Limit Bending Capacity of Steel Pipes Considering Strain Hardening Effect

Based on Hencky's total strain theory of plasticity, the limit bending capacity of steel pipes can be determined analytically assuming an elastic-linear strain hardening material. The simplified analytical solution is proposed as well. Good agreement is observed when limit bending capacities obtained from analytical solutions are compared with experimental results from full-size testing of steel pipes. It is shown that pipe considered to be strain hardening yields a higher bending capacity than that of pipe assumed as an elastic-perfectly plastic material. Thus, the ignorance of strain hardening effect, as commonly assumed in current codes, may underestimate the limit bending capacity of steel pipes. The solutions proposed in this paper are applicable in the design of offshore and onshore steel pipes, supports of offshore platforms and other tubular structural steel members.