Stochastic theory of plastic mechanism control: Parametric analysis

This work aims at the application of the Stochastic approach for the Theory of Plastic Mechanism Control. It is referred to stochastic frames assuring a collapse mechanism of global type despite of the influence of random material variability. A mechanism of global type develops when the plastic hinges at the ends of all the beams and at the bases of the first storey columns are formed. A parametric analysis has been performed on 25 steel moment resisting frames, by varying the number of storeys, the number of bays and by considering three values of the coefficient of variation, respectively 0.05, 0.10 and 0.15. Moreover, in order to achieve a predefined level of reliability in the attainment of the design goal, the parametric analysis has been repeated for increasing values of an overstrength factor of dissipative zones aiming to its calibration. Finally, a quadratic regression has been performed to provide a simple relationship to compute the value of the overstrength factor, as a function of number of storeys and number of bays, needed to include the influence of random material variability in the application of deterministic Theory of Plastic Mechanism Control.