Reaction · shear · moment
Simply supported beam diagram
Inputs
One simply supported span between reaction locations.
Enter 0 when no point load is present; upward loading is outside this bounded model.
Used only when point load is nonzero; must lie strictly between supports.
Enter 0 when absent; applies over the entire support span only.
Results
Left support reaction
6.8
Right support reaction
5.2
Shear left of point load
5.2
Shear right of point load
-2.8
Moment at point-load location
4.8
Largest-magnitude bending moment
4.8
Peak-moment location from left
0.8
RA = P(L−a)/L + wL/2; RB = Pa/L + wL/2; V(x) = RA − wx − P·H(x−a); M(x) = RAx − wx²/2 − P(x−a)H(x−a)
A first-pass number, not a code check, certification, or approval. Read the method and its limits below. What this is and is not.
Nearby: Axial response · Beam deflection & reactions · Elastic stability · Solid-shaft torsion
Method
Formula, when it applies, and when it does not
Calculate support reactions and selected shear/moment values for one simply supported span with one point load and/or full-span uniformly distributed load.
RA = P(L−a)/L + wL/2; RB = Pa/L + wL/2; V(x) = RA − wx − P·H(x−a); M(x) = RAx − wx²/2 − P(x−a)H(x−a)
When
- One downward point load
- Optional full-span uniform load
- Static equilibrium only
Don’t
- This is a static, simply supported single-span equilibrium screen with one downward point load and/or full-span downward uniform load. It does not produce a scaled plot, deflection, stress, connection, dynamic, plasticity, code, capacity, or approval result.