ABSTRACT
This chapter discusses statically indeterminate structures, in which there are more unknown forces than equations. The majority of structures in practice are statically indeterminate. A structure is said to be externally indeterminate if the number of reaction components exceeds the number of equations of equilibrium. The indeterminacy of a structure may either be external, internal, or both. The analysis of a structure is usually carried out to determine the reactions at the supports and the internal stress resultants. The objective of the analysis of structures is to determine the external forces reaction components and the internal forces stress resultants. The analysis of structures by the force or the displacement method involves the use of the principle of superposition, which allows a simple addition of displacements or actions due to the individual loads or displacements. This principle can, however, be applied only if Hooke's law is obeyed by the material of which a statically indeterminate structure is made.
