VIVEK DHAKAL: June 2021
Degree of Static & Kinematic Indeterminacy of Structures

Degree of Static & Kinematic Indeterminacy of Structures

A structural system that can be analyzed by using the equation of static equilibrium only is called statically determinate structure i.e. reaction components and internal stresses can be calculated using static equilibrium equations only. Eg: Simply supported beam. If it cannot be analyzed by the equation of static equilibrium alone, then it is called a statically indeterminate structure. Eg: Fixed beam. A structural system is said to be kinematically indeterminate if the displacement components of its joints cannot be determined by the compatibility equation alone. Eg: Simply supported beam. If those unknown quantities can be found by using compatibility equations alone then the structure is called kinematically determinate structure. Eg: Fixed beam. But before calculating the degree of indeterminacy of a structure, it is good to know about its stability. If a structure is unstable, then it doesn't matter whether it is statically determinate or indeterminate. In all cases, such types of structures should be avoided in practice.