What is Structural Analysis?
Structural analysis is used to predict the behavior of structures and find the reactions, stresses, and deformations of statically indeterminate structures by taking the structure's geometry, support conditions, material properties, loads, and other factors into account. More advanced structures will also take vibration, temperature, and fatigue into account. Common structural frameworks include: buildings, bridges, automobiles, towers, dams, etc.
In actual practice structural analysis is usually done with modeling programs. The demo version of RISA 3D is a great start to further understanding structural dynamics. These programs use stiffness matrices to determine the internal forces, deformations, and reactions. It is a brute force method of analysis, but the advent of the computer made this style of structural analysis possible.