Statically Indeterminate Structure

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: More unknowns than equations: Statically IndeterminateStatically Indeterminate Structure1ME101 -Division IIIKaustubh DasguptaPlane Truss :: DeterminacyNo. of unknown reactions = 3No. of equilibrium equations = 3: Statically Determinate(External)No. of members (m) = 9No. of joints (j) = 6No. of unknown reactions (R) = 3 m + R = 2j: Statically Determinate(Internal)2ME101 -Division IIIKaustubh DasguptaPlane Truss :: Determinacy3ME101 -Division IIIKaustubh DasguptaPresence of internal members: Additional sharing for forces: Additional StabilityFCFurther addition of internal members: Strengtheningof Joints C and F: Additional Stability and force sharing: m + R >2j: Statically Indeterminate (Internal)Plane Truss :: DeterminacyWhen more number of members/supports are present than are needed to prevent collapse/stability Statically Indeterminate Truss cannot be analysed using equations of equilibrium alone!

Plane Truss :: Determinacy Internal Redundancy or Degree of Internal Static Indeterminacy Extra Members than required Internal Redundancy Equilibrium of each joint can be specified by two scalar force equations

  Structure, Statically, Indeterminate, Statically indeterminate structure