Strain Capacity of X80 High-Strain Line Pipes

Two compression tests and two bending tests of X80 high-strain line pipes were conducted to investigate the compression capacity and the bending capacity. The high-strain line pipes had the outside diameter of 762 mm (30”) and the D/t ratio of 49. The compression tests revealed that the pipes had the critical compressive strains of 0.90 and 0.78%. The bending tests of the pipes clarified that the 2D average critical compressive strains were 2.40 and 2.15% and the 1D average were 2.67 and 2.28%. The analytical solutions gave very fine predictions about the critical compressive stress and strain of the pipes subjected to axial compression. Based on the FEA results, while almost no effects of the geometric imperfections on the compression capacity were recognized, the effects of the geometric imperfections on the bending capacity were significant.