Through bolt connection

[Michael Val]

Hello everyone, I could use your expertise. I'm working with through bolts anchored in a concrete slab, and I'm referencing Eurocode for design. Unfortunately, there’s limited guidance available for this specific case.
Here’s the situation (please refer to the image below):

green - beams
yellow - slab
I'm only concerned with the concrete slab—not the bolt or base plate. Based on my understanding, I need to check for the following failure modes:

Concrete cone failure due to tension from moment
Concrete pry-out failure
Concrete bearing compression

Am I on the right track?

I also have additional questions:

1. Edge Distance : If the anchor is placed in the middle of a slab bounded by beams, how should I treat edge distance? Can I assume the edge effects (like blow-out failure) are negligible, or do I need to account for them?
2. Eccentricity : Since the tension arises from moment, should I be concerned about eccentric loading effects on the anchor?

Thank you everyone.

 

[jhnblgr]

are you really anchoring to the slab in the traditional sense? It doesn’t seem like anchorage design really applies at all. The bolts aren’t pulling out of the concrete by some form of bond but through a backer plate to make a bolted clamp like connection. The bolts would be in tension as a result to create a friction force to prevent movement, like a slip critical connection. From there the forces are distributed through a thick plate across the slab. The slab needs to be checked for shear and bending as a result. Likely bi axial loading.

 

[Michael Val]

are you really anchoring to the slab in the traditional sense? It doesn’t seem like anchorage design really applies at all. The bolts aren’t pulling out of the concrete by some form of bond but through a backer plate to make a bolted clamp like connection. The bolts would be in tension as a result to create a friction force to prevent movement, like a slip critical connection. From there the forces are distributed through a thick plate across the slab. The slab needs to be checked for shear and bending as a result. Likely bi axial loading.

Yes, I’m planning to perform two calculation checks for this problem. This assumption will be used for my second check. However, I’m uncertain about how to handle the edge distance and eccentricity in cases like this.

 

[desertfox]

Hi Michael

Consider converting the concrete into an equivalent piece of steel , search for transformation of sections.
Once you have done that you can treat the whole thing has a steel block with through bolts.
Because of the offset load the bolts will see shear and bending, the first three rows of bolts will see more load than those closest to the load application point, so most of the loads will be on bolt rows 1,2,3.
I am busy right now but will post more detail later.