Analytical Model for Segmented Pipe Response to Tensile Ground Strain

2016 ◽  
Vol 32 (4) ◽  
pp. 2533-2548 ◽  
Author(s):  
Michael O'Rourke ◽  
Tatiana Vargas-Londono
Keyword(s):  
Cast Iron ◽  
Ground Deformation ◽  
Large Diameter ◽  
Small Diameter ◽  
Seismic Wave Propagation ◽  
Seismic Fragility ◽  
Buried Pipelines ◽  
Empirical Relations ◽  
Permanent Ground Deformation ◽  
Pipe Materials

Seismic fragility relations for segmented buried pipelines have, up to this point, been based almost exclusively upon empirical observations. There are drawbacks with the purely empirical approach, one being the lack of confidence in estimated damage for the more important large diameter pipelines. This paper presents mechanics-based models for small diameter cast iron pipelines subject to tensile ground strains. One model is for small to moderate ground strains (less than .0002) primarily associated with seismic wave propagation. A second model is for larger ground strains associated with the permanent ground deformation hazard. The predicted damage rates from these mechanics-based models are consistent with existing empirical relations for small diameter cast iron pipe. It is expected that in the future, these mechanics-based models can be extended to the more important large diameters and to different pipe materials.

scholarly journals Seismic Behaviour of Buried Pipelines: 3D Finite Element Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Smrutirekha Sahoo ◽  
Bappaditya Manna ◽  
K. G. Sharma
Keyword(s):  
Finite Element ◽  
Seismic Response ◽  
Ground Deformation ◽  
Seismic Wave Propagation ◽  
Pipe Diameter ◽  
Bend Angle ◽  
Burial Depth ◽  
Maximum Magnitude ◽  
Buried Pipelines ◽  
Seismic Behaviour

This paper presents a numerical investigation on six pipeline models to study the seismic response of single and double buried pipelines using finite element method. Different depth and spacing of pipes are considered to investigate their prominent role in the seismic response of buried pipelines under an earthquake loading having PGA of 0.2468 g. In case of single pipeline, the maximum magnitude of final displacement as well as the stress at the end of the seismic sequence is found at the burial depth equal to the pipe diameter. In case of double pipeline, the maximum magnitude of final displacement is found when the spacing between pipes is equal to half the pipe diameter and there is an increasing tendency of developed stress with increase in spacing between pipes. In addition to the above results, the response of the buried pipelines with a particular bend angle (artificially induced bend/buckle) to the permanent ground deformation which is assumed to be the result of seismic wave propagation has also been studied. Remarkable differences in these results are obtained and with these results the designers can reduce seismic risk to their buried pipelines by taking proper precautionary measures.

Towards Robust Fragility Relations for Buried Segmented Pipe in Ground Strain Areas

2015 ◽  
Vol 31 (3) ◽  
pp. 1839-1858 ◽  
Author(s):  
Michael O'Rourke ◽  
Evgueni Filipov ◽  
Eren Uçkan
Keyword(s):  
Wave Propagation ◽  
Linear Function ◽  
Ground Deformation ◽  
Unit Length ◽  
Ground Movement ◽  
Seismic Fragility ◽  
Ground Shaking ◽  
Permanent Ground Deformation

Seismic fragility relations of buried segmented pipelines are currently defined in terms of pipe repairs per unit length as a function of some measure of ground shaking or ground movement. In some current relations, both wave propagation (WP) and permanent ground deformation (PGD) damage are addressed by combining the hazard into a measure of ground strain. One troubling aspect of these fragility relations is that each new event seems to provide new data that in some cases, are significantly different from existing relations. Herein, we investigate the robustness of these expressions by using new data from the 1999 M = 7.4 Turkey earthquake. A methodology is presented to calculate ground strains, by considering relative PGD along the axis of the pipeline. Results indicate that, for the strain/damage range of interest, a linear function (on a log-log scale) provides a relatively robust fragility relation for buried segmented pipes.

Site Effects on Seismic Behavior of Pipelines: A Review

2000 ◽  
Vol 122 (4) ◽  
pp. 469-475 ◽  
Author(s):  
Jianwen Liang ◽  
Shaoping Sun
Keyword(s):  
Site Effects ◽  
Seismic Behavior ◽  
Ground Deformation ◽  
Lateral Spread ◽  
Site Condition ◽  
Buried Pipelines ◽  
Fault Movement ◽  
Local Site ◽  
Permanent Ground Deformation ◽  
Almost All

Post-earthquake investigations showed that local site condition had significant effect on seismic behavior of pipelines: almost all seismic damages to buried pipelines were either due to permanent ground deformation such as fault movement, landslide and lateral spread, or found in nonuniform ground, and there were few cases that pipelines were damaged only by wave propagation. Earthquake field observations did clearly indicate that relatively high strain occurred in pipelines laid through nonuniform ground. In this paper, an updated and detailed review of site effects on seismic behavior of pipelines is presented. For the purpose, quantitative analysis of damage, earthquake field observation, theoretical and experimental study, and related seismic design are discussed, and research needs are pointed out. [S0094-9930(00)01702-9]

scholarly journals Design of buried flexible pipelines during liquefaction

2018 ◽  
Vol 7 (2.21) ◽  
pp. 259
Author(s):  
Durga Prasad Valleti ◽  
Neelima Sathyam ◽  
S. Sivaranjani ◽  
C. Shahin ◽  
Sneha Mondal
Keyword(s):  
Seismic Design ◽  
Buoyancy Force ◽  
Ground Deformation ◽  
Soil Liquefaction ◽  
Buried Pipelines ◽  
Gujarat State ◽  
The World ◽  
Permanent Ground Deformation ◽  
Abaqus Software ◽  
Surrounding Soil

Pipelines are important facilities over the huge area to encounter a seismic hazards and conditions of soil. In India pipe lines run through high seismic areas and exposed to considerable risk. The pipelines have advanced in India compare through the world scenario there is no uniform guideline available for seismic design. Therefore we need to establish at least degree of safety for standard seismic design of pipelines. As a part of this, a number of flexible pipelines of different diameter, length, and thickness have been taken into consideration. The density, internal pressure and density of surrounding soil are taken into account and is checked against permanent ground deformation (PGD) due to liquefaction. Using ABAQUS SOFTWARE we will analyse the soil pipeline interaction and based on the results obtained some consideration are given for the design of pipeline in the Liquefied zone, which improve the capability of the pipeline to withstand buoyancy force due to soil liquefaction. The safety of buried pipelines is analyzed as per IITK-GSDMA (IIT-Kanpur-Gujarat state Disaster Management Authority) guidelines on seismic design.

Failure Analysis Of Buried Gas Pipelines Crossing Seismic Faults

2020 ◽  
Vol 3 (2) ◽  
pp. 781-790
Author(s):  
M. Rizwan Akram ◽  
Ali Yesilyurt ◽  
A.Can. Zulfikar ◽  
F. Göktepe
Keyword(s):  
Ground Deformation ◽  
Warning System ◽  
Strike Slip ◽  
Gas Pipelines ◽  
Steel Pipes ◽  
Seismic Fault ◽  
Fault Parameters ◽  
Dip Angle ◽  
Permanent Ground Deformation ◽  
Recent Earthquakes

Research on buried gas pipelines (BGPs) has taken an important consideration due to their failures in recent earthquakes. In permanent ground deformation (PGD) hazards, seismic faults are considered as one of the major causes of BGPs failure due to accumulation of impermissible tensile strains. In current research, four steel pipes such as X-42, X-52, X-60, and X-70 grades crossing through strike-slip, normal and reverse seismic faults have been investigated. Firstly, failure of BGPs due to change in soil-pipe parameters have been analyzed. Later, effects of seismic fault parameters such as change in dip angle and angle between pipe and fault plane are evaluated. Additionally, effects due to changing pipe class levels are also examined. The results of current study reveal that BGPs can resist until earthquake moment magnitude of 7.0 but fails above this limit under the assumed geotechnical properties of current study. In addition, strike-slip fault can trigger early damage in BGPs than normal and reverse faults. In the last stage, an early warning system is proposed based on the current procedure. 

Differences in the brain stem terminations of large- and small-diameter vestibular primary afferents

1995 ◽  
Vol 74 (3) ◽  
pp. 1362-1366 ◽  
Author(s):  
J. A. Huwe ◽  
E. H. Peterson
Keyword(s):  
Brain Stem ◽  
Large Diameter ◽  
Small Diameter ◽  
Movement Control ◽  
Three Dimensions ◽  
Significant Shift ◽  
Axon Diameter ◽  
Vestibular Complex ◽  
The Brain ◽  
Adjacent Brain

1. We visualized the central axons of 32 vestibular afferents from the posterior canal by extracellular application of horseradish peroxidase, reconstructed them in three dimensions, and quantified their morphology. Here we compare the descending limbs of central axons that differ in parent axon diameter. 2. The brain stem distribution of descending limb terminals (collaterals and associated varicosities) varies systematically with parent axon diameter. Large-diameter afferents concentrate their terminals in rostral regions of the medial/descending nuclei. As axon diameter decreases, there is a significant shift of terminal concentration toward the caudal vestibular complex and adjacent brain stem. 3. Rostral and caudal regions of the medial/descending nuclei have different labyrinthine, cerebellar, intrinsic, commissural, and spinal connections; they are believed to play different roles in head movement control. Our data help clarify the functions of large- and small-diameter afferents by showing that they contribute differentially to rostral and caudal vestibular complex.

Numerical Analysis of Metro Station Construction by Large-Diameter Shield and Pile-Beam-Arch Method

2011 ◽  
Vol 368-373 ◽  
pp. 2711-2715 ◽  
Author(s):  
De Yun Ding ◽  
Xiu Ren Yang ◽  
Wei Dong Lu ◽  
Wei Ning Liu ◽  
Mei Yan ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Large Diameter ◽  
Element Model ◽  
Construction Method ◽  
Shield Tunnel ◽  
Outer Diameter ◽  
Shield Tunneling ◽  
Metro Station ◽  
Dimensional Finite Element ◽  
New Construction

In more and more complicated urban building environment, a new construction method that metro engineering is constructed by large-diameter shield and shallow mining method can be regarded as a great attempt in China. By taking the Gaojiayuan station of Beijing metro line 14 as an engineering background, the main construction steps for the platform of the metro station built by a large-size shield with an outer diameter of 10 m and the Pile-Beam-Arch (PBA) method are introduced. Based on the soil-structure interaction theory, a two-dimensional finite element model is used to simulate the shield tunneling and the platform construction by the PBA method to enlarge the shield tunnel. The ground deformation and structural stress of the platform are predicted. The numerical results can be regarded as a valuable reference for the application of the new construction method in Beijing metro line 14.

scholarly journals Elastic Modulus and Elasticity Ratio of Malignant Breast Lesions with Shear Wave Ultrasound Elastography: Variations with Different Region of Interest and Lesion Size

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1015
Author(s):  
Antonio Bulum ◽  
Gordana Ivanac ◽  
Eugen Divjak ◽  
Iva Biondić Špoljar ◽  
Martina Džoić Dominković ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Shear Wave ◽  
Large Diameter ◽  
Small Diameter ◽  
Shear Wave Elastography ◽  
Lesion Size ◽  
Ultrasound Elastography ◽  
Breast Lesions ◽  
Malignant Breast ◽  
The Impact

Shear wave elastography (SWE) is a type of ultrasound elastography with which the elastic properties of breast tissues can be quantitatively assessed. The purpose of this study was to determine the impact of different regions of interest (ROI) and lesion size on the performance of SWE in differentiating malignant breast lesions. The study included 150 female patients with histopathologically confirmed malignant breast lesions. Minimal (Emin), mean (Emean), maximal (Emax) elastic modulus and elasticity ratio (e-ratio) values were measured using a circular ROI size of 2, 4 and 6 mm diameters and the lesions were divided into large (diameter ≥ 15 mm) and small (diameter < 15 mm). Highest Emin, Emean and e-ratio values and lowest variability were observed when using the 2 mm ROI. Emax values did not differ between different ROI sizes. Larger lesions had significantly higher Emean and Emax values, but there was no difference in e-ratio values between lesions of different sizes. In conclusion, when measuring the Emin, Emean and e-ratio of malignant breast lesions using SWE the smallest possible ROI size should be used regardless of lesion size. ROI size has no impact on Emax values while lesion size has no impact on e-ratio values.

Analysis Influence of Pile Embedded Depth and Diameter on Pile Tip Resistance

2013 ◽  
Vol 353-356 ◽  
pp. 459-462
Author(s):  
Ying Jie Zheng ◽  
Bin Fang ◽  
Lian Xiang Li
Keyword(s):  
Large Diameter ◽  
Small Diameter ◽  
Stiffness Ratio ◽  
Initial Stiffness ◽  
Tip Resistance

Pile tip absolute settlement curves and relative settlement curves of several working cases were analyzed. It is found that load-settlement curve characteristic related to the selection standard. The tip resistance initial stiffness of each case was analyzed. Results show that the small diameter pile has higher initial stiffness than large diameter pile, embedded depth has little influence on initial stiffness ratio, but increment of initial stiffness is linear with embedded depth growth.

Sign in / Sign up

Export Citation Format

Share Document