Calculator Inputs
Example Data Table
| Example Item | Sample Value | Explanation |
|---|---|---|
| Raft Size | 18 m × 12 m | Main foundation plan area. |
| Slab Thickness | 0.35 m | Uniform slab layer thickness. |
| Internal Beams | 6 beams × 10 m | Stiffening beams under the slab. |
| Internal Beam Extra Volume | 4.50 m³ | Calculated from width and extra depth. |
| Edge Beam Extra Volume | 7.20 m³ | Perimeter beam added below the slab. |
| Pedestal Volume | 1.57 m³ | Eight pedestals at 0.7 × 0.7 × 0.4 m. |
| Opening Deduction | 1.20 m³ | Reserved service pit and penetrations. |
| Total Order Volume | 92.05 m³ | Net structural volume plus 5% waste. |
| Daily Capacity | 96.00 m³/day | 8 hours × 12 m³/hour crew rate. |
| Total Truck Loads | 15.34 loads | Based on 6 m³ truck capacity. |
Formula Used
1) Base Slab Volume
Slab Volume = Length × Width × Slab Thickness
2) Internal Beam Volume
Internal Beam Volume = Beam Count × Beam Length × Beam Width × Extra Depth
3) Edge Beam Volume
Edge Beam Volume = Perimeter × Edge Beam Width × Edge Beam Extra Depth
4) Pedestal Volume
Pedestal Volume = Pedestal Count × Pedestal Length × Pedestal Width × Pedestal Height
5) Net Structural Volume
Net Structural Volume = Slab + Internal Beams + Edge Beams + Pedestals − Deductions
6) Waste and Order Volume
Waste Volume = Net Structural Volume × Waste %
Total Order Volume = Net Structural Volume + Waste Volume
7) Daily Production Planning
Daily Capacity = Work Hours per Day × Productivity per Hour
Estimated Pour Days = Total Order Volume ÷ Daily Capacity
8) Truck Planning
Total Truck Loads = Total Order Volume ÷ Truck Capacity
Trucks per Target Day = Required Daily Volume ÷ Truck Capacity
How to Use This Calculator
- Enter raft plan length, width, and slab thickness in metres.
- Add internal beam count, average length, width, and extra depth if beams project below the slab.
- Enter edge beam width and extra depth for the perimeter thickening.
- Add pedestal count and dimensions when the raft includes column blocks or local thickenings.
- Subtract any known openings or service pits using deduction volume.
- Set waste percentage to cover losses, trimming, and ordering tolerance.
- Enter daily work hours, crew productivity, truck capacity, and optional target days.
- Press Calculate to view volumes, daily planning outputs, truck loads, and the graph above the form.
- Use the export buttons to download CSV or PDF copies for project records.
FAQs
1) What does this calculator include?
It includes the raft slab, internal beams, perimeter beams, pedestals, deductions, waste allowance, daily crew capacity, target days, and truck planning outputs.
2) Should beam depth include the slab thickness?
No. Enter only the additional beam depth below the slab. The slab thickness is already counted in the base slab volume.
3) Why is there a waste allowance field?
Waste allowance helps cover spillage, uneven excavation, pump priming loss, trimming, and supplier rounding. It improves concrete ordering accuracy.
4) What should I enter as opening volume?
Use the total cubic metres of planned deductions, such as pits, sleeves, trenches, or boxed voids that reduce the final concrete quantity.
5) How is daily capacity calculated?
Daily capacity equals work hours per day multiplied by expected placing productivity in cubic metres per hour. It estimates how much concrete the team can place daily.
6) What if the target days result is not achievable?
The calculator flags that condition through the capacity gap and status message. Increase hours, raise productivity, or allow more target days.
7) Can I use this for irregular raft shapes?
Yes, but first break the raft into simpler rectangles or calculate an equivalent plan area. Then add deductions and thickenings carefully.
8) Why are truck loads shown as decimals?
Decimal loads show the exact theoretical requirement. In practice, round up to the next full truck after checking supplier batching rules.