Steel beam on top of ICF wall detail 2

[Rich Zimmerman]

I've got a steel beam coming in perpendicular to an ICF wall). It sits on top of the wall (no pocket per-se). Both ends of the beam are supported the same way. Normally I would just drop a bearing plate with non-shrink grout and then weld the beam to the plate at the job site. However on-site welding requires a special inspection by an engineer and a trip from a welder and it occurs to me that perhaps I could just work something up where the beam gets bolted to the top of the ICF wall somehow.
So, two question:

1. Anyone have a detail where the beam gets bolted to the wall rather than welded to a bearing plate? I'm thinking a couple 5/8" bolts at the beam gage through the bottom flange set maybe 8" into the ICF. Am I missing something important here?

2. It occurs to me that the design might allow me to drop the beam a few inches and mount it into a pocket. After the beam is set, grout around it. So, in that situation would I have to weld the beam or would the grout around the beam serve to hold the beam from moving.

 

[milkshakelake]

@Rich Zimmerman I use 1/2" lag screws at 16" OC staggered and 2 screws at the end, and got no complaints. It might be overkill. Your idea of 1/4" at 12" staggered seems okay. For me, it's just nominal; no calculations. I don't understand the pullout load thing. I only see gravity.

 

[KootK]

And this is the beam on wall detail I use just for reference, though you mentioned it won't work for you.

Thanks for that. It's always a great kindness, in my opinion, when someone is actually willing to share the the real life details that they use. Firstly, there's the intellectual property aspect of it. And secondly, you're exposing yourself to all manner of possible criticism on a detail that you've already put out into the wild so to speak. Anyhow, I was in the process of trying to develop something similar (non-ICF) when I saw your detail and yours served as helpful inspiration. Two additional comments:

1) In the interest of reciprocation, my detail is shown below (it will look a little familiar). I'm not suggesting that mine is any better. Just what I though best for my particular, non-ICF project.

2) What do you consider the purpose of those L3x3 angles to be in your detail? Web stiffeners? Fill concrete engagement? One thing that's always nagged at me with respect to the "fill block out with concrete" business is that I worry that beam end rotation will "pop" the concrete out. In that respect, I almost feel as though the angles would make things worse. That said, my detail for elevator hoist beams is nearly identical and, to my knowledge, no problems have ever resulted.

 

[milkshakelake]

@KootK I agree, it's a bit weird putting details out there for the reasons you mentioned. Anyway,

1) Thanks for sharing! And I'm glad that my detail could help in some way, but I can't claim credit, I modified a detail from a different company (thus the intellectual property problem).

2) Those angles will keep the beam from pulling out, similar to anchors. The concrete fill will engage with the concrete wall via friction. I've used this detail and had no complaints so far, but also no major earthquakes in my part of the world, so we'll see. In practice, my first employer, another company, and my own company now have used the angles instead of anchor bolts when there's no uplift.
I don't agree about rotation. A typical 20' beam will have about 0.4 to 0.6 degrees of rotation in worst case deflection, which isn't enough to pop out the fill. It's a different story for wood joists without fire cuts, which pop out CMU when they're on fire, but generally steel is fireproofed.

Also I'm wondering about the reason for using a hooked bolt? Is it for the development length? I try to specify threaded and nutted rods because I think they perform better.

Sorry OP if this is getting way off topic.

 

[KootK]

Also I'm wondering about the reason for using a hooked bolt? Is it for the development length?

- laziness, it was late.
- convention.
- desire to specify what is cheap/palatable (debatable there's a difference).
- no real loads other than those of a connection with nominal integrity.

I wanted to go with Hilti HUS but was concerned about access issues and the feasibility of building up the elevation with grout bed if required.

 

[Rich Zimmerman]

Wait, you prefer a 3/4” threaded rod over a 3/4” J-Bolt? I would think the J-bolt was a much better choice. No?

 

[KootK]

J-bolts kinda suck for pulling on. The concrete crushes in the knuckle and the bend tends to straighten. Not quite worthless in tension but getting there.

 

[Rich Zimmerman]

But worse than a threaded rod? To pull those out all you’ve got to do is break off the concrete surrounding in the threads? Or are you suggesting a threaded rod with a washer and nut embedded at the bottom?

 

[KootK]

Yes to washer and nut(s).

 

[milkshakelake]

@Rich Zimmerman: AISC Design Guide 1 section 2.5: "Hooked-type anchor rods have been extensively used in the past. However, hooked rods have a very limited pullout strength compared with that of headed rods or threaded rods with a nut for anchorage. Therefore, current recommended practice is to use headed rods or threaded rods with a nut for anchorage."