Extreme Bending of Concrete Coated Offshore Pipelines

* Final gross prices may vary according to local VAT.

Get Access

Abstract

This paper presents results from numerical analyses on the bending stiffness of discontinously concrete coated offshore pipelines in pure bending. A thorough description of the behaviour is given. The paper is particularly concerned with the strain concentrations at the field joints.

The problem is modeled numerically using the FE-program DIANA. Shell elements are used for the steel pipe and the concrete coating, and these two layers of elements are interconnected bu the used of an interface-element given bond-slip material properties in order to model the anti-corrosion coating (asphalt) and the slipping between the steel pipe and the concrete coating.

The results show that the concrete coating will cause significant strain concentrations at the field joints, especially when the steel at the joint is bent into the plastic area. The magnitude of the strain concentrations are, however, strongly dependent on the concrete thickness, the D/t-ratio and the shear transfer capacity of the anti-corrosion coating.