A plastic collapse solution for pipeline structures that is currently in use is given in CSA Z662, which is Canadian Standard for oil and gas pipeline systems: Ofc [1.03 18ca 2Rt] The variables in the above equation are defined in Figure 1, and R is pipe outer radius, oy is the specified minimum yield strength (SMYS) of pipeline steel. Construct a diagram showing critical crack length and depth that will cause pipeline failure by plastic collapse. Assume that it is a X-52 steel pipeline with 323.85 mm-diameter and 6.35 mm wall thickness under 0.72 SMYS maximum operating hoop stress. a = Oy Depth tip 2c Surface tip Figure 1 Surface crack geometries ID OD