Limit Loads of Buried Pipelines With Asymmetric Initial Imperfections

The effect of asymmetric imperfection on the limit-load response of pipelines buried in shallow trenches is investigated. The pipeline is modeled as a long beam resting on a rigid foundation and a small strain, large displacement formulation is used. Three different asymmetric imperfection shapes for the beam are considered and the corresponding limit loads are compared with that for a symmetric imperfection. It is found that the shape of initial imperfection plays an important role. The difference between limit loads based on a symmetric imperfection and a nonsymmetric imperfection can be quite significant.