted plasma oxidation modification grinding is suggested. The processing principle was introduced in this research, and based on that, the experimental apparatus was established. Then, the surface and cross-sectional morphologies of a workpiece with an oxide layer were characterized, followed by the detection of its microhardness and surface composition. On this basis, in the absence and presence of the oxide layer, the dynamic changes in wheel loading on the grinding wheel surface and the evolution behavior of chip adhesion on the grains were both investigated after gradually increasing the grinding passes. Finally, the effects of wheel loading on the ground surface morphologies were analyzed. The results showed that the oxide layer with low microhardness was mainly composed of TiO2 and Al2O3. Moreover, with an increase in grinding passes, the overall occupied area of chip adhesion on the grinding wheel surface increased proportionally in the absence of the oxide layer, which finally caused severe wheel loading. Conversely, yet at almost the same rate, the overall occupied area of chip adhesion increased after remaining comparatively unchanged in a short range of grinding passes in the presence of the oxide layer, which effectively inhibited the wheel loading. Compared with the ground surface obtained without an oxide layer, the generation of plastic-stacking was significantly restrained with the assistance of the oxide layer, thereby improving the ground surface quality.

Transient response of pavement structures under moving wheel loads using the ALE methodology

AbstractThe dynamic response of long structures (e.g., pavements) subjected to moving loads is generally difficult to simulate using conventional methods like the finite element method in the Lagrangian setting. This is because the entire length of the structure in the path of the moving load would need to be discretized, and in turn would require large meshes. Additionally, if improvement in quality of results through the use of finer mesh sizes is sought, the entire region of the mesh in the load path would require refinement. As a direct result, long simulation run‐times can be expected when using conventional methods. To overcome these drawbacks, and improve the efficiency of the finite element simulations, the Arbitrary Lagrangian Eulerian (ALE) approach can be used to simulate pavement structures, provided longitudinal homogeneity is assumed. This contribution uses an extension of the quasi‐static ALE framework to the transient domain, enabling the study of the dynamic response of pavement structures subjected to moving loads. In this work, some case studies are considered to highlight the capabilities of this dynamic ALE framework.