Upheaval Buckling and
Out-of-straightness Analysis

A Pioneer in the Field
Out-of-straightness (OOS) analysis is one of KW’s main strengths that enables the company to remain at the leading edge of upheaval buckling (UHB) analysis.

Unique Analysis Package
KW have developed an accurate and consistent OOS analysis methodology, which is based on the use of SAGE Profile FE package combined with the Download Monitoring System (DMS) to calculate the download requirement to prevent upheaval buckling in pipelines. The KW OOS analysis method is combined with a reliability-based approach in order to capture the uncertainty in the design input parameters. ABAQUS non-linear FEA is used to calibrate the OOS analysis models for HTHP and pipe-in-pipe applications.

The DMS analysis tool, pioneered and developed by KW staff, has been used on almost all the pipelines installed in the North Sea since 1999. The analysis method has been subject to DnV, Lloyds and Bureau Veritas scrutiny and verification on several projects.

In the past, assessment of the amount of rock cover has incorporated a large degree of conservatism, resulting in excessive cost to the installation contractor. Thus, KW's main OOS analysis objectives are:
• To provide an adequate level of safety in the operating pipeline to ensure that upheaval buckling will not occur during the operating life of the pipeline
• To minimise the volume of rock required to eliminate upheaval buckling, commensurate with the requirements for adequate safety

KW Assurance
A dedicated, proactive, and responsive engineering team with extensive experience of advanced structural mechanics and pipeline engineering can be assigned to respond to the project’s demands.

The ability of KW to perform the OOS analysis quickly and thoroughly can be demonstrated by reference to our track record in this field over the past years. Rock dump schedules can be provided as swiftly as within 24hrs, if required, from the receipt of raw OOS survey data.