Tall ICF wall...

[Jmeng1026]

I am designing a house that will use icf's for the basement walls and the house walls. See attached section.

Looking at the Logix design manual it when it refers to height of wall do I need to design it based on a 24' tall wall or would it be a 15' tall wall?

 

[phamENG]

Depends on your connection to that wall.

 

[DoubleStud]

It is just a form. You design it however you wish. It is basically designing concrete wall with sacrificial form that will act as insulation.

 

[Jmeng1026]

The floor joists will be fastened to the wall using the Simpson ICFVL ledger connection system.

 

[Brad805]

Depends on the contractor. Some will have enough bracing to build it all at once, others will want to build to the main, erect the main, and then build up from that using the floor to brace the wall. If they build it at once the location of the bracing will be important unless you design the wall so you can remove the bracing once the roof is in place. Regardless, this is not all that complicated to design. The logix is just as form as DoubleStud describes.

 

[Jmeng1026]

I guess I should have clarified in my original post. I am tying to determine the required vertical size and spacing of the rebar.

 

[XR250]

FYI, that connector does not resist out-of-plane loads.

 

[Brad805]

XR, the CAN version lists out of plane.

 

[XR250]

Interesting.

 

[driftLimiter]

You would need to decide if your floor to wall connection is sufficient to provide out of plane bracing to the wall. If so you get one buckled shape above the floor and one below the floor.

Its a slender concrete wall so regardless of form strategy it should be designed as such.

If you have seismic it is questionable whether the floor system would be above to provide sufficient out of plane anchorage to the wall.

 

[SJBombero]

There are many ways to detail the ledger connection for a more rigid connection to the concrete that would provide adequate out-of-plane resistance. The Simpson connectors seem marginal for that purpose. I would lean towards a detail that uses an embedded anchor bolt and purlin anchor.

 

[phamENG]

In terms of selecting size and spacing of rebar...are you designing based on accepted engineering practice (ACI) or prescriptive code requirements (IRC/ICF ESR)?

Makes a big difference. The IRC has some rather questionable concrete design that gets used by contractors without engineers. ICF rebar tables are usually based on those from what I've been able to put together. I'll tell you this: if you try to give a contractor that does a lot of prescriptive ICF an engineered design, he'll blow his top. We put a lot more rebar in there than they say is necessary. In some ways that's good...unless you're into a 12" ICF, those things are so congested already that honeycombing should just be expected.

 

[Alex A.]

Common residential practice is to design the wall for an unsupported storey height between floors/roof (i.e. 8' for the basement wall and 8'-4" / 15' for the above grade walls). Detail your ledger board to be anchored to the wall, either using the Simpson hangers or anchor bolts. Where the joists are parallel to the wall, add blocking between joists in rows to secure the ledger board to the floor diaphragm.

J.T. Donald Consultants Limited
Markham, ON, Canada

http://www.jtdonald.com