eccentric loads on edge strip footing that are supported by screw piles

[JasonS_001]

Can anyone please give advice on the analysis and design (detailling etc) on this eccentric loads applied on the edge beams that are supported by the screw piles? Thanks

 

[dik]

brad: not so much with 12" shafts (I just realised, the misplacement may have been due to a component of that; I'd always attributed it to the 'bevel cut'). I didn't see them installed, but there were no indications of problems... after the installation when they recorded the location, the wobble problem became a problem. The screwpiles were to support six 400K transformers plus a couple of buildings. Designed and resistance confirmed by a local geotekkie. First time I used screwpiles... nearly a decade back. My big concern was the design of the helix and I still haven't found a good and easy way to design them.

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

-Dik

 

[dik]

Missed this... the 300 is arbitrary. Just a distance below the slab... you can have a 150 slab and 150 compacted granular stuff... could be 200... just as easy.

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

-Dik

 

[JasonS_001]

Thank you. It is just a one story building (all on screw piles though) so not much lateral loads. I am just wondering if the soil-grade beam can provide some lateral capacity in this case. Or is it possible to have couple of inclined piles in inverted V shape so lateral load will transfer to compression / tension?

 

[dik]

or the wall...

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

-Dik

 

[JasonS_001]

Thank you dik.

 

[phamENG]

Check with your geotech. You typically can't count on anything within the frost depth to provide passive pressures, and if you're in an area prone to flooding you'd need to consider any effects of erosion and scour on the soils surrounding the wall/grade beam. In other words, if you can depend on the soil to be there and maintain its strength, you can use it. If you can't...then it has to be resisted by the piles.

 

[dik]

The slab usually provides the support at the bottom.

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

-Dik

 

[dold]

Not really related to OP's question, but I figured yall would like this. We recently did a fairly large building with piles. The site was on a reclaimed superfund site so excavation was to be avoided at all costs. And the costs were high. Supplier was out of California - DrillTech. The product is called TorqueDown, which I believe is just the auger head. IIRC, each cast auger head by itself was around $1k. ~10-12in diam, ~60ft to refusal typically. There were around 800 piles +/- 100. Battered piles were used at SFRS frames and walls. Note the spiral markings on the piles to indicate progress. Also note the ovalization (sp?) of the lug holes in the piles. Lotta torque.

for reference, the bars in those pile caps are #10 and #11.

 

[dik]

Are those friction piles, with the auger just to take them down?

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

-Dik

 

[dold]

End bearing and friction. Auger+downward(crowding) pressure takes them down.

description link

Lots of links

 

[Brad805]

That's a drill rig I like. The head seems ideal for difficult drilling, but otherwise, the design seems like a common driven pile.

 

[dik]

Funny what you can patent...

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

-Dik