Question

How does the static and kinematic indeterminacies of the structure influence the analysis and design of the structure?

Answer 1

The structure analysis method is choosen according to the degree of static indeterminacy(Ds) and degree of kinematic indeterminacy( Dk).

If the degree of static indeterminacy is less than the degree of kinematic indeterminacy then we use force method to analyse the structure and in that we choose force or reaction as redundant and that redundant is determined using compatibility equation.

If degree of kinematic indeterminacy is less than degree of static indeterminacy than the structure is analyse using displacement method in which displacement like rotation or settlement is taken as unknown which determines using equilibrium equation.

There is advantage of using method as per above criteria that it makes the analysis easy and less cumbersome and if we use vice versa then we also get the result but it will more cumbersome and include extra calculation to analyse the structure means if Ds<Dk and we use displacement method then it becomes cumbersome.so in that case force method is preferable.

Finally result we get is same whether if use force method or displacement method therefore design is same for both types of analysis as design is based on final moments or reaction which is same for a particular type of loading and structure condition not depending on the Ds or Dk.