- Author
- Ellingwood, B.
- Title
- Reliability Basis of Load and Resistance Factors for Reinforced Concrete Design.
- Coporate
- National Bureau of Standards, Washington, DC
- Report
- NBS BSS 110, February 1978,
- Distribution
- Available from National Technical Information Service
- Keywords
- buildings | reinforced concretes | design applications
- Abstract
- Engineering decisions must be made in the presence of uncertainties which arise as a consequence of imperfect information and knowledge and inherent randomness in many design parameters. It is on account of these uncertainties and potential risks arising therefrom that safety margins provided by load and resistance factors are required in design. Reliability methods are employed in this study to facilitate the selection of criteria for reinforced concrete design. These methods, which are based on probability theory, provide a logical basis for determining the manner in which uncertainties in resistance and loads affect design safety and how their effects should be controlled in building standards. Following a comprehensive analysis of uncertainty measures, safety indices associated with existing reinforced concrete design are evaluated. Design criteria commensurate with levels of uncertainty and required reliability are then presented. Simplification of these leads to practical reliability based criteria which retain the relatively simple characteristics of existing criteria and yet have a well established and documented rationale.