Cumulative damage assessment of pressurised piping branch junctions under in-plane run pipe simulated seismic bending

Abstract

The ASME Code, Section III, Subsection NB cumulative damage assessment method has been used to assess the results from tests performed on 23 pressurised piping branch junctions, subjected to simulated seismic loadings that induced resonant, in-plane run pipe bending. Other methods of component life evaluation are also briefly reviewed and their relative merits discussed. The significance of the relevant paramenters used in the assessment is described and the results are contrasted with others, obtained using the same method, from tests on similar components performed elsewhere. Usage factors greater than one, which are indicative of a conservative prediction of fatigue failure using the Code standard procedure, are reported. The level of conservatism of the Code method is discussed.