Blog – Full Width – Laman 41

Oktober 11, 2021

by admin

The Structural erformance of flexible pipe for landfill drainage

Authors:

D. F. Rogers, BSc, PhD, CEng, MICE, MIHT, Eur Ing, ,

The structural performance of perforated plastic pipelines used for landfill drainage is difficult to predict. This paper aims to describe their structural action on the basis of field measurements, and thereby make recommendations for their design and installation. The key requirements for structural support of buried plastic pipes and development of stable arching are described for both embankment and trench conditions. The most important is the relative stiffness of the pipe surround, which is directly related to the degree of confinement. The ‘ground conditions’ in a landfill, however, are far removed from those of embankment fill, the variable nature of the waste resulting in a complex loading pattern and variable degrees of local confinement. Field measurements of pipes buried in different surround conditions in a landfill as the waste progressively increases in height are reported and compared with laboratory results. The deformed shape in the smaller gravel surrounds was found to differ from that in simulated laboratory tests, although classical theory was found to predict baseline pipe deformations reasonably well. Landfilling practice close to the gravel mounds was found to be critical to pipe performance.

Article Source: https://www.icevirtuallibrary.com/doi/abs/10.1680/gt.1999.370410?src=recsys
Upload by: Evi, PT Shuanglin Pipe Indonesia

Oktober 4, 2021

by admin

Stress Concentrations Around Circular Holes in Perforated Drainage Pipes

Authors:
R.W.I. Brachman, , and R.P. Krushelnitzky,
Stress concentrations around circular holes in perforated buried pipes obtained from three-dimensional elastic finite element analysis are presented. The maximum stresses around the perforation were found to depend on the thickness and diameter of the pipe, the diameter of the perforation, the circumferential location of the perforation, and the axial and circumferential spacing between perforations. It was found that a stress concentration of 3.0, based on the simple hole in a plate solution, may be conservatively used for most perforated pipes. Better estimates of stress concentration factors derived from finite element analysis are presented. Guidelines are provided for specifying the location, size, and spacing of perforations that minimize the stress concentrations. Two example calculations are presented to illustrate the proposed procedure for estimating the maximum stresses around the perforations.

Article Source: https://www.icevirtuallibrary.com/doi/abs/10.1680/gein.9.0215
Upload by : Evi, PT Shuanglin Pipe Indonesia

September 28, 2021

by admin

Liner Buckling in Profiled Polyethilene Pipes

A.S. Dhar, , and I.D. Moore,

Thermoplastic pipes are often manufactured with profiled walls to maximize the flexural stiffness of the pipe for a given amount of polymer. Thin elements in the profile can buckle under the influence of large earth pressures associated with deep burial or other extreme loading conditions. Earth load tests have been conducted on high density polyethylene pipes with a number of different wall profiles. Two high-pressure pipe test cells have been used to conduct these tests. Observations of local buckling in the internal liners of these products have been examined and compared to stability assessments based on the conventional equation for buckling in stiffened plate structures (following modification of that equation to an equation that defines critical strain instead of critical stress). The strain levels that develop in the liner are, however, dependent on three-dimensional bending within the pipe profile. Provided the effects of three-dimensional bending in the pipe profile are considered, the modified Bryan equation appears to be a useful tool for quantifying liner stability and should be considered for inclusion in limit-state design procedures for these structures.

Article source: https://www.icevirtuallibrary.com/doi/abs/10.1680/geot.8.P.048?journalCode=jgeot
Upload by : Evi, PT Shuanglin Pipe Indonesia

September 20, 2021

by admin

Earth Pressure Measurements On Buried HDPE Pipe

Authors:

M.L. TALESNICK*, H.-W. XIA†, and I.D. MOORE†

An understanding of the stress distributions that act on buried pipes plays a key role in the development and use of design methods for these structures. The radial stresses that develop on buried flexible pipes have been investigated by a number of researchers through experimental, analytical and numerical methods. However, direct measurements of soil contact stresses acting on small-diameter pipes have not been possible, since commercial earth pressure cells are large, and the stiffness of the cell relative to the soil material is known to influence the measured stresses. A new technique is described for measuring the radial contact stresses acting on buried pipes, and experimental studies are reported that demonstrate the effectiveness of this new technique for measuring contact pressures for both loose and compacted sand backfills. Comparison of the measurements with computations from elastic soil–pipe interaction theory reveals significant discrepancies in the magnitude and distribution of radial pressure around the circumference of the pipe for both loose and compacted backfill conditions. The new measurement technology provides direct support for pressure distributions inferred in earlier studies from measurements of circumferential strains around the pipe circumference.

source : https://www.icevirtuallibrary.com/doi/full/10.1680/geot.8.P.048
upload by Evi, PT Shuanglin Pipe Indonesia

September 13, 2021

by admin

Compaction Effects On Strains Within Profiled Thermoplastic Pipes

Authors:
W. I. Brachman¹, , I. D. Moore², , and S. M. Munro³,

Results from laboratory tests are reported to establish how pipe deflections, strains and local bending are influenced by the selection of backfill soil and its placement for two profiled thermoplastic culverts. Lined-corrugated high-density polyethylene (HDPE) and poly vinyl chloride (PVC) pipes with a nominal inside diameter of 600 mm were tested in poorly graded sand and well-graded gravel backfills. The backfill was compacted using real compaction equipment and procedures, and then subjected to a maximum increase in vertical pressure of 200 kPa in a test cell that simulates deep burial. For the specific conditions tested, the largest deflections and strains were for the HDPE pipe when placed just above a rigid base and with uncompacted sand backfill placed below the springline, while local bending was greatest for the PVC pipe with well-compacted gravel backfill. A procedure is presented to account for the maximum local bending strain within a simplified design approach for profiled thermoplastic pipes using an empirical strain factor inferred from the measured results.

Keywords: Geosynthetics ; Geopipes ; Profiled thermoplastic culverts ; Local bending ; Construction practice ; Design

Article source : https://www.icevirtuallibrary.com/doi/10.1680/gein.2008.15.2.72
Upload by : Evi, PT Shhuanglin Pipe Indonesia

September 6, 2021

by admin

Performance Of Buried HDPE Pipes – Part II: Total Deflection Of The Pipe

Zhou¹F. Wang²Y. J. Du³ M. D. Liu⁴ PhD Candidate Associate Professor Professor and Director Senior Lecturer

Total deflection of buried thermoplastic pipes is extensively studied in previous work as it is a service limit state specified in design standards. In this paper, two-dimensional finite-element modeling is conducted to investigate the total deflection of buried high-density polyethylene (HDPE) pipes with a special consideration of the peaking behavior. The finite-element modeling method is evaluated using the data measured in a field trial which is presented in Part I. Parametric study are conducted. It is shown that the relative flexure stiffness, the type of compactor and the unit weight of soil cover have significant effects on the total deflection of the pipe. Based on analyses of the finite-element simulation results and experimental data, two empirical formulas with five parameters are proposed to describe the total deflection of HDPE pipes in both the vertical and horizontal directions. A comprehensive comparison is made between the calculated deflections made using the proposed equations and some existing methods and the measured data from published papers. It is seen that the proposed method significantly improves the accuracy of existing methods, and it also has advantages over existing methods because it has far fewer parameters and more convenient parameter determination.

Keywords: Geosynthetics Total deflection of pipes Construction phase Finite-element method HDPE pipe Empirical formulas

https://www.icevirtuallibrary.com/doi/full/10.1680/jgein.17.00010

Upload by : Evi , PT Shuanglin Pipe Indonesia

Free enquiry

(021) 89915151

The Structural erformance of flexible pipe for landfill drainage

Stress Concentrations Around Circular Holes in Perforated Drainage Pipes

Liner Buckling in Profiled Polyethilene Pipes

Earth Pressure Measurements On Buried HDPE Pipe

Compaction Effects On Strains Within Profiled Thermoplastic Pipes

Performance Of Buried HDPE Pipes – Part II: Total Deflection Of The Pipe

ADDRESS

ADDRESS

PHONE

EMAIL

Switch The Language

ADDRESS

ADDRESS

PHONE

EMAIL