Buckling Uncertainty Analysis for Steel Pipelines Buried in Elastic Soil Using FOSM and MCS Methods

摘要

Generally, buried steel pipes are designed for good transverse behavior by neglecting soil-structure interaction effect. Steel pipelines are also usually designed to prevent from the important failure mode of buckling. However, the design of this type of structures does not normally consider the uncertainties in soil and structural properties. To address the above issues, the paper estimates the uncertainties in terms of the coefficient of variation of critical buckling displacement, CVw using subgrade reaction theory (Winkler model) and first-order second-moment (FOSM) method. Two cases of boundary conditions have been considered in this study. In the first case, CVw is calculated within an infinitely thick soil as a function of uncertainty of subgrade reaction modulus (K-s). In the second case, CVw is calculated in a thick soil cylinder as a function of the uncertainty of the effective subgrade reaction modulus (KS). Furthermore, the uncertainty of pipe flexibility (S-f) is also taken into account in the two cases. Uncertainty calculations by the FOSM method are then validated with those obtained from traditional Monte Carlo simulations.