Enter Footing and Beam Data
Example Data Table
| Item | Sample Value | Unit | Meaning |
|---|---|---|---|
| Column Load | 650 | kN | Main vertical service load on footing. |
| Soil Bearing | 180 | kPa | Allowable pressure from soil report. |
| Footing Size | 2.4 × 2.0 × 0.45 | m | Length, width, and thickness. |
| Beam Span | 5.5 | m | Clear analysis span for simple support. |
| Beam Loads | 12 + 8 | kN/m | Dead load plus live load. |
| Point Load | 35 at 2.75 | kN, m | Single concentrated load position. |
Formula Used
Footing area: A = L × B
Concrete volume: V = L × B × D
Footing self weight: Wf = V × concrete density
Total service load: P = column load + surcharge + selected self weight
Required footing area: Areq = P / allowable soil bearing
Actual soil pressure: q = P / A
Footing cantilever moment: M = q × projection² / 2
Steel estimate: As = M × 10⁶ / (0.87 × fy × 0.9d)
Beam reactions: RA = wL/2 + P(L-a)/L, RB = wL/2 + Pa/L
Beam moment: Mx = RA × x - wx²/2 - P(x-a), when x is beyond the point load.
Beam deflection: numerical curvature integration is used from EIy'' = M.
These equations are simplified. They do not replace punching shear checks, development length checks, load combinations, seismic rules, or code detailing.
How to Use This Calculator
- Enter footing dimensions in meters.
- Enter service loads and allowable soil bearing pressure.
- Add concrete strength, steel strength, bar size, cover, and spacing.
- Enter beam span, section size, distributed loads, and point load data.
- Press Calculate to view soil pressure, moments, shears, deflection, volume, and steel estimates.
- Use CSV or PDF buttons to save the report.
Footing and Beam Design Guide
Why Combined Checks Matter
A footing and beam system transfers building loads into the ground. The footing spreads column load over soil. The beam transfers wall, slab, or point loads to supports. Both parts must work together. A safe footing with an undersized beam can still fail. A strong beam over weak soil can also cause settlement.
Reading Soil Pressure
Soil pressure is one of the first values to review. The calculated pressure should stay below the allowable soil bearing value. The allowable value should come from a soil report. A guessed value may be unsafe. If pressure is high, increase footing length or width. A thicker footing increases weight, but it may improve bending and shear behavior.
Understanding Footing Steel
A footing acts like a short cantilever from the column face. Soil pushes upward. The column load pushes downward. This creates bending near the column. The calculator estimates reinforcement per meter using the governing projection. It also compares provided bar spacing with required steel.
Understanding Beam Results
Beam reactions show how much load each support receives. Maximum moment helps estimate tensile steel. Maximum shear helps review web stress near supports. Deflection shows service performance. A beam may have enough strength but still feel flexible. The L/250 limit gives a practical serviceability check.
Best Use
Use this tool during early planning, quantity checks, and option comparison. Try several sizes before preparing drawings. Keep records with the export buttons. Always use local code factors before construction. Reinforcement anchorage, punching shear, crack control, and seismic detailing need separate professional review.
FAQs
1. Can this calculator be used for final design?
No. It is for preliminary checking only. Final design needs local code rules, load combinations, detailing, and review by a qualified structural engineer.
2. What soil bearing value should I enter?
Use the allowable soil bearing pressure from a geotechnical report. Do not guess this value for real construction, because settlement and soil failure can occur.
3. Does it check punching shear?
No. It includes a simple one-way shear estimate. Punching shear around the column must be checked separately using the governing design code.
4. What beam support condition is assumed?
The calculator assumes a simply supported beam with uniform load and one point load. Continuous beams need a different analysis method.
5. Why is self weight optional?
Some users include self weight within service load. Others prefer the calculator to add it. Choose the option that matches your load setup.
6. What does soil utilization mean?
It is the ratio between actual soil pressure and allowable soil pressure. A value above 100 percent means the footing is overloaded.
7. What does provided steel mean?
For footing, it is based on bar diameter and spacing per meter. For beam, it is based on bar diameter and number of bars.
8. Why is deflection important?
Deflection affects serviceability. Excessive deflection may cause cracks, ponding, vibration, or finish damage, even when strength appears acceptable.