Lever arm (distance between two bolt rows) = 1 m. Tension force per bolt pair = 4,500 / 1 = 4,500 kN / pair. Per bolt = 2,250 kN. This is too high – thus, increase bolt size or embedment.
As = M_Ed / (0.87 × fy × z) Assume z = 0.9d, d = 1.5m - 0.075m cover = 1.425 m. As = 744 × 10^6 / (0.87 × 500 × 0.9 × 1425) As ≈ 1,334 mm²/m. Use (1,570 mm²/m) top and bottom. Step 5: Anchor Bolt Design (Tension + Shear) Assume 4 anchor bolts, each M48 grade 8.8. Tensile force per bolt due to overturning = (M / lever arm) / 2. tower crane foundation design calculation example link
Section modulus, Z = (6 * 6²) / 6 = 36 m³. Lever arm (distance between two bolt rows) = 1 m
Required reinforcement (per meter):
SF = Mr / Mo = 7,650 / 4,500 = 1.7 (>1.5) → OK. Friction coefficient (concrete on soil) typically μ = 0.35. Resisting friction force = V_total × μ = 2,550 × 0.35 = 892.5 kN. Sliding force H = 150 kN. SF sliding = 892.5 / 150 = 5.95 → OK. Step 4: Bending Moment for Reinforcement Design Consider the foundation as an inverted cantilever. Critical section at face of mast base plate (assume 1.5m × 1.5m mast plate). For a 6m pad, the overhang from mast face to edge = (6 - 1.5)/2 = 2.25 m. This is too high – thus, increase bolt size or embedment
