The procedure follows the M-E design process, iterating the transfer function coefficients until the performance equation accurately predicts pavement distress.
effects, observed performance, and in situ material characterization was developed. A field calibration procedure for asphalt pavements that incorporates live traffic, environmental. Calibration of the pavement performance equations is essential to link pavement responses under load to observed field performance.
View full-textĪs mechanistic-empirical (M-E) pavement design gains wider acceptance as a viable design methodology, there is a critical need for a well-calibrated design system.
#Pavement design aashto method proposals software#
Adoption of the proposed factors within the MEPDG software does necessitate a recalibration of the performance models. Correction factors are thus presented to ensure the correctness of the loading time calculation in MEPDG. Ultimately, this would result in underestimation of the pavement response to a load and, therefore, greater errors in calibrations of the pavement response to field distress. Comparison of these two methods shows that the frequencies calculated on the basis of the MEPDG procedure are greater than the ones determined by the 3-D FE method, which indicates that the loading time determined from MEPDG is not conservative. In addition, laboratory-measured viscoelastic properties were incorporated into the FE model to describe the constitutive behavior of HMA. The model developed accurately simulated actual tire rib sizes and the applicable contact pressure for each rib. Therefore, to evaluate the MEPDG methodology for calculation of the loading time, the results of the MEPDG procedure were compared with those of an advanced three-dimensional (3-D) finite element (FE) approach that simulates the approaching-leaving rolling wheel at a specific speed. Concerns were raised that the current MEPDG methodology may be overestimating the frequency, which would result in underconservative distress predictions. used to transform the pavement structure into a single-layer system, and it is then assumed that the stress distribution occurs at a constant slope of 45 degrees in the equivalent pavement structure. By this approach, the Odemark method of thickness equivalency is first. To account for the time dependency of HMA, MEPDG recommends calculation of the frequency of the applied load as a function of the vehicle speed and the Pavement structure. The Mechanistic-Empirical Pavement Design Guide (MEPDG) uses the complex modulus to simulate the time and temperature dependency of hot-mix asphalt (HMA). Finally, the importance of considering these parameters in the rigid pavement design procedures is highlighted. The proposed technique is conducted using a non-linear finite element procedure considering the Soil Structure Interaction (SSI) under different soil erosion scenarios. In this technique the different parameters mentioned above are considered in evaluating the RP behavior and their significance in predicting the responses is examined. Therefore, in this research the ultimate RP responses obtained using the AASHTO design method are evaluated and compared with those obtained from a new proposed technique for modeling the soil erosion. In addition, the ultimate responses of the rigid pavement under the actual soil erosion scenarios may be affected by several other parameters such as percentages and location of soil erosion occurred, the value of subgrade stiffness, slab dimensions, and slab thickness which almost are neglected in the AASHTO design method. Therefore, damage generally occurs at these edges. However, the effect of soil erosion is localized beneath certain parts of the RP (generally beneath the edges of pavements). A reduced modulus of subgrade reaction is generally obtained in this method of design by considering the Loss of Support (LS) which is included in the AASHTO design of concrete pavements to account for the potential loss of support arising from subbase erosion and/or differential vertical soil movements. The AASHTO Method for rigid pavement (RP) design considers the influence of the localized soil erosion under the rigid pavement by reducing the stiffness of subgrade under the pavement to a certain constant value over the whole area.
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