[ Vertical Load (V) ] | v +-----------------+ | Mast Base | <----+| |+----> [Overturning Moment (M)] Horizontal | | Load (H) +-----------------+ | Concrete Pad | ================================= [ Soil Bearing Pressure ] Step 1: Initial Sizing Assume a trial size for the concrete pad: ) and Length ( ) – typically between 4.0m to 7.0m for standard cranes.
Calculate the bending moment at the face of the crane mast steel legs. Provide bottom steel mesh reinforcement to handle tension zones. Top reinforcement is also required to resist moments from self-weight when the crane experiences uplift on one side.
The next step is to calculate the size of the foundation. This involves determining the area of the foundation and the depth of the foundation. tower crane foundation design calculation example link
| | Scope | | :--- | :--- | | EN 1997 / Eurocode 7 | Geotechnical design, including bearing capacity and limit states. | | EN 1992 / Eurocode 2 | Concrete structural design, including flexure and punching shear. | | CIRIA C654 / C761 | UK guidance on tower crane stability and foundations; includes over 100 pages of worked examples. | | BS 8110 | Structural use of concrete (referenced in many design reports). | | GB 50007 (China) | Code for design of building foundations, often cited in Chinese practice. | | AS 1418.4 (Australia) | Tower cranes — design of support structures. |
The weight of the crane, the ballast, and the maximum lifted load. [ Vertical Load (V) ] | v +-----------------+
| 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 |
The stabilizing moment (created by the total vertical weight) must comfortably overcome the overturning moment. The Factor of Safety (FoS) against overturning is calculated as: Top reinforcement is also required to resist moments
): The massive bending moment exerted on the base due to wind forces and the leverage of the hook load at extended radii. Torsional Moment ( Mtcap M sub t
For engineers looking for open-source mathematical steps, comprehensive step-by-step math design scripts can be found via the PTC Mathcad Community Sheets. 5. Summary Checklist for Site Engineers
Tower Crane Footing Structural Design For All Cranes PDF - Scribd
The (Isolated pad or Piled foundation)