Concrete Breakout in Shear Above Opening

[LearningAlways]

Hello. My question is regarding breakout cones near a window blockout and if an effective area can be utilized.

An effective breakout area would be the full shear cone less any area for blockouts. This is pretty straightforward for tensile failures.

However, the concrete failure area is much larger in shear than in tension when the anchor furthest from an edge (ca₁) is large.

I've attached a diagram regarding what I think effective areas for tensile and shear breakouts should be. There is a screenshot from a software I'm using to backcheck my hand calcs.

I'm not entirely sure about the shear breakout area, my gut says that its the weighted average of two areas (blue & orange in the diagrams).

Feedback is greatly appreciated. Thank you in advance.

 

[LearningAlways]

To be a little clearer.

By weighted average, I intend to find two different capacities based on two different edge distances. The first capacity is based on an edge distance using the full height of the panel. The second (lower) capacity will be based on an edge distance using the window blockout.

I would find a capacity based on a weighted average of those two areas.

 

[KootK]

I think that this can be made simpler by recognizing that your shear pryout will govern over your shear breakout. I don't see a viable shear breakout failure mode here really. For shear pryout, I'd assume the frustum shown in blue below. By the look of it, you wouldn't be leaving much extra capacity on the table this way anyhow.

Do you actually have a direct anchor tension load on this?

 

[KootK]

One thing that I don't love about the weighted average method is that it inherently places some reliance on a breakout frustum that would be asymmetrical / asymmetrically loaded. That, in my opinion, takes you further from similitude with testing. I get that a lot of engineers would simply consider the averaging to be a reasonable thing to do though.

 

[LearningAlways]

I don't see a viable shear breakout failure mode here really.

Can you elaborate?

I'd assume the frustum shown in blue below.

Based on how I've input it into the software, that is the frustrum assumed for shear pryout. You can see the results below.

Ignore the parallel x+ results, the blockouts of this panel can't be input into the software (which is why I am doing this by hand), the point being that y+ breakout controls over pryout.

Do you actually have a direct anchor tension load on this?

The connection is a double angle which is bolted to the W-beam and welded to the embed. I assumed an eccentricity, based on the applied moment there is tension on the top few studs. There isn't an axial load applied to the plate.