Bending Capacity of Girth-Welded Pipes

2005 ◽  
Author(s):  
Enrico Torselletti ◽  
Luigino Vitali ◽  
Roberto Bruschi
Keyword(s):  
Longitudinal Strain ◽  
Local Buckling ◽  
Bending Moment ◽  
Experimental Tests ◽  
Reduction Factor ◽  
Fe Model ◽  
Moment Capacity ◽  
3 Dimensional ◽  
Bending Capacity ◽  
Pipe Bending

In the last ten years, several studies were completed with the aim to define a design format for the local buckling of pipes subjected to differential pressure, axial load and bending moment. Experimental tests were carried out and simplified analytical solutions were developed in order to predict the pipe bending moment capacity and the associated level of deformation. Standard finite element (FE) structural codes, such as ABAQUS, ADINA, ANSYS, etc., were and are used as a “numerical testing laboratory”, where the model is suitably calibrated to few experimental tests. The outcomes of these research efforts were implemented in the design equations enclosed in international design rules, as DNV OS-F101. The local buckling design formats, included in these rules, give the limit bending moment and associated longitudinal strain as a function of the relevant parameters. The effect of the girth weld is introduced with a reduction factor only for what regards the strain at limit bending moment. This paper addresses the effects of the presence of the girth weld on both limit bending moment and corresponding compressive longitudinal strain. A 3-dimensional (3D) FE model developed in ABAQUS has been developed to perform a parametric analysis. The FE model results are shown to compare reasonably well with full scale experiments performed for on-shore pipelines. The limit bending moment is reduced by the weld misalignment and this reduction is also dependent on both internal pressure load and linepipe material mechanical strength. The FE results are compared with the limit bending moment calculated with DNV OS-F101.

Parametric Study of Compound Cold-Formed Steel Sections as Flexural Members

2015 ◽  
Vol 74 (4) ◽  
Author(s):  
Ker Shin Mu ◽  
Poi Ngian Shek ◽  
Arizu Sulaiman ◽  
Boon Cheik Tan
Keyword(s):  
Parametric Study ◽  
Local Buckling ◽  
Bending Moment ◽  
Steel Plates ◽  
Pure Bending ◽  
Moment Capacity ◽  
Flexural Members ◽  
Bending Capacity ◽  
Steel Sections ◽  
Cold Formed Steel

This paper presents a parametric study on compound cold-formed steel sections as flexural members. The compound members are used to sustain higher load and solve the problems of local buckling and lateral torsional buckling. The aim of this study is to investigate the strength of compound cold-formed steel section subjected to pure bending. Moment capacity of the compound section is calculated in accordance to Eurocode 3. The compound cold-formed steel sections proposed in this study are made up of two cold-formed steel C-section and hot-rolled plates. Steel plates with thickness of 3 mm to 8 mm are added to the cold-formed double C-section with the purpose to increase the bending capacity. From the comparison, moment capacity of compound sections give higher value as compared to cold-formed steel C-section with the comparison ratios range between 1.15 and 3.30. Results from the study show that compound cold-formed steel sections able to enhance the strength in resisting pure bending by adding steel plate at the flanges and web of the section. On the other hand, finite element modeling using ANSYS is carried out on two of the selected compound cold-formed steel sections and the results show good agreement with analytical results.

Strength and Deformation Capacity of Corroded Pipes: The Joint Industry Project

2013 ◽  
Author(s):  
Erik Levold ◽  
Andrea Restelli ◽  
Lorenzo Marchionni ◽  
Caterina Molinari ◽  
Luigino Vitali
Keyword(s):  
Failure Modes ◽  
State Of The Art ◽  
Local Buckling ◽  
Bending Moment ◽  
External Pressure ◽  
Fe Model ◽  
Deformation Capacity ◽  
Offshore Pipelines ◽  
Strength And Deformation ◽  
Bending Loading

Considering the future development for offshore pipelines, moving towards difficult operating condition and deep/ultra-deep water applications, there is the need to understand the failure mechanisms and better quantify the strength and deformation capacity of corroded pipelines considering the relevant failure modes (collapse, local buckling under internal and external pressure, fracture / plastic collapse etc.). A Joint Industry Project sponsored by ENI E&P and Statoil has been launched with the objective to quantify and assess the strength and deformation capacity of corroded pipes in presence of internal overpressure and axial/bending loading. In this paper: • The State-of-the-Art on strength and deformation capacity of corroded pipes is presented; • The full-scale laboratory tests on corroded pipes under bending moment dominated load conditions, performed at C-FER facilities, are shown together with the calibrated ABAQUS FE Model; • The results of the ABAQUS FEM parametric study are presented.

Study of Bending Capacity of an HPHT CRA-Lined Seamless Pipeline

2014 ◽  
Author(s):  
Cyprian Gil ◽  
Knut Tørnes ◽  
Per Damsleth
Keyword(s):  
Internal Pressure ◽  
Strain Localization ◽  
Local Buckling ◽  
Bending Moment ◽  
Design Criteria ◽  
Design Codes ◽  
Moment Capacity ◽  
Wide Range ◽  
Global Buckling ◽  
The Moment

A study has been performed to better understand ultimate bending moment and strain capacities of pipelines in relation to criteria defined in the design codes. An 18″ HPHT flowline was designed to undergo global buckling on uneven seabed and to resist trawl gear interference. The high temperature (155 degC) and pressure (300 bar) posed considerable design challenges for material selection and design criteria. A CRA-lined X60 CMn pipeline was selected for the project. The pipeline was of seamless manufacture for which the stress/strain characteristics are subject to the effect of Lüders bands. The DNV-OS-F101 code covers a wide range of D/t but does not specifically address Lüder’s material behaviour which could significantly reduce the bending moment capacity of pipe. The global buckling and trawl pull-over FE analysis results indicated the pipe was highly utilized, requiring excessive amounts of seabed intervention at great cost to meet the DNV LCC criteria. Detailed FE simulation of limit states for local buckling and strain localization of a 3D solid element pipe model was performed, with both Roundhouse and Lüders material properties, to investigate pipe capacity in relation to that stipulated by the design codes. The pipe moment capacity was established by obtaining the moment curvature relationship by bending the local pipe section subject to internal pressure until the maximum resistance was reached. Imperfections were introduced to initiate local buckling at the desired location. To determine strain concentration factors and strain localization, the effects of thickness changes and weld misalignment were also studied. The DNV OS-F101 LCC moment criterion formulation computes a decreasing moment capacity for increasing internal pressure. It has been suggested in the literature that this is correct for higher D/t but the criterion may be conservative for pipes with lower D/t. The combination of Lüders material with low D/t is not specifically addressed by any design code. Clarification of these aspects will provide a better understanding of the risk of failure for highly utilized seamless pipelines and allow for modified design criteria that will reduce seabed intervention costs. The results of the study showed that a higher bending moment criterion and associated strain criterion could be adopted for the design that allows for the higher initial strain caused by Lüder’s plateau. The ultimate bending moment capacity of low D/t pipe with Lüder’s material was found to be similar to that of Roundhouse material due to work hardening. In addition, it was demonstrated that the potential strength of the CRA liner could enhance the moment capacity of the seamless pipe.

Bending Capacity of Pipes Subject to Point Loads

2003 ◽  
Author(s):  
Luigino Vitali ◽  
Enrico Torselletti ◽  
Maurizio Spinazze` ◽  
Roberto Bruschi ◽  
Luca Brunetto
Keyword(s):  
Relevant Literature ◽  
Experimental Tests ◽  
Fe Model ◽  
Load History ◽  
Load Combination ◽  
Sea Bottom ◽  
Cold Bending ◽  
Strength Capacity ◽  
Bending Capacity ◽  
Load Effects

Large bending moments may develop on free pipeline lengths in the proximity of pipe sections subject to a local force. Sometimes the local force is such as to cause a partial loss of the sectional strength capacity of the pipe. This is the case of a pipeline plastically bent over the stinger of an S-lay barge, or of a pipeline laid on the sea bottom and hooked by an anchor or trawling gear, or of a pipe subject to cold bending when it is made to cope with sharp bottom roughness etc. In such conditions, the limit bending capacity of the pipe section, subject to local load effects, is significantly influenced. This aspect is not covered by international design codes and the scope of this paper is to show that, in some circumstances, it must be taken into due account. In this paper: • The relevant literature as concerns experimental tests, interpretative models, analysis methodologies and design approaches, is reviewed; • The FE model and post-processing, purpose-developed to investigate the interaction between local and global effect, are discussed; • The findings of FE analyses, in particular the effect of load combination, load history, pipe geometric characteristics and loading — magnitude and shape of the contact area, are presented. It is concluded that the limit bending capacity reduces significantly when local effects are such as to develop stresses on the pipe wall that affect the activation of the sectional buckling mechanism.

scholarly journals Ultimate flexural strength of prestressed concrete beams: validation and model error evaluation

2018 ◽  
Vol 11 (2) ◽  
pp. 307-330
Author(s):  
M. W. MOURA ◽  
M. V. REAL ◽  
D. D. LORIGGIO
Keyword(s):  
Cross Section ◽  
Prestressed Concrete ◽  
Concrete Beams ◽  
Bending Moment ◽  
Experimental Tests ◽  
Error Evaluation ◽  
Moment Capacity ◽  
Percentage Difference ◽  
The Cross ◽  
Concrete Elements

Abstract In this work a computational model is presented to evaluate the ultimate bending moment capacity of the cross section of reinforced and prestressed concrete beams. The computational routines follow the requirements of NBR 6118: 2014. This model is validated by comparing the results obtained with forty-one experimental tests found in the international bibliography. It is shown that the model is very simple, fast and reaches results very close to the experimental ones, with percentage difference of the order of 5%. This tool proved to be a great ally in the structural analysis of reinforced and prestressed concrete elements, besides it is a simplified alternative to obtain the cross section ultimate bending moment.

Bending Capacity of Corroded Pipeline Subjected to Internal Pressure and Axial Loadings

2018 ◽  
Author(s):  
Jie Gao ◽  
Zengli Peng ◽  
Xin Li ◽  
Jing Zhou ◽  
Wenxing Zhou
Keyword(s):  
Internal Pressure ◽  
Local Buckling ◽  
Compressive Force ◽  
Bending Moment ◽  
Corrosive Media ◽  
Element Analysis ◽  
Axial Compressive Force ◽  
Offshore Pipelines ◽  
Bending Capacity ◽  
The Moment

Offshore pipelines operating in a harsh environment are usually subjected to combinations of bending moment and axial loadings in addition to internal pressure. Due to the corrosive media transported in the pipelines and corrosive substances within seawater and soil outside the pipelines, local corrosion defects will generate on the pipeline’s inner and outer walls, reducing its ultimate bearing capacity. This paper presents a series of full-scale failure tests and nonlinear finite element analysis (FEA) to study the bending capacity and failure mode of corroded pipelines with outside locally-thinned-areas (LTAs) subjected to combinations of internal pressure, axial compressive force and bending moment. The LTAs are loaded in compression to simulate corrosion. Material tests of API 5L X56 seamless pipe steel were conducted and the stress-strain relationship was obtained. FEA results of the moment versus curvature relation, bending capacity and local buckling behavior of each specimen model matched the experimental results very well, validating the accuracy of this simulation. Additional FEA is then performed to investigate the effect of corrosion geometric parameters, such as corrosion depth, corrosion width, and corrosion length, on the ultimate moment. Among them, the width is of the greatest impact, followed by is the depth, the length impact can be ignored.

scholarly journals Pengaruh Penambahan Tulangan Tekan Terhadap Momen Kapasitas Lentur dan Daktilitas Balok

2020 ◽  
Vol 3 (2) ◽  
pp. 97-106
Author(s):  
Jaya Permana ◽  
M. Muhtaris ◽  
Eka Susanti ◽  
Yanisfa Yanisfa
Keyword(s):  
Concrete Beams ◽  
Bending Moment ◽  
Strength Testing ◽  
Flexural Capacity ◽  
Moment Capacity ◽  
Know How ◽  
Beam Design ◽  
Bending Capacity ◽  
The Moment ◽  
Reinforcement Beam

Double reinforcement beam design, increasing the compressive reinforcement can increase the flexural capacity moment and ductility of concrete beams. This helps planners to improve flexural capacity moment with minimal dimensions, that are still acceptable in terms of aesthetics. The purpose of this study is to know how much influence the increasing compressive reinforcement can increase the flexural capacity moment and ductility of concrete beams. Experimental research with beam specimens 20x20x60 cm, 2D16 tensile reinforcement, fc’ 25 mpa and fy 320 mpa. With a ratio of compressive reinforcement to tensile reinforcement of 0.14; 0.25 and 0.59. Flexural strength testing uses flexible loading with a roll-pined joint. The process of load reading is yield phase until ultimate phase. The results of the analysis show an uses of increasing compressive reinforcement can increase the moment of flexural capacity and ductility. The addition of compressive reinforcement reached 25% from tensile reinforcement, can increase the moment of bending capacity by 4.47%, but uses compressive reinforcement reached 50% of tensile reinforcement, only increasing the bending moment capacity of 1.43%. For ductility, uses compressive reinforcement reaches 25% from tensile reinforcement, can increase ductility by 19.73% and an increase of 26.17% by adding compressive reinforcement up to 50% of tensile reinforcement. From these results it appears that the more improvements added, the more the ductility increases and the less the moment the flexural capacity increases.

Ultimate Bending Capacity and Buckling of Pressurized 90 deg Steel Elbows

2005 ◽  
Vol 128 (3) ◽  
pp. 348-356 ◽  
Author(s):  
S. A. Karamanos ◽  
D. Tsouvalas ◽  
A. M. Gresnigt
Keyword(s):  
Local Buckling ◽  
Bending Moment ◽  
General Purpose ◽  
Moderate Pressure ◽  
Cross Sectional ◽  
Finite Element Program ◽  
Shell Elements ◽  
Out Of Plane ◽  
Bending Capacity ◽  
Plane Bending

The paper examines the nonlinear elastic-plastic response of internally pressurized 90 deg pipe elbows under in-plane and out-of-plane bending. Nonlinear shell elements from a general-purpose finite element program are employed to model the inelastic response of steel elbows and the adjacent straight parts. The numerical results are successfully compared with real-scale experimental measurements. The paper also presents a parametric study, aimed at investigating the effects of diameter-to-thickness ratio and moderate pressure levels on the ultimate bending capacity of 90 deg elbows, focusing on the failure mode (local buckling or cross-sectional flattening) and the maximum bending moment. Special attention is given to the response of 90 deg elbows under out-of-plane bending moments.

Local and Global Stability of I Steel Members with Tapered Web via Advanced Nonlinear Analysis

2013 ◽  
Vol 710 ◽  
pp. 372-375
Author(s):  
Ionel Mircea Cristutiu ◽  
Adrian Ioan Dogariu
Keyword(s):  
Local Buckling ◽  
Bending Moment ◽  
Experimental Tests ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Beam Columns ◽  
Steel Members ◽  
Out Of Plane ◽  
Current Design ◽  
Partially Restrained

Steel structural elements with variable cross section, made of welded plates, are largely used in the construction industry for both beams and columns in accordance with the stress and stiffness demand in the structure. These types of elements are mainly used for the design of singles storey frames with pitched roof rafters and pinned column base. Although they are partially restrained against out of plane buckling by side-rails and roof purlins cooperating with sheeting, in current design practice it is quite difficult to evaluate their influence. Present paper deals with nonlinear elastic-plastic analysis of tapered beam-columns, parts of portal frames, subjected to both bending moment and compressive axial force. Failure of such members may occur by in-plane bending, local buckling and combination between these two, for members with low non-dimensional slenderness. Numerical results will be compared with experimental tests, obtained for a relevant number of specimens, in order to check the reliability of the numerically determined ultimate capacity of the elements. The influence of both lateral and torsional restraints applied on the beam-column will also be discussed.

scholarly journals Efisiensi Kapasitas Lentur Beton Pracetak (U-Ditch) Dengan Model Dinding Corrugated

2020 ◽  
Vol 14 (2) ◽  
pp. 99-103
Author(s):  
Erwin Syaiful Wagola ◽  
◽  
Muhammad Tharik Kemal ◽  
Keyword(s):  
Standard Method ◽  
Bending Moment ◽  
Crack Pattern ◽  
Flexural Behavior ◽  
Normal Type ◽  
Flexural Capacity ◽  
Moment Capacity ◽  
Structural Wall ◽  
International Standard ◽  
Bending Capacity

This study discusses to analyze the flexural capacity and efficiency of the corrugated U-Ditch type with dimensions of 50x50 cm to the normal U-Ditch type. In this research using JIS (Japan International Standard) method for The U-Ditch Corrugated test. The results showed that the flexural behavior of the Normal Type U-Ditch is linear to collapse with a crack pattern occurring on the U-Ditch wall. The bending of the U-Ditch Corrugated type tends to be linear until it collapses with a crack pattern occurring in the structural wall. The magnitude of the bending moment capacity for the normal type is 9.11 kN.m and capacity of the U-Ditch corrugated type is 8.05 kN. m where the efficiency of bending capacity is 98%.

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