Analysis of Stress- Strain and Deflection of Flexible Pavements Using Finite Element Method Case Study on Bako-Nekemte Road
Shiferaw Garoma Wayessa,
Emer Tucay Quezon,
Tarekegn Kumela
Issue:
Volume 2, Issue 4, August 2017
Pages:
100-111
Received:
19 June 2017
Accepted:
30 June 2017
Published:
7 September 2017
DOI:
10.11648/j.jccee.20170204.11
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Abstract: In Ethiopia the failure of roads are before handover period. Most roads found in Ethiopia are flexible pavements. Nowadays, the failure of surface of flexible pavement roads are common before the expected design period. For the example Bako-Nekemte road/ has become a critical issue in our country. The most common parameters that cause stress, strain and deflection of the roads are loads and pressures that come from vehicles. Moreover, modulus of elasticity, Poisson’s ratio and thickness of each layer needs to be characterized. Further, the load magnitude, contact pressure (or load radius) and location are defined for each load (wheel) considered. Finite element method (FEM) is a numerical analysis technique to obtain the stress-strain and deflection of each pavement layers. Analytical method usually uses layers thickness, loads, elastic modulus and Poisson’s ratio of the pavement materials as design parameters. The objective of this research was to study the sensitivity of the road parameters in analyzing the major causes of failure in asphalt pavement layers fatigue cracking and rutting deformation which came due to the critical tensile strains at the bottom of the asphalt layer and the critical compressive strains on the top of subgrade using the finite element method by relating the standard specification of ERA and laboratory test result. This thesis studied the analysis of stress-strain and deflection of flexible pavements using Everstress finite element method. The Ever stress program will take into account any stress dependent stiffness characteristics. This thesis dealt with ways to reduce deflections by varying the design configuration, such as increasing the HMA modulus, the base modulus, sub base modulus, the subgrade modulus and increasing thickness of each layers. Based on type of materials to use the value of elastic modulus and poison’s ratio are various in each layers, in layer 1 is varied from 1500 to 3500 MPa, in layer 2 is varied from 200 to 1000MPa, in layer 3 is varied from 100 to 250 MPa and in layer 4 is varied from 20MPa to 150MPa.
Abstract: In Ethiopia the failure of roads are before handover period. Most roads found in Ethiopia are flexible pavements. Nowadays, the failure of surface of flexible pavement roads are common before the expected design period. For the example Bako-Nekemte road/ has become a critical issue in our country. The most common parameters that cause stress, strai...
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Reverse Osmosis Process Membranes Modeling – A Historical Overview
Issue:
Volume 2, Issue 4, August 2017
Pages:
112-122
Received:
17 August 2017
Accepted:
4 September 2017
Published:
9 October 2017
DOI:
10.11648/j.jccee.20170204.12
Downloads:
Views:
Abstract: This paper presents an overview to the state-of-the-art area of mathematical modeling for reverse osmosis (RO) process. As a liquid-solid process, RO constitutes a valuable and vital physical solution for seawater desalination, wastewater depollution, and water treatment comparatively to the largely controversial and polluting chemical processes such as chlorination and coagulation/flocculation. Great works are required in modeling of RO technique in order to obtain a complete and exhaustive model. Complicated and varying raw water qualities and quantities parameters through time and space are rendering RO modeling hard. Be facing the increasing pollution levels and trying to satisfy the drinking water guidelines, RO membrane modification is often required. This situation made modeling this highly dynamic process more difficult to accomplish.
Abstract: This paper presents an overview to the state-of-the-art area of mathematical modeling for reverse osmosis (RO) process. As a liquid-solid process, RO constitutes a valuable and vital physical solution for seawater desalination, wastewater depollution, and water treatment comparatively to the largely controversial and polluting chemical processes su...
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