In this paper, the state-of-the-art regarding the “Theory of Plastic Mechanism Control” (TPMC) is presented.
TPMC is aimed at the design of structures assuring a collapse mechanism of global type. The theory has been developed
in the nineties with reference to moment-resisting steel frames (MRFs) and progressively extended to all the main structural
typologies commonly adopted as seismic-resistant structural systems. In particular, the outcome of the theory is the
sum of the plastic moments of the columns required, at each storey, to prevent undesired failure modes, i.e. partial mechanisms
and soft-storey mechanisms. The theory is used to provide the design conditions to be satisfied, in the form of a set
of inequalities where the unknowns are constituted by the column plastic moments. Even though the set of inequalities
was originally solved by means of an algorithm requiring an iterative procedure, now, thanks to new advances, a “closed
form solution” has been developed. This result is very important, because the practical application of TPMC can now be
carried out even with very simple hand calculations. In order to show the simplicity of the new procedure, numerical applications
are herein presented in detail with reference to Moment Resisting Frames (MRFs) and dual systems both composed
by Moment Resisting Frames and Eccentrically Braces Frames (MRF-EBFs) with inverted Y scheme and composed
by Moment Resisting Frames and Concentrically Braced Frames (MRF-CBFs) with X-braced scheme and V-braced
scheme. Finally, the pattern of yielding obtained is validated by means of both push-over analyses and incremental dynamic
analyses. A comparison in terms of structural weight of the designed structures is also presented and the corresponding
seismic performances are discussed.