is the friction coefficient between the soil and concrete (typically 0.35 to 0.45). Step 5: Concrete Structural Design
Provide (As,prov ≈ 1,570 mm²/m) top and bottom both ways.
Below is a typical example of designing a reinforced concrete square pad foundation for a fixed tower crane. A. Input Data and Assumptions Top-slewing tower crane. tower crane foundation design calculation example link
, the resultant force acts outside the central core. This causes zero-pressure zones (uplift) on one side of the pad. The maximum soil pressure ( qmaxq sub m a x end-sub
qmax=2×Ptotal3×L×(B2−e)q sub m a x end-sub equals the fraction with numerator 2 cross cap P sub t o t a l end-sub and denominator 3 cross cap L cross open paren the fraction with numerator cap B and denominator 2 end-fraction minus e close paren end-fraction is the friction coefficient between the soil and
q_max = (2×2,687.5) / [3×7×(3.5 – 1.29)] = 5,375 / [21×2.21] = 5,375 / 46.41 ≈ ≤ 150 kN/m² → OK
Verify that the crane's anchor legs will not punch through the concrete slab. This causes zero-pressure zones (uplift) on one side
To find the actual pressure on the soil, we must include the self-weight of the concrete pad.
): The most critical force, generated by the long jib extending outward and the horizontal wind pressure. Torsional Moment ( Mtcap M sub t