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Retrofit Transition

Question
State WI
Description Text

I was doing some digging around and found this a TTI crash test for a TL-2 beam guard transition to rigid barrier. I was thinking of adding this as a retro fit option for some location where beam guard is directly attached to a rigid barrier.


I was thinking of using the following restrictions for its use:

45 mph or less

Rigid barrier does not slope downward.

Rigid barrier is NJ, F or vertical.

No curb and gutter is installed under the beam guard transition, or between the face of rail and edge of lane.



I was also wondering if WisDOT could use this transition as a retro fit for higher speed facilities (55 mph or less), under the assumption that providing a TL-2 system until a facility is fully reconstructed is a more viable option than tearing the whole thing out and installing a TL-3 transition.



What input MwRSF could provide would be appreciated.

Keywords
  • Approach Guardrail Transitions
  • Guardrail
Other Keywords none
Date November 9, 2010
Attachment TRR_1904_Bligh_Transition.pdf


Response
Response

I am somewhat familiar with the TL-2 approach guardrail transition that you have identified. I am attaching a copy of a technical paper that was published on this topic in a Transportation Research Record. The general guidelines that you have noted seem reasonable. There may be situations where this design could be used on higher speed roadways if traffic volumes were sufficiently low, thus warranting the use of a TL-2 barrier system.

 

I believe that we provided a test level chart in one of our prior reports as a function of traffic volume and speed. That chart was based on work performed for NCHRP project no. 22-8. We may have published that chart in the ZOI-Barrier Attachment Report or the Guidelines for Bicycle-Pedestrian Facilities Report.

Date November 10, 2010


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