Towards second-order and advanced analysis of frames by a single crooked element per member

In design of practical structures, initial crookedness of axially loaded members must be included in the computation of strength and stability. The use of a single member with initial crookedness is an elegant and convenient means to account for the behaviour of a crooked member due to its consistent formulation in parallel with the linear analysis which permits the modeling of a member by a single element. The availability of such an element should encourage the designer to adopt the second-order analysis in design. This paper is addressed to the development of the Pointwise Equilbrating Element (PEP) element with dominant axial force (i.e. the Timoshenko's beam-column theory) and the effect of initial crookedness is studied in a snap-through problem.