Steel designing

A plane truss is defined as a two- dimensional framework of straight prismatic members connected at their ends by frictionless hinged joints, and subjected to loads and reactions that act only at the joints and lie in the plane of the structure.
Space trusses are three-dimensional structures with longitudinal members connected at their ends by hinges assumed to be frictionless. The loads on space trusses are applied only at the nodes or joints, thus the self-weight is allocated for each element at its two ends joining other elements of the truss.