Probabilistic models for resistance variables in fib Model Code 2020 for design and assessment

Authors

  • Miroslav Sýkora Czech Technical University in Prague, Klokner Institute, Šolínova 7, 166 08 Prague, Czech Republic
  • Wouter Botte Ghent University, Faculty of Engineering and Architecture, Department of Structural Engineering and Building Materials, Technologiepark-Zwijnaarde 60, 9052 Zwijnaarde, Belgium
  • Robby Caspeele Ghent University, Faculty of Engineering and Architecture, Department of Structural Engineering and Building Materials, Technologiepark-Zwijnaarde 60, 9052 Zwijnaarde, Belgium
  • Dimitris Diamantidis OTH Regensburg, Faculty of Civil Engineering, Galgenbergstrasse 30, 93053 Regensburg, Germany
  • Aurelio Muttoni École Polytechnique Fédérale de Lausanne, School of Architecture, Civil and Environmental Engineering, Station 18, CH-1015 Lausanne, Switzerland
  • Raphaël D.J.M. Steenbergen Ghent University, Faculty of Engineering and Architecture, Department of Structural Engineering and Building Materials, Technologiepark-Zwijnaarde 60, 9052 Zwijnaarde, Belgium; TNO Delft, Department of Structural Reliability, P.O. Box 155, NL-2600 AD Delft, Netherlands

DOI:

https://doi.org/10.14311/APP.2022.36.0206

Keywords:

assessment of existing concrete structures, Eurocodes, fib Model Code 2020, partial factors, probabilistic models, reliability, updating

Abstract

The fib Model Code offers pre-normative guidance based on the synthesis of international research, industry and engineering expertise. Its new edition (draft MC 2020) will bring together coherent knowledge and experience for both the design of new concrete structures and the assessment of existing concrete structures. This contribution presents an overview of the main developments related to the partial factors for materials. In the draft MC2020, the partial factors are presented in tables for clusters of cases depending on consequence classes and variability of basic variables. Furthermore, formulas and background information are provided to facilitate updating of the partial factors. This contribution discusses the different assumptions adopted in MC 2020 for design and assessment. Main changes with respect to the previous version are related to description of the difference between in-situ concrete strength and the material strength measured on control specimens, and to modelling of geometrical variables. The presented comparison of the requirements imposed by Eurocodes and MC 2020 for design reveals insignificant differences. The assessment requirements may be decreased by about 25% when the conditions specified in MC 2020 are satisfied. Hence, the revised MC 2020 will provide designers and code makers with wider possibilities to utilise actual data and long-term experience in assessments of existing structures.

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Published

2022-08-18