Fixed–fixed, uniform load
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About this case
How to analyze a fixed–fixed beam with uniform load
This page pre-loads a beam fixed at both ends with a uniform distributed load over the full span. Edit the span, load, section or material directly. Results update instantly.
Textbook values: reactions R = wL/2 at each end, fixed-end moments M = wL²/12 (hogging, negative), midspan moment M = wL²/24 (sagging, positive), midspan deflection δ = wL⁴/(384EI). The moment diagram is parabolic with hogging at the supports and sagging at midspan.
What to watch for with fixed–fixed beams
The support moments (wL²/12) are larger in magnitude than the midspan moment (wL²/24). The design is typically governed by the negative moment at the supports — the top flange is in compression there, so lateral-torsional bracing of the top flange is critical.
If the fixity is not perfect (real connections have some flexibility), the actual moments fall between the fixed–fixed and simply supported cases. The full calculator lets you model spring rotational supports to study this.
Related calculators
Compare with the simply supported UDL (no fixity moments, 5× the midspan deflection). For a fixed–fixed beam with a center point load, the full calculator can model it: add a point load at midspan and fixed supports at both ends.