DEFINITION OF MECHANICAL PROPERTIES OF EXISTING MASONRY ACCOUNTING FOR EXPERIMENTAL KNOWLEDGE BY BAYESIAN UPDATING

The current approach of the Italian and European building codes to account for knowledge-based uncertainties in the seismic assessment of masonry buildings consists in selecting a knowledge level and reducing material strengths by means of the associated value of confidence factor. Previous works showed that, in the case of masonry structures, the codified approach leads in many cases to inconsistent and unrealistic results and does not properly consider the experimental tests performed. This paper proposes a methodology for taking into account the knowledge on material properties acquired by experimental tests, using Bayesian updating techniques. The use of the Bayesian approach allows to update the values of the material properties assumed a priori as knowledge on the building increases, by taking into account all the information (experimental or judgement-based) gained during the assessment process. The material parameters resulting from this method could be used as input in numerical models, with the aim of calibrating confidence factors on material properties. Finally, analytical expressions are provided, which approximate the results obtained by Bayesian updating, allowing the analyst to obtain the values of material properties to be used in the analysis, as a function of the experimental information gained, without the need of performing a case-by-case Bayesian updating.

[1]  A. Penna.  Seismic assessment of existing and strengthened stone-masonry buildings: critical issues and possible strategies , 2015, Bulletin of Earthquake Engineering.

[2]  Guido Magenes,et al.  Consideration of modelling uncertainties in the seismic assessment of masonry buildings by equivalent-frame approach , 2015, Bulletin of Earthquake Engineering.

[3]  S. Cattari,et al.  Sensitivity analysis for setting up the investigation protocol and defining proper confidence factors for masonry buildings , 2014, Bulletin of Earthquake Engineering.

[4]  Sergio Lagomarsino,et al.  A nonlinear macroelement model for the seismic analysis of masonry buildings , 2014 .

[5]  P. Fajfar,et al.  A Nonlinear Analysis Method for Performance Based Seismic Design , 2001 .

[6]  Yuri Z. Totoev,et al.  Shear modulus and stiffness of brickwork masonry: An experimental perspective , 2005 .

[7]  Durgesh C. Rai,et al.  Masonry Structures , 2002 .

[8]  Sergio Lagomarsino,et al.  ON THE USE OF PUSHOVER ANALYSIS FOR EXISTING MASONRY BUILDINGS , 2006 .

[9]  Guido Magenes,et al.  A framework for the seismic assessment of existing masonry buildings accounting for different sources of uncertainty , 2014 .

[10]  Aníbal Costa,et al.  Evaluation of the EC8-3 confidence factors for the characterization of concrete strength in existing structures , 2012 .

[11]  Guido Magenes,et al.  Evaluation of Uncertainties in the Seismic Assessment of Existing Masonry Buildings , 2012 .

[12]  Giorgio Monti,et al.  Application of Bayesian techniques to material strength evaluation and calibration of confidence factors , 2009 .

[13]  Luís F. Ramos,et al.  A Bayesian approach for NDT data fusion: The Saint Torcato church case study , 2015 .

[14]  A. Penna,et al.  Experimental characterisation of stone masonry mechanical properties , 2010 .

[15]  Serena Cattari,et al.  TREMURI program: An equivalent frame model for the nonlinear seismic analysis of masonry buildings , 2013 .

[16]  Fatemeh Jalayer,et al.  Structural modeling uncertainties and their influence on seismic assessment of existing RC structures , 2010 .