Resistance partial factors for high strength steel rods and spiral strands

Due to lack of experimental statistical data, most practical design codes for cables are based on either the empirical 'Allowable Stress Design (ASD)' method or such method taking the form of the so-called ' Load Resistance Factor Design (LRFD)' approach. However, these two cable design methods are not appropriate for the current design codes that should be based on structural reliability analysis. In order to solve this problem, a great deal of statistical data about high strength steel rods and spiral strands have been gained to find out the probability distribution of these two kinds of cable materials, and the uncertain factors that influence structural resistance are analyzed simultaneously. The equation which takes the combination of simple load effects into account with partial factors can be changed into a limit state equation by adopting proportions of load effects, which are proved to have an approximate linear relationship between loads and effects. The partial factors for high strength steel rods and spiral strands are eventually obtained based on the First-Order Second-Moment (FOSM) theory, and they may serve as a reference for the amendment of structural design codes.