THE INFLUENCE OF THE STEEL GRADE ON THE PROBABILISTIC THEORY OF PLASTIC MECHANISM CONTROL FOR STEEL MOMENT RESISTING FRAMES Alessandro Pisapia 1* , Vincenzo Piluso 1 1 University of Salerno Via Giovanni Paolo II, 132, 84084 Fisciano SA e-mail: alpisapia@unisa.it, v.piluso@unisa.it Abstract This work aims at the extension of the Probabilistic Theory of Plastic Mechanism Control (P- TPMC) for Steel Moment Resisting Frames (MRFs) to other steel grades. P-TPMC is based on the application of First Order Reliability Method and Ditlevsen Bounds, which represents the reliability method for series systems, considering as random variable the yield strength of steel members. As in previous work, only the S275 steel grade has been investigated in this paper the analyses are extended to a different grade of steel, in particular, S235 and S355, to evaluate its influence on the failure probability of TPMC. Finally, a simple relationship to computing the value of the overstrength factor needed to include the importance of random material variability in the application of TPMC is proposed. Keywords: Theory of Plastic Mechanism Control, collapse mechanisms, moment resisting frames, stochastic frames, probability of failure, series systems. 5016 COMPDYN 2019 7 th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering M. Papadrakakis, M. Fragiadakis (eds.) Crete, Greece, 24–26 June 2019 Available online at www.eccomasproceedia.org Eccomas Proceedia COMPDYN (2019) 5016-5027 ISSN:2623-3347 © 2019 The Authors. Published by Eccomas Proceedia. Peer-review under responsibility of the organizing committee of COMPDYN 2019. doi: 10.7712/120119.7285.19981