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Transcripción del abstract original del autor: This study proposed an appropriate design for X80 pipelines subjected to large ground deformation, that is, the design for the straight pipes, the induction bends and cold bends having excellent deformability and for overmatching weld joints with adequate fracture toughness and hardness. First, the factors affecting deformability of the straight pipes, the induction bends and cold bends were experimentally and analytically evaluated. For the straight pipes and the induction-bent pipes, it was confirmed that the appropriate material design, including not only YS, TS and Y/T, but also the stress-strain curve shape, was essential for ensuring excellent deformability of the high-grade line pipes. For the cold bends, a FE model for evaluating the deformability taking into account the tensile properties after cold bending was proposed. The FE model was applicable for the large deformation behavior instead of full-scale experiments. Next, the effects of the welding conditions on the mechanical properties were investigated by conducting several welding tests. It was confirmed that stricter control of the weld process was required in order to achieve overmatching with adequate fracture toughness and hardness in the case of taking into account the distribution of the X80 pipes.