Pinned-down Portable Concrete Barrier – what pin type to use when the surface is concrete with an asphalt overlay?
Other
Report No. 605071, April 2016 provides guidance for pinned-down temporary concrete barriers. Two options are given depending on if the surface is asphalt or concrete. However, what if the surface is concrete with an asphalt overlay (such as on a bridge deck)? Would the concrete pin type with a custom length work? Just long enough to account for the thickness of the asphalt and still be anchored in the concrete?
Nauman Sheikh ( )
Use of a longer pin that partially passes through an asphalt overlay and then into concrete pavement is not recommended. For reference, please see Figure 13 of report 605071, which contains a photo of the anchoring pin deformation under the barrier segment after vehicle impact in MASH Test 3-11. The anchoring pin deforms significantly.
The concern with the alteration proposed in the question is that the lateral moment in the anchoring pin is likely to increase due to the increase in the length of the pin. Since asphalt is weaker than concrete, it is not likely to resist the bending of the pin portion above the concrete pavement in the same manner as the portion of the pin inside concrete. This is likely to cause greater bending of the anchoring pin, which can lead to greater lateral barrier roll, causing greater vehicle instability.