Methods of safe assessment for offshore pipeline

Given crack size and load, two methods of Structure Integrity Assessment Procedure(SINTAP)sponsored by the European Commission and BS910 were applied to assessment for welded joints of the API 5LX65 pipeline steel with surface flaw at the weld toe. The assessment was carried out according to Limit Load Solutions and the CTOD(Crack Tip Opening Displacement) test result. The failure lines of level 0 and level 1(level 1 and level 2 of BS7910) of the weld were derived from the tensile test results. The assessment showed that the assessment point is located within the failure line of analysis level 0 and level 1(level 1 and level 2 of BS7910). So welded joint of the pipeline is safe and the values obtained by using the two methods are very similar. Analysis of these two methods gives a help to use different methods for pipeline structure assessment, This study laid the foundation of choosing different methods of pipeline structure assessment.