https://forum.rubicontoolbox.com/pages/topic39-selection-and-application-of-drainage-coefficients.aspx Rubicon Online Help - AASHTO (1986/1993) Design Tool - Selection and application of drainage coefficients - Messages en-us http://blogs.law.harvard.edu/tech/rss Jitbit AspNetForum Thu, 15 Oct 2020 05:09:43 GMT Thu, 15 Oct 2020 05:09:43 GMT https://forum.rubicontoolbox.com/pages/topic39-selection-and-application-of-drainage-coefficients.aspx

SN = a1ˑD1 + a2ˑm2ˑD2 + a3ˑm3ˑD3


The drainage coefficient only applies to the effects of drainage on untreated/natural materials. The designer should assess the level or quality of drainage achieved considering average rainfall and prevailing drainage conditions. The following table contains definitions of drainage levels associated with typical mi ranges as a function of percentage time during a year the pavement structure would approach saturating moisture levels.


For comparison purposes, the conditions at the AASHTO Road Test site are considered “Fair” (free water removed within 1 week) with a drainage coefficient of 1.0.


Recommended drainage coefficient values for modifying the layer structural layer coefficients of untreated layers in flexible pavements (adapted from AASHTO, 1993)



Reference: AASHTO Guide for Design of Pavement Structures (1993). American Association of State Highway and Transportation Officials, Washington, D.C.


edited by on 10/21/2020
edited by on 10/17/2023]]> Thu, 15 Oct 2020 05:09:43 GMT