| 1. |
- Khavassefat, Parisa, 1984-, et al.
(författare)
-
A computational framework for viscoelastic analysis of flexible pavements under moving loads
- 2012
-
Ingår i: Materials and Structures. - : Springer Science and Business Media LLC. - 1359-5997 .- 1871-6873. ; 45:11, s. 1655-1671
-
Tidskriftsartikel (refereegranskat)abstract
- A general quasi-static computational procedure is established to evaluate stresses and strainsinduced in the viscoelastic flexible pavement bymoving traffic. The procedure is based on superposition principle and is computationally favourable, as itrequires only reduced incremental problem to besolved numerically. The impact of traffic speed anddensity on the mechanical response of flexible pavement is examined numerically. Results relevant fortwo major modes of pavement’s distress, i.e. crackingand rutting, are reported. It is shown that the state-ofpractice layered elastic analysis used in pavementdesign is unable to capture several important qualitative and quantitative aspects of pavements response.
|
|
| 2. |
|
|
| 3. |
- Khavassefat, Parisa, 1984-, et al.
(författare)
-
Dynamic Response of Flexible Pavements at Vehicle-Road Interaction
- 2015
-
Ingår i: International Journal on Road Materials and Pavement Design. - : Taylor & Francis. - 1468-0629 .- 2164-7402. ; 16:2, s. 256-276
-
Tidskriftsartikel (refereegranskat)abstract
- In the present paper a robust and general computational framework that captures the dynamic response of flexible pavements to a moving vehicle is presented. A finite element method is relied upon in order to establish the response function for a linear viscoelastic pavement structure with dynamic effects taken into account. In order to characterise the dynamic loads induced on the pavement by moving traffic, a quarter car model combined with measured road profiles is used. Once both the traffic loads and pavement response functions are known, the stresses and strains induced in the pavement can be obtained in the frequency-wavenumber domain through the convolution procedure. The computational procedure developed is applied in the present study to evaluate the effect of the pavement surface roughness on the pavement structure response to truck traffic loading. Stress field parameters governing fracture initiation in asphalt layers are reported for two measured road roughness profiles. It is shown that the dynamic effects at vehicle-road interaction may have a profound influence on the stresses induced in flexible pavements; therefore, these effects need to be taken into account for the accurate estimation of the road resistance to cracking.
|
|
| 4. |
- Khavassefat, Parisa, 1984-, et al.
(författare)
-
Impact of Long and Heavy Vehicles on Pavement Damage
- 2013
-
Konferensbidrag (refereegranskat)abstract
- In the present paper the effect of vehicle configuration and traffic characteristics on the damage induced in pavements by traffic is investigated numerically. A three dimensional time-dependent pavement-vehicle interaction analysis is performed in order to study the impact of the parameters mentioned above on the mechanical response of flexible pavements. The analysis is based on a fast and robust computational procedure, developed by the authors. The numerical algorithm utilizes the three-dimensional finite element solution of the reduced problem of one tyre pavement interface loaded with tyre pressure. Afterwards, a superposition procedure based on fast Fourier transform techniques is applied to find the pavement response to moving loads. The method is general and capable of capturing the stress-strain response to any arbitrary loading history.One particular area of study with employing the current procedure is the analysis of long and heavy vehicle impact on pavement damage. Two major modes of distress, i.e. cracking and rutting have been discussed for 6 different truck types with 2 speeds. It is shown that an accurate numerical model provides a more accurate explanation of different distress modes. Moreover the conventional analysis and design methods with layered linear elastic behaviour assumption for asphalt layer are unable to capture several important aspects of pavement response.
|
|
| 5. |
- Khavassefat, Parisa, 1984-, et al.
(författare)
-
Non-stationary Response of Flexible pavements to Moving Vehicles
- 2016
-
Ingår i: The international journal of pavement engineering. - : Taylor & Francis. - 1029-8436 .- 1477-268X. ; 17:5, s. 458-470
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper the pavement surface deterioration is investigated based on field measurements of surface roughness profiles obtained in Sweden. A predictive function for surface deterioration, based on average gradient of yearly measurements of the road surface profile in Swedish road network, is proposed. In order to characterise the dynamic loads induced on the pavement by moving traffic a quarter car model is used. Afterwards a non-stationary stochastic approach is used to obtain the yearly response of the pavement to moving loads. The solution is in frequency-wavenumber domain and is given for a non-stationary random case as the pavement surface deteriorates in pavement service life influencing thus the magnitude of the dynamic loads induced by the vehicles. The effect of pavement surface evolution on the stress state induced in the pavement by moving traffic is examined for a specific case of quarter car model and pavement structure. The results showed approximately a 100% increase in the dynamic component of stresses induced in the pavement.
|
|
| 6. |
- Khavassefat, Parisa, 1984-
(författare)
-
Pavement Response to Moving Loads
- 2014
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The response of flexible pavements at vehicle-road interaction has been studied in this thesis. A quasi-static and a dynamic framework for analysing the pavement structure under moving load has been developed. Both frameworks are general, robust and computationally efficient.The quasi-static procedure is based on superposition principle and is computationally favourable, as it requires only reduced incremental problem to be solved numerically. Using the developed framework the effect of vehicle configuration and traffic characteristics on the damage induced in pavements is investigated numerically. It is shown that the developed numerical model provides a more accurate explanation of different distress modes. Moreover the conventional analysis and design methods with layered linear elastic behaviour assumption for asphalt layer are unable to capture several important aspects of pavement response.In the dynamic analysis approach the pavement roughness and vehicle suspension system is linked to a dynamic pavement model in order to account for the dynamic effects at vehicle-road interaction on pavement response. A finite element method is relied upon in order to establish the response function for a linear viscoelastic pavement structure with dynamic effects taken into account. The computational procedure developed is applied to evaluate the effect of the pavement surface roughness on the pavement structure response to truck traffic loading. Stress field parameters governing fracture initiation in asphalt layers are reported for two measured road roughness profiles. It is shown that the dynamic effects at vehicle-road interaction may have a profound influence on the stresses induced in flexible pavements; therefore these effects need to be taken into account for accurate prediction of the road performance in the field.
|
|
| 7. |
- Khavassefat, Parisa, et al.
(författare)
-
The effect of road surface deterioration on pavement service life
- 2014
-
Ingår i: Expanding horizons: 13th International Symposium on Heavy Vehicle Transport Technology, San Luis, Argentina, 27-31 October 2014.
-
Konferensbidrag (refereegranskat)abstract
- The effect of pavement surface deterioration on pavement service life has been studied for a set of case studies. The Swedish mechanistic empirical design method is used in order to analyse the pavement performance under dynamic moving loads while the longitudinal profile unevenness is updated on yearly basis. The surface evolution assumed in the case scenarios are chosen in relevance with the general trend of surface deterioration in Swedish road network. Results from the case studies indicate that the pavement service life is highly affected by pavement surface deterioration, especially for pavement segments with high traffic. Moreover predictive maintenance for high traffic road segments might be beneficial as it increases pavement service life and decreases the user related costs, e.g. vehicle fuel consumption.
|
|
| 8. |
- Khavassefat, Parisa, 1984-
(författare)
-
Vehicle-Pavement Interaction
- 2014
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Several aspects of vehicle-pavement interaction have been studied and discussed in this thesis. Initially the pavement response is studied through a quasi-static and a dynamic computationally efficient framework under moving traffic loads. Subsequently, a non-stationary stochastic solution has been developed in order to account for the effect of pavement surface deterioration on pavement service life.The quasi-static procedure is based on a superposition principle and is computationally favourable, as it requires only a reduced incremental problem to be solved numerically. Using the developed framework, the effect of vehicle configuration and traffic characteristics on the damage induced in pavements is investigated numerically. It is shown that the developed numerical model provides a more accurate explanation of different distress modes.In the dynamic approach the pavement roughness and vehicle suspension system are linked to a dynamic pavement model in order to account for the dynamic effects of vehicle-pavement interaction on pavement response. A finite element method is employed in order to establish the response function for a linear viscoelastic pavement structure with dynamic effects taken into account. The developed computational procedure is applied to evaluate the effect of the pavement surface roughness on the pavement structure response to truck traffic loadings.Furthermore, the deterioration trends for the flexible pavement surface have been investigated based on field measurements of longitudinal profiles in Sweden. A predictive function is proposed for surface deterioration that is based on the average gradient of yearly measurements of the road surface profiles in Swedish road network. The developed dynamic framework is further elaborated to a non-stationary stochastic approach. The response of the flexible pavement is given for a non-stationary random case as the pavement surface deteriorates in pavement service life, thus influencing the magnitude of the dynamic loads induced by the vehicles. The effect of pavement surface evolution on the stress state induced in the pavement by moving traffic is examined numerically.Finally the effect of surface deterioration on pavement service life has been investigated and discussed in the thesis by incorporating the proposed prognostic surface deterioration model into a ME design framework. The results are discussed for different case studies with different traffic regimes. It was indicated that the predicted pavement service life decreases considerably when the extra dynamic loads, as a result of pavement surface deterioration, has been taken into account. Furthermore, the effect of performing a predictive rehabilitation process (i.e. resurfacing) has been studied by employing a LCC framework. The application of preventive maintenance was shown to be effective, especially when the deterioration rate is high.
|
|
