Guidelines for implementing nchrp 7a me design procedures in ohio. So when it came time for aashto to update its pavement design guidance to state dots, engineers needed a new approach. Aashto joint task force on pavements december 3 5, 2003. These values are computed through backcalculation as mentioned in the nchrp 1 37a main report and double letter appendices. Evaluation of nchrp 7a rigid pavement design software.
Nchrp 7a, mechanistic empirical pavement design, distress. Comprehensive pavement design procedure structural analysis software available at. Background national cooperative highway research program nchrp project 1 37a, the largest in the over 40year history of the program, was recently concluded with the successful delivery of a recommended mechanisticempirical pavement design guide to nchrp by the research team of eres consultants, its subcontractors arizona state university and fugro consultants lp, and numerous individual. In 1996, an in house study was initiated to identify or develop a new driving formula to be used for routine piledriving acceptance in the wsdot standard specifications. Won the azite graduate transportation paper award in 2005 given by the arizona institute of transportation engineers azite, march 2005. Nchrp develops mepdg 2008 mepdg is an aashto standard 2009 cdot begins implementation 2011 cdot adopts mepdg 1999.
Arizona state university, tempe, arizona, usa, february 2004. Introduction to mechanisticempirical pavement design guide. The nchrp 7a software also includes a provision for entering local or regional field calibration factors instead of the national values derived from the ltpp database. Nchrp 919 project superpave support and performance models management, national cooperative highway research program. Effect of lime modification on dynamic modulus stiffness of hma for use with the new nchrp 1 37a me pavement design guide procedures.
It is sponsored by american association of state highway and transportation officials aashto and the u. With innovations ranging from the advent of superpave, the data generated by the long term pavement performance ltpp project, to the recent release of the mechanisticempirical pavement design guide developed under nchrp study 7a, the field of pavement engineering is experiencing significant development. The overall objective of nchrp project 1 37a is to develop and deliver the 2002 guide for design of new and rehabilitated pavement structures, based on mechanisticempirical principles, accompanied by the necessary computational software, for adoption and distribution by aashto. A database will need to be prepared that will house all of the inputs for the. This guide describes the engineering study process for evaluating the operational effectiveness of various intersection improvements. Development of the 2002 guide for the design of new and rehabilitated pavement structures. Nchrp 7a initial mepdg development nchrp 140 continued evolution of. The nchrp 7a mepdg procedurea s software for design of ac overlay of ac allows the user to select some or all of the following performance criteria by which the adequacy of a trial overlay design is judged. Mar 30, 2004 view all documentation of nchrp 1 37a key chapters of the documentation that relate to crcp design include. Pdf comparing witczak nchrp 140d with hirsh e predictive. Implementation of the nchrp 7a design guide final report. The calibrated models in nchrp 7a software can be used by wsdot pavement specialists to better predict future pcc pavement performance. Department of transportation s federal highway administration fhwa. This approach incorporates traffic analyses, calibration to local conditions and design reliability measures.
A methodology for evaluation of bmps will be approved at this meeting. Sensitivity of the nchrp 1 37a pavement design guide, a global approach. Recently, compiled databases of pile load test results were used as the basis for developing improvements to the gates formula to improve the prediction accuracy of pile. The design guide developed under national cooperative highway research program nchrp 1 37a project is a very complex pavement analysis tool, with many input factors which characterize materials, climate, traffic and construction. Evaluation of mechanisticempirical design procedure mdsha project no. A comprehensive, stateoftheart guide to pavement design and materials. Nchrp report 350 testing and evaluation of netc bridge rail transitionsnetc project 99 1 presentation of results presentated by dean c. Note that these values are for soils compacted at optimum moisture and density conditions.
Mdots implementation plan for the mechanisticempirical. Nchrp 9 lrequired traffic loads are defined by the nchrp 1 37a project software lnchrp 1 39 supplies a more robust mechanism to enter that data l9 software converts traffic monitoring data into pavement design inputs. Nchrp 1 37a level 3 inputs see table 535 for typical ranges and default values as functions of aashto and uscs soil class. Nchrp project 7a a lot has changed on our highways since the 1950straffic volumes, pavement materials, truck weights, and customer expectations. Aashto joint task force on pavements december 3 5, 2003 st. The advantage of using this level of complexity is that it offers an improved representation of asphalt concrete pavements while using the same inputs that are required for the nchrp 1 37a mechanistic empirical pavement design guide. National cooperative highway research program wikipedia. The research described herein was performed under nchrp project 1 43 by the transportation sector of applied research associates ara, inc. Development of new piledriving formula and its calibration. Introduction to mepdg flexible pavement design 3 pdhs. Sep 27, 20 researchers are now incorporating the latest advances in pavement design into the new mechanisticempirical pavement design guide mepdg, developed under the national cooperative highway research program nchrp 7a project and adopted and published by aashto. The in house developed software mitigates the need to use expensive commercial packages.
This guide incorporates pavement knowledge and experiences, which were developed during the last 50 years. Fhwas introduction to the nchrp 7a pavement design workshop empirical design workshop held in mystic, connecticut august 26th, 2004 modified asphalt course hosted by the northeast asphalt userproducer group on july 15,2004 2004 national research advisory committee held in mystic, connecticut, july 18 to july 22,2004. Pccp models for rehabilitation and reconstruction decisionmaking. This feature permits local agencies to adjust the mechanisticempirical performance predictions to better reflect their local conditions. Implementing mechanistic empirical pavement design and darwinme. Linda pierce, washington dot the rigid design concrete portion of the design guide and software is solid, but. The overarching goals of the four mepdg regional peer exchange meetings included. Discussion of nchrp 7a by panel members the jtf members who are also members of the 7a panel were asked to give their perspective on the guide. This paper focuses on the implementation of the me design in the kingdom of saudi arabia by developing a. The nchrp 7a design software takes all of these traffic inputs and computes the number of applications of each axle load magnitude by axle type single. Peter stephanos director, office of material technology. Nchrp 7a models are able to be calibrated with some limited exceptions.
Traffic data required for each of the three hierarchical input levels. Better designs mean longer pavement life nchrp project 7a. Comparisons of flexible pavement designs aashto empirical. Training materials nchrp 7a design guide the 2002 pavement design guide mechanisticempirical design of new and rehabilitated pavements eres consultants, a division of ara, inc. Response and fatigue performance modeling of alf pavements. The results suggest that the default design criteria incorporated in the nchrp project 7a software are broadly consistent with what would be observed. Nchrp project 1 37a a lot has changed on our highways since the 1950straffic volumes, pavement materials, truck weights, and customer expectations. This report provides the details associated with these findings.
Implementation of the nchrp 1 37a design guide final report volume 2. The results suggest that the default design criteria incorporated in the nchrp project 7a software are broadly consistent with what would be observed historically from pavements designed with. After using the finite element package to assess the impacts of wheel. June 1922, 2005 nchrp associated projects o nchrp 1 40. Peter stephanos director, office of material technology maryland state highway administration lutherville, md 21093 written by. An evaluation of the probable aging effects of plant mixtures used in the nchrp 919 project. The objective of nchrp 7a is to develop a pavement design tool based on mechanisticempirical. A mechanisticempirical pavement design guide mepdg has been developed in the usa under the nchrp 1 37a in 2004 to address shortcomings in the current pavement design methods. Discussion of nchrp 1 37a by panel members the jtf members who are also members of the 1 37a panel were asked to give their perspective on the guide. Calibration of nchrp 7a software for the washington. Introduction to mechanisticempirical pavement design. In short, the dynamic kvalue is specific to the subgrade layers while the effective base modulus represents all base layers. The mechanisticempirical pavement design guide, related documentation, and the latest version of its software are available online for evaluation through 30.
Development of the 2002 guide for the design of new. Summary of findings and implementation plan mdsha project no. The national cooperative highway research program was established in 1962 under trb with a view to promote research on serious problems related to highway. Nchrp fy 2021 program announcement and solicitation for panel nominations. Washington state transportation center trac publication date. Alberson 2bar curbmounted and 4bar sidewalkmounted bridge rails. Provide an opportunity for peers to discuss issues related to the mepdg and the accompanying aashtoware software. Peter stephanos director, office of material technology maryland state highway administration lutherville, md 21093 submitted by.
Classification of wim data as level 1 through 3 is based on the specific location at which data are collected e. The contractor will be expected to meet with the nchrp panel approximately 1 month later. Aashto guide for design of pavement structures or one of its predecessors. Mepd was developed by the national cooperative highway research program nchrp in the early 2000s as a more realistic characterization of inservice pavements with uniform guidelines for designing flexible, rigid, and composite pavements. Nchrp 9 lrequired traffic loads are defined by the nchrp 7a project software lnchrp 9 supplies a more robust mechanism to enter that data l9 software converts traffic monitoring data into pavement design inputs. Better designs mean longer pavement life nchrp project 1. Freeware, available through transportation research board until 2012. A mechanisticempirical pavement design guide mepdg has been developed in the usa under nchrp 1 37a in 2004 to address shortcomings in the current pavement design methods. Implementation of the nchrp 1 37a design guide final report volume 1. The results suggest that the default design criteria incorporated in the nchrp project 1 37a software are broadly consistent with what would be observed historically from pavements designed with.