Large Scale Experiments of Buried Steel Pipelines With Elbows Subjected to Permanent Ground Deformation

Yoshizaki, Koji; O’Rourke, Thomas D.; Hamada, Mareomi

doi:10.2208/jscej.2003.724_1

Cited by 3 publications

(2 citation statements)

References 5 publications

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“…1b), mainly for the purpose of changing direction in pipeline alignment. Interesting work on soil-pipe interaction behavior of buried pipelines with 90°elbows has been reported by Yoshizaki et al (2000Yoshizaki et al ( , 2003; a series of tests on stand-alone elbows has been reported in Yoshizaki et al (2000), followed by finite element simulations, whereas in Yoshizaki et al (2003), experiments on 100-mm-diameter 4.1-mm-thick 90°pipe elbows have been reported, also supported by finite element calculations, which employed shell elements and nonlinear springs. In a more recent publication, Suzuki et al (2014) reported experimental works on stand-alone cold-formed low-angle elbows, followed by a finite element simulation to determine numerically their bending deformation limits.…”

Section: Introductionmentioning

confidence: 99%

Structural behavior of buried pipe bends and their effect on pipeline response in fault crossing areas

Vazouras

Karamanos

2017

Bull Earthquake Eng

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Pipe bends, often referred to as ''elbows'', are special pipeline components, widely used in onshore buried steel pipelines. They are sensitive to imposed deformations and their structural behavior is quite flexible and associated with the development of significant stress and strain, which may lead to failure. In the present paper, the mechanical performance of buried steel pipeline bends is investigated first, using rigorous finite element models that account for the pipe-soil interface. Three 36-inch-diameter pipe elbows are considered, subjected to pull-out force and embedded in cohesive soils. The elbows have bend angles equal to 90°, 60°and 30°, and bend radius-over-diameter ratio (R/D) equal to 5. The results show the increased flexibility of the pipeline bend with respect to the straight pipe, and are reported in the form of force-displacement diagrams. Furthermore the deformation limits of each elbow are identified in terms of appropriate performance criteria. The second part of the paper investigates the effect of pipe bends on the response of pipelines crossing active faults using a three-dimensional rigorous finite element model. The numerical results refer to a 36-inch-diameter pipeline crossing a strike-slip fault, and show that the unique mechanical response of pipe bends, in terms of their flexibility, may offer an efficient tool for reducing ground-induced deformations. The three-dimensional model employs the load-displacement curves of the first part of the paper as end conditions through nonlinear springs. Furthermore, the results show that there exist an optimum distance of the elbow from the fault plane, which corresponds to the maximum allowable ground displacement. Therefore, pipeline elbows, if appropriately placed, can be employed as ''mitigating devices'', reducing ground-induced action on the pipeline at fault crossings.

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Section: Introductionmentioning

confidence: 99%

Structural behavior of buried pipe bends and their effect on pipeline response in fault crossing areas

Vazouras

Karamanos

2017

Bull Earthquake Eng

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“…During earthquakes, permanent ground deformation (PGD) can damage buried pipelines. Recent earthquakes, including the 1999 Kocaeli and Duzce earthquakes in Turkey, and the 1999 Chi-chi earthquake in Taiwan, have provided evidence of the importance of liquefaction, fault rupture, and landslides through their effects on a variety of highway, electrical, gas, and water supply lifelines [2].…”

Section: Introductionmentioning

confidence: 99%

Vectorial dislocation monitoring of pipelines by use of Brillouin-based fiber-optics sensors

Bernini

Minardo²,

Zeni³

2007

Smart Mater. Struct.

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In this paper, we propose and experimentally validate the use of a distributed optical fiber sensor for monitoring pipeline dislocation. The proposed technique is based on the measurement of the normal strain, by use of stimulated Brillouin scattering, along three longitudinal directions running along the pipeline. We demonstrate that, by choosing three lines reciprocally displaced by 120 • around the circumference of the pipeline, it is possible to measure the amount and direction of pipeline dislocation. The longitudinal position at which the deformation occurs is also evaluated. The measurements achieved by using the proposed technique can be directly used to monitor the structural integrity of the pipeline, as well as to monitor the deformations of the rock/soil surrounding the pipeline. This can be of importance to monitor geological events. Numerical simulations carried out by the finite-element method have been employed to evaluate the accuracy of the measurements.

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Scattering function for wormlike chains with finite thickness

Nakamura

Norisuye

2004

J Polym Sci B Polym Phys

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The particle scattering function P(k) is approximately evaluated for the Kratky-Porod wormlike chain with a circular cross section to examine the effect of chain diameter d on the scattering curve of k 2 P(k) versus k, the magnitude of the scattering vector, for stiff chains and also the applicability of the cross-section plot of ln[kP(k)] versus k 2 to them. In the evaluation, series expansions from the rod and coil limits up to the fifth-order and third-order deviations, respectively, are combined together. The major results or conclusions derived are as follows. First, the conventional equation, P(k) ϭ P 0 (k) exp(Ϫk 2 d 2 /16), for straight cylinders overestimates k 2 P(k) at relatively large values of k, whereas its alternative, P(k) ϭ P 0 (k)[2J 1 (kd/2)/(kd/2)] 2 , is a good approximation to exact P(k) unless contour length L is shorter than 10d. Here, P 0 (k) denotes the scattering function for the chain contour, and J 1 (x) is the Bessel function of the first order. Second, as d is increased for a fixed value of L (relative to the Kuhn segment length), the k 2 P(k)-k curve lowers with a pronounced maximum, and the peak position shifts to a lower scattering angle. Third, if the chain is somewhat flexible, the cross-section plot has an approximately linear region, with a slope fairly close to Ϫd 2 /16 expected from the aforementioned conventional equation. This plot for rods appreciably bends down, and thus the experimental observation of an approximately linear relation (over a wide k range) implies that, in contrast to the prevailing notion, the polymer examined is not completely rigid but instead is somewhat flexible.

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Large Scale Experiments of Buried Steel Pipelines With Elbows Subjected to Permanent Ground Deformation

Cited by 3 publications

References 5 publications

Structural behavior of buried pipe bends and their effect on pipeline response in fault crossing areas

Structural behavior of buried pipe bends and their effect on pipeline response in fault crossing areas

Vectorial dislocation monitoring of pipelines by use of Brillouin-based fiber-optics sensors

Scattering function for wormlike chains with finite thickness

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