Analysis & loading · Frame & beam analysis
Continuous beam (stiffness method) calculator
Any number of spans with UDLs; exact BMD, SFD, reactions and deflected shape. End fixity selectable.
Standard: Direct stiffness · BMD / SFD / reactions
Open the live calculator → All analysis & loading calculators
Inputs in the worked example
The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.
| Input | Value | Unit |
|---|---|---|
| Span lengths (m, comma separated) | 6, 7.5, 6 | |
| UDL per span (kN/m, one value or one per span) | 25, 25, 18 | |
| End supports | Pinned – pinned | |
| EI | 50000 | kNm² |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Max sagging M* | 65.7 | kNm |
| Max hogging M* | 119.8 | kNm |
| Max shear | 96.3 | kN |
| Reaction at support 1 (x = 0.00) | 55.0 | kN |
| Reaction at support 2 (x = 6.00) | 191.3 | kN |
| Reaction at support 3 (x = 13.50) | 161.9 | kN |
| Reaction at support 4 (x = 19.50) | 37.3 | kN |
- ✓ Equilibrium: ΣR = Σw·L
Method, formulas and assumptions
- Beam elements (EI constant), fixed-end forces for UDL, global stiffness solved by Gaussian elimination
- M(x) = −M1 + V1·x − w·x²/2 inside each span from member end forces
- Pattern loading is not generated automatically: run the arrangements you need
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.