Experimental Investigation of Stress-Strain State of the Thin–Walled Steel Pipe Subjected to Combined Loads

When a pipeline crosses an area with potential landslide, it could be subjected to combined loads. External load conditions can result in bending and subsequent rupture of the pipe. When compressive stresses cause buckling and rupture, the tensile stresses rarely cause failures. Reliable mitigation measures could be completed quickly at modest cost if pipe monitoring is performed with consideration of elastic-plastic deformations. This paper presents the response of thin-walled cylindrical pipe subjected to combined beam load factors and internal pressures, using a new engineering approach. The main focus in this paper is on experimental investigation of the pipe performance and validity of the supplementary numerical approach. This approach uses formulas for longitudinal force and bending moment as a function of deformational parameters. The relationship between material model parameters as input to the analysis and the elastic-plastic deformation beyond limit of elasticity is investigated by performing a series of experimental tests. The applicability of the proposed formulas for the local plastic deformation assessment is also discussed.