Upheaval Buckling of Small Diameter Pipelines Induced by Strong Ground Shaking

2012 ◽  
Author(s):  
Hiroyuki Horikawa ◽  
Yoji Tsunasawa ◽  
Hajime Shinkai ◽  
Nobuhisa Suzuki
Keyword(s):  
Local Buckling ◽  
Small Diameter ◽  
Field Tests ◽  
Bending Moment ◽  
Design Guidelines ◽  
Combined Loading ◽  
Pipe Material ◽  
Effective Parameters ◽  
Ground Shaking ◽  
Upheaval Buckling

Upheaval buckling of small diameter gas pipeline occurred due to strong seismic excitation during the 2007 Niigata-ken Chuetsu-Oki earthquake whose diameters were 4″ and smaller. This paper deals with investigation of the upheaval buckling of gas pipes conducted by Ministry of Economy, Trade and Industry of Japan to establish seismic design guidelines to mitigate upheaval buckling. Sand box and field tests were conducted using small diameter pipes to simulate the upheaval buckling behaviors and construct a simple finite element model. The results clarified that the tensile properties of pipe material and pipe-soil interaction were the most effective parameters to explain the buckling behaviors. Interaction curve of pipes can be found in the relationship between compression and bending moment in the combined loading tests. The deformation behaviors of the buried pipe tests followed the interaction curve and local buckling of buried pipes occurred in lower bending moment than that of pipes not buried.

Influence of Geotechnical Loads on Local Buckling Behavior of Buried Pipelines

2008 ◽  
Author(s):  
Hiva Mahdavi ◽  
Shawn Kenny ◽  
Ryan Phillips ◽  
Radu Popescu
Keyword(s):  
Large Scale ◽  
Mechanical Performance ◽  
Load Capacity ◽  
Local Buckling ◽  
Small Diameter ◽  
Ground Movement ◽  
Combined Loading ◽  
Fe Model ◽  
Buried Pipelines ◽  
Limit States

Buried pipelines can be subjected to differential ground movement events. The ground displacement field imposes geotechnical loads on the buried pipeline and may initiate pipeline deformation mechanisms that exceed design acceptance criteria with respect to serviceability requirements or ultimate limit states. The conventional engineering approach to define the mechanical performance of pipelines has been based on combined loading events for “in-air” conditions. This methodology is assumed to be overly conservative and ignores soil effects that imposes geotechnical loads and also provides restraint, on buried pipelines. The importance of pipeline/soil interaction and load transfer mechanisms that may affect local buckling of buried pipelines is not well understood. In this study a three-dimensional continuum finite element (FE) model, using the software package ABAQUS/Standard, was developed and calibrated based on large-scale tests on the local buckling of linepipe segments for in-air and buried conditions. The effects of geotechnical boundary conditions on pipeline deformation mechanism and load carrying capacity were examined for a single small diameter pipeline with average diameter to thickness ratio and deep buried condition. The calibrated model successfully reproduced the large-scale buried test results in terms of the local buckling location, pipeline carrying load capacity, soil deformation and soil failure mechanism.

Seismic Design Guidelines to Mitigate Upheaval Buckling of Small Diameter Pipes

2012 ◽  
Author(s):  
Hajime Shinkai ◽  
Yoshito Hatsuda ◽  
Nobuhisa Suzuki
Keyword(s):  
High Pressure ◽  
Ground Motion ◽  
Seismic Design ◽  
Research Program ◽  
Strong Ground Motion ◽  
Small Diameter ◽  
Design Guidelines ◽  
Upheaval Buckling ◽  
Offshore Earthquake ◽  
Strong Ground

This paper describes The Draft Seismic Design Guidelines to Mitigate Upheaval Buckling of Small Diameter Pipes which were reported by Ministry of Economy, Trade and Industry in 2011. Upheaval buckling of small diameter gas pipes occurred in a high-pressure gas pipeline and three middle-pressure city lines due to the strong ground motion during the 2007 Niigata Chuetsu Offshore earthquake which was a powerful earthquake with moment magnitude of 6.6. A three year research program had been conducted since 2008 to investigate the upheaval buckling behaviors and develop seismic design guidelines to ensure seismic integrity of small diameter high-pressure gas pipelines and middle-pressure main distribution lines.

MODELING AND SIMULATION OF BUCKLING AND POSTBUCKLING OF PLANT STEMS UNDER COMBINED LOADING CONDITIONS

2011 ◽  
Vol 03 (01) ◽  
pp. 119-130 ◽  
Author(s):  
HAO-LEI CUI ◽  
HUI-SHEN SHEN
Keyword(s):  
Axial Compression ◽  
Local Buckling ◽  
Bending Moment ◽  
Wind Pressure ◽  
Combined Loading ◽  
Equilibrium Path ◽  
Governing Equations ◽  
Postbuckling Behavior ◽  
Finite Element Package ◽  
Plant Stem

Numerical simulations for local buckling and postbuckling behavior of plant stems are presented under two combined loading cases: (1) axial compression (caused by axial grains) combined with wind pressure; and (2) bending moment (caused by eccentric axial grains) combined with wind pressure. Based on its microstructure, a hollow plant stem is modeled as a stringer stiffened multiwalled shell. The material properties of the stem are assumed to be orthotropic. The nonlinear governing equations for buckling and postbuckling of plant stems are solved through arc-length method along with Newton–Raphson technique. The numerical calculations are carried out using the finite element package ABAQUS. The results show that the postbuckling equilibrium path is unstable for plant stems subjected to axial compression or bending combined with relatively low values of wind pressure. Large reduction in buckling load and in postbuckling strength can be found even if the applied wind pressure is relatively small, which results in the easy occurrence of stem lodging.

Novel Design of Small Diameter Pipelines on Uneven Seabed

2011 ◽  
Author(s):  
Frode Hove ◽  
Tore H. So̸reide ◽  
Anne Cecilie Nordsve ◽  
Sigurd D. Trier
Keyword(s):  
Crack Growth ◽  
Local Buckling ◽  
Small Diameter ◽  
Design Procedure ◽  
Bending Moment ◽  
Potential Cost ◽  
Traditional Design ◽  
Separate Control ◽  
Major Attention ◽  
Girth Welds

The paper deals with design philosophy for small diameter HP/HT flowlines on uneven seabed with major emphasis on controlled snaking expansion design of free spanning flowlines subject to fishing gear interaction loads. The response from trawl pull-over is given major attention as part of the overall design procedure including ECA (Engineering Criticality Assessment), covering high and low cycle crack growth. The background for the design procedure is reference projects in the Norwegian sector, where REINERTSEN performed the flowlines detail engineering. Iceberg plough marks make an irregular seabed with partly sharp and deep valleys crossing the flowline routes, resulting in free spans. The bathymetry and extent of unevenness varies for the lines, resulting in different behavior and design approaches, especially for trawl pull-over. The major criterion for a robust design is strong sectioning by intermittent rock berms. For operation loads these serve as locking points and as such they are termed ARBs (Anchoring Rock Berms), whereas for trawl pull-over axial motion through the berms is allowed, depending on seabed profile, and as long as the pipeline deforms without unacceptable crack growth in girth welds. Design criteria for the ARBs are presented, covering the expansion phases of buckle initiation, post-buckle and shutdown, respectively. For trawl pull-over separate control of the intermittent rock dumps is shown, covering the cases of section interaction and complete locking, respectively. Criteria for the choice of trawl design approach are evaluated. Traditional design handles the trawl impact capacity of pipelines by a local buckling criterion, in which axial force and bending moment are the response parameters. For expansion control this is a relevant approach, however for a concentrated and curvature. Applying the latter criterion is illustrated by numerical example in view of displacement- or load controlled behaviour. A summary on rock saving potential is made for a typical reference project from a traditional design involving infill of spans to the new approach where free spans are allowed also for trawl pull-over. The potential cost saving for seabed intervention work by rock dumping is found to be well above 5000 NOK/m (>1000 $/m) for very irregular seabed, while typically in the order of 1000 $ for normal uneven seabed.

Extending the Limits for Thick Walled Pipe (D/t<20) for External Pressure and Combined Loading

2017 ◽  
Author(s):  
Henk Smienk ◽  
Erwan Karjadi ◽  
Steven Huiskes
Keyword(s):  
Limit State ◽  
Local Buckling ◽  
Bending Moment ◽  
External Pressure ◽  
Combined Loading ◽  
Load Path ◽  
Material Models ◽  
Axial Tension ◽  
Geometrical Imperfections ◽  
2D And 3D

During the operational and installation phase of submarine pipelines, the collapse and local buckling behaviour is of interest. Existing research [1] shows conservatism in the pure collapse DNV formula for thick walled pipe. The first part of the paper will focus on the collapse behaviour of empty thick walled pipe under external pressure. Using 2D and 3D FE Analysis an investigation into the collapse behaviour of pipe with a D/t < 20 is conducted. The analysis also covers an extensive sensitivity analysis with regard to geometrical imperfections and different material models. The local buckling behaviour during the combined external pressure, bending moment and effective axial force loading encountered in the sagbend is also investigated. To obtain a realistic load path for the sagbend loading, static Flexcom analyses are performed. If the load case is not sufficient to initiate collapse because of the stiffness of the catenary due to the low D/t, the pipe will be bent to the limit state while setting the effective tension to zero. The effect of each sensitivity on the collapse and local buckle behaviour of thick walled pipe in the sagbend including effective axial tension is discussed.

The Influence of Loads Superposition, Deterioration Due to Cracks and Residual Stresses on the Strength of Tubular Junction

2017 ◽  
Vol 68 (6) ◽  
pp. 1267-1273
Author(s):  
Valeriu V. Jinescu ◽  
Angela Chelu ◽  
Gheorghe Zecheru ◽  
Alexandru Pupazescu ◽  
Teodor Sima ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Residual Stresses ◽  
Bending Moment ◽  
Combined Loading ◽  
Torsional Moment ◽  
Calculation Methods ◽  
State Of Stress ◽  
Cracked Structures ◽  
Total Participation ◽  
Theoretical Results

In the paper the interaction of several loads like pressure, axial force, bending moment and torsional moment are analyzed, taking into account the deterioration due to cracks and the influence of residual stresses. A nonlinear, power law, of structure material is considered. General relationships for total participation of specific energies introduced in the structure by the loads, as well as for the critical participation have been proposed. On these bases: - a new strength calculation methods was developed; � strength of tubular cracked structures and of cracked tubular junction subjected to combined loading and strength were analyzed. Relationships for critical state have been proposed, based on dimensionless variables. These theoretical results fit with experimental date reported in literature. On the other side stress concentration coefficients were defined. Our one experiments onto a model of a pipe with two opposite nozzles have been achieved. Near one of the nozzles is a crack on the run pipe. Trough the experiments the state of stress have been obtained near the tubular junction, near the tip of the crack and far from the stress concentration points. On this basis the stress concentration coefficients were calculated.

scholarly journals Influence of Construction Joint and Bridge Geometry on Integral Abutment Bridges

2021 ◽  
Vol 11 (11) ◽  
pp. 5031
Author(s):  
Wooseok Kim ◽  
Jeffrey A. Laman ◽  
Farzin Zareian ◽  
Geunhyung Min ◽  
Do Hyung Lee
Keyword(s):  
Prestressed Concrete ◽  
Extreme Temperature ◽  
Bending Moment ◽  
Design Guidelines ◽  
Time Dependent ◽  
Steel Bridge ◽  
Integral Abutment ◽  
Integral Abutment Bridges ◽  
Construction Joint ◽  
Abutment Bridges

Although integral abutment bridges (IABs) have become a preferred construction choice for short- to medium-length bridges, they still have unclear bridge design guidelines. As IABs are supported by nonlinear boundaries, bridge geometric parameters strongly affect IAB behavior and complicate predicting the bridge response for design and assessment purposes. This study demonstrates the effect of four dominant parameters: (1) girder material, (2) bridge length, (3) backfill height, and (4) construction joint below girder seats on the response of IABs to the rise and fall of AASHTO extreme temperature with time-dependent effects in concrete materials. The effect of factors influencing bridge response, such as (1) bridge construction timeline, (2) concrete thermal expansion coefficient, (3) backfill stiffness, and (4) pile-soil stiffness, are assumed to be constant. To compare girder material and bridge geometry influence, the study evaluates four critical superstructure and substructure response parameters: (1) girder axial force, (2) girder bending moment, (3) pile moment, and (4) pile head displacement. All IAB bridge response values were strongly related to the four considered parameters, while they were not always linearly proportional. Prestressed concrete (PSC) bridge response did not differ significantly from the steel bridge response. Forces and moments in the superstructure and the substructure induced by thermal movements and time-dependent loads were not negligible and should be considered in the design process.

Effect of Torsion on Collapse Bending Moment for 24-Inch Diameter Schedule 80 Pipes With Wall Thinning

2012 ◽  
Author(s):  
Kunio Hasegawa ◽  
Yinsheng Li ◽  
Bostjan Bezensek ◽  
Phuong Hoang
Keyword(s):  
Power Plants ◽  
Bending Moment ◽  
Combined Loading ◽  
Bending Moments ◽  
Compressive Stresses ◽  
Wall Thinning ◽  
Nominal Thickness ◽  
Calculation Results ◽  
Loading Modes ◽  
Local Wall Thinning

Piping items in power plants may experience combined bending and torsion moments during operation. Currently, there is a lack of guidance in the ASME B&PV Code Section XI for combined loading modes including pressure, torsion and bending. Finite element analyses were conducted for 24-inch diameter Schedule 80 pipes with local wall thinning subjected to tensile and compressive stresses. Plastic collapse bending moments were calculated under constant torsion moments. From the calculation results, it can be seen that collapse bending moment for pipes with local thinning subjected to tensile stress is smaller than that subjected to compressive stress. In addition, equivalent moment is defined as the root the sum of the squares of the torsion and bending moments. It is found that the equivalent moments can be approximated with the pure bending moments, when the wall thinning length is equal or less than 7.73R·t for the wall thinning depth of 75% of the nominal thickness, where R is the mean radius and t is the wall thickness of the pipe.

Prediction Method for Plastic Collapse of Pipes Subjected to Combined Bending and Torsion Moments

2010 ◽  
Author(s):  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Phuong H. Hoang ◽  
Bostjan Bezensek
Keyword(s):  
Entire Range ◽  
Estimation Method ◽  
Prediction Method ◽  
Bending Moment ◽  
Combined Loading ◽  
Plastic Collapse ◽  
Finite Element Analyses ◽  
Pure Torsion ◽  
Stainless Steel Pipe ◽  
Service Inspection

When a crack is detected in a pipe during in-service inspection, the failure estimation method given in the codes such as ASME Boiler and Pressure Vessel Code Section XI non-mandatory Appendix C or JSME S NA-1-2008 Appendix E-8 can be applied to assess the integrity of the pipe. In the current editions of these codes, the failure estimation method is provided for bending moment and pressure. Torsion load is assumed to be relatively small and is not considered in the method. In this paper, finite element analyses are conducted for 24-inch stainless steel pipe with a circumferential surface crack subjected to the combined bending and torsion moments, focusing on large and pure torsion moments. Based on the analysis results, a prediction method for plastic collapse under the combined loading conditions of bending and torsion is proposed for the entire range of torsion moments.

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