Question:
Criteria is drawing expressway gutter with a 6:1 back slope
rather than a 4:1 as per Std. 846.01 sht. 1 of 3.
Answer:
There are two main problems with the current way Criteria is drawing the expressway gutters.
1. Dimensions and slopes of the expressway gutter are from 1998 Drawing Standards. At that time the nominal
gutter back slope was 0.17'/1' (or 6:1) and the gutter back depth was 10".
Since then, beginning with the 2002 to the current 2006 Drawing Standards, the nominal gutter back slope is
currently 0.25'/1' (or 4:1) and the gutter back depth is set to 12".
2. Current Criteria fixed the expressway gutter back slope to be always 0.17'/1' (or 6:1). Criteria will have to be
modified to be in compliance with 2006 Drawing Standards 486.01 Sheet 2 of 3, Section Views of
Expressway Gutter in Super Elevation. The gutter base slope, foreslope, and back slope are variable and
exclusively DEPENDENT on the superelevation of the proposed pavement. See diagram below.
The Criteria Library (L:\ Drive) has been updated for these required modifications for expressway gutter standards.
NC DOT
NC DOH
NC GOV
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