Seismic risk assessment of buried steel gas pipelines under seismic wave propagation based on fragility analysis

Tunnelling and Underground Space Technology

et al. 2019

Section: Discussionmentioning

confidence: 99%

Section: Peak Ground Velocity (Pgv)mentioning

confidence: 99%

Section: Peak Ground Velocity (Pgv)mentioning

confidence: 99%

See 1 more Smart Citation

A critical review on the vulnerability assessment of natural gas pipelines subjected to seismic wave propagation. Part 1: Fragility relations and implemented seismic intensity measures

Tunnelling and Underground Space Technology

et al. 2019

“…Regardless of the selected method, a critical step in the fragility assessment of a structure is the development of an adequate numerical methodology that will account for the majority of salient parameters that control the seismic response of the structure, being at the same time computationally efficient. Both Lee et al (2016) and Jahangiri and Shakib (2018) performed IDA analyses to examine numerically the seismic vulnerability of buried steel NG pipelines and propose analytical fragility relations. However both studies disregarded critical parameters that affect the seismic response and vulnerability of buried steel NG pipelines.…”

Section: Analytical Methods To Define the Edp-im Relationshipmentioning

confidence: 99%

“…The only way to simulate accurately these imperfections is by means of shell elements with a quite refined mesh. The available analytical studies on the seismic vulnerability assessment of NG pipelines (Lee et al, 2016;Jahangiri and Shakib, 2018) have modelled the examined pipelines by means of inelastic beam elements and fibers, disregarding the critical effect of geometric imperfections.…”

Section: Geometric Imperfections Of Steel Pipelinesmentioning

confidence: 99%

A critical review on the vulnerability assessment of natural gas pipelines subjected to seismic wave propagation. Part 2: Pipe analysis aspects

Tunnelling and Underground Space Technology

et al. 2019

The socioeconomic and environmental impact, in case of severe damage on Natural Gas (NG) pipeline networks, highlights the importance of a rational assessment of the structural integrity of this infrastructure against seismic hazards. Up to date, this assessment is mainly performed by implementing empirical fragility relations, while a limited number of analytical fragility curves have also been proposed recently. The critical review of available fragility relations for the assessment of buried pipelines under seismically-induced transient ground deformations, presented in the first part of this paper, highlighted the need for further investigation of the seismic vulnerability of NG pipeline networks, by employing analytical methodologies, capable of simulating effectively distinct damage modes of this infrastructure. In this part of the paper, alternative methods for the analytical evaluation of the seismic vulnerability of buried steel NG pipelines are presented. The discussion focuses on methods that may appropriately simulate buckling failures of buried steel NG pipelines since these constitute critical damage modes for the structural integrity of this infrastructure, when subjected to seismically-induced transient ground deformations. Salient parameters that control the seismic response and vulnerability of buried pressurized steel pipelines and therefore should be considered by the relevant analytical methods, such as the operational pressure of the pipeline, the geometric imperfections of the pipeline walls, the trench backfill properties, the site characteristics and the spatial variability of the seismic ground motion along the pipeline axis, are thoroughly discussed. Finally, a new approach for the assessment of buried steel NG pipelines against seismically-induced buckling failures is introduced. Through the discussion, recent advancements in the field are highlighted, whilst acknowledged gaps are identified, providing recommendations for future research.

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

et al. 2019

Bull Earthquake Eng

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 pipetrench 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 (PGV) 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.