Accessory building without slab

[Papareis]

I've been designing a storage building at a residential site for the owner to store a backhoe and tractor along with other items. The building is to be 32'x60'..... basically a large garage. The plans initially called for typical 4' frost walls on an 8x16 strip footing (the frost depth is 4' here, the soil is mostly sand). The walls were to be 2x6's and the roof structure from trusses. The owner told me that he does not want a slab inside the building. He wants stone or "dirt".

In spite of the presence of backfill on the outside of the foundation wall, I'm a bit concerned about the adequacy of 8" poured concrete walls in resisting soil pressure from the equipment inside if it's driven close to the foundation wall. I'd at least spec crushed stone. 'Any suggestions on how to approach evaluating the foundation wall thickness adequacy?

 

[oldestguy]

I'd beef up the wall some, such as going to 12" wall and re bars horizontal and vertical, say #4 @18" each way. What is in the plan for the situation when the operator doesn't stop before the wall and damages the material above the concrete. If that is not a potential problem, then your question is not likely a problem.

 

[BAretired]

If the interior grade is approximately level with the exterior grade, a frost wall 8" x 48" deep with nominal reinforcement should be sufficient to resist the lateral pressure from equipment stored inside, even if parked adjacent to the wall. Increasing the thickness by four inches seems arbitrary and will increase costs significantly. I would opt to maintain the 8" thickness.



BA

 

[cvg]

why wouldnt you just analyze your foundation wall with a surcharge load? see if you need a slightly wider footing or more reinforcement. probably not. I'm with oldest, I would be most worried about the backhoe bucket hitting the wall or hitting a truss and less worried about the foundation moving. Make sure you get good compaction on both sides of the wall.