Shelf angle Precast Wall

[structural2010]

I have a new precast wall that a hollowcore roof plank needs to be connected to. There was a coordination issue and the contractor missed areas that needed an embedded angle to the precast. See attached section we are proposing using the same size angle that is everywhere else with an expansion anchor @ 18" O.C.. I am not sure on how to check the angle along with the anchor. I know the anchor will be subjected to combined loading (shear & tension). I just need a design example in which I follow. Any help would be greatly appreicated.

 

[structSU10]

i would get the moment due to eccentric load on the horizontal leg, and check the bending & shear stress. I would then take that moment and divide it by the moment arm, which can conservatively be taken from the angle toe to the CL of bolt. check the bolt for the shear and tension. Can check bearing of angle to concrete; if a large area is required it may be of concern, but i doubt that will be a problem.

 

[CANPRO]

Check the manufacter for allowable tension/shear for the anchor...Hilti has values listed and design examples in the manual. While you're there check the minimum thickness of the base material (looks like your expansion anchor is awfully close to the insulation in your panel). Quick look at hilti says 3" or 1.3xembedment (whichever is greater)...looks like that might kill your detail.

For checking the angle, I would take your loads multiply by the trib width and check the angle for bending.

 

[msquared48]

I would add #5 horizontal bars X 3'0" @24" long, or whatever is needed, drilled and epoxied to the wall to take the tension forces rather than add additional eccerintic load to the afterset bolt holding the angle.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[ztengguy]

The angle design should be no different than the original, other than the span between the anchors. I would assume with CIP anchors you didnt need them at 18" o.c.

After that, just find your tension and shear, design the anchor. I think the HILTI manual has a design example.

@Msquared, where would you put your dowels? I dont see how that would help.

 

[msquared48]

This is hollow plank that could have a grout dam inserted and grouted at the ends of the panel. The panels frequently are constructed with portions of the ends of the slab omitted for installation of these horizontal ties.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com