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I can attempt to address these items, but I will need additional details as we were not involved in this development and testing.

Can we get the following from you?

1. Test reports for all of the tests
2. CAD details of the tested systems and the noted changes below.
3. Test videos

Thanks

I just copied the test reports and videos to a OneDrive folder and sent you think link.  Please let me know if you don’t receive it or if you have any problems.  I didn’t find any CAD files in the first folder that I checked, but there are drawings included in the test reports.  Please let me know if you still need CAD drawings and I can do some more searching.

Thanks,

I have some comments on your questions. Sorry for the delay in replying, I had NCHRP panel meetings this week and just got back.

Thanks

1. Crash Test 2
   (4/16/15) and Crash Test 3 (5/19/15) both used J-J Hooks to connect adjacent
   barriers rather than the pin and loop connection as shown on 801-TCCB-02. 
   The current standard drawing for unanchored temporary barrier (801-TCCB-02)
   indicates that the J-J Hooks may be used in lieu of the pin and loop
   connection.  We’re wondering if the pin and loop can be used in lieu of
   the J-J Hooks for our anchored temporary barrier.
1. The system was evaluated with the JJ-Hooks connection and noted above. However, we believe that the testing may have been conducted with the JJ-Hook in a more favorable position that makes the connection stronger. From what I can see in the test reports, the hooks are bearing on each other when loaded, which is less critical than if they are impacted in the reverse orientation where the hooks would pull apart. It appears that the joint sustained a significant load and damage. Thus, we would recommend that InDOT use the barrier with the loops in the stronger orientation that was tested with the anchorages to ensure that the system performs adequately.

We are unable to determine the exact effect of the conversion to a pin and loop system at this time. I am not sure what type of pin and loops system you wish to implement. The connection would have to have similar moment, shear, and tensile capacity at the joint. Thus, it is difficult to say if a pin an loop system would sustain similar loads without further information.

Additionally, the implementation of a pin and loops design would like increased the gap between barrier segments. Doing so would increase the loading of the barrier toes and toe fracture as well as create more exposure of the vehicle to the ends of the barrier segments. We have seen in other anchored PCB tests that contact and snag with the barrier segment joints can cause increased decelerations, vehicle instability, and or occupant compartment deformation issues. Thus, we cannot recommend switching the joint type without further research.

2. Crash Test 2
   (4/16/15) and Crash Test 3 (5/19/15) both used 1” dia. wedge anchors to secure
   the lower anchor bracket plates to the unreinforced concrete test apron. 
   Based on the descriptions and photos in the test reports, it doesn’t appear
   that the anchors were placed near a free edge of the concrete apron.  We’re
   wondering if there is a minimum distance from the center of the anchor to the
   edge of the supporting concrete surface.  Our internal discussions
   have lead us to proposing a minimum edge distance from the back of the barrier
   to a free edge of 12”, but we’d like to get your opinion on this distance.
1. This question may also be a little difficult to answer. I don’t have any details on the exact wedge bolt anchor used. However, manufacturers of these anchors provide minimum edge distances or edge distance reduction factors when using these systems. I would follow their minimum guidance. You may also want to account for the anchor spacing when you look at these anchors. Typically, anchor spacing will affect their capacity as well. This may add to the edge distance issue if two anchors are spaced relatively close together. The issue is that the concrete area adjacent to the edge is loaded by both anchors rather than a single anchor which reduces its overall resistance. Thus, you may want to increase the edge distance accordingly based on the anchor spacing as well.

3. Crash Test 2 (4/16/15)
   used two (2) 1” dia. F42 cast-in ferrule loops on each end of the barrier
   segments for the top connection detail.  Crash Test 3 (5/19/15) used one
   (1) 1” dia. drop-in wedge anchor on each end of the barrier segments for the
   top connection detail.  We’re wondering if the 1” dia. F42 ferrule
   loops can be considered equivalent to the 1” dia. drop-in wedge anchors, such
   that one (1) 1” dia. F42 cast-in ferrule loop anchors can be used on each end
   of the barrier segments.
1. Not to sound like a broken record, but I would need more details to answer this effectively. Drop-in wedge anchors can have different capacities than ferrule loops. Thus, one would need to compare the capacities of both attachments to see which was more critical. I cannot tell from the reports what specific versions were used. I only know the bolt grade and diameter.

4. Crash Test 2
   (4/16/15) and Crash Test 3 (5/19/15) both used 1” dia. wedge anchors to secure
   the lower anchor bracket plates to the unreinforced concrete test apron. 
   It’s our understanding that these large wedge anchors aren’t able to be removed
   after use, so they’ll need to be cut off and the exposed steel will be left
   flush with the bridge deck.  We’re wondering if 1” dia. drop-in wedge
   anchors (the anchors that were used in the top connections in Crash Test 3) can
   be considered equivalent to the 1” dia. wedge anchors, so that the 1” dia. drop-in
   wedge anchors can be used to secure the lower anchor bracket plates. 
   This would allow us to fill the drop-in anchor with epoxy after removal of the
   bolt, thereby eliminating the exposed steel at the bridge deck surface.”
1. Potentially, but in order to do so, one has to compare the capacities of the anchors for the spacing and edge distances of your problem. The different anchors can have different capacities. Thus, you would need to check and see if they were equivalent for the given anchor spacing and edge distances. However, the report does not contain the details on the specific anchors used, so I cannot look them up.

Thanks for your responses.  I’ve included some follow-up questions/responses below in green.  I’ve also attached some information for you reference.  Thanks again for all your help and I hope you have a great holiday!

Thanks,

Pete

From: Robert Bielenberg [mailto:rbielenberg2@unl.edu]
Sent: Friday, December 21, 2018 12:31 PM
To: White, Peter <PeWhite@indot.IN.gov>; Smutzer, Katherine <KSMUTZER@indot.IN.gov>
Subject: RE: InDOT Anchored PCB Questions

**** This is an EXTERNAL email. Exercise caution. DO NOT open attachments or click links from unknown senders or unexpected email. ****

Hi Pete and Katherine,

I have some comments on your questions. Sorry for the delay in replying, I had NCHRP panel meetings this week and just got back.

Thanks

1. Crash Test 2
   (4/16/15) and Crash Test 3 (5/19/15) both used J-J Hooks to connect adjacent
   barriers rather than the pin and loop connection as shown on 801-TCCB-02. 
   The current standard drawing for unanchored temporary barrier (801-TCCB-02)
   indicates that the J-J Hooks may be used in lieu of the pin and loop
   connection.  We’re wondering if the pin and loop can be used in lieu of
   the J-J Hooks for our anchored temporary barrier.
1. The system was evaluated with the JJ-Hooks connection and noted above. However, we believe that the testing may have been conducted with the JJ-Hook in a more favorable position that makes the connection stronger. From what I can see in the test reports, the hooks are bearing on each other when loaded, which is less critical than if they are impacted in the reverse orientation where the hooks would pull apart. It appears that the joint sustained a significant load and damage. Thus, we would recommend that InDOT use the barrier with the loops in the stronger orientation that was tested with the anchorages to ensure that the system performs adequately.

We are unable to determine the exact effect of the conversion to a pin and loop system at this time. I am not sure what type of pin and loops system you wish to implement. The connection would have to have similar moment, shear, and tensile capacity at the joint. Thus, it is difficult to say if a pin an loop system would sustain similar loads without further information.

Additionally, the implementation of a pin and loops design would like increased the gap between barrier segments. Doing so would increase the loading of the barrier toes and toe fracture as well as create more exposure of the vehicle to the ends of the barrier segments. We have seen in other anchored PCB tests that contact and snag with the barrier segment joints can cause increased decelerations, vehicle instability, and or occupant compartment deformation issues. Thus, we cannot recommend switching the joint type without further research.

Just FYI, I’ve attached the current INDOT Standard Drawing which shows the pin and loop system in question.  Thanks for your thorough explanation on why you can’t recommend switching the joint type at this time.

2. Crash Test 2
   (4/16/15) and Crash Test 3 (5/19/15) both used 1” dia. wedge anchors to secure
   the lower anchor bracket plates to the unreinforced concrete test apron. 
   Based on the descriptions and photos in the test reports, it doesn’t appear
   that the anchors were placed near a free edge of the concrete apron.  We’re
   wondering if there is a minimum distance from the center of the anchor to the
   edge of the supporting concrete surface.  Our internal discussions
   have lead us to proposing a minimum edge distance from the back of the barrier
   to a free edge of 12”, but we’d like to get your opinion on this distance.
1. This question may also be a little difficult to answer. I don’t have any details on the exact wedge bolt anchor used. However, manufacturers of these anchors provide minimum edge distances or edge distance reduction factors when using these systems. I would follow their minimum guidance. You may also want to account for the anchor spacing when you look at these anchors. Typically, anchor spacing will affect their capacity as well. This may add to the edge distance issue if two anchors are spaced relatively close together. The issue is that the concrete area adjacent to the edge is loaded by both anchors rather than a single anchor which reduces its overall resistance. Thus, you may want to increase the edge distance accordingly based on the anchor spacing as well.

I’ve attached information on the anchor bolts that were used.  I completely understand where you’re coming from with following the manufacturer’s recommendations for minimum edge distance and spacing in order to get full capacity.  Based on the manufacturer’s design charts we already have a reduced capacity due to spacing.  I’m hoping to develop a justification for using an edge distance that’s slightly less than the ‘full capacity’ edge distance given in the design charts, since this become critical in phased construction of bridges.  Without knowing a design load to apply to the anchors I’m struggling to figure out a way to make this justification.  Since my current focus is on bridge decks and these are always reinforced, I might be able to compare unreinforced capacity (basis for design tables) and capacity with typical deck reinforcing.  In your opinion, could that be a reasonable approach?

3. Crash Test 2 (4/16/15)
   used two (2) 1” dia. F42 cast-in ferrule loops on each end of the barrier
   segments for the top connection detail.  Crash Test 3 (5/19/15) used one
   (1) 1” dia. drop-in wedge anchor on each end of the barrier segments for the
   top connection detail.  We’re wondering if the 1” dia. F42 ferrule
   loops can be considered equivalent to the 1” dia. drop-in wedge anchors, such
   that one (1) 1” dia. F42 cast-in ferrule loop anchors can be used on each end
   of the barrier segments.
1. Not to sound like a broken record, but I would need more details to answer this effectively. Drop-in wedge anchors can have different capacities than ferrule loops. Thus, one would need to compare the capacities of both attachments to see which was more critical. I cannot tell from the reports what specific versions were used. I only know the bolt grade and diameter.

I’ve attached information on the ferrule loops and drop-in wedge anchors that were used in the tests.  It appears that the ferrule anchors have less capacity than the drop-in wedge anchors, but the reductions in capacity due to edge distance muddy the water.  My intuition leads me to think that a cast in anchor should have at least as much capacity as a post-installed anchor, but the documentation appear to contradict this assumption.  Can you think of anything I might be overlooking?  Could it be possible that the capacity of the ferrule loop could be controlled by the bolt pulling out of the threads in the loop?

4. Crash Test 2
   (4/16/15) and Crash Test 3 (5/19/15) both used 1” dia. wedge anchors to secure
   the lower anchor bracket plates to the unreinforced concrete test apron. 
   It’s our understanding that these large wedge anchors aren’t able to be removed
   after use, so they’ll need to be cut off and the exposed steel will be left
   flush with the bridge deck.  We’re wondering if 1” dia. drop-in wedge
   anchors (the anchors that were used in the top connections in Crash Test 3) can
   be considered equivalent to the 1” dia. wedge anchors, so that the 1” dia. drop-in
   wedge anchors can be used to secure the lower anchor bracket plates. 
   This would allow us to fill the drop-in anchor with epoxy after removal of the
   bolt, thereby eliminating the exposed steel at the bridge deck surface.”
1. Potentially, but in order to do so, one has to compare the capacities of the anchors for the spacing and edge distances of your problem. The different anchors can have different capacities. Thus, you would need to check and see if they were equivalent for the given anchor spacing and edge distances. However, the report does not contain the details on the specific anchors used, so I cannot look them up.

I’ve attached information for the two different anchor systems.  Based on the capacities given in the design tables it appears that the drop-in anchors can be used in lieu of the wedge anchors that were used in the tests.  Please let me know your thoughts.

More comments below in purple

From: White, Peter <PeWhite@indot.IN.gov>
Sent: Friday, December 21, 2018 2:37 PM
To: Robert Bielenberg <rbielenberg2@unl.edu>; Smutzer, Katherine <KSMUTZER@indot.IN.gov>
Subject: RE: InDOT Anchored PCB Questions

Bob,

Thanks for your responses.  I’ve included some follow-up questions/responses below in green.  I’ve also attached some information for you reference.  Thanks again for all your help and I hope you have a great holiday!

Thanks,

Pete

From: Robert Bielenberg [mailto:rbielenberg2@unl.edu]
Sent: Friday, December 21, 2018 12:31 PM
To: White, Peter <PeWhite@indot.IN.gov>; Smutzer, Katherine <KSMUTZER@indot.IN.gov>
Subject: RE: InDOT Anchored PCB Questions

**** This is an EXTERNAL email. Exercise caution. DO NOT open attachments or click links from unknown senders or unexpected email. ****

Hi Pete and Katherine,

I have some comments on your questions. Sorry for the delay in replying, I had NCHRP panel meetings this week and just got back.

Thanks

1. Crash Test 2
   (4/16/15) and Crash Test 3 (5/19/15) both used J-J Hooks to connect adjacent
   barriers rather than the pin and loop connection as shown on 801-TCCB-02. 
   The current standard drawing for unanchored temporary barrier (801-TCCB-02)
   indicates that the J-J Hooks may be used in lieu of the pin and loop
   connection.  We’re wondering if the pin and loop can be used in lieu of
   the J-J Hooks for our anchored temporary barrier.
1. The system was evaluated with the JJ-Hooks connection and noted above. However, we believe that the testing may have been conducted with the JJ-Hook in a more favorable position that makes the connection stronger. From what I can see in the test reports, the hooks are bearing on each other when loaded, which is less critical than if they are impacted in the reverse orientation where the hooks would pull apart. It appears that the joint sustained a significant load and damage. Thus, we would recommend that InDOT use the barrier with the loops in the stronger orientation that was tested with the anchorages to ensure that the system performs adequately.

We are unable to determine the exact effect of the conversion to a pin and loop system at this time. I am not sure what type of pin and loops system you wish to implement. The connection would have to have similar moment, shear, and tensile capacity at the joint. Thus, it is difficult to say if a pin an loop system would sustain similar loads without further information.

Additionally, the implementation of a pin and loops design would like increased the gap between barrier segments. Doing so would increase the loading of the barrier toes and toe fracture as well as create more exposure of the vehicle to the ends of the barrier segments. We have seen in other anchored PCB tests that contact and snag with the barrier segment joints can cause increased decelerations, vehicle instability, and or occupant compartment deformation issues. Thus, we cannot recommend switching the joint type without further research.

Just FYI, I’ve attached the current INDOT Standard Drawing which shows the pin and loop system in question.  Thanks for your thorough explanation on why you can’t recommend switching the joint type at this time.

                                Ok

2. Crash Test 2
   (4/16/15) and Crash Test 3 (5/19/15) both used 1” dia. wedge anchors to secure
   the lower anchor bracket plates to the unreinforced concrete test apron. 
   Based on the descriptions and photos in the test reports, it doesn’t appear
   that the anchors were placed near a free edge of the concrete apron.  We’re
   wondering if there is a minimum distance from the center of the anchor to the
   edge of the supporting concrete surface.  Our internal discussions
   have lead us to proposing a minimum edge distance from the back of the barrier
   to a free edge of 12”, but we’d like to get your opinion on this distance.
1. This question may also be a little difficult to answer. I don’t have any details on the exact wedge bolt anchor used. However, manufacturers of these anchors provide minimum edge distances or edge distance reduction factors when using these systems. I would follow their minimum guidance. You may also want to account for the anchor spacing when you look at these anchors. Typically, anchor spacing will affect their capacity as well. This may add to the edge distance issue if two anchors are spaced relatively close together. The issue is that the concrete area adjacent to the edge is loaded by both anchors rather than a single anchor which reduces its overall resistance. Thus, you may want to increase the edge distance accordingly based on the anchor spacing as well.

I’ve attached information on the anchor bolts that were used.  I completely understand where you’re coming from with following the manufacturer’s recommendations for minimum edge distance and spacing in order to get full capacity.  Based on the manufacturer’s design charts we already have a reduced capacity due to spacing.  I’m hoping to develop a justification for using an edge distance that’s slightly less than the ‘full capacity’ edge distance given in the design charts, since this become critical in phased construction of bridges.  Without knowing a design load to apply to the anchors I’m struggling to figure out a way to make this justification.  Since my current focus is on bridge decks and these are always reinforced, I might be able to compare unreinforced capacity (basis for design tables) and capacity with typical deck reinforcing.  In your opinion, could that be a reasonable approach?

This may be difficult to achieve. I have attached a couple of images to shown how we (and ACI) think about the loading of these anchors adjacent to an edge. When the anchors are loaded in shear, they apply a load to a shear block of the concrete. For a single anchor with sufficient distance from an edge, the concrete can develop load based on that shear block area. When you have closely space anchors and an edge, that shear block area is reduced in effectiveness due to the areas of adjacent anchors overlapping and loss of capacity due to concrete not being present past the edge of the deck.

There is likely an effect of having reinforcement present that increases the capacity, but it is not well defined. Current ACI procedures do not have methods for calculating this and we have tried to develop research in this area and have had limited luck generating funding. You amy want to see an attached report that began to look into this and a recent study I did for Iowa on bridge rail anchoring to a parapet where shear capacity was critical but difficult to calculate.

https://mwrsf.unl.edu/researchhub/files/Report14/TRP-03-264-12.pdf

https://mwrsf.unl.edu/researchhub/files/Report313/TRP-03-325-15.pdf

So I think the concept of your approach is reasonable, but it may be difficult to realize through calculations. We may be able to develop dynamic component tests that could evaluate this if you were interested. Full-scale testing would be able to evaluate this as well. In that case, even if the some anchors did disengage, we could determine if the system remained crashworthy.

3. Crash Test 2 (4/16/15)
   used two (2) 1” dia. F42 cast-in ferrule loops on each end of the barrier
   segments for the top connection detail.  Crash Test 3 (5/19/15) used one
   (1) 1” dia. drop-in wedge anchor on each end of the barrier segments for the
   top connection detail.  We’re wondering if the 1” dia. F42 ferrule
   loops can be considered equivalent to the 1” dia. drop-in wedge anchors, such
   that one (1) 1” dia. F42 cast-in ferrule loop anchors can be used on each end
   of the barrier segments.
1. Not to sound like a broken record, but I would need more details to answer this effectively. Drop-in wedge anchors can have different capacities than ferrule loops. Thus, one would need to compare the capacities of both attachments to see which was more critical. I cannot tell from the reports what specific versions were used. I only know the bolt grade and diameter.

I’ve attached information on the ferrule loops and drop-in wedge anchors that were used in the tests.  It appears that the ferrule anchors have less capacity than the drop-in wedge anchors, but the reductions in capacity due to edge distance muddy the water.  My intuition leads me to think that a cast in anchor should have at least as much capacity as a post-installed anchor, but the documentation appear to contradict this assumption.  Can you think of anything I might be overlooking?  Could it be possible that the capacity of the ferrule loop could be controlled by the bolt pulling out of the threads in the loop?

Based on the information you sent, it would appear that the ultimate tensile capacities of the ferrule loops are slightly higher than the Power Stud while the ultimate shear capacities are lower. Thus, it would be difficult to recommend the ferrule loops over the tested system as the tested option has higher capacity.

I am not sure of the cause of the difference, but we have seen similar differences with other types of anchors. For example, drop-in anchors have higher shear capacity than mechanical screw-in type anchors. Generally, when we have seen an anchor with higher shear capacity it is based on higher grade steel, a larger diameter anchor, or increased embedment. In this case,  I would guess that the cylindrical portion of the ferrule anchor is only 1 1/8” long. Thus, it does not develop shear loads in the concrete as well as the 1” Power stud which extends several inches farther into the concrete with a similar area. Similar to the question above, one would likely need some form of dynamic component testing or full-scale testing to verify the performance. We did similar testing for the steel strap tie-down anchors for KDOT and NDOT. See below.

https://mwrsf.unl.edu/researchhub/files/Report266/TRP-03-182-07.pdf

I would doubt that the cause is the threads pulling out of the loop as the shear loads don’t tend to load the threads in pullout. Again tensile capacities seem similar when ignoring edge effects and spacing effects.

4. Crash Test 2
   (4/16/15) and Crash Test 3 (5/19/15) both used 1” dia. wedge anchors to secure
   the lower anchor bracket plates to the unreinforced concrete test apron. 
   It’s our understanding that these large wedge anchors aren’t able to be removed
   after use, so they’ll need to be cut off and the exposed steel will be left
   flush with the bridge deck.  We’re wondering if 1” dia. drop-in wedge
   anchors (the anchors that were used in the top connections in Crash Test 3) can
   be considered equivalent to the 1” dia. wedge anchors, so that the 1” dia. drop-in
   wedge anchors can be used to secure the lower anchor bracket plates. 
   This would allow us to fill the drop-in anchor with epoxy after removal of the
   bolt, thereby eliminating the exposed steel at the bridge deck surface.”
1. Potentially, but in order to do so, one has to compare the capacities of the anchors for the spacing and edge distances of your problem. The different anchors can have different capacities. Thus, you would need to check and see if they were equivalent for the given anchor spacing and edge distances. However, the report does not contain the details on the specific anchors used, so I cannot look them up.

I’ve attached information for the two different anchor systems.  Based on the capacities given in the design tables it appears that the drop-in anchors can be used in lieu of the wedge anchors that were used in the tests.  Please let me know your thoughts.

I would concur with that. If they have similar shear and tensile capacities, then you should be ok.

You should consider the grade of the bolt you use with the drop-in. We have typically used Grade 5/A325/A449 capacity bolts with our drop-ins to ensure that the steel is not shearing off at lower loads than the concrete capacity.

I hope all is well with you.  We’ve come across another challenge with our anchored temporary barrier and I’m hoping you might be able to share your opinion.  This question is a follow-up on question #4 shown in the email chain below.  It occurred to us that leaving the drop-in wedge anchors in the concrete could pose problems in the future during milling operations.  A Contractor that we spoke to suggesting using threaded rod epoxied into the concrete, which they indicated can be removed after use. 

Crash Test 2 (4/16/15) and Crash Test 3 (5/19/15) both used 1” dia. wedge anchors to secure the lower anchor bracket plates to the unreinforced concrete test apron. It’s our understanding that these large wedge anchors aren’t able to be removed after use, so they’ll need to be cut off and the exposed steel will be left flush with the bridge deck.  We’re wondering if 1” dia. threaded rod epoxied into the concrete can
be considered equivalent to the 1” dia. wedge anchors.  I’ve attached some information on the tested wedge anchor and an epoxy anchoring system.  Based on this information, it appears to me that since the epoxy system has as much ultimate capacity as the wedge anchor, this should be an equivalent method of anchoring the lower bracket. 

Thanks again for all of your help.  Please let me know if you have any questions.

Thanks,

Your anchors can potentially be replaced with epoxy anchors. We have used similar arguments previously. You would need to show that the epoxied rods have equal or greater capacity in shear and tensile to the tested anchors. The determination on if it can be done would be based on several factors.

1. The embedment of the anchor will be critical to determining the load capacity of the anchor. I am not sure what embedment you are thinking, but you would need sufficient anchorage to develop the equivalent strength to the tested anchor.
2. The grade of the threaded rod would need to such that the threaded rod has greater strength than the tested anchor. This may require a higher grade steel as the shear section of the tested anchor appears to be a solid shank, while a threaded rod would have reduced section.
3. Similar to what we discussed previously, edge spacing and anchor spacing would need to be considered. Like we discussed previously, this may make the anchorages difficult to calculate. As such we have often done dynamic component tests to compare anchorages.

This is a fairly conservative approach, but it needs to be if no additional testing is conducted. 

Thanks