Probabilistic calibration of codes

Abstract

Calibration of codes of practice is currently an important topic in many countries implementing newly developing codes based on the partial factor method. Up to now the reliability elements involved in these codes are mostly established upon past experience or previously used design rules based on permissible stresses or global safety factors. Probabilistic approach to calibration of the partial factor method is theoretically well established and supported already by a number of software tools.
However, application of the known methodology requires assumptions concerning load combination rules and numerous input data. Available results reveal a large scatter leading to dissimilar reliability levels and different recommendations given in codes or their National annexes in various countries. It is recognised that the theoretical models accepted for basic variables including, their mutual dependence, model uncertainties and level of quality control may have substantial effects on resulting values of reliability elements such as partial and combination factors.
Furthermore, design of structural components having nonlinear response to actions or components under dynamic effects of actions requires introduction of global resistance and the global load effect factors. It appears the concept of global factors related to the mean or characteristic values of the resistance and load effects depends on specific conditions of a structural member and its loading.
Substantial background concerning general methodology of code calibration and theoretical models of basic variables is already provided by JCSS. Nevertheless further improvements, concerning particularly model uncertainties, mutual dependence of basic variables and concept of the global factors, are desirable. The proposed mini session/symposium should provide an opportunity to improve and harmonise current procedures used for probabilistic calibration of codes and outline needs for further development.

Organizers

Milan Holický, Klokner Institute, Prague, Czech Republic, (Milan.Holicky@klok.cvut.cz)