Adjustment factors for MEPDG pavement responses considering three- dimensional analysis and wide-base tire

Gungor, Osman Erman

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https://hdl.handle.net/2142/89243 Copy

Description

Title

Adjustment factors for MEPDG pavement responses considering three- dimensional analysis and wide-base tire

Author(s)

Gungor, Osman Erman

Issue Date

2015-12-11

Director of Research (if dissertation) or Advisor (if thesis)

Al-Qadi, Imad L.

Department of Study

Civil & Environmental Engineering

Discipline

Civil Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Mechanistic-Empirical Pavement Design Guide (MEPDG)
• Adjustment Factors
• Finite element (FE) Analysis
• AASHTOWare Pavement ME

Abstract

The Mechanistic-Empirical Pavement Design Guide (MEPDG) provides a superior methodology as compared to its predecessor in the design and analysis of pavement structures. The mechanistic (MEDPG analysis) calculates critical pavement responses due to pavement-tire interactions. On the other hand, the empirical part refers to the prediction of pavement distress propagation over time using transfer functions. Transfer functions link critical pavement responses to particular pavement distresses. Although MEPDG analysis provides a theoretically framework for pavement simulations, its limitations and simplifications may produce inaccurate pavement response calculations. In contrast, finite element (FE) analysis has proven capable of overcoming these limitations by simulating pavement more realistically in terms of material characterization and loading conditions. However, the high computational cost of the FE analysis precludes its use as a pavement analysis engine within the MEPDG’s framework. Therefore, this study suggests two adjustment factors based on FE analysis to bridge the gap between reality and MEPDG analysis. The first adjustment factor—developed utilizing 480 cases performed in ABAQUS and considering similar material properties and pavement structure—converts pavement responses obtained from dual tire assembly (DTA) loading to new generation wide base tire (NG-WBT) loading. The second adjustment factor—developed from running 336 cases in MEPDG and FE analyses using compatible input parameters—accounts for the limitations of MEPDG analysis regarding the material characterization and loading conditions. The simulated cases were selected to capture extreme conditions—e.g., thick and thin pavement structures with strong and weak material properties—so that extrapolation could be avoided during the implementation of the equations. The adjustment factors revealed that NG-WBT produces higher responses than DTA, which can cause greater pavement damage. Additionally, MEPDG analysis fails to capture the effect of non-uniformity and the three dimensionality of contact stress on pavement response. The discrepancy becomes significant; especially for the pavement responses near the pavement surface, such as tensile strain at the AC surface and vertical shear strain within the AC layer, that are believed to cause top-down cracking.

Graduation Semester

2015-12

Type of Resource

text

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http://hdl.handle.net/2142/89243

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Copyright 2015 Osman Erman Gungor

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