Probabilistic Structural Analysis and Design

Some of the important advantages of probabilistic design procedures are presented and compared with deterministic techniques. The problem of the compounding of hazards is illustrated by comparing a series type of structure with a parallel type of structure. Both structures have the same characteristics from a deterministic viewpoint, but the parallel type clearly is superior to the series type if probabilistic concepts are employed. The specification of material properties in manufacture is clearly probabilistic. These same material properties are specified and treated deterministically in structural practice without regard to the actual properties of the materials. Similarly, real loadings, although probabilistic in nature are treated as deterministic. Analysis and design procedures employ models of loading and response that have little relationship to reality. The design decision process for seismic loading is illustrated using statistical decision theory. The formulation of optimization of decisions under uncertainty is considered.