The foundation must not tip over. We check the , which should generally be >1.5is greater than 1.5 Restoring Moment ( Mrcap M sub r ): Overturning Moment ( Mocap M sub o ): if shear is significant) FoS Calculation:
Result: . The FoS is less than 1.5. We must increase the footing size (e.g., to ) or increase the thickness to add more dead weight. 4. Soil Bearing Pressure Check We use the formula for bearing pressure ( Tower Crane Foundation Design Calculation Example
For the purpose of this article and the calculation example, we will focus on the , as it is the most prevalent scenario engineers face on urban construction sites. The foundation must not tip over
Provide T20 @ 200 mm c/c (both directions top and bottom) → (A_s = 1570 , \textmm^2/m) ✓. We must increase the footing size (e
Moment about column edge = pressure resultant × lever arm. Use trapezoidal distribution? For simplicity, take average pressure = (204.5 + 0)/2? No, partial uplift. Actually, use effective width method: