Browsing by Subject "MEPDG"

Now showing 1 - 4 of 4
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    Cracking of the PCC layer in composite pavement.
    (2011-12) Saxena, Priyam
    An asphalt concrete (AC) overlay of a jointed plain concrete pavement (JPCP) is intended to extend the service life of the existing pavement structure. Also known as composite pavements, such pavements exhibit features of both rigid and flexible pavements. While behavior of rigid pavements is mainly elastic, behavior of asphalt layer is load-duration dependent. At the same time, temperature curling causes non-linear interaction with the foundation. The available models of composite pavement ignore the behavior of the load duration dependent asphalt layer when the composite pavement is subjected to a combination of temperature curling and traffic loads. This research concentrates on the improvement of structural modeling of composite pavements subjected to slow developing temperature curling and instantaneous traffic loads. A finite element (FE)-based model accounting for the viscoelastic behavior of the asphalt layer in composite pavements is developed and verified using comparisons with semi-analytical solutions obtained in this study. In order to maintain compatibility with the Mechanistic-Empirical Pavement Design Guide (MEPDG) framework, a simplified procedure is developed. The procedure uses a different asphalt modulus for curling than for axle loading and determines the total stresses in the pavement as a combination of the stresses from solutions of three elastic boundary value problems. The simplified procedure is compared with the existing MEPDG model for fatigue cracking in AC overlaid JPCP. A framework for the implementation of the proposed model into the MEPDG is also developed.
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    Development of a longitudinal cracking fatigue damage model for jointed plain concrete pavements using the principles of similarity
    (2014-07) Lederle, Rita Elizabeth
    Mechanistic-empirical (M-E) pavement design computes stresses induced in a concrete slab due to applied traffic and environmental loads, and correlates these stresses to distress levels using empirical correlations. Currently, the Mechanistic-Empirical Pavement Design Guide (MEPDG) is one of the most advanced and prevalent methods of M-E pavement design. While the MEPDG predicts transverse cracking, longitudinal cracking is not predicted, even though longitudinal cracking is commonly observed in jointed plain concrete pavements (JPCPs). In this research, an MEPDG compatible model was developed to predict longitudinal cracking fatigue damage in JPCPs. This modeled adapts the framework of the MEPDG specifically for longitudinal cracking. In order to develop an M-E longitudinal cracking fatigue damage model, it is necessary to compute stresses at the critical location for longitudinal cracking due to the various traffic and environmental loads to which a pavement could be exposed. The principles of similarity were used to map the original problem into similar space, which drastically reduces the complexity of the problem without introducing any error. To avoid the computational inefficiency associated with embedding a finite element program within the program, neural networks are used for rapid stress solutions. Stresses determined in similar space are converted back into real space for damage computation. Modifications were made to the MEPDG fatigue damage computation process to eliminate simplifying assumptions and to make the procedure applicable to longitudinal cracking. A study was also conducted to determine characteristics of pavement susceptible to longitudinal cracking based on various parameters. This study made use of the principles of similarity to examine almost all pavements which could be considered in M-E design. By identifying the characteristics of pavements susceptible to longitudinal cracking, engineers can identify pavements for which longitudinal cracking analysis should be conducted. The model and design procedure developed in this research provides the tools needed to conduct such an analysis.
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    Development of Data Warehouse and Applications for Continuous Vehicle Class and Weigh-in-Motion Data
    (Minnesota Department of Transportation, 2009-10) Kwon, Taek M.
    Presently, the Office of Transportation Data & Analysis (TDA) at the Minnesota Department of Transportation (Mn/DOT) manages 29 Vehicle Classification (VC) sites and 12 Weigh-in-Motion (WIM) sites installed on various Minnesota roadways. The data is collected 24/7 from all sites, resulting in a large amount of data. The total amount of data is expected to substantially grow with time due to the continuous accumulation of data from the present sites and future expansion of sites. Therefore, there is an urgent need to develop an efficient data management strategy for dealing with the present needs and future growth of this data. The solution proposed in this research project is to develop a centralized data warehouse from which all applications can acquire the data. The objective of this project was to develop software for creating a VC/WIM data warehouse and example applications that utilize it. This project was successfully completed by developing the software necessary to build the VC/WIM data warehouse and the application software packages that utilize the data. The main contribution of this project is that it provides a single access point for querying all of the Mn/DOT’s WIM and VC data, from which many more applications can be developed without concerns of proprietary binary formats.
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    Evaluation of In-Situ variability of concrete pavement characteristics and their effect on performance
    (2013-12) Vancura, Mary Elizabeth
    Pavement performance prediction must account for uncertainties in pavement characteristics, climate, traffic loading, etc. Past research identified that concrete thickness and flexural strength were two pavement characteristics that significantly affected transverse cracking in Jointed Plain Concrete Pavements (JPCP). This dissertation concentrated on quantifying the effect of concrete thickness variability and, to a lesser extent, flexural strength variability on the reliability analysis of jointed plain concrete pavement (JPCP) performance. Concrete thickness is typically assessed by measuring the length of concrete cores, but this procedure limits the amount of information collected. The possibility of using non-destructive testing to assess concrete thickness was evaluated and significant efforts were dedicated to quantification of the variability of constructed pavement concrete thickness and determination of requirements for thickness sampling spacing using autocorrelation concepts. The Mechanistic Empirical Pavement Design Guide (MEPDG) is a tool used to evaluate the performance of JPCP, which predicts pavement distresses based on a desired reliability of design. MEPDG's current reliability analysis does not allow the MEPDG to quantify the effect of improved material characterization prior to design or the effect of quality control on pavement performance. In this study, a method to account for pavement characteristic variability in the reliability analysis is presented and evaluated the measured variability of rigid pavement concrete thickness and flexural strength.