Reliabilty Based Desing Of Structural Elements

Abstract

Structural codes and standards provide the foundation of good engineering practice newlineand a framework for addressing safety and serviceability issues in structural design. They identify natural and man-made forces that must be considered, define magnitudes of these newlineforces for design, and prescribe methods for determining structural resistance to these newlineforces. The documents on which the structural engineer places so much reliance must newlineaddress the question: quot How safe is safe enough?quot on behalf of society as a whole. In the existing limit state design procedure, which is semi-probabilistic in nature, even though the newlinedesign load is calculated statistically, research for determining the actual loading on the newlinestructure has not yielded adequate data to enable one to calculate theoretical values of newlinevariations for arriving at the actual loading of the structure. Thus, at the root of the structural newlinesafety problem is the uncertain nature of newline( ) the man-made and environmental forces that act on structures, newline(ii) material strengths, and newline(iii) structural analysis procedures that at best are only theoretical models. newlineThe traditional practice of setting safety factors and revising codes based solely on newlineexperience does not work in this environment, where such trial and error approaches to newlinemanaging uncertainty and safety may have unacceptable consequences. In an era in which newlinestandards for public safety are being increasingly questioned in public forum, more newlinesystematic and quantitative approaches, for public safety, are essential. The probabilistic newlineapproach which accounts for the said uncertainties has. in the past two decades, been newlinewidely accepted worldwide as a new paradigm, for design of structures and evaluation of the newlinesafety of exiting ones. newlineReliability-based design is based on the concept that one can estimate the probability newlineof an undesirable event such as fracture, occurring over the lifetime of a structure, despite the uncertainties involved.