View Q&A

Can you send me that simulation video (in .wmv, I cannot
open the .avi’s) of the guardrail/temporary barrier overlap failure?  I
want to provide highlights to our Work Zone Traffic Managers…

The simulation was for an unanchored guardrail end, correct?

However, per our conversation the other day…

-When it does have a downstream anchor, the Guardrail is
redirective at post #6 from the end. 

-Unanchored Temp Concrete Barrier is redirective about 100’
from the end of a run (in general is that for either direction?)

-so basically if I have these 2 barriers overlap for at
least 130’, and the guardrail has room to deflect without impacting the temp
concrete barrier it would be crashworthy…?

I have attempted to address your questions in red below.

Videos can be downloaded below. The guardrail and PCB were unanchored

However, per our conversation the other day…

-When it does have a downstream anchor, the Guardrail is redirective at post #6 from the end. 

                This should be true for the MGS with the downstream anchor that we investigated in TRP-03-279-13.

-Unanchored Temp Concrete Barrier is redirective about 100’ from the end of a run (in general is that for either direction?)

Yes. We currently have no better answer for the beginning of LON for PCB systems other than eight 12.5’ segments from the end of the system. It may well be shorter, but the research to determine that has yet to be done. Note the a 5’ offset is shown. This should be a working width number and should represent the distance from the face of the rail to the toe of the PCB.

-so basically if I have these 2 barriers overlap for at least 130’, and the guardrail has room to deflect without impacting the temp concrete barrier it would be crashworthy…?

This should be true for the most part. The only concern is that it is not well defined what happens when the vehicle impacts inside the last 30’ of the guardrail and gates through. The interaction of the vehicle gating through the end terminal and impact the PCB’s has not been fully defined. However, this setup is likely the best option for overlap of the barriers that we currently have. Note that this would only be good for one direction of traffic as shown.