Mechanical Properties of Cold Bend Pipes

2006 ◽  
Author(s):  
M. Sen ◽  
J. J. R. Cheng ◽  
D. W. Murray ◽  
J. Zhou
Keyword(s):  
Yield Strength ◽  
Bauschinger Effect ◽  
Moment Capacity ◽  
Initial Imperfections ◽  
Horizontal Orientation ◽  
Cold Bending ◽  
Pipeline Route ◽  
The Moment ◽  
Cold Bends ◽  
Pipe Joint

Cold bends are frequently required in energy pipelines in order to change the vertical and horizontal orientation of the pipeline route. They are produced by plastically bending a pipe joint in a cold bending machine, by creating a series of uniformly spaced kinks. This procedure acts to reduce the moment capacity and buckling strain of the pipe, and studying the changes in pipe properties caused by cold bending is valuable in assessing the level of this strength reduction. Accordingly, the initial imperfections and material transformations of five full-scale cold bend pipes were assessed in this research program. The imperfections were measured at several locations around the circumference of the specimens, along the entire bend length. It was determined that the distribution of imperfections was similar in shape to a sine function, and their amplitude ranged from 0.3 to 1.0 mm. Tension coupon tests were conducted on material from the intrados, extrados, and virgin material of the specimens. It was revealed that the extrados material exhibited an increase in yield strength due to work hardening, and that the intrados material demonstrated a reduction in yield strength due to the Bauschinger Effect. It was established that the imperfections, and material transformations in the specimens were predominantly unaffected by the kink magnitude or spacing that was employed during the cold bending procedure.

Mechanical Properties of Cold Bend Pipes

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
M. Sen ◽  
J. J. R. Cheng ◽  
D. W. Murray ◽  
J. Zhou
Keyword(s):  
Yield Strength ◽  
Bauschinger Effect ◽  
Strength Reduction ◽  
Moment Capacity ◽  
Initial Imperfections ◽  
Cold Bending ◽  
Pipeline Route ◽  
The Moment ◽  
Cold Bends ◽  
Pipe Joint

Cold bends are frequently required in energy pipelines in order to change the vertical and horizontal orientations of the pipeline route. They are produced by plastically bending a pipe joint in a cold bending machine by creating a series of uniformly spaced incremental bends. This procedure acts to reduce the moment capacity and buckling strain of the pipe, and studying the changes in pipe properties caused by cold bending is valuable in assessing the level of this strength reduction. Accordingly, the initial imperfections and material transformations of five full-scale cold bend pipes were assessed in this research program. The imperfections were measured at several locations around the circumference of the specimens, along the entire bend length. It was determined that the distribution of imperfections was similar in shape to a sine function, and their amplitude ranged from 0.3mmto1.0mm. Tension coupon tests were conducted on the intrados, extrados, and virgin materials of the specimens. It was revealed that the extrados material exhibited an increase in yield strength due to work hardening and that the intrados material demonstrated a reduction in yield strength due to the Bauschinger effect. It was established that the imperfections, and material transformations in the specimens were predominantly unaffected by the incremental-bend magnitude or spacing that was employed during the cold bending procedure.

Changes in Tensile Properties Due to Cold Bending of Line Pipes

2002 ◽  
Author(s):  
Naoki Fukuda ◽  
Hiroshi Yatabe ◽  
Tomoki Masuda ◽  
Masao Toyoda
Keyword(s):  
Tensile Properties ◽  
Analytical Model ◽  
Bauschinger Effect ◽  
Estimation Method ◽  
Tensile Tests ◽  
Full Scale ◽  
Small Scale ◽  
Cold Bending ◽  
Cold Bends ◽  
Good Agreement

The changes in the tensile properties of line pipes due to cold bending were experimentally and analytically investigated. Full-scale cold bending experiments were performed on API X60 and X80 grade line pipes. The reduction in the yield stress of the cold bends due to the Bauschinger effect was approximately 20% and 35% for X60 and X80, respectively. In order to evaluate the changes in the tensile properties of the pipes quantitatively, finite element (FE) analyses and small-scale experiments were conducted. The FE analytical model for simulating the strain distribution at various bending angles was verified with the results of the full-scale experiments. The tensile properties of the cold bends were in good agreement with those of the small-scale experiments using uni-axially prestrained specimens. Based on the present results, an estimation method was proposed for evaluating the distribution of the tensile properties after cold bending with the analytical model using the results of the tensile tests for prestrained specimens.

Flexural Resistance of Steel-Coconut Shell Concrete-Steel Composite Beam with Normal and J-Hook Shear Studs

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
Lakshmi Thangasamy ◽  
◽  
Gunasekaran Kandasamy ◽  
Keyword(s):  
Concrete Strength ◽  
Steel Plates ◽  
Coconut Shell ◽  
Core Material ◽  
River Sand ◽  
Concrete Core ◽  
Conventional Concrete ◽  
Moment Capacity ◽  
The Moment ◽  
Core Concrete

Many researches on double skin sandwich having top and bottom steel plates and in between concrete core called as steel-concrete-steel (SCS) were carried out by them on this SCS type using with different materials. Yet, use of coconut shell concrete (CSC) as a core material on this SCS form construction and their results are very limited. Study investigated to use j-hook shear studs under flexure in the concept of steel-concrete-steel (SCS) in which the core concrete was CSC. To compare the results of CSC, the conventional concrete (CC) was also considered. To study the effect of quarry dust (QD) in its place of river sand (RS) was also taken. Hence four different mixes two without QD and two with QD both in CC and CSC was considered. The problem statement is to examine about partial and fully composite, moment capacity, deflection and ductility properties of CSC used SCS form of construction. Core concrete strength and the j-hook shear studs used are influences the moment carrying capacity of the SCS beams. Use of QD in its place of RS enhances the strength of concrete produced. Deflections predicted theoretically were compared with experimental results. The SCS beams showed good ductility behavior.

scholarly journals Flexural Behavior of Steel Beam Strengthening by Prestressing Strands

2018 ◽  
Vol 7 (4.20) ◽  
pp. 572
Author(s):  
Dr. Mohammed M. Rasheed ◽  
Mr. Ali F. Atshan ◽  
Mr. Kamal Sh. Mahmoud
Keyword(s):  
Reference Beam ◽  
Flexural Behavior ◽  
Radius Of Curvature ◽  
Steel Beams ◽  
Steel Beam ◽  
Bottom Flange ◽  
Moment Capacity ◽  
External Prestressing ◽  
Prestressing Strands ◽  
The Moment

Seven simply supported steel beams were tested to explain the effect of strengthening by external prestressing strands. All of the beams have the same steel section, clear span length and the strengthening samples which implemented by two external prestressing strands. The tested beams are divided into two categories according to existing of external prestressing strands, the first category consists of one steel beam as a reference, while, the second group deals with steel beams strengthening by external prestressing strands and consists of six steel beams divided according to the eccentricity location of prestressing strand with jacking stress (815 MPa). From experimental results, it was found that the moment curvature curves behavior for the tested beams are stiffer and with less ductility than the reference beams and the ultimate moment capacity is increased with increasing the eccentricity location. While, the maximum radius of curvature at bottom flange decreases with increasing the eccentricity location as compare with the reference beam.   

Database of rocking shallow foundation performance: Slow-cyclic and monotonic loading

2020 ◽  
Vol 36 (3) ◽  
pp. 1585-1606 ◽  
Author(s):  
Manouchehr Hakhamaneshi ◽  
Bruce L. Kutter ◽  
Andreas G. Gavras ◽  
Sivapalan Gajan ◽  
Angelos Tsatsis ◽  
...  
Keyword(s):  
Monotonic Loading ◽  
Testing Equipment ◽  
Shallow Foundation ◽  
Moment Capacity ◽  
Wide Range ◽  
Supporting Soil ◽  
Rocking Foundations ◽  
System Properties ◽  
The Moment ◽  
Cyclic Loading Tests

Many physical model tests have examined the performance of rocking foundations during cyclic and seismic loading. These tests varied in model size, testing equipment, superstructure properties, footing shape, supporting soil environment, and loading protocol. “FoRCy, Foundation Rocking database of Cyclic and Monotonic Loading” is a new database (published at https://datacenterhub.org/ ), summarizing the results of monotonic and slow-cyclic loading tests of rocking foundations. The database consists of columns identifying testing equipment and facility, soil, superstructure, and system properties, as well as loading protocol and results. The database contains 456 records (rows), each one being unique in either model configuration or loading amplitude. To illustrate its value, this article shows correlations between (1) settlement, rotation, and factor of safety with respect to bearing capacity and (2) moment and cumulative rotation for shallow footings. Data indicate that the rotation required to mobilize the moment capacity is surprisingly constant (about 0.01 radians) for a wide range of experiments.

Conventional and centrifuge model studies of the moment carrying capacity of short pier foundations in clay

1995 ◽  
Vol 32 (6) ◽  
pp. 976-988 ◽  
Author(s):  
G.J.W. King ◽  
M. Laman
Keyword(s):  
Carrying Capacity ◽  
Three Dimensional ◽  
Model Tests ◽  
Rotational Stability ◽  
Moment Capacity ◽  
Centrifuge Model ◽  
Model Studies ◽  
Saturated Clay ◽  
The Moment ◽  
Centrifuge Model Tests

An experimental investigation into the moment carrying capacity of short rigid pier foundations in saturated clay is described. Scale models of square piers with different breadths and depths were used in both conventional and centrifugal studies. The results show that the relationships between moment and rotation are nonlinear but do not exhibit any peak values, and that moment limits, defined by limiting angular rotations, increase with increases in pier depth and breadth. Empirical equations are derived between moment carrying capacity and pier geometry, for a range of limiting rotations, and a very close fit is demonstrated between the moment–rotation relationships obtained using these equations and the actual data obtained from the model tests. It is shown that, at the same pier rotations, the moment carrying capacities observed in the centrifugal model tests are significantly larger than those in the conventional model tests. Numerical analyses of the prototype geometries were also carried out using a three-dimensional nonlinear finite-element computer program. The results are shown to provide satisfactory agreement with the moment–rotation behaviour and working limits observed in the centrifuge model tests. Thus, even though conventional modelling is usually legitimate for determining the immediate bearing capacity of rigid foundations in saturated clay, their rotational stability is shown to be significantly affected by self-weight stresses. Some of the existing methods for designing short piers subjected to moments are examined and compared with the results from the centrifuge model tests. Key words : pier foundation, clay, moment capacity.

Simulation-Based Tracking of UOE Pipe Yield Strength Considering Various Thickness-to-Diameter Ratios

2018 ◽  
Author(s):  
Jiwoon Yi ◽  
Soo-Chang Kang ◽  
Hyun-Moo Koh ◽  
Jinkyo F. Choo
Keyword(s):  
Yield Strength ◽  
Bauschinger Effect ◽  
Steel Plate ◽  
Tensile Yield Strength ◽  
Forming Process ◽  
Factors Influencing ◽  
Simulation Based ◽  
Plastic Forming ◽  
Final Yield ◽  
Flattening Process

The plastic forming processes involved in the production of UOE pipes alter significantly the yield strength of the original steel plate. Numerous studies indicated that the work hardening and Bauschinger effect are the main factors influencing the alteration of the yield strength. Moreover, apart from the forming process itself, the flattening executed on strips sampled from the formed pipe appears to have also nonnegligible effect on the final yield strength that is used as quality index of the formed pipe. Therefore, this study tracks the yield strength of UOE pipe made of API-X70 steel with various thickness-to-diameter ratios by FE-simulation of the forming and flattening processes so as to identify the factors influencing the yield strength of the UOE pipe. The results show that the flattening process constitutes a critical phase in which steel experiences large loss of its tensile yield strength.

Bridge Girders with Corrugated Webs

2000 ◽  
Vol 1696 (1) ◽  
pp. 162-170 ◽  
Author(s):  
Mohamed Elgaaly ◽  
Anand Seshadri ◽  
Roberto Rodriquez ◽  
Sherif Ibrahim
Keyword(s):  
Moment Capacity ◽  
Design Recommendations ◽  
Plate Girders ◽  
Analytical Results ◽  
Corrugated Webs ◽  
Shear Buckling ◽  
The Moment ◽  
The Cost ◽  
Web Plates ◽  
The Web

In plate girders, the use of corrugated webs permits the use of thin web plates without stiffeners, which reduces the cost of beam fabrication and improves fatigue life. Experimental and analytical studies on the behavior of girders with corrugated webs were conducted that have led to design recommendations. For girders with corrugated webs subjected to shear, it was noted from the experimental as well as the analytical results that failure of the web occurs because of local or global shear buckling, which depends on the corrugation configuration. For girders with corrugated webs subjected to uniform bending, the failure was due to yielding and vertical buckling of the compression flange into the web. The test and analytical results indicate that the web offered negligible contribution to the moment-carrying capacity of the beam, and the ultimate moment capacity may be calculated on the basis of the flange yielding, ignoring any contribution from the web. The behavior of girders with corrugated webs under in-plane compressive edge loads applied directly on the top flange was investigated, and design recommendations are made. Tests to examine the behavior of girders with corrugated webs under repeated loads are few. The results from the available tests are reported and compared with the results from test on conventionally stiffened girders with flat webs.

The Bauschinger Effect in a High-Strength Steel

1966 ◽  
Vol 88 (2) ◽  
pp. 480-488 ◽  
Author(s):  
R. V. Milligan ◽  
W. H. Koo ◽  
T. E. Davidson
Keyword(s):  
Heat Treatment ◽  
Yield Strength ◽  
Strain Hardening ◽  
Uniaxial Tension ◽  
High Strength Steel ◽  
Bauschinger Effect ◽  
High Strength ◽  
The Other ◽  
Material Structure ◽  
Permanent Strain

The object of this work was to evaluate quantitatively the Bauschinger effect in a 4330 modified steel as a function of strength level and structure as derived from variations in heat-treatment. Material having martensitic, pearlitic, and bainitic structures was studied utilizing a uniaxial tension-compression specimen. Various ways of defining the magnitude of the Bauschinger effect are explained. One is a conventional approach as suggested by Welter, the other a technique which takes strain-hardening into account. The results show the Bauschinger effect to be independent of yield strength for three different strength levels of the martensitic material. It is only mildly influenced by material structure and independent of the direction of overstrain. The Bauschinger effect increases with increasing permanent strain up to approximately 2 percent and thereafter remains essentially constant.

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