scholarly journals Performance Evaluation of Buried Concrete Pipe Considering Soil Pressure and Crack Propagation Using 3D Finite Element Analysis

2021 ◽  
Vol 11 (7) ◽  
pp. 3292
Author(s):  
Hoki Ban ◽  
Seungjun Roh ◽  
Won-Jun Park
Keyword(s):  
Finite Element ◽  
Crack Propagation ◽  
Environmental Conditions ◽  
Soil Pressure ◽  
Concrete Pipes ◽  
Pressure Distributions ◽  
Concrete Pipe ◽  
Backfill Materials ◽  
Adjacent Soil ◽  
Buried Concrete

Numerous factors affect the soil pressure distributions around buried pipes, including the shape, size, and stiffness of the pipe, burial depth, and the stiffness of the surrounding soil. Additionally, to some extent, a pipe can benefit from the soil arching effect, where the overburden and surcharge pressure at the crown can be supported by the adjacent soil. As a result, a buried pipe only needs to support the portion of the load that is not transferred to the adjacent soil. This paper presents numerical investigations of the soil pressure distributions around buried concrete pipes and crack propagation under different environmental conditions, such as loading, saturation level, and the presence of voids. To this end, a nonlinear elastoplastic model for backfill materials was implemented using finite element software and a user-defined subroutine. Three different backfill materials and two different native soils were selected to examine the material-specific behaviors of concrete pipes, including soil pressure distributions and crack propagation. For each backfill material, the effects of the loading type, groundwater, and voids were investigated. These simulation results provide helpful information regarding pressure redistribution and buried concrete pipe behavior under various environmental conditions.

A new test method for evaluating the long-term performance of fiber-reinforced concrete pipes

2019 ◽  
Vol 23 (7) ◽  
pp. 1336-1349 ◽  
Author(s):  
Fouad T Al Rikabi ◽  
Shad M Sargand ◽  
Issam Khoury ◽  
John Kurdziel
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Steel Reinforcement ◽  
Fiber Reinforced Concrete ◽  
Synthetic Fiber ◽  
Concrete Pipes ◽  
Concrete Pipe ◽  
Long Term Performance ◽  
Term Performance

Synthetic fibers have been used recently to minimize the need for steel reinforcement in the concrete pipe to enhance their ductility. However, synthetic fiber has properties that may change over time due to its viscoelastic behavior. The objective of this study is to investigate the long-term performance of fiber-reinforced concrete pipes using a new test frame. A three-dimensional finite element model was created for the long-term testing frame to ensure its compliance with the American Society for Testing and Materials requirement. The finite element results showed that the testing frame successfully transferred the load to the concrete as the pipe cracked at the location where high flexural stresses are expected. Concrete pipe reinforced with synthetic fiber dosage of 9 kg/m3 along the steel reinforcement area of 5.7 cm2/m was tested to evaluate the concrete pipe system performance. The pipe was tested under two load stages for 120 days each. Load stages 1 and 2 included applying 40% and 70% of the ultimate load obtained by the authors in a previous study, respectively. The strain and deflection increased linearly within 5 days of applying the load and then leveled off. The pipe showed a slight increase in the crack width and deflection, indicating that fiber creep did not have a significant impact on the long-term performance of the concrete pipe. Also, it was observed that strain values surpassed those for plain concrete material, suggesting that including synthetic fiber in the concrete pipe mix enhanced the pipe ductility.

scholarly journals Mechanical Properties of Concrete Pipes with Pre-Existing Cracks

2020 ◽  
Vol 10 (4) ◽  
pp. 1545
Author(s):  
Zongyuan Zhang ◽  
Hongyuan Fang ◽  
Bin Li ◽  
Fuming Wang
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Bearing Capacity ◽  
Three Dimensional ◽  
Compressive Load ◽  
Full Scale ◽  
Element Analysis ◽  
Concrete Pipes ◽  
Concrete Pipe ◽  
Full Scale Tests

Concrete pipes are the most widely used municipal drainage pipes in China. When concrete pipes fall into years of disrepair, numerous problems appear. As one of the most common problems of concrete pipes, cracks impact on the deterioration of mechanical properties of pipes, which cannot be ignored. In the current work, normal concrete pipes and those with pre-existing cracks are tested on a full scale under an external compressive load. The effects of the length, depth, and location of cracks on the bearing capacity and mechanical properties of the concrete pipes are quantitatively analyzed. Based on the full-scale tests, three-dimensional finite element models of normal and cracked concrete pipes are developed, and the measured results are compared with the data of the finite element analysis. It is clear that the test measurements are in good agreement with the simulation results; the bearing capacity of a concrete pipe is inversely proportional to the length and depth of the crack, and the maximum circumferential strain of the pipe occurs at the location of the crack. The strain of the concrete pipe also reveals three stages of elasticity, plasticity, and failure as the external load rises. Finally, when the load series reaches the limit of the failure load of the concrete pipe with pre-existing cracks, the pipe breaks along the crack position.

Field Performance of Instrumented Concrete Pipe Under Deep Burial

1997 ◽  
Vol 1594 (1) ◽  
pp. 224-234 ◽  
Author(s):  
Glenn A. Hazen ◽  
Shad M. Sargand ◽  
Mohammed Haque ◽  
John O. Hurd
Keyword(s):  
Reinforced Concrete ◽  
Computer Program ◽  
Field Performance ◽  
Concrete Pipes ◽  
Deep Burial ◽  
Direct Design ◽  
Concrete Pipe ◽  
Design Calculations ◽  
Buried Concrete ◽  
Contact Pressures

Two 1.524-m-diameter, reinforced concrete pipes were instrumented to compare field results with design calculations. A computer program, Standard Installation Direct Design, developed by the American Concrete Pipe Association was used to design the pipe. Instrumented pipes were completely monitored until 11.9 m of cover had been placed. Measurements of soil contact pressures and vertical and horizontal deflections continued for 6 months. The computer-simulated and observed responses of the buried concrete pipe installations were compared. Pipe contact pressures measured at the invert were much smaller than those assumed from calculations of thrust and moment. Design moments were conservative compared with the experimentally measured values. Thrusts are difficult to calculate accurately and show large experimental variations.

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