Dead Loads and Live Loads on Pile Cap

[ketanco]

In a question I was solving for a group of piles, where it asks max uplift force, It gives the total Dead Loads from the building, and the Live Loads, and the wind lateral force, (so that you have moment too)

in the calculation it of course take dead load and wind load into account but it doesnt take live loads into account at all. Why is that?

This is the question by Goswami Practice book, Geotech depth question number 6 by the way

 

[Ble_PE]

When you are checking for uplift on foundations you combine the dead load with whatever lateral load you are analyzing, e.g. wind or seismic. This is because the live load would help to counteract the uplift, therefore lead to an unconservative design. Live load is a transient load, so you can't count on it to be there at all times. Check out Chapter 2 of ASCE 7 for more info on load combinations.