Fixed-Fixed Beam — UDL Calculator
Deflection and end/midspan moments for a built-in beam under UDL.
Fixing the ends cuts deflection 5× and peak moment 33% versus simply supported — why monolithic concrete frames are so stiff.
Formula
Fixed-Fixed Beam — UDL Calculator is a free fixed beam udl for structural engineers, fabricators and site engineers — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Fixed-Fixed Beam — UDL Calculator
Deflection and end/midspan moments for a built-in beam under UDL. The calculation implements δ = wL⁴/384EI; M_end = wL²/12; M_mid = wL²/24 (Roark's Formulas for Stress and Strain; AISC Steel Manual beam tables). Fixing the ends cuts deflection 5× and peak moment 33% versus simply supported — why monolithic concrete frames are so stiff.
How to use Fixed-Fixed Beam — UDL Calculator
- 1Enter Load intensity w in kN/m.
- 2Enter Span L in m.
- 3Enter Elastic modulus E in GPa (Steel 200 · concrete 25–30 · timber 11 · aluminium 69).
- 4Enter Moment of inertia I in cm⁴ (ISMB 250 ≈ 5,131 cm⁴ · 230×450 RC ≈ 17,500).
- 5Read Max deflection, Max bending moment, Max reaction instantly — no submit button needed.
- 6Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Fixed-Fixed Beam — UDL Calculator?
- ✓Implements the standard formula — δ = wL⁴/384EI; M_end = wL²/12; M_mid = wL²/24
- ✓Reference cited on-page: Roark's Formulas for Stress and Strain; AISC Steel Manual beam tables
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Fixed-Fixed Beam — UDL Calculator use?+
It computes δ = wL⁴/384EI; M_end = wL²/12; M_mid = wL²/24, per Roark's Formulas for Stress and Strain; AISC Steel Manual beam tables. The formula is displayed under the result.
What should I keep in mind when using this calculator?+
Fixing the ends cuts deflection 5× and peak moment 33% versus simply supported — why monolithic concrete frames are so stiff.
Can I use this for real structural design?+
It implements the exact textbook/code formula cited below the result and is ideal for sizing, checking and learning. Final designs should be verified by a qualified engineer against the full code with all load cases.
Is the Fixed-Fixed Beam — UDL Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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