Evaluating the Effect of Oʻahu Climate Data on MEPDG Distress Predictions

Abstract

The purpose of this project was to create new climatic data files for Oʻahu that represent the variation of conditions found on the island, and determine if the use of these files has any significant impact on distress predictions using the Mechanistic Empirical Pavement Design Guide (MEPDG). The Enhanced Integrated Climatic Model (EICM), used by the MEPDG to predict the climatic effects on material properties, cannot accept missing values in the hourly datasets; therefore, Amelia II was used to perform a multiple imputation analysis on the weather data that was collected. MEPDG runs were conducted with both the default climate file and the new climate files; the impact of these new files on the top-down fatigue cracking, bottom-up fatigue cracking, and rutting predictions was evaluated. It was found that, while most of the stations predicted similar levels of distresses, the climate station using data from Wheeler Army Air Field had consistently slower distress predictions. The primary cause of this was the consistently lower temperatures measured at this station compared to the others. While differences in precipitation amounts had a quantifiable impact on the resilient modulus of the subgrade, the precipitation data from each station were too low to have a significant impact on the final prediction results. Ultimately, it was determined that while Oʻahu's climate is not as variable as most areas in the United States, the climate variation found in different parts of the island can play a significant role in the prediction of pavement distresses; thus, the development of additional climate station files is warranted.