Structural
Are the actions of other bodies on the structure under consideration.
External Forces
Usually referred to as loads
Applied forces
Are the forces exerted by supports on the structure and have a tendency to prevent its motion and keep it in equilibrium.
Reaction forces
Are the forces and couples exerted on a member or potion of the structure by the rest of the structure.
Internal forces
Are used to attached structures to the ground or other bodies thereby restricting their movements under the action of applied loads.
Supports
Describes the complexity of analysis to determine the reactions.
Determinacy
When all the forces in a structure can be determined strictly from these equations.
Statically determinate
Structures having more unknown forces than available equilibrium equations.
Statically indeterminate
If it maintains its shape and remains a rigid body when detached from the support.
Internally stable
if it cannot maintain its shape and may undergo large displacements under small disturbances when not supported externally.
Internally unstable
Is a strucure somposed of slender member joined together at their end points.
Truss
Are often used as part of an industrial building frame.
Roof truss
Is formed by connecting two or more simple trusses together.
Compound Truss
is one that cannot be classified as being either simple or compound.
Complex Trusses