Step 3 — Compute foundation width
Checked along a perimeter trailing out from the mast legs. Given the massive thickness ( ), the punching shear capacity of the
The design process typically follows three checks: , Geotechnical Capacity (Bearing Pressure) , and Structural Integrity (Reinforcement) . Below is a worked example based on a typical manufacturer's data sheet.
This example demonstrates the design of a square, shallow concrete pad foundation resting on a soil strata with known bearing capacity. Step 2.1: Input Parameters
Crane is parked, free to weather-vane, resisting extreme storm wind speeds. 2. Step-by-Step Foundation Design Methodology
Before jumping into the numbers, it is essential to understand the forces acting upon the crane's base. The foundation does not just support the dead weight of the crane; it acts as an anchor against lateral and rotational forces. Dead Loads ( DLcap D cap L
): The total weight of the crane structure, counterweights, and maximum rated lifting capacity. Horizontal Load (
Wf=6.5 m×6.5 m×1.4 m×25 kN/m3=1,478.75 kNcap W sub f equals 6.5 m cross 6.5 m cross 1.4 m cross 25 kN/m cubed equals 1 comma 478.75 kN
| Parameter | Value | Source | |-----------|-------|--------| | Crane model | Potain MD 235 | Manufacturer datasheet | | Max vertical load (unfactored) | 850 kN | Crane manual | | Max overturning moment (unfactored) | 3,200 kNm | Crane manual | | Horizontal shear (unfactored) | 180 kN | Crane manual | | Concrete grade | C30/37 (fck = 30 MPa) | Structural spec | | Steel reinforcement | B500B (fy = 500 MPa) | Structural spec | | Allowable soil bearing pressure | 150 kN/m² | Geotech report | | Soil type | Dense sand, φ = 35° | Geotech report | | Safety factor (bearing) | 2.5 (serviceability) | Local code |
This exceeds allowable (150 kN/m²) → .
For those seeking step-by-step numerical examples, the following types of resources are the most reliable: