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This article talks about lateral and upheaval buckling of pipelines. Know about them, their causes, prevention and the guidelines and recommendations.

We know that the piping systems are the integral component of a plant facility. In industries such as oil & gas, petrochemicals and more, engineers maximize the use of onshore and offshore pipelines. It helps for easy moving of liquid or gas from one place to another.

Sometimes, the pipes expand because of the high temperature and pressure of the fluid flow. It results in the buckling of pipelines.

In this article, we will highlight the two types of pipeline buckling:

It covers their introduction, causes, prevention & some guidelines that you can consider for them.

Overview

Lateral buckling takes place when the pipeline laid on the seabed or sand bands sideways. It happens due to the high pressure and high temperature of the material.

If we talk about upheaval buckling, it occurs when a pipeline in a trench or buried under the surface buckles vertically.

Both these types of pipeline buckling are usually bound to happen in environments with low soil cohesion. They can occur at offshore pipelines as well as onshore pipelines. Also, they can be global or local in type. A global buckling affects the complete section of the pipeline. In comparison, the local buckling stays within the specific areas of the pipe.

Causes of Upheaval and Lateral Buckling

The primary reason for pipeline buckling is the difference in temperature and pressure in the pipes than the surroundings. When it reaches higher values, tubes try to expand. If there is no space to enlarge, pipes create an axial expansion force.

The friction between the ambient soil and pipe surface resists the expansion of the pipe. It results in a restraining force in the overall pipe section. Based on the type of installation of the piping system, it tends to move upward or sideways.

How to Calculate & Prevent Lateral and Upheaval Buckling

There are a couple of ways to calculate upheaval buckling in the pipeline that helps prevent it.

Many engineers follow the calculations shown in the technical paper released by Dr. K. Peters for the underground piping. It is available with the name “About Upheaval and Lateral Buckling of embedded pipelines” (International third edition 2006).

Software such as Hexagon and more also helps calculate the maximum allowable over-bend angle and other parameters.

You might know about the SABKHA area, a.k.a. flat area in a desert or coastal surface where the lateral buckling mostly occurs. You can calculate the sideways force needed to resists lateral buckling as per the guidelines provided at the end of the article. Your pipe stress analysis consultant should also provide how much change in direction would be allowed for a lateral bend angle based on the geography.

One of the precautions to prevent upheaval buckling is to use extra soil cover at the pipeline route. To avoid lateral buckling, you may also need to keep berm reinforcement in check.

A Few Vital Guidelines

Conclusion

To summarize, buckling in pipelines can occur in areas with less vertical or horizolaoji.orgntal resistance to an axial compressive force. It includes sections between road crossings, interfaces between non-sabkha and sabkha locations & more.

Judith Morrison is an expert in the field of industrial engineering and writes articles related to piping, civil, equipment engineering related articles.