Beam-Mode Buckling of Buried Pipeline Subjected to Seismic Ground Motion

2012 ◽  
Author(s):  
Masaki Mitsuya ◽  
Takashi Sakanoue ◽  
Hiroyuki Motohashi
Keyword(s):  
Finite Element ◽  
Ground Motion ◽  
Critical Strain ◽  
Peak Load ◽  
Earthquake Resistance ◽  
Past Study ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Seismic Ground Motion ◽  
Beam Mode

During seismic events, buried pipelines are subjected to deformation by seismic ground motion. In such cases, it is important to ensure the integrity of the pipeline. Both beam-mode and shell-mode buckling may occur in the event of compressive loading induced by seismic ground motion. In this study, the beam-mode buckling of a buried pipeline that occurred after the 2007 Niigataken Chuetsu-oki earthquake in Japan is investigated. A simple formula for estimating the critical strain, which is the strain at the peak load, is derived, and the formula is validated by finite-element analysis. In the formula, the critical strain increases with the pipeline diameter and hardness of the surrounding soil. By comparing the critical strain derived in this study for beam-mode buckling with the critical strain derived in a past study for shell-mode buckling, the formula facilitates the selection of the mode to be considered for evaluating the earthquake resistance of a pipeline. In addition to the critical strain, a method to estimate the deformation caused by seismic ground motion is proposed; the method can be used to evaluate the earthquake resistance of buried pipelines. This method uses finite-element analyses, and the soil–pipe interaction is considered. This method is used to reproduce the actual beam-mode buckling observed after the Niigataken Chuetsu-oki earthquake, and the earthquake resistance of a buried pipeline with general properties is evaluated as an example.

Beam-Mode Buckling of Buried Pipeline Subjected to Seismic Ground Motion

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Masaki Mitsuya ◽  
Takashi Sakanoue ◽  
Hiroyuki Motohashi
Keyword(s):  
Finite Element ◽  
Ground Motion ◽  
Critical Strain ◽  
Earthquake Resistance ◽  
Past Study ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Seismic Ground Motion ◽  
Critical Buckling Strain ◽  
Beam Mode

During seismic events, buried pipelines are subjected to deformation by seismic ground motion. In such cases, it is important to ensure the integrity of the pipeline. Both beam-mode and shell-mode buckling may occur in the event of compressive loading induced by seismic ground motion. In this study, the beam-mode buckling of a buried pipeline that occurred after the 2007 Niigataken Chuetsu-oki earthquake in Japan is investigated. A simple formula for estimating the critical buckling strain, which is the strain at the peak load, is derived, and the formula is validated by finite-element analysis. In the formula, the critical buckling strain increases with the pipeline diameter and hardness of the surrounding soil. By comparing the critical strain derived in this study for beam-mode buckling with the critical strain derived in a past study for shell-mode buckling, the formula facilitates the selection of the mode to be considered for evaluating the earthquake resistance of a pipeline. In addition to the critical buckling strain, a method to estimate the deformation caused by seismic ground motion is proposed; the method can be used to evaluate the earthquake resistance of buried pipelines. This method uses finite-element analyses, and the soil–pipe interaction is considered. This method is used to reproduce the actual beam-mode buckling observed after the Niigataken Chuetsu-oki earthquake, and the earthquake resistance of a buried pipeline with general properties is evaluated as an example.

Comparison of Buried Pipeline Crossing Assessments Using API RP 1102, Analytical Method and Finite Element Approach

2020 ◽  
Author(s):  
Nikhil Joshi ◽  
Pritha Ghosh ◽  
Jonathan Brewer ◽  
Lawrence Matta
Keyword(s):  
Finite Element ◽  
Analytical Method ◽  
Rapid Assessment ◽  
Buried Pipeline ◽  
The Finite Element Method ◽  
Buried Pipelines ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Element Approach ◽  
Multiple Loading

Abstract API RP 1102 provides a method to calculate stresses in buried pipelines due to surface loads resulting from the encroachment of roads and railroads. The API RP 1102 approach is commonly used in the industry, and widely available software allows for quick and easy implementation. However, the approach has several limitations on when it can be used, one of which is that it is limited to pipelines crossing as near to 90° (perpendicular crossing) as practicable. In no case can the crossing be less than 30° . In this paper, the stresses in the buried pipeline under standard highway vehicular loading calculated using the API RP 1102 method are compared with the results of two other methods; an analytical method that accounts for longitudinal and circumferential through wall bending effects, and the finite element method. The benefit of the alternate analytical method is that it is not subject to the limitations of API RP 1102 on crossing alignment or depth. However, this method is still subject to the limitation that the pipeline is straight and at a uniform depth. The fact that it is analytical in nature allows for rapid assessment of a number of pipes and load configurations. The finite element analysis using a 3D soil box approach offers the greatest flexibility in that pipes with bends or appurtenances can be assessed. However, this approach is time consuming and difficult to apply to multiple loading scenarios. Pipeline crossings between 0° (parallel) and 90° (perpendicular) are evaluated in the assessment reported here, even though these are beyond the scope of API RP 1102. A comparison across the three methods will provide a means to evaluate the level of conservatism, if any, in the API RP 1102 calculation for crossing between 30° and 90° . It also provides a rationale to evaluate whether the API RP 1102 calculation can potentially be extended for 0° (parallel) crossings.

Theoretical Formula for Determining the Maximum Straight Length of a Buried Pipeline That Can Prevent Seismic Buckling

2020 ◽  
Author(s):  
Shoma Onuki ◽  
Masaki Mitsuya
Keyword(s):  
Ground Motion ◽  
Design Method ◽  
Axial Stress ◽  
Theoretical Formula ◽  
Axial Loads ◽  
Buried Pipelines ◽  
Straight Pipe ◽  
Element Analysis ◽  
Pipe Length ◽  
Seismic Ground Motion

Abstract Buried pipelines must exhibit the appropriate seismic performance to be applied practically and securely. One major pipeline failure mode is buckling caused by seismic ground motion. Buckling typically occurs in straight pipeline sections because seismic axial loads mainly accumulate along straight lines. The design method for defining a maximum straight pipe length to decrease seismic axial loads is known to be effective in preventing buckling. Based on this previous knowledge, this study develops a theoretical formula for estimating the maximum straight length to prevent buckling. The proposed formula is derived using an analytical pipeline model with soil springs under seismic ground motion. Using this analytical model, the seismic loads which are applied to the straight pipe and the pipe connected to the straight pipe are calculated respectively. Then, the formula for the maximum straight length is derived by calculating the straight pipe length where the axial stress in the straight pipe is equal to the yield stress. The proposed formula is validated through finite element analysis. The maximum straight lengths obtained by the theoretical formula are in good agreement with FEM or shorter, thus providing a margin of safety. This work can be useful in designing buried pipelines to prevent buckling failures, thus enabling safer and more viable pipelines.

Comprehensive Seismic Response Analysis for Estimating the Seismic Behavior of Buried Pipelines Enhanced by Three-Dimensional Dynamic Finite Element Analysis of Ground Motion and Soil Amplification

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Tsuyoshi Ichimura ◽  
Kohei Fujita ◽  
Pher Errol Quinay ◽  
Muneo Hori ◽  
Takashi Sakanoue ◽  
...  
Keyword(s):  
Finite Element ◽  
Ground Motion ◽  
Three Dimensional ◽  
Element Model ◽  
Response Analysis ◽  
Soil Amplification ◽  
Buried Pipelines ◽  
Seismic Input ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

We demonstrate a comprehensive earthquake response analysis method for improving the seismic input force estimation of buried pipelines by combining ground motion and soil amplification analyses. Using this method, the seismic input force of an actual pipeline was estimated and its seismic performance was checked for a largest assumed seismic fault scenario. Three-dimensional inhomogeneity of ground and surface topography is known to greatly affect the results of ground motion and soil amplification analyses. To consider these effects, a linear wave propagation analysis using a 10 × 109 degree-of-freedom three-dimensional finite element model was conducted for the ground motion analysis, and a nonlinear wave propagation analysis using an 80 × 106 degree-of-freedom three-dimensional finite element model was conducted for the soil amplification analysis. The application example showed that three-dimensional inhomogeneity of ground and surface topology caused complex seismic input forces to buried pipelines, and demonstrated the effectiveness of the comprehensive seismic analysis method proposed in this study.

scholarly journals Experimental and Numerical Study on the Strain Behavior of Buried Pipelines Subjected to an Impact Load

2019 ◽  
Vol 9 (16) ◽  
pp. 3284 ◽  
Author(s):  
Feifei Dong ◽  
Xuemeng Bie ◽  
Jiangping Tian ◽  
Xiangdong Xie ◽  
GuoFeng Du
Keyword(s):  
Finite Element ◽  
Impact Load ◽  
Numerical Study ◽  
Scale Model ◽  
Peak Strain ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Strain Behavior ◽  
Geological Conditions ◽  
The Impact

Long-distance oil and gas pipelines are inevitably impacted by rockfalls during geologic hazards such as mud-rock flow and landslides, which have a serious effect on the safe operation of pipelines. In view of this, an experimental and numerical study on the strain behavior of buried pipelines under the impact load of rockfall was developed. The impact load exerted on the soil, and the strains of buried pipeline caused by the impact load were theoretically derived. A scale model experiment was conducted using a self-designed soil-box to simulate the complex geological conditions of the buried pipeline. The simulation model of hammer–soil–pipeline was established to investigate the dynamic response of the buried pipeline. Based on the theoretical, experimental, and finite element analysis (FEA) results, the overall strain behavior of the buried pipeline was obtained and the effects of parameters on the strain developments of the pipelines were analyzed. Research results show that the theoretical calculation results of the impact load and the peak strain were in good agreement with the experimental and FEA results, which indicates that the mathematical formula and the finite element models are accurate for the prediction of pipeline response under the impact load. In addition, decreasing the diameter, as well as increasing the wall thickness of the pipeline and the buried depth above the pipeline, could improve the ability of the pipeline to resist the impact load. These results could provide a reference for seismic design of pipelines in engineering.

scholarly journals Analysis and Evaluation on Residual Strength of Pipelines with Internal Corrosion Defects in Seasonal Frozen Soil Region

2021 ◽  
Vol 11 (24) ◽  
pp. 12141
Author(s):  
Xiaoli Li ◽  
Guitao Chen ◽  
Xiaoyan Liu ◽  
Jing Ji ◽  
Lianfu Han
Keyword(s):  
Finite Element ◽  
Residual Strength ◽  
Orthogonal Design ◽  
Equivalent Stress ◽  
Frozen Soil ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Internal Corrosion ◽  
Mechanical Coupling ◽  
Corrosion Defects

In order to study the residual strength of buried pipelines with internal corrosion defects in seasonally frozen soil regions, we established a thermo-mechanical coupling model of a buried pipeline under differential frost heave by using the finite element elastoplastic analysis method. The material nonlinearity and geometric nonlinearity were considered as the basis of analysis. Firstly, the location of the maximum Mises equivalent stress in the inner wall of the buried non-corroded pipeline was determined. Furthermore, the residual strength of the buried pipeline with corrosion defects and the stress state of internal corrosion area in the pipeline under different defect parameters was analyzed by the orthogonal design method. Based on the data results of the finite element simulation calculation, the prediction formula of residual strength of buried pipelines with internal corrosion defects was obtained by SPSS (Statistical Product and Service Solutions) fitting. The prediction results were analyzed in comparison with the evaluation results of B31G, DNV RP-F101 and the experimental data of hydraulic blasting. The rationality of the finite element model and the accuracy of the fitting formula were verified. The results show that the effect degree of main factors on residual strength was in order of corrosion depth, corrosion length, and corrosion width. when the corrosion length exceeds 600 mm, which affects the influence degree of residual strength will gradually decrease. the prediction error of the fitting formula is small and the distribution is uniform, it can meet the prediction requirements of failure pressure of buried pipelines with internal corrosion defects in seasonally frozen soil regions. This method may provide some useful theoretical reference for the simulation real-time monitoring and safety analysis in the pipeline operation stage.

Three-Dimensional Nonlinear Seismic Ground Response Analysis of Local Site Effects for Estimating Seismic Behavior of Buried Pipelines

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Tsuyoshi Ichimura ◽  
Kohei Fujita ◽  
Muneo Hori ◽  
Takashi Sakanoue ◽  
Ryo Hamanaka
Keyword(s):  
Ground Motion ◽  
Large Scale ◽  
Three Dimensional ◽  
Response Analysis ◽  
Buried Pipelines ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Seismic Ground Motion ◽  
Local Site ◽  
Seismic Ground Response

Damage to buried pipelines caused by local amplification of seismic ground motion in highly nonuniform grounds is not yet fully understood. The development of methods to evaluate the amplification of ground motion in complex ground structures is thus desirable. Here, we report large-scale nonlinear seismic ground response analysis using a 3D nonlinear finite element method (FEM) and attempt to reproduce observed seismic ground motion. We also discuss the strain amplification processes and their effects on buried pipelines in detail. The findings are expected to aid in improving the seismic resistance of buried pipelines.

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