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Barrier Design

Roadside Design Guide

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#1 miloc

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Posted 10 April 2012 - 10:31 PM

Does anyone knows where L2 (Barrier Offset) comes from?

I came across this problem when reviewing the Roadside Design Guide (Update) Page 5-42

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#2 Ambrug20

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Posted 11 April 2012 - 01:10 AM

see p. 5-32 fig. 5.24. This page was revised. See revisions for this page.

#3 miloc

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Posted 11 April 2012 - 02:50 PM

Hi Ambrug20, thanks for your answer. The errata I have for the RDG erd adition doesn't include that page. The page I have (5-32) has the Figure 5.24 "Approach barrier layout variables" without any numbers, just generic variables (Lc, La, Lr, X, L1, L2, L3, etc) can you please post it or email it to me? thanks.

#4 miloc

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Posted 11 April 2012 - 03:09 PM

Link to the RDG 3rd edition errata: https://bookstore.tr...ils.aspx?ID=148

#5 Ambrug20

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Posted 12 April 2012 - 03:11 PM

Miloc,
that is exactly what I have. You can see L2 shown on revision page. Can't help more. Good luck for tomorrow

#6 ptatohed

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Posted 24 May 2012 - 08:32 PM

Does anyone knows where L2 (Barrier Offset) comes from?

I came across this problem when reviewing the Roadside Design Guide (Update) Page 5-42



miloc,

L2, the Barrier Offset, is the distance from the edge of travel way to the roadside barrier. Unfortunately, there is no nifty chart for determining L2. L2 is to be selected by the design engineer. As a general rule, the barrier should be placed as far from the traveled way as possible but there are many variables that could affect the barrier placement (slope/terrain of the shoulder, the distance from the traveled way to the obstruction L3 (obviously L2 needs to be less than L3), the type and deflection of the selected barrier, etc.). Please see RDG Section 5.6. If the exam were to give you a problem like those in RDG Figs 5.29 - 5.32, they would most likely provide you with L2 (as did these RDG examples). I hope that helps.

Edited by ptatohed, 29 May 2012 - 03:25 PM.

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