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Beam calculator – beam on 3 supports under line load

Use this beam calculator to investigate the statically indeterminate beam on 3 supports (or beam on three bearings). Beam profile specifications like area moment of inertia or section modulus can be found in the profile assistant.

Some notes

With a symmetrical load distribution, the online calculator still calculates only one point of the maximum deflection. Both the maximum deflection and the maximum bending moment and the maximum bending stress are calculated by the online calculator with a resolution of 100 steps over the entire length of the beam. This means that there can be minimal deviations from analytically determined maxima.

Statically indeterminate systems are most common in practice, the beam shown here on 3 supports (also called multi-span beam) is a classic example. In order to be able to determine the bearing reactions in the system shown above, the deformations of the beam must also be taken into account, i.e. the system can only be calculated with the help of elastostatics or strength theory.

Try for yourself some different support distances and see how the bending curve changes. There can be quite symmetric bending curves if you have equal distant supports, but as soon as you change this, the shorter side begins to reduce the deflection until it flips to the other side.

Here we have some more beam deflection calculators.