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ODOT completed some MASH testing on a single slope
|Other Keywords||F-Shaped Median Barrier|
|Date||June 27, 2018|
Unreinforced barriers crack over time, even to the point where visual gaps may exist throughout the cross section. In this scenario, no rail continuity would exist, and vehicle redirection is dependent on a combination of several factors, including the inertial resistance of the thick concrete barrier, any bond between the barrier and support surface and/or asphalt keyway, and the limited structural capacity of the concrete cross section (shear, tension, torsion, bending, etc.) away from the gap location. Your barrier appears to have a similar or greater footing resistance to the Ohio barrier we tested. However, because your barrier section has no reinforcement, the only comparison we can make between the tested Ohio barrier and your shape is the inertial resistance.
I have reviewed your F-shape section and compared it with the Ohio single-slope section. Your barrier is 9” shorter with nearly the same base width. Thus, the Ohio single-slope has approximately 19 percent more mass per unit length as your F-shape. Because the F-shape barrier has lower mass and inertia, we cannot say definitively that the section will meet MASH TL-3. Based on the lack of damage observed in the testing of the Ohio barrier, there is potential for your F-shape to meet MASH TL-3, but there is no way for use to prove it. Thus, we have to take a conservative approach and say that for a section to be equivalent to the Ohio barrier that was tested, it would need to have equivalent or greater section properties (similar width through the height of the barrier) and mass per unit length.
Thus, we cannot make a concrete argument for your barrier being MASH TL-3 compliant at this time. This discussion is very similar to the discussion I had with Ohio that led to the full-scale crash testing of their barrier. We have also had similar discussions with Kansas DOT regarding a smaller F-shape barrier with minimal reinforcement and not shear steel.
|Date||June 28, 2018|
130 Whittier Research Center
2200 Vine Street
Lincoln, NE 68583-0853
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