Below is a walkthrough of the essential design steps and a simplified calculation example to help you understand the process. Common Foundation Types
$$ P_total = P_crane + G = 774.4 + 1296 = 2070.4\ \textkN $$
thickness = 1.5 m, LГ—B = 5.5Г—5.5 m Self-weight = ( 5.5^2 \times 1.5 \times 25 = 1,134 , kN ) ( V_d = 1.35(950 + 1134) = 2,813 , kN ) [ \sigma_max = \frac281330.25 + \frac6 \times 39005.5 \times 30.25 = 93.0 + 140.8 = 233.8 , kPa ] Still high в†’ the soil is too weak. Conclusion: Either use piles or improve bearing capacity to ~250 kPa.
(Reasonable defaults are assumed so the example proceeds decisively; in practice replace with project site values and local code factors.) tower crane foundation design calculation example link
qmax/min=VtotalBГ—LВ±6Г—MtotalBГ—L2q sub m a x / m i n end-sub equals the fraction with numerator cap V sub t o t a l end-sub and denominator cap B cross cap L end-fraction plus or minus the fraction with numerator 6 cross cap M sub t o t a l end-sub and denominator cap B cross cap L squared end-fraction Ensure that qmaxq sub m a x end-sub
The crane is operating. Includes maximum lifted load, operating wind speeds (typically up to 20 m/s), and dynamic slewing forces.
e=M+(HГ—h)Vtotale equals the fraction with numerator cap M plus open paren cap H cross h close paren and denominator cap V sub t o t a l end-sub end-fraction Below is a walkthrough of the essential design
Depending on site conditions and space, engineers typically choose from:
[ \sigma_max = \frac229525 + \frac6 \times 39005 \times 25 = 91.8 + 187.2 = 279 , kPa ]
) must be sufficient to prevent the mast legs from punching directly through the slab. (Reasonable defaults are assumed so the example proceeds
The critical bending moment is found at the face of the mast. For a 1.5 m thick footing with a mast width of 1.6 m, the cantilever length L' is:
Result: . The soil bearing capacity is safe. 4. Overturning Stability Verification