Safety format in non-linear analysis of concrete structures

Abstract

It is only comparatively recently that the more advanced forms of non-linear analysis have been much used in practice. This leads to issues of how the safety factors should be applied as the partial safety factor format used in current design standards was largely developed for use with linear analysis. Various approaches have been developed and problems with some (notably that advocated by EN 1992-2) are identified. The simple approach of analysis of the structure with design properties throughout is advocated for most cases. However, it is noted that, because this underestimates stiffness, it could be unsafe where imposed deformations are critical. The topic is of major importance because there is no agreed solution to how safety factors should be applied to non-linear analysis, because non-linear analysis is being increasingly used in practice and because the author is aware of several cases where the material partial safety factors have been omitted, giving unsafe results.