Construction of high-pressure gas pipelines with API (American Petroleum Institute) X80 grade welded large diameter pipes is progressing for the improvement of transportation efficiency. The issue has been suggested that the benefit of higher strength steel of thinner wall pipe diminishes the strain capacity of line pipes by larger D/T(diameter to thickness) ratio and higher Y/T (yield to tensile) ratio of higher strength steel pipe in general. Authors reported that API X80 grade 48-inch (1219 mm) diameter line pipe has enough strain capacity against ground displacement by seismic wave propagation and lateral spread by liquefaction in seismic area based on the JGA (Japan Gas Assocation) guide line. However the pipelines are not always straight, but also curved to follow the route. Hot bends are employed to make curved portion. Mechanical properties and pipe dimensions of hot bends are different from straight pipes due to the heat treatment and deformation during bending. The characteristics of X80 hot bend are going to be investigated, and the strain capacity and the strain demand of curved portion in pipeline are evaluated by FEA (finite element analysis) for the assessment based on SBD (strain based design) concept.
Strain capacity of large diameter X80 pipeline including hot bend
2009
7 Seiten, 18 Quellen
Conference paper
Storage medium
English
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