Risk-Based Evaluation of Design Criteria

The development of risk-based structural design criteria is described. The analysis of design uncertainties arising from the statistical nature of some variables and incomplete information regarding others is examined. The risk of unfavorable performance commensurate with the level of uncertainty is shown to provide a consistent measure of design safety and thus furnish a systematic means for comparing design alternatives. Current design provisions for reinforced concrete beams are appraised in terms of their underlying uncertainties and risks. It is shown that practical risk-based design criteria can be prescribed without unreasonable increase in design code complexity.