scholarly journals Sensitivity Analysis of Rigid Pavement Design Based on Semi-Empirical Methods: Romanian Case Study

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 168
Author(s):  
Costel Pleșcan ◽  
Elena-Loredana Pleșcan ◽  
Mariana D. Stanciu ◽  
Marius Botiș ◽  
Daniel Taus
Keyword(s):  
Input Data ◽  
Design Method ◽  
Design Procedure ◽  
Plain Concrete ◽  
Empirical Method ◽  
Traffic Volume ◽  
Pavement Design ◽  
Mountainous Area ◽  
Rigid Pavement ◽  
Pavement Structures

Due to the intensive process of road construction or rehabilitation of pavement caused by an increase in traffic volume, in the field of rigid pavement design and research in Romania, we can say that there is a need to improve the design method. In the last decade, more and more researchers have been concerned about climate change and the increase in traffic volume; hence, there is a need for a renewal of the climatological, as well as traffic, databases because these are part of the input data for the design process. The design method currently used in Romania for jointed plain concrete pavement design is NP081/2002. The limitation of the data and the lack of lifetime estimation of structural and functional performance are the main aspects that need to be addressed in the new design procedure. The Mechanistic–Empirical Pavement Design (MEPDG) method offers the possibility of the design of pavement structures by estimating the structural and functional performances. This paper aims to obtain a comparative study of these two methods for the analysis of the input data collected from the field corresponding to the three failure criteria, while the symmetry of the characteristics of the material and their asymmetrical thicknesses are compared, thus contributing to the design of viable and long-lasting pavement structures using a rigid pavement with the specific characteristics of the mountainous area in northeastern Romania on the national road DN17 Suceava—Vatra Dornei. The novelty of this study consists of the implementation of the mechanistic–empirical method MEPDG instead of the old NP081/2002 method used in Romania.

scholarly journals An Artificial Intelligence–Assisted Design Method for Topology Optimization without Pre-Optimized Training Data

2021 ◽  
Vol 11 (19) ◽  
pp. 9041
Author(s):  
Alex Halle ◽  
Lucio Flavio Campanile ◽  
Alexander Hasse
Keyword(s):  
Topology Optimization ◽  
Input Data ◽  
Design Method ◽  
Design Procedure ◽  
Computational Effort ◽  
Training Data ◽  
Geometry Design ◽  
Random Input Data ◽  
Degree Of Filling ◽  
Initial Process

Engineers widely use topology optimization during the initial process of product development to obtain a first possible geometry design. The state-of-the-art method is iterative calculation, which requires both time and computational power. This paper proposes an AI-assisted design method for topology optimization, which does not require any optimized data. An artificial neural network—the predictor—provides the designs on the basis of boundary conditions and degree of filling as input data. In the training phase, the so-called evaluators evaluate the generated geometries on the basis of random input data with respect to given criteria. The results of those evaluations flow into an objective function, which is minimized by adapting the predictor’s parameters. After training, the presented AI-assisted design procedure generates geometries that are similar to those of conventional topology optimizers, but require only a fraction of the computational effort. We believe that our work could be a clue for AI-based methods that require data that are difficult to compute or unavailable.

Reliability Analysis of Cracking and Faulting Prediction in the New Mechanistic–Empirical Pavement Design Procedure

2005 ◽  
Vol 1936 (1) ◽  
pp. 150-160 ◽  
Author(s):  
Michael Darter ◽  
Lev Khazanovich ◽  
Tom Yu ◽  
Jag Mallela
Keyword(s):  
Monte Carlo ◽  
Reliability Analysis ◽  
Design Procedure ◽  
Practical Method ◽  
Pavement Design ◽  
Rigid Pavement ◽  
Pavement Distress ◽  
Reliability Based Design ◽  
Definition Of ◽  
Reliability Performance

Reliability analysis is an important part of the mechanistic–empirical pavement design guide (M-E PDG). Even though mechanistic concepts provide a more accurate and realistic methodology for pavement design, a practical method to consider the uncertainties and variations in design and construction is needed so that a new or rehabilitated pavement can be designed for a desired level of reliability (performance as designed). Several methods, ranging from closed-form approaches to simulation-based methods, can be adopted to perform reliability-based design. However, some methods may be more suitable than others, given the complexities of the design procedure. A formal definition of reliability within the context of the M-E PDG, as well as two reliability analysis approaches considered for incorporation into the design procedure for evaluating the reliability of the rigid pavement design for cracking and faulting, was evaluated. A Monte Carlo–based simulation was combined with the damage accumulation procedure for rigid pavement distress prediction. This approach is recommended for future improvements of the procedure. The development of the reliability analysis procedure implemented into the M-E PDG also was documented. It was demonstrated that although the adopted approach is not as sophisticated as a Monte Carlo–based one, it still represents a step forward compared with AASHTO-93 reliability analysis.

scholarly journals Development of a Design Catalog for Bonded Concrete Overlay Pavements Considering the Regional Characteristics of Korea

2021 ◽  
Vol 13 (17) ◽  
pp. 9876
Author(s):  
Hae-Won Park ◽  
Jin-Seok Seo ◽  
Jae-Hoon Lee ◽  
Jin-Hoon Jeong
Keyword(s):  
Design Method ◽  
Empirical Method ◽  
Climatic Conditions ◽  
Traffic Volume ◽  
Concrete Pavement ◽  
Element Analysis ◽  
Concrete Overlays ◽  
Volume Elastic Modulus ◽  
Bonded Concrete Overlay ◽  
Empirical Design

The design of overlay pavement in Korea, using the American empirical method, does not consider the unique Korean climate, pavement material, and traffic conditions. Therefore, in this study, a mechanistic–empirical design catalog for bonded concrete overlays (BCO) that are appropriate for Korean pavement conditions was developed. First, the thickness of the new pavement slab was determined through the Korean pavement design method, which uses a mechanistic–empirical design program according to the traffic volume of the region with the worst climatic conditions in Korea. Then, finite element analysis models of new jointed concrete and BCO pavements were developed to determine the BCO thickness by adjusting it until the stress–strength ratio of an existing slab of BCO pavement was equal to that of a new concrete pavement slab. By repeating this procedure, a design catalog was developed for the sustainable management of concrete pavement according to the traffic volume, elastic modulus, and thickness of the existing slab after milling. The appropriateness of the BCO thickness predicted by the design catalog was verified by comparing it with that predicted by other design methods.

scholarly journals Mechanistic-empirical approach to evaluate new and rehabilitated flexible pavements

2021 ◽  
Author(s):  
Wais Mehdawi
Keyword(s):  
Flexible Pavements ◽  
Empirical Method ◽  
Pavement Design ◽  
Empirical Approach ◽  
Integrated Analysis ◽  
Highway Traffic ◽  
Design Guide ◽  
The Difference ◽  
Pavement Structures ◽  
Empirical Design

The Mechanistic-Empirical Design provides more insight into pavement behaviour and performance than the 1993 AASHTO empirical method. The new Mechanistic-Empirical Pavement Design Guide (MEPDG) developed under the National Corporation Highway Research Program (NCHRP) 1-37A. A hierarchical approach is employed upon traffic, climate and materials input to produce pavement performance predictions of smoothness and numver of distress types. One of the most significant changes offered in the Mechanistic Empirical Design Guide (ME PDG) is the difference in the method used to account for highway traffic loading. Traffic volume and traffic loads, the two most important aspects required to characterize traffic for pavement design are treated separately and independently and its use-oriented computational software implements an integrated analysis approach for predicting pavement condiditon over time that accounts for the interaction of traffic, climate and pavement structures. The recently developed guide for mechanistic-empirical (M-E) design of new and rehabilitated pavement structures will change the way in which pavements are designed by replacing the traditional emprirical design approach in the AASHTO 1983 Guide. The M-E Pavement Design Guide will allow pavement designers to make better-informaed decisisions and take cost-effect advantage of new materials and features. However, the proposed design guide is substantially more complex than the 1983 AASHTO design guide. It requires more imput values from the designer. There is limited availability of the data for many MEPDG inputs. This project report presents the Mechanistic-Empirical approach of Pavement Design for New and Rehabilitated Flexible Pavements using the new ME PDG. The main objectives of the report are: (1)to demonstrated how the Mechanistic-Empirical design of pavement is more precise than the existing empirical method, (2)to explain the software input and output parameters, (3)to present a complete overview of the M-E design process and to gain a thorough understanding of the materials, traffic, climate and pavement design inputs required for M-E design.

A Pavement Design and Rehabilitation System

1996 ◽  
Vol 1539 (1) ◽  
pp. 110-115 ◽  
Author(s):  
Jacob Uzan
Keyword(s):  
Load Distribution ◽  
Design Method ◽  
Design Procedure ◽  
Pavement Design ◽  
Equivalent Temperature ◽  
Pavement Condition ◽  
Rehabilitation System ◽  
Overlay Design ◽  
Available Information ◽  
Pavement Thickness

Because the Superpave system is not readily available for use, an interim pavement design and rehabilitation method was developed that can be used for Israeli traffic and environmental conditions. The existing method was upgraded to include most of the relevant available information and to produce reliable pavement design for the specific conditions in Israel. The upgrading concentrated on multiple topics. An axle-load distribution specific to Israeli conditions was included because analysis indicates that axle loads in Israel are typically above the standard 80-kN single axle load. The extended California bearing ratio (CBR) method was adapted to a variety of axle-load combinations by using Miner's law for damage accumulation. Converting the axle-load distribution to the standard 80-kN equivalent single axle load leads to underdesign of approximately 10 percent in pavement thickness (or to a reduction of about 70 percent of the design life). A fatigue consideration to determine the asphalt-layer thickness was added. Local temperatures were analyzed to determine an equivalent temperature for fatigue calculation. For Israeli conditions, an equivalent temperature of 14°C can be used countrywide for asphalt-layer thicknesses up to 250 mm. An overlay design method consistent with the upgraded design procedure was assembled. It includes backcalculation of layer moduli to determine the subgrade CBR and the quality of the pavement layers; pavement condition surveys to evaluate a representative effective thickness of the asphalt layer; and component-layer analysis to determine the overlay thickness.

Load Transfer Characteristics of Roller-Compacted Concrete Pavement Joints and Cracks

1996 ◽  
Vol 1525 (1) ◽  
pp. 1-9
Author(s):  
David W. Pittman
Keyword(s):  
Load Transfer ◽  
Design Procedure ◽  
Pavement Design ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Rigid Pavement ◽  
Corps Of Engineers ◽  
Roller Compacted Concrete ◽  
Transfer Characteristics ◽  
Falling Weight

The U.S. Army Corps of Engineers’ design procedure for roller-compacted concrete (RCC) pavements assumes that no load transfer is achieved at RCC joints or cracks. This is in contrast to the Corps of Engineers’ rigid pavement design procedure for airfields, parking areas, and open storage areas, where a 25 percent load transfer is assumed for all joints and cracks. The no-load-transfer assumption for RCC pavements is conservative and is based upon limited data that indicated that RCC pavement joints did not achieve a 25 percent load transfer. The purpose of this study was to identify common types of RCC pavement joints and cracks, to determine the load transfer characteristics of these joint and crack types at 12 RCC pavement test sites using the falling weight deflectometer and to indicate the effect of incorporating these load transfer characteristics within the corps’ RCC pavement design procedure. Thirteen RCC pavement joint and crack types were identified. The mean load transfer achieved at these joints and cracks varied from 4 percent to 32 percent, and was no less than 10 percent for the most common joints and cracks found. In two design examples comparing the existing corps RCC pavement design procedure with a modified version incorporating 10–15 percent load transfer, the design RCC pavement thickness decreased 8–17 percent.

Development of Mechanistic-Empirical Pavement Design in Minnesota

1998 ◽  
Vol 1629 (1) ◽  
pp. 181-188 ◽  
Author(s):  
David Timm ◽  
Bjorn Birgisson ◽  
David Newcomb
Keyword(s):  
Material Characterization ◽  
Design Method ◽  
Laboratory Data ◽  
Design Procedure ◽  
Computer Models ◽  
Pavement Design ◽  
University Of Minnesota ◽  
Motion Data ◽  
Load Spectra ◽  
Weigh In Motion

The next AASHTO guide on pavement design will encourage a broader use of mechanistic-empirical (M-E) approaches. While M-E design is conceptually straightforward, the development and implementation of such a procedure are somewhat more complicated. The development of an M-E design procedure at the University of Minnesota, in conjunction with the Minnesota Department of Transportation, is described. Specifically, issues concerning mechanistic computer models, material characterization, load configuration, pavement life equations, accumulating damage, and seasonal variations in material properties are discussed. Each of these components fits into the proposed M-E design procedure for Minnesota but is entirely compartmentalized. For example, as better computer models are developed, they may simply be inserted into the design method to yield more accurate pavement response predictions. Material characterization, in terms of modulus, will rely on falling-weight deflectometer and laboratory data. Additionally, backcalculated values from the Minnesota Road Research Project will aid in determining the seasonal variation of moduli. The abundance of weigh-in-motion data will allow for more accurate load characterization in terms of load spectra rather than load equivalency. Pavement life equations to predict fatigue and rutting in conjunction with Miner’s hypothesis of accumulating damage are continually being refined to match observed performance in Minnesota. Ultimately, a computer program that incorporates the proposed M-E design method into a user-friendly Windows environment will be developed.

scholarly journals Structural Evaluation of Full-Depth Flexible Pavement Using APT

2021 ◽  
Author(s):  
Tommy E. Nantung ◽  
Jusang Lee ◽  
John E. Haddock ◽  
M. Reza Pouranian ◽  
Dario Batioja Alvarez ◽  
...  
Keyword(s):  
Asphalt Concrete ◽  
Prediction Models ◽  
Design Method ◽  
Permanent Deformation ◽  
Pavement Design ◽  
Asphalt Pavements ◽  
Statistical Parameters ◽  
Significant Difference ◽  
Pavement Structures ◽  
Rutting Behavior

The fundamentals of rutting behavior for thin full-depth flexible pavements (i.e., asphalt thickness less than 12 inches) are investigated in this study. The scope incorporates an experimental study using full-scale Accelerated Pavement Tests (APTs) to monitor the evolution of each pavement structural layer's transverse profiles. The findings were then employed to verify the local rutting model coefficients used in the current pavement design method, the Mechanistic-Empirical Pavement Design Guide (MEPDG). Four APT sections were constructed using two thin typical pavement structures (seven-and ten-inches thick) and two types of surface course material (dense-graded and SMA). A mid-depth rut monitoring and automated laser profile systems were designed to reconstruct the transverse profiles at each pavement layer interface throughout the process of accelerated pavement deterioration that is produced during the APT. The contributions of each pavement structural layer to rutting and the evolution of layer deformation were derived. This study found that the permanent deformation within full-depth asphalt concrete significantly depends upon the pavement thickness. However, once the pavement reaches sufficient thickness (more than 12.5 inches), increasing the thickness does not significantly affect the permanent deformation. Additionally, for thin full-depth asphalt pavements with a dense-graded Hot Mix Asphalt (HMA) surface course, most pavement rutting is caused by the deformation of the asphalt concrete, with about half the rutting amount observed within the top four inches of the pavement layers. However, for thin full-depth asphalt pavements with an SMA surface course, most pavement rutting comes from the closet sublayer to the surface, i.e., the intermediate layer. The accuracy of the MEPDG’s prediction models for thin full-depth asphalt pavement was evaluated using some statistical parameters, including bias, the sum of squared error, and the standard error of estimates between the predicted and actual measurements. Based on the statistical analysis (at the 95% confidence level), no significant difference was found between the version 2.3-predicted and measured rutting of total asphalt concrete layer and subgrade for thick and thin pavements.

scholarly journals Mechanistic-empirical approach to evaluate new and rehabilitated flexible pavements

2021 ◽  
Author(s):  
Wais Mehdawi
Keyword(s):  
Flexible Pavements ◽  
Empirical Method ◽  
Pavement Design ◽  
Empirical Approach ◽  
Integrated Analysis ◽  
Highway Traffic ◽  
Design Guide ◽  
The Difference ◽  
Pavement Structures ◽  
Empirical Design

The Mechanistic-Empirical Design provides more insight into pavement behaviour and performance than the 1993 AASHTO empirical method. The new Mechanistic-Empirical Pavement Design Guide (MEPDG) developed under the National Corporation Highway Research Program (NCHRP) 1-37A. A hierarchical approach is employed upon traffic, climate and materials input to produce pavement performance predictions of smoothness and numver of distress types. One of the most significant changes offered in the Mechanistic Empirical Design Guide (ME PDG) is the difference in the method used to account for highway traffic loading. Traffic volume and traffic loads, the two most important aspects required to characterize traffic for pavement design are treated separately and independently and its use-oriented computational software implements an integrated analysis approach for predicting pavement condiditon over time that accounts for the interaction of traffic, climate and pavement structures. The recently developed guide for mechanistic-empirical (M-E) design of new and rehabilitated pavement structures will change the way in which pavements are designed by replacing the traditional emprirical design approach in the AASHTO 1983 Guide. The M-E Pavement Design Guide will allow pavement designers to make better-informaed decisisions and take cost-effect advantage of new materials and features. However, the proposed design guide is substantially more complex than the 1983 AASHTO design guide. It requires more imput values from the designer. There is limited availability of the data for many MEPDG inputs. This project report presents the Mechanistic-Empirical approach of Pavement Design for New and Rehabilitated Flexible Pavements using the new ME PDG. The main objectives of the report are: (1)to demonstrated how the Mechanistic-Empirical design of pavement is more precise than the existing empirical method, (2)to explain the software input and output parameters, (3)to present a complete overview of the M-E design process and to gain a thorough understanding of the materials, traffic, climate and pavement design inputs required for M-E design.

scholarly journals An overview of asphalt pavement design for streets and roads

2020 ◽  
Author(s):  
Luis Ricardo Vásquez-Varela ◽  
Francisco Javier García-Orozco
Keyword(s):  
Design Method ◽  
Design Procedure ◽  
Pavement Design ◽  
Asphalt Pavements ◽  
Analysis And Design ◽  
Incremental Design ◽  
History Of ◽  
Design Factors ◽  
Geotechnical Problems ◽  
Proper Analysis

Pavements are geotechnical problems; consequently, a geotechnical framework is useful to describe their constitutive elements. The design of asphalt pavements for streets and roads evolved from empiric to mechanistic-empiric (M-E) procedures throughout the 20th century. The mechanistic-empiric method, based on layered elastic theory, became a common practice with the publication of separate procedures by Shell Oil, Asphalt Institute, and French LCPC, among others. Since its origin, the M-E procedure can consider incremental pavement design but, only until the beginning of the 21st century, the computational power became available to practicing engineers. American MEPDG represents the state-of-the-art M-E incremental design procedure with significant advantages and drawbacks, the latter mainly related to the extensive calibration activities required to assure a proper analysis and design according to subgrade, climate, and materials at a particular location and for an intended level of reliability. Perpetual pavements are a subset of M-E designed pavements with a proven history of success for the particular conditions where they are warranted. No design method, either the most straightforward empirical approach or the most elaborated incremental mechanistic one, is appropriate without proper knowledge about the fundamental design factors and calibration of the performance models for each distress mode upon consideration.

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