Pipeline Bending

What is pipeline bending?

Pipeline bending is a type of pipeline deformation. It refers to changes in a pipeline’s shape that deviate from its intended alignment. Although pipelines contain bends formed during manufacturing (fabricated bends) and construction (field bends), these bends were taken into account during the design process. However, additional loads may occur during construction or operation that can introduce unwanted bending, resulting in stresses or strains that may exceed safe limits1.

Why is pipeline bending a risk for pipeline safety?

Compressive stresses on the inside of a bend can lead to localized buckling and wrinkling. Tensile stresses on the outside of a bend can lead to fracture, especially in the presence of an anomaly in the pipe wall, such as circumferential cracking1. 

How does pipeline bending occur?

Bending loads can arise in many ways, for example, due to landslides, ground settlement, thermal expansion, third-party activity, or ground movement caused by construction work or frost heaving1. 
 

Image of a pipeline wall showing a crack.

  • Bending is a deformation that affects the entire pipeline shape.

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Pipeline Deformation Management

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Source reference

1 The Competence Club, ROSEN, 2025.

Related terms

Picture of a dent in a pipeline

Dents

Pipeline dents are deformations in a pipe’s wall caused by an external force. They represent a common defect that occurs when the circular cross-section is permanently altered.
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Picture of pipeline wrinkles.

Wrinkles

Pipeline wrinkles are localized deformations of the pipe wall that resemble a waveform and are characterized by alternating inward and outward bulges. 
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Illustration of how roof topping on a pipeline can look like.

Roof topping

Roof topping, also referred to as tenting, peaking, or angular misalignment, is a geometric anomaly that occurs at the seam weld of longitudinally welded pipes.
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Picture of a pipeline with an ovality anomaly.

Ovality

Pipeline ovality refers to the out-of-roundness of a pipeline, meaning the pipe’s cross-section deviates from a perfect circle. 
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Pipeline segment with a buckle

Buckles

A buckle is a severe deformation, or partial collapse, of a pipe, caused by lateral instability. This defect occurs when a pipe experiences excessive bending.
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Close up of a dent in the surface of a pipeline.

Geometry defects

Pipeline geometry defects refer to deviations from the ideal circular shape of a pipeline that lead to pipeline deformation.
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Picture of a coating failure on a pipeline.

Mechanical defects

Mechanical damage is caused by external forces acting on a pipeline. This broad term includes defects such as dents, gouges, and coating damage. 
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Picture of a lack of fusion anomaly on a pipeline.

Manufacturing-related defects

Manufacturing-related defects are imperfections in the pipe wall that originate during the production of steel plates or the pipe-forming process. 
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Pipeline running through a landscape affected by ground movements.

Pipeline movement

Pipeline movement refers to the displacement or deformation of a pipeline from its original position, often caused by external forces, such as ground shifts or natural hazards.

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