I have a warehouse with a 6" concrete slab on 12" compacted gravel. Control joints were made within 12 hours at approximately 15'-0" x 20'-0" panels. (No vapor barrier was necessary.)
The slab is reinforced with Fiber mesh and it was poured with the building fully enclosed using chutes (no...
SteelPE, I agree that simply giving maximum and minimum loading combinations for each column is particularly dangerous when designing foundations against sliding for vertical bracing systems. It's often advisable to combine the two (or more) footings in order to pick up vertical load from one...
I agree with JAE regarding the dumpster and the drive through apron - those can both be built up at a later time if they settle excessively (as long as they are kept independent of the building). However, I am more nervous of the pad in front of the loading/leveling docks. This will get constant...
I find most decent GC's use concrete bricks to hold the required cover to slab bottom reinforcement. This seems to eliminate the possibility of slab bolsters from punching through the subgrade or vapor barrier.
If the slab then settles under it's own self weight you probably haven't done a good...
SteelPE: I wouldn't be concerned about curling of a structural slab tied to grade beams. Slabs-on-Grade can give you curling problems which may indeed be enhanced by putting a vapor barrier directly beneath them.
In "Designing Floor Slabs On Grade" (jointly authored by Boyd C. Ringo - past chairman of ACI Committee 360)- Commentary to Section 3.8 it states that the 3" cover for concrete poured on soil is not required.
Unlike a footing which is often poured directly on soil, the subgrade being used as a...
A commonly seen “standard detail” for a concrete column or pilaster supporting a steel column with embedded anchor bolts shows column ties closely spaced in the top 8” – 12” of the column – presumably to enclose the anchor bolts. I can’t find the code reference (ACI, IBC?)requiring this. Can...
