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Do you have any guidance or research available for a permanent concrete barrier next to a 2:1 slope.  The barrier is unanchored except for the end sections.  At locations with pavement on only one side, we allow 3" of compacted soil but do not specify a minimum length before a slope drop off.  Attached is the Ohio standard.

Thanks!

To start, there has been no research to date determining anchorage requirements for median and roadside permanent concrete barriers. We do have a proposal in the Year 30 Pooled Fund that we hope will move forward to address this. However, at this time, the data we have is only a function of what we can compare from similarly tested barriers and anchorages.

To the best of our knowledge, no testing of the permanent concrete barriers adjacent to slopes has been completed at this time. The concerns with such a system is that the lack of anchorage or a footing may allow the barrier to displace and translate and affect the barrier performance. The concern would be less for barriers with a foundation or footing below grade, a barrier with some form of anchorage, or a reinforced barrier as these factors would all tend to resist displacement and translation or provide lateral resistance.

Thus, we cannot determine for certain if the installation shown is sufficient to adequately restrain barrier motions, and there are limited options to recommend without further study. One could install dowel rods similar to what OhDOT uses in some instances for barrier anchorage in addition to the 3” fill and 1’ offset shown. If the offset can be increased, a large offset to the slope would only reduce the concerns and perform better. A more conservative and more costly option would be to provide a dedicated footing below grade for barrier close to the steep slope to provide more resistance.

One other item to note with respect to the proposed configuration shown is that the weight of that barrier segment may lead to degradation of the slope over time. At some point, placement of that section close to a steep slope may creep and cause movement of the barrier and damage to the slope. It is not clear what point that is, but it may be something to consider.