Flexural buckling behaviour and design of offshore lined pipes under compression

Abstract

Lining internally a thin corrosion resistance alloy (CRA) layer within an ordinary carbon steel pipe provides one economical approach, when transmitting highly corrosive offshore hydrocarbons. The lined pipe is expected to make optimize usage of the two types of materials, providing significant corrosion and structural resistance. Existing studies mostly covered the lined pipe under bending, corresponding to the load case during Reel-lay procedure. The behaviour of the lined pipe under axial compression, which can be induced by thermal field when transporting hot hydrocarbons, however, has received much less attention. The present paper describes a series of laboratory tests performed on lined pipes, including tensile coupon tests of the outer and the liner materials, initial geometric imperfection measurements and lined pipes tested under axial compression. Results of the column tests were used to validate numerical models and employed for subsequent parametric investigations. Based on the results, design provisions DNV–OS–F101 and EN 1993-1-1 were assessed for lined pipes under axial compression and a buckling curve was proposed for lined pipes for the first time.