Floor Slab for Pedestrian Loads

[joelperez]

Hi guys, I need to design and slab on grade for a facility where there's going to be
only people walking around, do you have design guide about this case?

Thanks in advanced

 

[phamENG]

Around here, the "minimum standard" for a concrete slab is 100psf. Might put 40psf on the drawings if it's a house slab, but it's no different from the design of a 100psf floor. Compacted porous fill, insulation, vapor barrier, 4" minimum slab with some sort of reinforcement and crack control. Above 100psf and things start to change. Keep in mind, enough people walking around close enough can easily hit 90psf.

 

[dik]

This might help...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[BAretired]

The people load is inconsequential. If it were a structural slab, 100 psf would be a reasonable figure to use and would be consistent with most codes.

As a grade slab, the most significant stresses in the slab are likely to be caused by soil properties, volume change, moisture regime, frost heave and temperature effects, all of which vary with site location, but which should be taken into account when designing the slab.

BA

 

[RabitPete]

From my experience, subgrade preparation usually is the key to a long lasting SOG. Most sidewalks around here are roughly 4" thick with fibers. Wire mesh is not common, as it is both more expensive and I am yet to see one slab which had it placed correctly. Rebar is virtually unheard of even for driveways and parking lots.
That said, I've seen lots of failed slabs and the most common reason was poorly compacted subgrade, number one place to look at is utility trenches, those contractors rarely, if ever, compact their backfill at proper intervals.

 

[BAretired]

Three of my neighbors have had either new or replacement driveways installed recently. They all used deformed bars spaced at about 24" centres each way. Bars were lying on grade before the pour without chairs, but there may have been an attempt to raise them during concrete placement. I wasn't present during the pour. In my area, bars are fairly typical, but I suspect bars are not typically placed properly.

BA

 

[HTURKAK]

In this case, subgrade preparation, shrinkage, temp. reinf. of sog will govern..

Better to look ACI 360R Design of Slabs on Grade ..

 

[dik]

another thing to consider... is it possible that this facility may have a future use? You may seriously be affecting any future 're-sale' value. For very light usage, depending on the soil conditions, you may have a slab as thin as 4", properly constructed. That would work.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[RabitPete]

Proper design and spacing of joints is also important to prevent cracking. Just inspected a large pedestrian walkway which cracked in numerous places weeks after placement. Most saw cut joints were less than 3/4" deep, so it cracked all over.

Someone also decided that it was a good idea to stagger the saw cuts. Guess what? The cracks which did originate at the cuts, kept propagating right through the middle of the adjacent tiles.