www.ernst‐und‐sohn.de Page 1 Structural Concrete This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/suco.201500118. Submitted: 03‐Aug‐2015 Revised: 28‐Nov‐2015 Accepted: 31‐Jan‐2016 © 2015 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin Technical Paper The structural redistribution coefficient K Rd : a numerical approach to its evaluation Marco di Prisco 1 , Paolo Martinelli 2* and Daniele Dozio 3 1 Professor, Department of Civil and Environmental Engineering, Politecnico di Milano, P.za L. da Vinci 32, 20133 Milan (Italy). 2* Corresponding author, Assistant Professor, Department of Civil and Environmental Engineering, Politecnico di Milano, P.za L. da Vinci 32, 20133 Milan (Italy). e-mail: paolo.martinelli@polimi.it; tel: 0039-0223998785; fax: 0039-0223998771 3 Senior Structural Engineer, ARUP, Corso Italia, 13 20122 Milan (Italy) ABSTRACT Structures made of a material with a very high standard deviation, such as fibre– reinforced concrete, show a too safe prediction of the maximum bearing capacity when derived from characteristic values identified by means of small specimens. This is emphasized when the structures are characterized by a large redundancy. In this regard, two reference tests representing two extreme situations are considered: (a) simply supported unnotched full–scale beams characterized by a statically determinate loading scheme and (b) full–scale slabs on the ground characterized by a statically indeterminate loading scheme. The Italian Standard and more recently Model Code 2010 have introduced a coefficient (structural redistribution factor) that is able to take into account the reduced variability of the mechanical strength when associated with a large volume involved in the failure process or when the structure is able to significantly redistribute stresses, favouring the average strength rather than the minimum one. A numerical procedure taking into account the expected heterogeneity of the mechanical characteristics in the structure is introduced for the first time to evaluate the redistribution factor. Keywords: fibre–reinforced concrete (FRC); structural redundancy; Model Code 2010; material heterogeneity; redistribution coefficient; statistical approach Accepted Article