When you look at the structure, you can remove either a bottom chord, a top chord, or one of the diagonals, and the truss is still stable and now internally statically determinate and solvable by the equilibrium equations. I am not sure how you solved for your member forces with all members in there.eurekameh said:
A statically indeterminate structure is a type of structure where the number of unknown forces and reactions is greater than the number of available equations of equilibrium. This means that the structure cannot be solved using traditional methods of statics alone.
The degree of indeterminacy of a structure can be determined by counting the number of unknown forces and reactions and subtracting it from the number of available equations of equilibrium. The resulting number is the degree of indeterminacy.
There are several methods used to analyze statically indeterminate structures, including the force method, displacement method, and slope-deflection method. These methods involve solving simultaneous equations to determine the unknown forces and reactions in the structure.
The force method can only be used for structures that have a determinate degree of freedom. It also assumes that the structure is linearly elastic and that the material properties are constant throughout the structure.
Boundary conditions, such as fixed supports or roller supports, can be used to solve a statically indeterminate structure. These conditions provide additional equations that can be used to determine the unknown forces and reactions in the structure.