Strain-based design rules for Spiral-welded tubes using analytical modelling

Abstract

Spiral-welded steel tubes with diameter to wall thickness ratios between 60 and 140 are often employed in combined wall systems with local buckling as governing failure mode. In a European research project called Combitube, the structural behavior of spiral-welded steel pipes has been investigated because the current design rules in Eurocode 3 are not capable to obtain a good estimate of the real strength and deformation capacity. An analytical model has been developed that enables more economic designs with a better balanced safety level. Comparisons are made with full scale test results and numerical simulations. The results of this research project are also relevant for strain-based pipeline design, where more emphasis is on the critical curvature. © Copyright 2016 by the International Society of Offshore and Polar Engineers (ISOPE).