# Introduction to the statically indeterminate systems

Section of Structural Mechanics: statically indeterminate systems is a department that closes our long way to getting acquainted with mechanical subjects in engineering faculties. It is a continuation of the Section of Building Mechanics, but I decided to separate the guides on statically determinate and indeterminate layouts, because of your convenience when searching for the topic you are interested in and to emphasize the importance of the ability to calculate statically indeterminate systems.

In life when designing various types of structures, you will be using statically indeterminate systems. What are they?
These are constructions in which there are more unknown numbers than the number of equilibrium equations.
So far, we have dealt with statically determinate systems. Now we are entering a new and the hardest subject. We will learn the two most commonly used methods, which are:

1. Force Method
2. Displacement Method

In order to begin learning the above methods, one should be able to calculate displacements in statically determinate structures very well. Therefore, without a well-controlled calculation of displacements, I advise you not to start the adventure with statically indeterminate systems.

I will describe each method, present the algorithm of calculation and I will give an example to make it clear.

Finally, I would like to warn you again before starting to learn how to calculate statically indeterminable systems without knowledge from the previous section.