PROBABILISTIC ANALYSIS OF THE MR-FRAMES EQUIPPED WITH FREEDAM DAMPERS

The goal of this work is to provide a probabilistic approach to achieve a global collapse mechanism for a fixed goal reliability in moment-resisting frames equipped with “FREEDAM” dampers. First, a benchmark structure equipped with FREEDAM connections is designed through the Theory of Plastic Mechanism Control (TPMC). Then, the computation of the partial safety factors and the overstrength coefficient needed to account for the influence of random variability of column steel, friction coefficient and tightening torque in the seismic design of FREEDAM connections are reported. The probabilistic version of the Theory of Plastic Mechanism Control (P-TPMC) is applied to MR-frames equipped with FREEDAM connections to design the non-dissipative zones by considering aleatoric uncertainty on the material properties. The method proposed evaluates the probability of failure in the attainment of a collapse mechanism of global type. It constitutes the Probabilistic version of the Theory of Plastic Mechanism Control (P-TPMC). Stochastic frames have random values of the yield strength of members, so that the random variables are the plastic moments of both beam and column sections, thus randomly affecting the collapse mechanism developed under seismic horizontal forces. The selected study case has been performed by accounting for three different coefficients of variation equal to 0.05, 0.10 and 0.15. Results show that for increasing value of the overstrength factor R the probability of failure decrease.