Vehicle-pavement Interaction Research Articles

An overview of a unified theory of dynamics of vehicle–pavement interaction under moving and stochastic load

This article lays out a unified theory for dynamics of vehicle–pavement interaction under moving and stochastic loads. It covers three major aspects of the subject: pavement surface, tire–pavement contact forces, and response of continuum media under moving and stochastic vehicular loads. Under the subject of pavement surface, the spectrum of thermal joints is analyzed using Fourier analysis of periodic function. One-dimensional and two-dimensional random field models of pavement surface are discussed given three different assumptions. Under the subject of tire–pavement contact forces, a vehicle is modeled as a linear system. At a constant speed of travel, random field of pavement surface serves as a stationary stochastic process exciting vehicle vibration, which, in turn, generates contact force at the interface of tire and pavement. The contact forces are analyzed in the time domain and the frequency domains using random vibration theory. It is shown that the contact force can be treated as a nonzero mean stationary process with a normal distribution. Power spectral density of the contact force of a vehicle with walking-beam suspension is simulated as an illustration. Under the subject of response of continuum media under moving and stochastic vehicular loads, both time-domain and frequency-domain analyses are presented for analytic treatment of moving load problem. It is shown that stochastic response of linear continuum media subject to a moving stationary load is a nonstationary process. Such a nonstationary stochastic process can be converted to a stationary stochastic process in a follow-up moving coordinate.

Finite element analysis of rigid pavement on a nonlinear two parameter foundation model

A numerical iterative procedure based on finite element method has been presented for analyzing the dynamic response of pavement to moving load resting on a nonlinear subgrade. The pavement is descretized by finite and infinite beam elements. The foundation is modeled by Pasternak's two parameter soil medium. The nonlinear stress-strain relationship in the soil is considered. The dynamic vehicle-pavement interaction (VPI) effects are incorporated in the analysis. The effect of the material nonlinearity of the supporting soil medium on the pavement response is investigated by conducting a parametric study.

2-D finite element analysis of rigid pavement considering dynamic vehicle–pavement interaction effects

In the present study, an improved solution algorithm based on Finite Element Method for dynamic analysis of rigid pavements under moving loads is presented incorporating vehicle–pavement interaction which is having significant effect on the response. The concrete pavement is discretized by finite and infinite plate elements. The underlying soil medium is modeled by Pasternak model. An attempt is made to consider the infinite extent of the pavement with introduction of infinite elements at both ends. A detailed study is carried out for the range of velocities for pavements of finite and infinite lengths resting on two parameter soil medium. The effect of soil modulus, shear modulus, pavement thickness and the vehicle–pavement interaction on the response of pavement is presented. Relationships are suggested in non-dimensional form to predict critical velocity and maximum deflection for three prominent peaks in case of analysis without VPI and first critical velocity range of analysis with VPI. Predicted values using these relationships are in good agreement with the actual values. The comparison between the response of finite and infinite pavement lengths revealed that the deflections are decreased and the critical velocity range is narrowed in case of pavements of infinite length.

Effect of vehicle–pavement interaction on dynamic response of rigid pavements

In the present paper, dynamic response of rigid pavements subjected to moving vehicular loads is presented using an analytical procedure based on the finite element method. The vehicle–pavement interaction effects are taken into account while developing the solution algorithm. The concrete pavement is discretized by finite and infinite beam elements. Infinite elements are helpful in appropriate modeling of end conditions. The main purpose of the development of infinite elements is to model the unbounded domain. The underlying soil medium is modeled by Pasternak model which assumes the existence of shear interaction between the spring elements. The moving vehicle is represented by a mass supported by a spring-dashpot system. The vehicle -pavement interaction force is modeled with Dirac-delta function. Dynamic equilibrium equation is solved with Newmark-Beta integration scheme. It has been observed that the dynamic interaction between the moving load and the pavement has significant effect on pavement response. Parametric study is carried out to investigate the effect of vehicle–pavement interaction (VPI) and soil parameters on the response of pavement.

Simulation of Dynamic Effects of Vehicles on Pavement Using a 3D Interaction Model

The present study formulated a three-dimensional (3D) vehicle-pavement coupled model to simulate the pavement dynamic loads induced by the vehicle-pavement interaction where both the vehicle vibration and pavement deformation were considered. Based on this model, the effects of road surface conditions, vehicle parameters, and driving speed on pavement dynamic loads were analyzed. The impact factor, dynamic load coefficient, and frequency distribution of pavement loads were mainly concerned in this study. The simulated results indicated that under rough road conditions the dynamic loads of vehicles are significantly higher than the static loads. The developed methodology can be used to further study the vehicle-induced pavement response, and the loading information will be useful in analyzing vehicle-induced pavement damage.

Dynamic analysis of rigid pavement with vehicle–pavement interaction

Study of the dynamic response of pavements due to moving loads such as vehicles and aircraft has received significant attention in recent years because of its relevance to the design of pavements and airport runways. This paper presents an improved solution algorithm based on the finite-element method to analyse rigid pavements under moving vehicular or aircraft loads. The concrete pavement is discretised by thick plate elements that account for the transverse shear deformation and bending. The underlying soil medium is modelled by elastic spring and dashpot systems. The dynamic interaction between the moving load and the pavement is considered by modelling the vehicle by spring–dashpot unit. Graphical results are presented to demonstrate the significance of the dynamic interaction between the pavement and the vehicle on pavement response. Results indicated that slab thickness, soil modulus and velocity of aircraft had a significant effect on the response of the pavement.

A wavelet interpretation of vehicle-pavement interaction

This paper utilizes a wavelet approach to interpret the interaction between truck dynamic axle loads and pavement roughness profile. The experimental data used was obtained from an instrumented 5-axle semi-trailer truck equipped with an air and a rubber suspension in the drive and trailer axles, respectively. Wavelet decomposes the original signal into a number of sub-band levels depending on its characteristics. The size of the dataset used allowed 11 levels of wavelet decomposition with test speed dependent frequencies ranging up to 4 cy/m. For dynamic load, the extent of variation in each of these wavelength sub-bands, was summarized through an energy metric effectively computed as the sum of the squares of the wavelet coefficients in each sub-band. Total energy was computed as the sum of the energy of all sub-bands and was normalized by dividing by the length of the test section. Relative energy was computed as the percent of total energy in each sub-band. The results were summarized through 3D plots of relative energy versus load frequency versus profile frequency. The profile frequencies mostly affecting dynamic loads depend on speed and range from 0.65 to 3.76 cy/m.

Stochastic Spatial Excitation Induced by a Distributed Contact on Homogenous Gaussian Random Fields

The contact between vehicle tire and pavement surface random field is typically modeled as a point contact in the literature of vehicle-pavement interaction. In reality, tire-pavement interface can be considerably larger than a point contact, particularly when a tire is not very stiff and pavements are relatively soft. This paper developed a methodological framework that approximately aggregates one- and two-dimensional random fields within the contact area by taking local, weighted spatial average to account for the distributed contact. Statistical properties such as power spectral density, autocorrelation function and variance of the induced spatial excitation are related to the counterparts of the original random field. It was found that the distributed contact acts like a low-pass filter whose bandwidth is governed by the contact interface and the weight function.

Computer simulation and field measurement of dynamic pavement loading

Two methods, i.e. computer simulation and field measurement, are used in this paper to investigate dynamic pavement loading (DPL) generated by vehicle–pavement interaction. A profilometer is used for measuring road surface roughness. Based on the power spectral density of the measured surface roughness, a computer simulation program is developed using quarter vehicle model. In field measurement methods, an experiment is designed to gain the time history of DPL. An IVECO vehicle is taken as a test vehicle and eight vibration cells were used to pick up vertical accelerations of vehicle body and axle. The test data are collected and recorded while the test vehicle is moving along 11 different pavement sections of highway and bridge at six different speeds. Statistical characteristics of vertical accelerations and DPL of the test vehicle are obtained and analyzed by means of random process theory. The result of computer simulation matches the result of field measurement very well. It is found that DPL is primarily concentrated between 1.8 and 14.8 Hz and coefficient of variation of DPL falls into the range of 5–35% of static vehicle load. An approximate relationship between coefficient of variation of DPL and vehicle speed and road surface roughness is established.

Predicting Vertical Dynamic Loads Caused by Vehicle-Pavement Interaction

Dynamic loads caused by vehicle-pavement interaction are either moving loads or random loads. Motion property of dynamic loads was described by means of Dirac-delta and Heaviside functions, and its randomness property was studied using a quarter-truck vehicle model. A series of statistical characteristics of wheel loads in frequency domain and time domain are presented in this paper. It was found that dynamic loads are a constant mean Gaussian stationary ergodic process whose power spectral density is in proportion to the power spectral density of pavement roughness, whereas the ratio coefficient relates to dynamic properties of vehicle and velocities of travel. Numerical simulation based on the specifications of the International Organization for Standardization (ISO) indicated that only at low speed could dynamic loads be treated as quasi-narrow band-width random processes, which covers the frequency range of 1.0–4.0 Hz. At high speed, main frequency distributions of dynamic loads occur in 1.0–4.0 and 10.0–15.0 Hz. Further analysis also showed that according to the International Organization for Standardization specifications, the root mean square of dynamic loads is proportional to CSP, the square root of an important index related to pavement levels.

General Outlook of Pavement and Vehicle Dynamics

The interaction between vehicle and pavement is complex since pavement roughness excites the dynamic forces generated by vehicles, while these dynamic forces simultaneously increase the pavement roughness. The objective of this paper is to provide an overview of the results of recent research related to pavement and vehicle dynamics and their interaction and to evaluate their potential use in the design and management of pavements. Pavement dynamic models are capable of determining stresses, strains, and deflections in various directions when harmonic, pulse, or transient loads are applied. Vehicle dynamic models simulate the effect of pavement roughness on the inertia of various vehicle components. These models can predict the dynamic forces produced by different axles and wheels of traveling vehicles at different locations along the pavement. Pavement response computed using dynamic models matches field measurements closer than those computed using static models. The concept of vehicle-pavement interaction can be applied to weigh-in-motion, pavement design and performance, and vehicle regulations.

Bridge Vibrations Due to Vehicle Moving Over Rough Surface

The dynamic response of a simply supported box girder bridge due to a vehicle moving across the span is presented. The effect of the randomly varying dynamic force generated by the vehicle moving over a rough bridge deck is considered in the analysis. A comparison is made of results obtained by modeling the vehicle and vehicle-pavement interaction as a single unsprung mass and as a concentrated time-dependent force. A statistical analysis of the results shows that peak impact factors for deflection, moments, and shear are considerably greater than those normally prescribed in bridge codes, especially when the vehicle is moving at high speeds. The effect of vehicle mass is also more significant at higher speeds.