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Footing Uplift
. Continuous footings - they include strips, footing slabs/raft slabs, stiffened slabs. When foundations are of a poor material and cannot support the load of the structure, piers are used to bear the footings on better foundation deep down and can be used in combinations of pier and beam, pier and slab, etc. Section 3 of AS 2870. Foundation Design Examples Bearing Pressure in Shallow Foundations Example 2 - Calculating the bearing pressure on a continuous footing subjected to a. Example 1 - Calculating the Factor of Safety for Overturning and Sliding, Semigravity Retaining Wall.
Footing Uplift
![Spot footing vs spread footing Spot footing vs spread footing](/uploads/1/2/5/7/125702906/255006352.jpg)
Folks,
When you calculate the uplift load on a footing, the code requires the use 0.6D + W. Assume this gives a net uplift of 30 kips.
When you calculate your resistance to uplift in terms of the footing weight and the weight of a truncated soil pyramid (based on a 30 degree angle), do you use a 0.6 factor on the uplift resistance and compare it to the above calculated uplift of 30 kips?
It seems like double dipping (very conservative) to use a 0.6 factor on the resistance side also. Thoughts?
When you calculate the uplift load on a footing, the code requires the use 0.6D + W. Assume this gives a net uplift of 30 kips.
When you calculate your resistance to uplift in terms of the footing weight and the weight of a truncated soil pyramid (based on a 30 degree angle), do you use a 0.6 factor on the uplift resistance and compare it to the above calculated uplift of 30 kips?
It seems like double dipping (very conservative) to use a 0.6 factor on the resistance side also. Thoughts?
![](/uploads/1/2/5/7/125702906/798967553.jpg)