I see what you're saying about heaving. But IMO it depends completly on the soil type at the project site and the subgrade prep. Most gravity retaining walls simple have a compacted fill base that doesn't extend to frost level but only acts in bearing. BSFS show no signs of settlement or heaving at the field level where it interfaces with the first riser of the seating bowl. I just don't buy the argument that the foundation system for the proposed wall would make it cost prohibitive compared to other projects.
Frost footings on buildings create a perimeter to keep the interior subbase in a temp controlled area separated from the exterior. Interior footings don't need to extend to frost because they are not located at a location with a temperature differential. The heaving is caused by the tramp diff and gets worse with certain soils.
Interior footings don't need to be frost footings, because unless there is a major problem, there will never be frost under a building. Has nothing to do with temperature differential. There would be frost potential on a site wall.
Segmented (read block) retaining walls don't need a frost footing, because they have no rigid joints. No mortar to crack. The will move and at worst not be nice and level. But a laid up masonry wall will crack at the joints, and with the reinforcement in a CMU wall, likely not totally return to it's original position.
I'm not arguing it's cost prohibitive, only that the cost would be much higher than the non-nerds think, and that is likely why it is not on the priority list.
Nerd off/
Measuring tape off/
We're both pretty, let's go eat some turkey!
Poll