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AGT Post Obstruction

Question
State NE
Description Text Post # 6 has a footing blocking the placement.
The footing is 2’ below the ground.
What can be done with other post spacing to alleviate this? 
Keywords
  • Approach Guardrail Transitions
Other Keywords none
Date November 12, 2015
Attachment 74000e01.pdf


Response
Response

I am not a big fan of moving either post #5 or post #6 approximately 8” or more when only placed within a span of 18.75” due to the potential for increased pocketing when striking just upstream from this location and near asymmetric transition segment. Instead, I would rather use the dual-post straddle and beam system that was developed for Erik Emerson and the Wisconsin DOT in a recent research study. Have you considered this system?

 

Now, as a last resort, I maybe could live with the post shift method if the transition were extended more upstream to include another thrie beam panel (6 ft – 3 in.) and more ¼-post spacings to mitigate any concerns with a shifted post of 8”.

 

I will ask that Bob/Scott comment as well. Please let me know if you have any questions related to the information noted above. Thanks!

Date November 19, 2015


Response
Response

What about 2 more W6x15’s @ 37.5” as in the clip – in the place of the standard posts at ¼ space.

For post 5 of our original sketch fix: the below would span the footing but we would use an additional 6’-3” of thrie beam &  the 31” rail to the right as in our original sketch.

For post 6 fix: this would require moving the last W6x15 8” which would be behind the 6-‘-3” thrie beam
Date November 20, 2015
Attachment sstr.jpg


Response
Response

The noted transition below does not have include the transition to the standard AGT that is now used. However and in terms of our prior discussion, one could add a few more ½-post spacings of W6x15, another 6 ft 3 in. segment of thrie to include 12 ft 6 in. of single thrie, then the asymmetric segment, etc. The 37.5 in. span would straddle the hazard. You would still then have Scott’s stiffness transition with 18.75” spacings and design K or L of prior report. Let me know if this makes sense. If not we could sketch on paper a few versions.

Date November 21, 2015


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