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Temporary anchor application

Question
State MN
Description Text

We have a contractor request to substitute an anchor bolt
for our portable concrete barrier tie-down strap anchor.



 



See the attached PPCMB Anchor Plan.pdf, the detail is
on the middle top of the sheet.



 



This anchor would be used in leu of the 3/4" drop in
anchor outlined in the detail.  The anchor is a 3/4" diameter anchor
and would have a similar embedment in the detail 3-1/2" or greater. 



 



Please take a look at the anchor properties and let us know
if you have any concerns with this be used in place of the standard tested
anchor.



 



Thanks

__________________________________________________________________________________


Mike,

 

Please find the attached submittal package for our Screw
Bolt+ anchor.  This anchor would be used
in leu of the 3/4" drop in outlined in the detail that I had attached in
previous emails.  The anchor is a
3/4" diameter anchor and would have a similar embedment in the detail
3-1/2" or greater.  As I mentioned
in our conversation it's fully removable and outperforms the drop in anchor in
this application. 

 

Our contractor has the project and is looking for a more
user friendly anchor for this application. As stated it has better performance
values in shear as well as tension. 
Also, for the roadway it is fully removable after the barrier is no
longer in use.  Please let me know if there
is anymore information needed to be able to use this anchor for the application.

 

 

http://www.powers.com/submittal_generator/generate_submittal.php

 



















 

Keywords
  • Temporary Barriers
Other Keywords Tie Down
Date May 1, 2017
Attachment PPCMB Anchor Plan.pdf
Attachment screw-boltplus_manual.pdf


Response
Response

Hi Mike,

 

We looked at alternative anchors for the steel strap tie-down in some previous research for KDOT. I have attached a letter report that details that work.

 

During that work, we looked at several mechanical anchor alternatives like the one you sent. We found that those anchors compared well to the drop-in style anchors in terms of tensile capacity, but tended to have trouble developing the required shear loads. The difference in shear capacity was largely attributed to the larger diameter of the sleeve used for the drop-in and the higher grade steel used for the drop-in bolt.

 

Two potential mechanical anchor alternatives were identified.

 

1. Red Head Large Diameter Tapcon (LDT) 0.75-in. diameter x 4.5-in. long

2. Simpson Titen HD 0.75-in. diameter x 5.0-in. long

 

In the case of the Screw-Bolt+, we would need to ensure that the anchor could match a tensile capacity of 18.7 kips and a shear capacity of 25.6 kips that was found for the drop-in anchor used in the original crash testing of the system. We have used the approach that any replacement anchor must meet or exceed the capacity of the tested anchors in order to ensure similar performance. The shear capacities of the Screw-Bolt+ anchor are currently limited to 24.3 kips, so it would fall just beneath the tested anchorage. This anchor is very similar to the Wedge Bolt anchor used by Powers Fasteners, which did not meet the shear load criteria in the KDOT work. Thus, we could not recommend it at this time.

 

However, either of the alternative anchorages noted in the attached study are acceptable.

 

Let me know if you have any further questions.

 

Thanks

 

Date May 2, 2017
Attachment TRP-03-182-07.pdf


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