Will a buried composite pipeline system fail at its joints under the effects of overburden soil, pipe operating pressurization, and traffic loads?

2020 ◽  
Vol 54 (18) ◽  
pp. 2433-2448
Author(s):  
Kwong Ming Tse ◽  
William Toh ◽  
Long Bin Tan ◽  
Heow Pueh Lee ◽  
Vincent Beng Chye Tan
Keyword(s):  
Pipeline System ◽  
Buried Pipeline ◽  
Pipe Failure ◽  
Traffic Loading ◽  
Traffic Loads ◽  
Reinforced Plastic ◽  
Overburden Soil ◽  
Predominant Factor ◽  
Pipe Joints ◽  
Soil Pipe

In real world applications, buried pipelines span across great lengths. It is inevitable that certain sections of a buried pipeline experience external loads in addition to top soil overburden, such as weights of aboveground buildings and traffic loads located directly above these sections. The present study investigated the effects of overburden soil, pipe internal pressurization, and traffic loads on fiber-reinforced plastic pipelines at various pipe sections with particular emphasis on pipe joints using finite element method. This study includes realistic modeling of traffic loading on service road running across a buried pipeline system, consisting of straight, bent, and joint sections. Our results also revealed that surcharge loading might not be a predominant factor in pipe failure or leakage issues as compared to the cyclic pipe internal pressurization. Moreover, it was also confirmed in our study that the pipe joint remained as the most critical region for pipe failure or leakage issues.

Experimental Study on Orbital Drilling Force and Machining Quality of CFRP

2014 ◽  
Vol 1061-1062 ◽  
pp. 542-549
Author(s):  
Xue Mei Chen ◽  
Qing Liang Chen ◽  
Feng Tao He ◽  
Xi Feng Fan
Keyword(s):  
Thrust Force ◽  
Orthogonal Experiment ◽  
Cutting Parameters ◽  
Force Model ◽  
Drilling Process ◽  
Drilling Force ◽  
Drilling Tool ◽  
Orbital Drilling ◽  
Reinforced Plastic ◽  
Predominant Factor

This paper aims to investigate orbital drilling process in carbon-fiber reinforced plastic (CFRP) composites with multi-point orbital drilling tool based on the robot automatic drilling system. One orthogonal experiment has been carried out, and the cutting forces of different parameters were measured online by dynamometer. Furthermore, the cutting force model was established through regression analysis, and the impacts of cutting parameters on thrust force were deeply analyzed. In addition, delamination and tear defects were inspected respectively, and the relationship between thrust force and delamination and tear was discussed. Our results indicate that thrust force increased with the increasing feed rate and axial feed depth, while decreased with the increasing spindle speed. Axial feed depth was found as the predominant factor on thrust force and defects. At last, the cutting parameters was optimized and then thrust force decreased more than 26% with almost none tear and burr around the hole, which indicates a better machine quality.

scholarly journals Study on Vibration of Reciprocating Pump Pipelines Based on Pressure Pulsation Theory

2017 ◽  
Author(s):  
Hongfang Lu
Keyword(s):  
Numerical Simulation ◽  
Vibration Amplitude ◽  
Pressure Pulsation ◽  
Fluid Pressure ◽  
Simulation Method ◽  
Pipeline System ◽  
Beam Model ◽  
Pipe Failure ◽  
Periodic Movement ◽  
Reciprocating Pump

Due to the periodic movement of the piston in the reciprocating pump, the fluid will cause pressure pulsation, and the vibration of the pipeline will lead to instrument distortion, pipe failure and equipment damage. Therefore, it is necessary to study the vibration phenomena of the reciprocating pump pipeline based on the pressure pulsation theory. This paper starts from the reciprocating pump pipe pressure pulsation caused by fluid, pressure pulsation in the pipeline and the excited force is calculated under the action of the reciprocating pump. Then, the numerical simulation model is established based on the pipe beam model, and the rationality of the numerical simulation method is verified by the indoor experiment. Finally, a case study is taken as an example to analyze the vibration law of the pipeline system, and proposed the stress reduction and vibration reduction measures. The main conclusions are drawn from the analysis: (1) Excited force is produced in the bend or tee joint, and it can also influence the straight pipe in different levels; (2) In this pipeline system, the pump discharge pipe has a larger vibration amplitude and lower natural frequency; (3) The vibration amplitude increases with the pipe thermal stress, and when the oil temperature is higher than 85°C, it had a greater influence on the vertical vibration amplitude of the pipe.

Uncertainty Quantification of Wall Thickness of Onshore Gas Transmission Pipelines

2020 ◽  
Author(s):  
Wenxing W. Zhou ◽  
Ji Bao
Keyword(s):  
Wall Thickness ◽  
Pipe Wall ◽  
Metal Loss ◽  
Pipeline System ◽  
Pipe Wall Thickness ◽  
Reliability Based Design ◽  
Wide Range ◽  
Pipe Joints ◽  
Welded Pipe ◽  
Transmission Pipelines

The present study quantifies probabilistic characteristics of the wall thickness of welded pipe joints in onshore gas transmission pipelines based on about 5900 field-measured wall thicknesses collected from a pipeline system in Canada. The collected data cover a wide range of the pipe nominal wall thickness, from 3.18 to 16.67 mm. By considering the measurement error involved in the collected wall thickness data, statistical analyses indicate that the actual-over-nominal wall thickness ratio (AONR) follows a normal distribution with a mean of 1.01 and a coefficient of variation (COV) ranging from 1.6 to 2.2% depending on the nominal pipe wall thickness. The implications of the developed AONR statistics for the reliability analysis of corroded pipe joints are investigated. This study provides key input to the reliability-based design and assessment of pipelines with respect to various threats such as metal-loss corrosion and stress corrosion cracking.

The effects of traffic loads on drinking water main failure frequencies in the Netherlands

2016 ◽  
Vol 11 (3) ◽  
pp. 524-530
Author(s):  
A. Moerman ◽  
B. A. Wols ◽  
R. Diemel
Keyword(s):  
Drinking Water ◽  
Asset Management ◽  
Pipe Material ◽  
Regression Analyses ◽  
Pipe Failure ◽  
Water Pipes ◽  
Traffic Loads ◽  
Diameter Pipe ◽  
Water Companies ◽  
External Loads

Understanding pipe failure is essential for effective asset management. Buried drinking water pipes are exposed to several types of external loads, e.g. soil weight, loads due to soil settling differences and traffic loads. The hypothesis that traffic loads positively affects the number of failures was statistically tested. For three out of four studied water companies significant higher failure frequencies than average were found at road crossings. Frequencies equal to average were found for pipes which are installed under other road sections. Frequencies higher than average–but not statistically significant–were found around speed bumps. The results of the multiple regression analyses show that the overall contribution of the parameter ‘road classification’ to pipe failure is small compared to the influence of pipe diameter, pipe material and year of installation.

Financial Risk Analysis for Crude Oil Buried Pipeline System

2019 ◽  
pp. 307-328
Author(s):  
Narendra Rajaram Gade ◽  
Ravi Dhondiba Suryavanshi ◽  
Pravin Suryawanshi ◽  
Arati Barik ◽  
Rahul Bhalerao
Keyword(s):  
Continuous Flow ◽  
Financial Risk ◽  
Pipeline System ◽  
Buried Pipeline ◽  
Repair Cost ◽  
Engineering Software ◽  
Financial Gain ◽  
Flow Through ◽  
The Individual ◽  
Financial Losses

Buried pipelines are the most lucrative deal in today's transportation for transmission of vital fluids and liquids. However, with the advent of disasters, the continuous flow through these indispensable systems gets hampered. The purpose of this chapter is twofold: one is to develop a simulation approach to capturing the effect of risk/disaster due to unforeseen events on buried pipeline, and the second is to gauge financial losses due to such uncertain events. A simulation model considering hoop, longitudinal, and radial stresses on continuous flow carrying buried pipeline subjected to uncertain and risky events is developed in CAESAR II engineering software. The authors performed statistical analysis to carry node-based analysis to describe the repair cost associated with the individual node or throughout the whole pipeline system under study. Although with a limitation in terms of model accuracy and reliability as the actual scenario could differ from the simulated model, the study outlines financial gain over total repair cost using simulation modeling approach in face of disruptions.

Traffic loads for the assessment of existing bridges

2021 ◽  
Author(s):  
Vazul Boros ◽  
Roman Lenner ◽  
Alan O'Connor ◽  
Andre Orcesi ◽  
Franziska Schmidt ◽  
...  
Keyword(s):  
Road Traffic ◽  
Traffic Load ◽  
Traffic Loading ◽  
Traffic Loads ◽  
Universal Solution ◽  
Load Effects ◽  
Characteristic Values ◽  
Existing Bridges ◽  
Partial Factor

<p>IABSE TG 1.3 aims to identify appropriate approaches for applications of the partial factor format in assessment of existing bridges. A sub-group was formed to investigate and provide recommendations on updating road traffic loads. Commonly, these are assessed by complex numerical simulations. While this study does not provide a universal solution, it demonstrates by a case study a simple and reasonably conservative way of using simulations to update traffic load effects, meanwhile continuously highlighting the objectives, potential alternatives or pitfalls of simulations. The results indicate that, for the short, single span bridge under consideration, the characteristic values given in Eurocodes provide conservative estimates. The probabilistic model for traffic loading obtained by bridge- and route-specific simulations will yield substantially more favourable reliability levels in comparison to the general model in fib Bulletin 80.</p>

Soil-Pipeline Interaction Modeling and Assessment in Unstable Slopes

2013 ◽  
Author(s):  
Mauricio Pereira ◽  
Maria Fernanda Contreras ◽  
Carlos Vergara
Keyword(s):  
Oil And Gas ◽  
Combined Effect ◽  
Real Field ◽  
Pipeline System ◽  
Current State ◽  
Interaction Modeling ◽  
Realistic Description ◽  
Interaction Problem ◽  
Geotechnical Problems ◽  
Soil Pipe

Due to their length, oil and gas pipelines usually face different geotechnical problems along their routes (fast or slow, shallow or deep landslides) that impact the pipe integrity. In the current state of practice, this problems are analyzed considering the system as a beam on elastic foundation (Winkler type models), in which the loads on the pipe (e.g. internal pipe pressure and geostatic loads) are studied independently. A more realistic description of the soil-pipe interaction phenomenon that allows the prediction and explanation of the pipe failures found in the practice requires more advanced methodologies, involving the constitutive behavior of soil and pipe and the combined effect of different types of loads. In order to assess in a better way the soil-pipe interaction problem in landslides, this paper presents a 3D numerical model of the system, including the combined effect of different loads (such as landslide loads, geostatic loads and pipe internal pressure). The results obtained with the model were validated against real field measures in the OCENSA pipeline system and are expressed as soil displacement versus pipe strain relations. These relations are being used successfully in the evaluation of the behavior of the pipeline in unstable slopes, resulting in an important tool in the OCENSA pipeline integrity program.

Contribution of MnROAD Research to Improvements in Concrete Pavement Technology from 1994–2019

2020 ◽  
Vol 2674 (7) ◽  
pp. 56-66
Author(s):  
Thomas Burnham ◽  
Benjamin Worel ◽  
Bernard Izevbekhai
Keyword(s):  
American Association ◽  
Monitoring And Evaluation ◽  
Concrete Pavement ◽  
Research Facility ◽  
Traffic Loading ◽  
State Highway ◽  
Traffic Loads ◽  
Pavement Monitoring ◽  
National Road ◽  
Research Alliance

By the late 1980s several states, including Minnesota, began to wonder if American Association of State Highway Official (AASHO) based asphalt and concrete pavement designs were still valid, given the significant changes in traffic loads, materials and construction practices over time. This interest in validating current designs, as well as seeking improved and more efficient designs and materials, led to the creation of the Minnesota Road Research facility, known as MnROAD. Construction of the first phase of test sections at MnROAD took place from 1991 to 1994, and it was open to traffic loading commencing on July 15, 1994. Since 1994, three phases of pavement research have been, and continue to be, conducted at MnROAD. In its first 25 years of operation, an overwhelming amount of pavement research and development has been accomplished at MnROAD. The focus of this paper is to describe many of the more unique and significant findings that have improved concrete pavement technology not only in Minnesota, but throughout the U.S. and other parts of the world. The contributions are categorized into the following areas: design, materials, construction, rehabilitation, pavement monitoring and evaluation, and full-scale testing. In each of the areas, the significant contributions are described and relevant references are cited. The positive contributions of MnROAD toward concrete pavement knowledge and technology have been recognized, and as a result, the MnROAD facility will continue to operate successfully into the future under the National Road Research Alliance (NRRA).

scholarly journals CENTRIFUGE MODELING OF LARGE DIAMETER UNDERGROUND PIPES SUBJECTED TO HEAVY TRAFFIC LOADS

2016 ◽  
Vol 16 (3) ◽  
pp. 31-46
Author(s):  
B Rakitin ◽  
◽  
X Ming
Keyword(s):  
Soil Cover ◽  
Heavy Traffic ◽  
Large Diameter ◽  
Initial Stresses ◽  
Centrifuge Test ◽  
Test Results ◽  
Traffic Loading ◽  
Cover Depth ◽  
Traffic Loads ◽  
Heavy Truck

impose uncertainties on pipe design. This paper describes the procedure and results of a series of geotechnical centrifuge tests performed on a large 1400 mm-diameter reinforced concrete pipe with a footing subjected to heavy traffic loading. The influence of soil cover depth, as well as the positions and magnitude of traffic loads, on the bending moments of the pipe were investigated. A heavy truck with a maximum load of 850 kN was simulated in the majority of the tests, and a medium truck of 252 kN was also simulated. The centrifuge test results were found to be in reasonable agreement with those from full-scale tests. The pipe would experience the most unfavorable conditions when the heaviest axis of the traffic vehicle was located directly above the pipe crown. A deeper soil cover would lead to higher initial stresses in the pipe, as well as reduced influence of traffic load. However, even for a soil cover depth of 4 m, there is significant bending moment induced by the heavy truck loading, which could not be ignored during the pipeline design. Comparison was made between the centrifuge test results and several widely adopted design methods, and unconservative calculation results were noticed for large diameter rigid pipes lying at a shallow soil cover depth subjected to heavy traffic loading.

scholarly journals Fairness Oriented Neighbor-Channel-Aware MAC Protocol for Airborne Sensor Networks

2017 ◽  
Author(s):  
Xiaolin Gao ◽  
Jian Yan ◽  
Jianhua Lu
Keyword(s):  
Sensor Networks ◽  
Mac Protocol ◽  
Traffic Load ◽  
Media Access Control ◽  
Media Access ◽  
Traffic Loading ◽  
Protection Mechanism ◽  
Traffic Loads ◽  
The Media ◽  
Inter Frame

In airborne sensor networks (ASNs), the media access control (MAC) protocol is facing with serious unfairness problem due to the traditional protection mechanism of air-to-air communications among aircrafts. Actually by using the binary exponential back-off algorithm at high traffic loads to minimize collisions among users, the latest successful node can always benefit from this kind of MAC to obtain channel resources. Moreover, when taking the existence of the hidden nodes in ASNs into account, the inaccurate traffic load information will further aggravate the system&rsquo;s unfairness. In this paper, a neighbor-channel-aware (NCA) protocol is proposed to improve the fairness of MAC protocol in ASNs. In the proposal, the NCA frame is firstly added and exchanged between neighbor nodes periodically, which helps to resolve the inaccurate traffic load information, so as to avoid reducing the probability of successful message transmission. Then a traffic-loading based back-off algorithm is involved to make the neighbor nodes cooperatively adjust the inter-frame space (IFS) interval to further reduce the unfairness. The simulation results show that, the proposed MAC protocol can guarantee the satisfied fairness, simultaneously avoiding heavy network overloads to protect key messages&rsquo; successful transmissions in ASNs.

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