×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Anchor in precast plank

Anchor in precast plank

Anchor in precast plank

(OP)
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?

RE: Anchor in precast plank

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

RE: Anchor in precast plank

(OP)
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.
 

RE: Anchor in precast plank

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.

RE: Anchor in precast plank

Yes.

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

RE: Anchor in precast plank

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.

RE: Anchor in precast plank

(OP)
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.

RE: Anchor in precast plank

(OP)
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.

RE: Anchor in precast plank

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.

RE: Anchor in precast plank

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.

RE: Anchor in precast plank

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.  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources