Light Pole Pile Footing and Broms

[Tropical Engineer]

Would any one know how to treat the soil weight in Broms theorem for laterally loaded piles if its below the water table ?

Would there be a reduction in contributing soil weight as there is a buoyant affect ? ie :-

Design unit weight below water table = Weight of soil (ɣ) – density of water ɣw

Thanks in advance .

 

[EireChch]

Yes, you should be using effective unit weight

 

[HENRYZAU]

For sandy material use effective unit weight, for clayey material unit weight "doesn't matter" it's the undrained shear strength Cu or Su that matters.

 

[Tropical Engineer]

Thanks EireChch and Henryzau.

So for clarification I assume this is correct ?
Effective unit weight for sand will be = Wet Dense Sand (ɣ = 20kN/m3) - water (ɣ = 10kN/m3) = 10kN/m3 ?

Thanks,