Ltpp rigid pavement design software software#

However, this particular model requires additional site factors that often dominate the analysis. At first, the roughness model was also in the scope. Two models were considered-rutting and fatigue cracking.

This task was accomplished by applying the MEPDG models using the mechanistic responses calculated by KENPAVE. The MEPDG performance prediction models were used to compare predicted distress performance at the end of the design life with the estimated structural condition obtained from the logistic structural model. Deflection parameter I 1 as a function of SN for a flexible pavement with HMA modulus of 500,000 psi (3,445,000 kPa).Ĭomparison with MEPDG Predicted Performance Deflection parameter CI 3 as a function of SN for a flexible pavement with HMA modulus of 500,000 psi (3,445,000 kPa).įigure 92. Deflection parameter I 2 as a function of SN for a flexible pavement with HMA modulus of 500,000 psi (3,445,000 kPa).įigure 91. I 1 is the deflection parameter chosen for the final structural logistic model based on fatigue cracking.įigure 90. Figure 92 describes the trends between I 1 and SN. Figure 91 describes the trends between deflection parameter CI 3 and the SN.ĬI 3is the deflection parameter chosen for the final structural logistic model based on rutting performance. The deflection parameter chosen for the final structural logistic model based on roughness performance. For simplicity, the data were grouped by subgrade modulus. Figure 90 describes the trends between deflection parameter I 2and the SN. In figure 89, E 2 refers to M rof the base course in pounds per square inch. Where a 1 and a 2 are the layer coefficients of the asphalt concrete and base layers, respectively, D 1 and D 2are the layer thicknesses in inches, and m 2 is the base layer drainage coefficient, assumed as unity for simplicity. Computation of the layer coefficient a2 for base course. The SN and layer coefficients for a three-layer system can be computed using the following equations:įigure 89. The layer coefficients are measures of the relative ability of a unit thickness of a given material to function as a structural component of the pavement. It is a function of layer thicknesses, layer coefficients, and drainage coefficients. The SN gives a quantitative description of the structural capacity of the different layers in a pavement section. The choice was the SN used in the 1993 AASHTO Guide for Design of Pavement Structures. It was necessary to find a common variable for comparing the mechanistic responses among different combinations of the input parameters. The combination of all parameters in the factorial experiment resulted in 1,296 sections. A factorial study was designed and is presented in table 18.

(28) The intention was to evaluate different asphalt concrete and base layer thicknesses at different stiffnesses and different subgrade moduli. Several pavement structures were simulated using the KENLAYER computer program, which is part of the KENPAVE software. (27) MECHANISTIC-EMPIRICAL ANALYSIS OF FLEXIBLE PAVEMENTS (28) The mechanistic responses were then used to predict performance using the MEPDG.

Ltpp rigid pavement design software software#

The software KENPAVE, developed by Huang, was used to model typical flexible and rigid pavement structures. The mechanistic validation was conducted using linear elastic models to predict the responses of the pavement (stresses, strains and deflections) to load. Simplified Techniques for Evaluation and Interpretation of Pavement Deflections for Network-Level Analysis