Seismic fragility of buried steel natural gas pipelines due to axial compression at geotechnical discontinuities



Tsinidis, Grigorios, Di Sarno, Luigi ORCID: 0000-0001-6244-3251, Sextos, Anastasios and Furtner, Peter
(2020) Seismic fragility of buried steel natural gas pipelines due to axial compression at geotechnical discontinuities. Bulletin of Earthquake Engineering, 18 (3). pp. 837-906.

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Abstract

This paper presents an extended set of numerical fragility functions for the structural assessment of buried steel natural gas (NG) pipelines subjected to axial compression caused by transient seismic ground deformations. The study focuses on NG pipelines crossing sites with a vertical geotechnical discontinuity, where high compression straining of a buried pipeline is expected to occur under seismic transient ground deformations. A de-coupled numerical framework is developed for this purpose, which includes a 3D finite element model of the pipe–trench system employed to evaluate rigorously the soil–pipe interaction effects on the pipeline axial response in a quasi-static manner. One-dimensional soil response analyses are used to determine critical ground deformation patterns at the vicinity of the geotechnical discontinuity, caused by the ground shaking. A comprehensive parametric analysis is performed by implementing the proposed analytical framework for an ensemble of 40 recorded earthquake ground motions. Crucial parameters that affect the seismic response and therefore the seismic vulnerability of buried steel NG pipelines namely, the diameter, wall thickness, burial depth and internal pressure of the pipeline, the backfill compaction level, the pipe–soil interface friction characteristics, the soil deposits characteristics, as well as initial geometric imperfections of the walls of the pipeline, are systematically considered. The analytical fragility functions are developed in terms of peak ground velocity at the ground surface, for four performance limit states, considering all the associated uncertainties. The study contributes towards a reliable quantitative risk assessment of buried steel NG pipelines, crossing similar sites, subjected to seismically-induced transient ground deformations.

Item Type: Article
Uncontrolled Keywords: Natural gas pipelines, Seismic response, Fragility curves, Soil-pipe interaction, Transient ground deformations, Steel pipelines, Local buckling
Depositing User: Symplectic Admin
Date Deposited: 06 Feb 2020 08:33
Last Modified: 19 Jan 2023 00:22
DOI: 10.1007/s10518-019-00736-8
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3058531