Assessment of the flexural capacity of corroded steel pipes

Flexural capacity of corroded pipes can be determined analytically assuming a full plastic failure mode for the pipe. A set of generalized solutions for flexural capacity of the pipe can be developed if the shape of the corrosion is known a priori. The generalized solutions derived in this paper are able to account for the simultaneous action of internal pressure and axial force. For practical purposes, the generalized solutions thus derived are simplified into approximate closed-form equations using three idealized corrosion shapes, namely, constant-depth, elliptical, and parabolic corrosions. Numerical examples indicate that the closed-form approximate solutions provide good comparison with the generalized solutions. The closed-form approximate solutions are subsequently compared to experimental results from full-size tests of pipes with different corrosion depth and width. Parameter study conducted as part of this paper indicates that the shape of a corrosion defect has significant influence on the flexural capacity of the corroded pipes.