Parametric study of buried steel and high density polyethylene gas pipelines due to oblique-reverse faulting

2015 ◽  
Vol 42 (3) ◽  
pp. 178-189 ◽  
Author(s):  
Fayaz Rahimzadeh Rofooei ◽  
Himan Hojat Jalali ◽  
Nader Khajeh Ahmad Attari ◽  
Hadi Kenarangi ◽  
Masoud Samadian

A numerical study is carried out on buried steel and high density polyethylene (HDPE) pipelines subjected to oblique-reverse faulting. The components of the oblique-reverse offset along the horizontal and normal directions in the fault plane are determined using well-known empirical equations. The numerical model is validated using the experimental results and detailed finite element model of a 114.3 mm (4″) steel gas pipe subjected to a reverse fault offset up to 0.6 m along the faulting direction. Different parameters such as the pipe material, the burial depth to the pipe diameter ratio (H/D), the pipe diameter to wall thickness ratio (D/t), and the fault–pipe crossing angle are considered and their effects on the response parameters are discussed. The maximum and minimum compressive strains are observed at crossing angles of 30° and 90°, respectively. It is found that the dimensionless parameters alone are not sufficient for comparison purposes. Comparing steel and HDPE pipes, it is observed that HDPE pipes show larger compressive strains due to their lower strength and stiffness. For both steel and HDPE pipes, peak strains increase with increasing D/t and H/D ratio for a constant pipe diameter and fault offset. For a given H/D ratio, compressive strains increase with increasing D/t ratio in HDPE pipes, while in steel pipes considered in this study, this effect is negligible. Finally, the peak strains of the pipes are compared to those suggested by Canadian Standard Association for Oil and Gas Pipeline System, CSA Z662.

2003 ◽  
Vol 1845 (1) ◽  
pp. 182-187
Author(s):  
Steven L. Folkman ◽  
A. P. Moser

Buried parallel pipes are used for storm retention systems. Traditional retention-detention systems have spaced parallel pipes that permit soil columns between pipes. A new design allows for the parallel pipes to be placed side by side in contact with each other. The performance of such a system of bundled high-density polyethylene (HDPE) pipes that is subjected to vertical earth loads is reported. This bundled system consists of parallel HDPE pipes wrapped with a geogrid and a geofabric. The actual loads ranged from shallow cover to vertical loads equivalent to 55 ft (16.8 m) of cover. The embedment soil selected for the research was a silty sand. This soil was selected because its structural qualities are generally considered to be the least acceptable for these types of applications. The soil that typically would be specified is a crushed stone. Therefore, the results from the tests are conservative. Structural performance is reported, and photographs present the pipes in the bundled system during installation and after subjection to earth loads. Load-deflection curves for the pipes in the system are also given.


Author(s):  
Yang Wang ◽  
Hui-qing Lan ◽  
Tao Meng ◽  
Bing Wang ◽  
Du du Guo ◽  
...  

Abstract The purpose of this study was to propose low gas pressure effects on lifetime of natural gas high density polyethylene (HDPE) pipes by thermal-oxidative aging (TOA). The new method to assess the lifetime of HDPE natural gas pipes is based on gas pressure testing. An approach to monitor oxidative induction time (OIT) has been used to predict lifetime. Natural gas HDPE pipes were used to evaluate the effects of low gas pres-sures on oxidative induction time. In order to emphasize the pressure effects, relatively low temperatures at 45, 55, 65 and 75 °C were utilized for the exposure. The low-pressure conditions were created using air at levels of 0, 0.1, 0.2, 0.3 and 0.4 MPa. The property of high density polyethylene pipes was effectively moni-tored using the low pressure oxidative induction time (OIT) test. The results show that the aging reaction rate of high density polyethylene pipes increased exponentially with temperature and gas pressure according to the Arrhenius equation. Analytical models were developed to predict the aging reaction rate and lifetime of natural gas HDPE pipes.


2011 ◽  
Vol 99-100 ◽  
pp. 885-890
Author(s):  
Jie Tang ◽  
Ping Ping Xu

This paper analyses the technology characteristics of HDPE pipes and UPVC pipes that used in drainage. Using a residential building project in Hangzhou as an example, it compares the economic benefits and comprehensive benefits of HDPE pipes with those of UPVC pipes. It concludes that it’s better to use HDPE pipes in same floor drainage system, and the using of HDPE pipes will bring benefits in the promoting of the same floor drainage system.


Author(s):  
Timothy M. Adams ◽  
Jie Wen ◽  
Shawn Nickholds ◽  
Douglas Munson

For corroded piping in low temperature systems replacement of buried carbon steel pipe with high density polyethylene (HDPE) pipe is a cost-effective solution. The ASME Boiler and Pressure Vessel Code, Section III, Division 1, Code Case N755-1 currently permits the use of HDPE in buried Safety Class 3 piping systems. This paper presents the results of tensile testing of PE 4710 cell classification 445574C pipe compliant with the requirements of Code Case N755-1. This information was developed to support and provide a strong technical basis for tensile properties of HDPE pipe. The data may also be useful for applications of HDPE pipe in commercial electric power generation facilities and chemical, process, and waste water plants via its possible use in the B31 series piping codes. The paper provides values for yield stress, yield strain, ultimate strain, and elastic modulus. The standard tensile tests were conducted consistent with the requirements of ASTM D638-10. Specimens were cut in the axial direction from cell composition PE 4710 cell classification 445574C HDPE piping spools. In addition, the results are compared to previous tensile testing conducted on the PE 3608 cell classification 345464C and PE 4710 cell classification 445474C HDPE materials.


2009 ◽  
Vol 40 (5) ◽  
pp. 404-412 ◽  
Author(s):  
Jun S. Kang ◽  
Taek H. Han ◽  
Young J. Kang ◽  
Chai H. Yoo

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