Consistent Partial Safety Factors

Several reliability-based structural code formats have been suggested in recent literature. To clarify their logical structure their differences and similarities are compared with reference to a set of formal postulates. Such a set is outlined and explained in detail: a postulate concerning the nature of the load; of the strength; a design procedure; a design principle (constant reliability with respect to a formal model and a body of knowledge); and other postulates relating to the format of an individual code. It is shown how a partial safety factor format can be calibrated to achieve nearly constant reliability within the framework of a member-by-member design theory. Explicit results are given for a simple second moment theory, and calibration is illustrated by an example.