Post Installed Anchors to a Sandwich Precast PANEL ( 3 inch concrete concrete)

[Bor_An_Struc]

Hi All.
I am a early structural EIT trying to design post Installed anchors on to 75 mm thick RC concrete wall panels.
The minimum thickness of the concrete member needs to be effective depth of anchor +30 mm cover which does not work. ( Hilti tables). The triangular structure made out of angles is supporting small W beams with the shown loads.
Is there a way to design the anchors for (shear + tension)?

Thanks.

 

[KootK]

You might consider through bolts for the tension connection even though:

1) There is not really a great, code accepted design method available for running the numbers. At least not in North American codes.

2) You will have to take care to not interrupt any of the reinforcing in the wall, particularly any prestressed reinforcing.

One of the problems with attachment to sandwich panels is setting things up such that you engage the entire wall thickness for resistance rather than just one wythe. It's rare that a thin wythe on it's own can do the job and the composite action connecters that connect the two wythe are not always great at transferring localized tension across the full structural thickness of the wall panels.

 

[Brad805]

Are both skins only 75mm?

 

[Bor_An_Struc]

Are both skins only 75mm?

Hi Brad.
Yes both skins are 75 mm with insulation layer of 100 mm. Thanks

 

[Bor_An_Struc]

You might consider through bolts for the tension connection even though:

1) There is not really a great, code accepted design method available for running the numbers. At least not in North American codes.

2) You will have to take care to not interrupt any of the reinforcing in the wall, particularly any prestressed reinforcing.

One of the problems with attachment to sandwich panels is setting things up such that you engage the entire wall thickness for resistance rather than just one wythe. It's rare that a thin wythe on it's own can do the job and the composite action connecters that connect the two wythe are not always great at transferring localized tension across the full structural thickness of the wall panels.

Hi KootK.
Thanks for the insights of what might go wrong. In this I am specifically out of anchors to fasten to 3" concrete skins as none of the wedge anchors or HAS threaded rods work for 3" concrete ( HILTI tables for minimum embedment and concrete thicknesses). So there are no strength guides for post installed anchors for this condition. Do you have any suggestions on what might work? Thanks.

 

[Brad805]

I asked about the skins as we typically have a thicker skin on one side. In your case you will be relegated to 1/4" or 5/16" screws or thru bolts as suggested. We deal with this a lot when people decide to add canopies late in the day.

 

[Bor_An_Struc]

I asked about the skins as we typically have a thicker skin on one side. In your case you will be relegated to 1/4" or 5/16" screws or thru bolts as suggested. We deal with this a lot when people decide to add canopies late in the day.

Thanks Brad. The suggestions are very helpful. Do you think there will be any issues if I go with the screws to about 39 mm effective embed ( 51 mm of nominal embed) 24 mm clear cover on the other side of panel?