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If the number of reactions occurring in the nodes laid on the beam
exceeds the number of equations of statistics that can be made up,
the beam is called statically indeterminate.
The degree of statically indetermination k can be calculated by
the formula
k  m s ,
where m – number of reactions in the nodes that are laid on the
beam; s – number of equilibrium equations, which can make up
for a given beam. For example, beam, shown in fig. 3.2 b
k  5 3 2  , i.e. that beam is double statically indeterminate.
They usually say that on k times statistically indeterminate beam
k extra nodes are laid. This "extra" is called a node, which the
beam does not need to maintain its stability of geometrical shape.
Recall that a beam with the stability of geometrical shape is
called one moving points of which are possible only due to its
deformation.
For calculating statistical indetermination it is necessary to add
compatibility equations to equilibrium equation, as we did in
tension and compression and torsion problems.

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