Small Foundation Design calculation (Simple Design)
In this article we are going to learn how to calculate the simple foundation design.
- Weight of Panel : 25 Ton (OR) 2.5 KN
- Size of Foundation` : 900 (L) x 750 (W) x 750 (D) mm.
- Volume of Foundation : 90x.075×0.75 = 0.5063 M3
- Unit Weight of Concrete : 5 Ton/M3
- Self weight of Foundation : 5063 Cum @ 2.50 Ton/ M3 =1.266 Tons
(OR) 12.66 KN
- Soil Data
- Assuming existing soil Allowable (permissible) bearing capacity : 100 KN/ M2
(considered in the obscene of Geo technical Investigation Recommendation)
- Check for Soil Stress
- Total weight including Panel : 12.66+02.5 = 15.16 KN
- Multiplying factor : 30
- Total factored weight (W) : 16 KN x 1.30 = 19.71 KN
- Area of Panel foundation (A) : 90 x 0.75 = 0.675 M2
- Soil stress (W/A) : 71/0.675 = 29.20 KN/ M2
Allowable bearing pressure : 100 KN/ M2
Since, Applied bearing pressure < Allowable bearing pressure.
Panel foundation is safe.
- Check for Sliding
- Design service load (Total vertical force of foundation) : 66 KN
- Total horizontal Force (Htotol) : 20% of Vertical force
: = 12.66 x 20%=2.532 KN
- Foundation depth : 75 m
- Design service moment : 532 x 0.75 = 1.899 KN.m
- Restoring force : 4 x Total vertical force
: 0.4 x 12.66 = 5.064 KN
- Factor of safety against sliding : Restoring Force/Total Horizontal force
: 5.064/2.532 = 2
Hence, foundation is safe against sliding.