Federal Highway Administration Research Library and List of Online Publications The Federal Highway Administration (FHWA) Research Library is located at the Turner-Fairbank Highway Research Center (TFHRC) in McLean, Virginia. The FHWA Research Library staff can help find information on a topic, perform comprehensive literature searches in support of research projects, and search library catalogs, article databases and the Internet, and locate facts and statistics.

Pavements were added and identified. This document outlines the requirements for a CD-ROM based Multimedia Companion to the 1993 AASHTO Guide for Design of Pavement Structures, sponsored by NJDOT and developed by Rutgers CAIT, AID Inc. And ATC Brunswick. Revised section to allow the use of AASHTO design procedure (1993) for CPCD designs only and not to be used for flexible. FPS 21 has the capability of designing pavement structures with up to six layers over the subgrade. In this manual. Past manual notices are available in a pdf archive. In 1991 AASHTO released a pavement design software package entitled Design Analysis and. Rehabilitation for Windows (DARWin). A new version of DARWin was released in 1993 along with a revised edition of AASHTO®. Guide for Design of Pavement Structures (1993 Guide (AASHTO, 1993)). MDT currently uses a. Task Group on Experimental Design and Analysis, the Pavement Performance Advisory. Committee, the Strategic Highway. Studies to Examine Fit of the AASHTO Design Equation to Observed Data. Comparisons of Inference. Concept for Pavements (AASHTO. Guide for Design of Pavement Structures 1993).

Many research reports and publications published by TFHRC are available online.

Dear Colleagues, I have a problem by understanding the following: The granular Subbase is supposed to be a lower quality material than the granular base. If I refer to the '1993 AASHTO Guide for Design of Pavement Structures' to obtain the layer coefficients, I get the following: a) Layer coefficient a2 for a granular base with CBR 30% is 0.095 (Part II, Table 2.6) b) Layer coefficient a3 for a granular Subbase with CBR 30% is 0.11 (Part II, Table 2.7). Hence a granular Subbase with same thickness and same CBR would create a higher SN than a granular Base though it is in general 'lower quality'. What have I missed??? Thank you, MARTIN RE: Subbase vs. Base (AASHTO Design Guide) (Structural) 16 Jun 10 09:58.

AASHTO should clarify those figures a bit. Even though the figure shows a straight line correlation between the different test parameters, that is not so, particularly with respect to the resilient modulus vs. Secondly, if you have a base material with a CBR of 30, then you have a very poor base material (the basis of the correlations is for a base CBR=100). The correlations do not hold when the base material is that poor.

In short, that figure should not even have base correlation values below a CBR of about 70 or 80. Use the correlation equation and compute the a2 value based on a resilient modulus of 15ksi being equal to CBR 30.you'll find the a2 value will be even lower than the figure shows! RE: Subbase vs. Base (AASHTO Design Guide) (Structural). Hi Ron, thanks for your quick reply. I have plot a graph 'Modulus vs. Layer coefficient' (see enclosed pdf) and obviously for each value the Sub-base has a higher coefficient!?! Baixar Musica De Abertura Do Desenho South Park on this page.