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Tied-Down TCB with Asphalt Overlay

Question
State WI
Description Text

There is a project that requires  anchoring temporary concrete barrier to a bridge deck with an overlay.  I sent the project team the attached drawing from MwRSF.

 

Could MwRSF respond to the contractor's questions?

 

  1. When performing the coring, how concerned are we going to be with capturing the slurry and the cores?
  2. The detail indicates a 4" nominal diameter schedule 100 pipe can be used versus the 2.875" x 0.625 x 1.626 Cold Drawn DOM Steel Tube but it does not increase the plate washer size, does the plate washer need to be a larger diameter as well.
  3. Is the threaded rod to be centered in the steel tube or off to one side?  The detail appears to have the rod centered but if a 4" diameter pipe is used and the rod would have room to move around.  In our case the barrier is to be mounted with one edge being directly over the saw cut. If the barrier moves as all it could be hanging over the cut edge that we are protecting.  Please address.
Keywords
  • Temporary Barriers
Other Keywords none
Date March 3, 2010
Attachment Tie-down_through_asphalt_concept.pdf
Attachment SWC11_10-22-2008.pdf


Response
Response

I have responded to the questions below in red.

 

  1. When performing the coring, how concerned are we going to be with capturing the slurry and the cores
    1. I have no comment on this issues as it is not related to the performance of the system from a safety standpoint.
  2. The detail indicates a 4" nominal diameter schedule 100 pipe can be used versus the 2.875" x 0.625 x 1.626 Cold Drawn DOM Steel Tube but it does not increase the plate washer size, does the plate washer need to be a larger diameter as well.
    1. The plate washer would be larger for the 4" schedule 100 pipe. We would recommend a 7"x7"x3/4" plate washer for the larger pipe.
  3. Is the threaded rod to be centered in the steel tube or off to one side?  The detail appears to have the rod centered but if a 4" diameter pipe is used and the rod would have room to move around.  In our case the barrier is to be mounted with one edge being directly over the saw cut. If the barrier moves as all it could be hanging over the cut edge that we are protecting.  Please address.
    1. We intend the rod to be centered in the hole as much as possible. You are correct that with the larger pipe size you can expect a shift of the barrier due to the extra room. This distance would be a maximum of 2". Thus, we would recommend that you allow for 2" of additional room on the back of the barrier adjacent to the saw cut to account for the additional translation. I also want to note that you should not be installing this system with the back of the barrier flush with the saw cut. The design was developed and tested for use with a minimum of a 1" gap between the backside of the barrier and the edge of the concrete. As such, we would recommend that you keep the 1" gap for all installations and increase the gap to 3" when using the larger pipe.
Date March 4, 2010


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