Calibration of MEPDG Performance Models for Flexible Pavement Distresses to Local Conditions of Ontario PDF Download
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Author: Nelson Fernando Cunha Coelho
Publisher:
ISBN:
Category :
Languages : en
Pages : 93
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Book Description
The implementation of the American Association of State Highway and Transportation Officials (AASHTO) Mechanistical-Empirical Pavement Design requires the development of a design procedure that can be used by the agencies and engineering consultants to design new and reconstructed rigid and flexible pavements. To calibrate the design procedure for a region, a large dataset representing the particular local conditions is needed. It includes traffic, climate, site material characteristics, performance requirements and historical data. The performance models were calibrated in North America using the Long Term Pavement Database Program (LTPP), therefore, the models must be calibrated to local conditions in order to obtain more suitable parameters, formulas and predictions. It is expected that calibrated performance models using site-specific data will predict pavement performance approximated to the performance measured in the field. Gathering data related with observed distresses is essential for subsequent comparison with predicted distresses. The primary objective of this project is to calibrate the performance models of flexible pavement distresses, including total rutting (permanent deformation) and asphalt concrete (AC) bottom-up fatigue cracking, to the local conditions of new flexible pavement in Ontario, Canada. Sixteen (16) representative pavement sections from widening and reconfiguration highway projects were selected. Performance data, traffic data, structure information, materials properties and performance data were obtained from site-specific investigation and pavement design reports provided by the Ministry of Transportation Ontario (MTO). The AASHTOWare Pavement ME DesignTM was used to run the initial predictions using the global calibration coefficients. Then, the obtained predicted distresses were compared with the measured distresses to assess for local bias and goodness of fit. The analysis showed that, using the global calibration coefficients, the AASHTOWare model under predicted alligator cracking and over predicted total rutting. Statistical analysis, such as, Regression Analysis and the Microsoft Solver numerical optimization routine were used to find the regression coefficients, using the approach of minimizing the sum of squared error (SSE). Concerning alligator cracking, the local calibration factors have improved the bias and standard error of the estimate (SEE). Plots also showed that points are randomly scattered along equality line and predicted values closer to the measured values. Regarding permanent deformation (rutting), the local calibration factors have improved the bias and standard error of the estimate. The accuracy of the transfer function has increased in comparison to the use of the global calibration values, suggesting that the local calibration procedure has improved the rutting model. Analyzing the plots measured versus predicted, points are better scattered and a shift is clearly noted in the chart from global to local calibration, indicating that local calibration coefficients improved distress estimations.
Author: Nelson Fernando Cunha Coelho
Publisher:
ISBN:
Category :
Languages : en
Pages : 93
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Book Description
The implementation of the American Association of State Highway and Transportation Officials (AASHTO) Mechanistical-Empirical Pavement Design requires the development of a design procedure that can be used by the agencies and engineering consultants to design new and reconstructed rigid and flexible pavements. To calibrate the design procedure for a region, a large dataset representing the particular local conditions is needed. It includes traffic, climate, site material characteristics, performance requirements and historical data. The performance models were calibrated in North America using the Long Term Pavement Database Program (LTPP), therefore, the models must be calibrated to local conditions in order to obtain more suitable parameters, formulas and predictions. It is expected that calibrated performance models using site-specific data will predict pavement performance approximated to the performance measured in the field. Gathering data related with observed distresses is essential for subsequent comparison with predicted distresses. The primary objective of this project is to calibrate the performance models of flexible pavement distresses, including total rutting (permanent deformation) and asphalt concrete (AC) bottom-up fatigue cracking, to the local conditions of new flexible pavement in Ontario, Canada. Sixteen (16) representative pavement sections from widening and reconfiguration highway projects were selected. Performance data, traffic data, structure information, materials properties and performance data were obtained from site-specific investigation and pavement design reports provided by the Ministry of Transportation Ontario (MTO). The AASHTOWare Pavement ME DesignTM was used to run the initial predictions using the global calibration coefficients. Then, the obtained predicted distresses were compared with the measured distresses to assess for local bias and goodness of fit. The analysis showed that, using the global calibration coefficients, the AASHTOWare model under predicted alligator cracking and over predicted total rutting. Statistical analysis, such as, Regression Analysis and the Microsoft Solver numerical optimization routine were used to find the regression coefficients, using the approach of minimizing the sum of squared error (SSE). Concerning alligator cracking, the local calibration factors have improved the bias and standard error of the estimate (SEE). Plots also showed that points are randomly scattered along equality line and predicted values closer to the measured values. Regarding permanent deformation (rutting), the local calibration factors have improved the bias and standard error of the estimate. The accuracy of the transfer function has increased in comparison to the use of the global calibration values, suggesting that the local calibration procedure has improved the rutting model. Analyzing the plots measured versus predicted, points are better scattered and a shift is clearly noted in the chart from global to local calibration, indicating that local calibration coefficients improved distress estimations.
Author: Amin Hamdi
Publisher:
ISBN:
Category :
Languages : en
Pages : 115
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Book Description
Well designed built and maintained pavements will sustain the safe and comfortable transportation of people and goods. Effective monitoring requires information about evolving pavement condition, including details about factors such as pavement distresses, climate conditions and traffic pattern which are important factors impacting the pavement conditions. Keeping track of the degree of distress over time can help extending the pavement life by applying the suitable maintenance and rehabilitation at the right time. Pavement management systems (PMSs) were originally created to archive this kind of data so that decision makers could predict future pavement performance. The Ministry of Transportation of Ontario (MTO) employs an advanced PMS tool, entitled PMS2, to record, store, and analyze data about the current and past pavement performance conditions of its network of 16,500 centre-lane kilometers of freeways, collectors, arterials, and local roads. The research presented in this thesis was focused on the use of PMS2 data for the calibration of flexible pavement performance models coefficients for Ontario as a case study Performance model coefficients were created for application with the Mechanistic-Empirical Pavement Design Guide (MEPDG), now known as AASHTOWare®, and were calibrated using statistical tools through a series of analyses of historical pavement condition data that were collected in the field. The data were classified according to pavement type and annual average daily traffic. For this study, three categories were examined and calibrated: low traffic volume (AADT 10,000), high traffic volume (AADT 10,000), and overall network. The spilt in data was Eighty-five percent to be used in calibration development of the performance model calibration coefficients and the remaining fifteen percent of the data were employed for validating the performance models using a variety of statistical tools. A comparison of the results with the field measurements revealed that rutting model coefficients should be locally calibrated for each category. For the low-volume, high-volume, and overall network categories, local calibration produced significant reductions in the rutting root-mean-square error (RMSE) of 30, 37, and 37 %, respectively, and in the IRI showed there was no significant correlation. The procedure and analysis methodology used in the calibration of the performance model coefficients provide a framework for the local calibration of AASHTOWare® based on a comparison of the predicted pavement distress and that documented in the PMS. This work will have important benefits to the transportation agencies as it will enable them to evaluate the feasibility of using the ASHTOWare® Design system to improve pavement management and to enhance future design and construction strategies.
Author:
Publisher: AASHTO
ISBN: 1560514493
Category : Technology & Engineering
Languages : en
Pages : 202
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Book Description
This guide provides guidance to calibrate the Mechanistic-Empirical Pavement Design Guide (MEPDG) software to local conditions, policies, and materials. It provides the highway community with a state-of-the-practice tool for the design of new and rehabilitated pavement structures, based on mechanistic-empirical (M-E) principles. The design procedure calculates pavement responses (stresses, strains, and deflections) and uses those responses to compute incremental damage over time. The procedure empirically relates the cumulative damage to observed pavement distresses.
Author: Shariq A. Momin
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The Mechanistic-Empirical Pavement Design Guide (MEPDG) developed under the National Cooperative Highway Research Program (NCHRP) 1-37A project is based on mechanistic-empirical analysis of the pavement structure to predict the performance of the pavement under different sets of conditions (traffic, structure and environment). MEPDG takes into account the advanced modeling concepts and pavement performance models in performing the analysis and design of pavement. The mechanistic part of the design concept relies on the application of engineering mechanics to calculate stresses, strains and deformations in the pavement structure induced by the vehicle loads. The empirical part of the concept is based on laboratory developed performance models that are calibrated with the observed distresses in the in-service pavements with known structural properties, traffic loadings, and performances. These models in the MEPDG were calibrated using a national database of pavement performance data (Long Term Pavement Performance, LTPP) and will provide design solution for pavements with a national average performance. In order to improve the performance prediction of the models and the efficiency of the design for a given state, it is necessary to calibrate it to local conditions by taking into consideration locally available materials, traffic information and the environmental conditions. The objective of this study was to calibrate the MEPDG flexible pavement performance models to local conditions of Northeastern region of United States. To achieve this, seventeen pavement sections were selected for the calibration process and the relevant data (structural, traffic, climatic and pavement performance) was obtained from the LTPP database. MEPDG software (Version 1.1) simulation runs were made using the nationally calibrated coefficients and the MEPDG predicted distresses were compared with the LTPP measured distresses (rutting, alligator and longitudinal cracking, thermal cracking and IRI). The predicted distresses showed fair agreement with the measured distresses but still significant differences were found. The difference between the measured and the predicted distresses were minimized through recalibration of the MEPDG distress models. For the permanent deformation models of each layer, a simple linear regression with no intercept was performed and a new set of model coefficients (ßr1, ßGB, and ßSG) for asphalt concrete, granular base and subgrade layer models were calculated. The calibration of alligator (bottom-up fatigue cracking) and longitudinal (topdown fatigue cracking) was done by deriving the appropriate model coefficients (C1, C2, and C4) since the fatigue damage is given in MEDPG software output. Thermal cracking model was not calibrated since the measured transverse cracking data in the LTPP database did not increase with time, as expected to increase with time. The calibration of IRI model was done by computing the model coefficients (C1, C2, C3, and C4) based on other distresses (rutting, total fatigue cracking, and transverse cracking) by performing a simple linear regression.
Author:
Publisher:
ISBN:
Category : Highway engineering
Languages : en
Pages : 0
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Book Description
In an effort to move toward pavement designs that employ mechanistic principles, the AASHTO Joint Task Force on Pavements initiated an effort in 1996 to develop an improved pavement design guide. The project called for the development of a design guide that employs existing state-of-the-practice mechanistic-based models and design procedures. The product of this initiative became available in 2004 in the form of software called the Mechanistic-Empirical Pavement Design Guide (MEPDG). The performance prediction models in the MEPDG were calibrated and validated using performance data measured from hundreds of pavement sections across the United States. However, these nationally calibrated performance models in the MEPDG do not necessarily reflect local materials, local construction practices, and local traffic characteristics. Therefore, in order to produce accurate pavement designs for the State of North Carolina, the MEPDG distress prediction models must be recalibrated using local materials, traffic, and environmental data. The North Carolina Department of Transportation (NCDOT) has decided to adopt the MEPDG for future pavement design work and has awarded a series of research projects to North Carolina State University. The primary objective of this study is to calibrate the MEPDG performance prediction models for local materials and conditions using the data and findings generated from this series of research projects. The work presented in this report focuses on four major topics: (1) the development of a GIS-based methodology to enable the extraction of local subgrade soils data from a national soils database; (2) the rutting and fatigue cracking performance characterization of twelve asphalt mixtures commonly used in North Carolina; (3) the characterization of local North Carolina traffic; and (4) calibration of the flexible pavement distress prediction models in the MEPDG to reflect local materials and conditions.
Author: Y. Richard Kim
Publisher:
ISBN:
Category : Highway engineering
Languages : en
Pages : 234
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Book Description
In an effort to move toward pavement designs that employ mechanistic principles, the AASHTO Joint Task Force on Pavements initiated an effort in 1996 to develop an improved pavement design guide. The project called for the development of a design guide that employs existing state-of-the-practice mechanistic-based models and design procedures. The product of this initiative became available in 2004 in the form of software called the Mechanistic-Empirical Pavement Design Guide (MEPDG). The performance prediction models in the MEPDG were calibrated and validated using performance data measured from hundreds of pavement sections across the United States. However, these nationally calibrated performance models in the MEPDG do not necessarily reflect local materials, local construction practices, and local traffic characteristics. Therefore, in order to produce accurate pavement designs for the State of North Carolina, the MEPDG distress prediction models must be recalibrated using local materials, traffic, and environmental data. The North Carolina Department of Transportation (NCDOT) has decided to adopt the MEPDG for future pavement design work and has awarded a series of research projects to North Carolina State University. The primary objective of this study is to calibrate the MEPDG performance prediction models for local materials and conditions using the data and findings generated from this series of research projects. The work presented in this report focuses on four major topics: (1) the development of a GIS-based methodology to enable the extraction of local subgrade soils data from a national soils database; (2) the rutting and fatigue cracking performance characterization of twelve asphalt mixtures commonly used in North Carolina; (3) the characterization of local North Carolina traffic; and (4) calibration of the flexible pavement distress prediction models in the MEPDG to reflect local materials and conditions.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The 1993 American Association of State Highway and Transportation Officials (AASHTO) Guide for Design of Pavement Structures is a mere modification of the empirical methods found in its earlier versions that are based on regression equations relating simple material and traffic inputs. Although the various editions of the AASHTO design guide have served well for several decades, they contain too many limitations to be continued as the nation's primary pavement design procedures. The Mechanistic-Empirical Pavement Design Guide (MEPDG) procedure, on the other hand, provides the tools for evaluating the effect of variations in input data on pavement performance. The design method in the MEPDG is mechanistic because it uses stresses and strains in a pavement system calculated from the pavement response model to predict the performance of the pavement. The empirical nature of the design method stems from the fact that the pavement performance predicted from laboratory-developed performance models is adjusted based on the observed performance from the field to reflect the differences between predicted and actual field performance. The performance models used in the MEPDG are calibrated using limited national databases and, thus, it is necessary to calibrate these models for local highway agencies implementation by taking into account local materials, traffic information, and environmental conditions. Two distress models, permanent deformation and bottom-up fatigue cracking (hereafter referred to as alligator cracking), were employed for this effort. Fifty-three pavement sections were selected for the calibration and validation process: 30 long-term pavement performance (LTPP) pavements, which include 16 new flexible pavement sections and 14 rehabilitated sections, and 23 North Carolina Department of Transportation (NCDOT) sections. All the necessary data were obtained from the LTPP and the NCDOT databases. To provide reasonable values in cases where data were missing, MEP.
Author: Jian Zhong
Publisher:
ISBN:
Category : Highway engineering
Languages : en
Pages : 85
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Book Description
The Mechanistic-Empirical Pavement Design Guide (MEPDG) has been introduced to transportation agencies as an innovative method for analysis and design of pavements. However, the MEPDG cannot be used by highway agencies without calibration due to the different situations in Canada. Local calibration the MEPDG, which means adjusting the coefficients of performance prediction models to meet the local conditions, should be an essential step for any agencies before the official acceptation of the MEPDG. As the part of the project, Local Calibration of the MEPDG Prediction Models Using More Accurate Field Measurements funded by Highway Infrastructure Innovation Funding Program (HIIFP), this research involved the local calibration of the models for Jointed Plain Concrete Pavement (JPCP) in the Province of Ontario. Using the field measurements collected by Ministry of Transportation in Ontario (MTO), the study performed local calibration for 32 rigid (JPCP) pavement sections. The primary objective of this study was to examine prediction results using global models; then if not agree with the measurements, refine the coefficients of the MEPDG performance models using the nonlinear optimization methods. The proposed calibration was applied by using the sections located in different zones throughout Ontario to represent the local features, including climate and traffic conditions. Finally, the local calibration results are presented and compared with previous results of global models to assess the robustness of local calibration. The research shows the feasibility of the mathematical optimization method for in local calibration in Ontario, and it also provides some useful findings for future uses of the MEPDG.
Author: Zahid Hossain
Publisher:
ISBN:
Category : Pavements
Languages : en
Pages : 524
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Book Description
"The new mechanistic-empirical pavement design guide (MEPDG), based on the National Cooperative Highway Research Program (NCHRP) study 1-37A, replaces the widely used but more empirical 1993 AASHTO Guide for Design of Pavement Structures. The MEPDG adopted a mechanistic-empirical pavement analysis and design procedure by using material properties, traffic and climate data for local conditions as input. Among material properties, resilient modulus (Mr) of underlying soil and aggregate layers is one of the most important parameters for the analysis and design of flexible pavements. Also, dynamic modulus (E*) of the asphalt mixes and rheological properties of asphalt binders are needed to predict pavement distresses for its design life. To this end, Mr data of 712 samples from five unbound subgrade soils, 139 samples from four stabilized subgrade soils, and 105 samples from two aggregates in Oklahoma were evaluated to develop stress-based models. Among selected models for unbound subgrade soils, the universal model outperformed other stress-based models. For stabilized soils and aggregates, the octahedral model, recommended by the MEPDG, performed better than the other models. Also, reasonably good correlations were established to predict Mr values of these materials by using routine material properties (i.e., gradation, index properties). Furthermore, MEPDG input parameters of three performance grade (PG) binders, collected from three different refineries in Oklahoma, were determined as per Superpave(R) test methods. It was observed that the rheological properties (i.e., viscosity, dynamic shear modulus (G*)) of the same PG grade binders varied significantly based on their sources. The present study is expected to provide ODOT with useful data and correlations that can be used to calibrate the MEPDG for local materials and conditions."--Technical report documentation page
Author: Peter Nabhan
Publisher:
ISBN:
Category : Electronic books
Languages : en
Pages : 534
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Book Description
The Mechanistic-Empirical Pavement Design Guide (MEPDG) consists of transferring pavement mechanical responses such as stresses and strains into predicted distresses. The nationally calibrated models for rutting, bottom-Up fatigue cracking, top-down fatigue cracking, International roughness Index (IRI), thermal cracking and reflective cracking need to be recalibrated to properly fit Nevada's local conditions for materials, traffic, and climate. This study focuses on the local calibration of the fatigue bottom-up cracking and the rutting models. For this purpose, data was collected from the Nevada Department of Transportation (NDOT) Pavement Management Systems (PMS) database and converted to match the MEPDG models requirements. Additionally, field-produced mixtures were sampled from 45 paving projects to develop a materials database. These mixtures were collected from all three districts and tested for dynamic modulus, binder properties, rutting, and fatigue. This was completed to characterize the polymer-modified asphalt binder mixtures technologies in Nevada which was one of the main factors that mandated a local Pavement-ME calibration as the nationally calibrated models used unmodified binders. The calibration was performed by optimizing the local calibration factors to reduce the sum of error squared between predicted and measured distresses data. The calibration for rutting was conducted for new and rehabilitated sections from the three districts. On the other hand, the fatigue calibration separated new and rehabilitated sections but combined between district II and III as most mixes from these districts use the PG64-28NV binder as opposed to District I where PG 76-22NV binder is predominantly used. The final calibration sets for rutting and fatigue cracking were 6 and 4 respectively. This thesis recommends additional performance monitoring of the polymer-modified paved sections as the calibration was validated using only 10 years of performance data. Future recalibration could be undertaken to increase the accuracy of the models.
