Field Stress and Strain Testing on Damaged Pipe Segment in LuNing Oil Pipeline

Oil-stealing orifice, residual stress by welding repair and the stress concentration by repair structures such as welding hats and welding sheets will lead to distinct decrease of pipelines to bear internal pressure.A field testing on the distribution of stress and strain over a service pipe segment in LuNing Oil Pipeline is made and an analysis to the distribution of stress and strain over the damaged pipe segment with resistivity stram measurement is conducted.Results show that it is enough to take the circumferential stress intoaccount when assessing the residual strength, and the max.stress coneentration value in oil-stealing orificeand welding repair location is 2.1.