Anchor in precast plank

[JoeBaseplate]

I have to attach a sunshade hanger from an 8" precast plank. The cores around have been grouted solid. In my design I am assuming that the grouted area+plank concrete (aprox 8”x24”) is one solid concrete area. Is that a correct assumption?

 

[msquared48]

The grouted cores are solid grout, and may bve grouted for reasons of end shear or wall rebar attachment. So, they may have some rebar bent into the grouted space from bearing walls below.

Do not drill into the area that is not grout - the original ungrouted section, and be careful not to hit any rebar in the grouted section too, although that area is probably less critical.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[JoeBaseplate]

Mike, so I should space my anchors @ core spacings (4" oc) and place the anchors at center of the core as long as I don't hit rebar and I should be able to use a minimum edge distance of 4" all around.

 

[a2mfk]

Building on what Mike said, the original panel section could have PT strands depending on the type of panel, I'd have that field verified.

 

[msquared48]

Yes.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[concretemasonry]

Do not assume the plank are grouted solid. It is difficult or impossible to fully grout a plank when placed. Often something (foam, paper, etc.) is pushed 2"-4" into the cores to create a backing for a "plug" to seal off the cores for air flow purposes.

At 24" wide, it could be a wet cast plank that has larger holes with a smooth interior face. In that even, there are creative ways to benefit from the large cores.

What kind of loads are you looking at and in what direction?

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[JoeBaseplate]

Dick,

I have huge loads, I have a horizontal (tension in anchor) of 5.6 K and vertical (shear) of 1.86 K. I am not so much worried about the shear on through the plank because it sits on a cmu wall but the tension is too high.

The cores are 7 3/8" oc.

 

[JoeBaseplate]

I am proposing to place a channel with multiple HSL anchors into cores. The plate for canopy hanger is then to be welded to this channel.

 

[csd72]

Make sure they use a stud finder to locate as many tendons as possible and use a regular percussion drill as this will not cut through tendons or rebar.

Use an anchor that is designed for hollow masonry.

 

[concretemasonry]

The concept will work as long as the hollow core planks are not grouted.

The precast plank supplier can supply information on the strand location. From the information on the core location and plank width, is sound like a "Flexicore" type plank that usually has round, smooth horizontal cores instead of the more common rough, irregular texture on the inside of the cores of extruded or zero slump concrete. This may help to track down the supplier.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[a2mfk]

Joe- you got handed a turd to polish, at least it sounds like you are making the arch and GC go back to the drawing board, rightfully so.

It may be moot if they may scrap the entire idea, but the reactions from Joe's last post were what concerned me about that detail, plus there are not many situations where I would be comfortable mounting to the end of a hollow core panel.... For those of us doing lots of anchor design, you know this could be an issue even in a tilt panel:


New PostJoeBaseplate (Structural)
31 May 11 14:21
Dick,

I have huge loads, I have a horizontal (tension in anchor) of 5.6 K and vertical (shear) of 1.86 K. I am not so much worried about the shear on through the plank because it sits on a cmu wall but the tension is too high.

The cores are 7 3/8" oc.