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Wildlife Barrier Attached to MGS

State GA
Description Text

I have two questions for y’all. 


  1. We have a corridor that has terrapins and as part of the environmental coordination we are being asked to provide deterrents to the terrapins’ crossing the road.  I was wondering Midwest’s opinion of a treatment such as the one below and if there were any more generic solutions that you though would work (e.g., woven wire fence attached).  (GDOT uses MGS with 8” composite blocks and steel posts as our standard w-beam.)

  1. Has there been any testing of steel butterfly delineators for guardrail or is the recommendation to not use these still Midwest’s guidance on this topic.  I just recently read the Q&A with Kansas that is on the website.


  • Guardrail
Other Keywords Wildlife Fence
Date July 19, 2021
  1. We have looked at a similar issue before for WYDOT. In that case, WYDOT wanted to attach a wooden board curb to the base of the posts to reduce runoff and erosion. At that time, we noted that a board-type curb installed at the base of the post in the MGS system posed some concerns. The addition of the curb could affect the post-soil rotation forces. Similarly, post behavior could be affected due to load transfer through the board curb to adjacent posts depending on the stiffness and strength of the board and the curb-to-post attachment. In addition, the curb could potentially interact with the vehicle’s wheels, thus resulting in vehicular instability or barrier override. As such, we recommended that the MGS with an attached board curb b could negatively affect the crashworthiness of the MGS when attached to the lower front face of the posts, and thought it would need to be crash tested.


The system you have attached would have similar concerns. It is not entirely clear how much section and what material the barrier modification you sent was. We would believe that the effect would on guardrail performance would be less if the material had lower strength and/or section.


An alternative would be to install a separate, low-height fencing as denoted on their website 1’-2’ behind the barrier. In that case, there would be little concern.

  1. Our recommendations on butterfly delineators has not changed from the previous guidance on the Q&A site. If you have a more specific question, let me know.




Date July 20, 2021