THE DEPARTMENT OF CIVIL ENGINEERING, INSTITUTE OF TECHNOLOGY, SCHOOL OF GRADUATE STUDIES, ARBA MINCH UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN ROAD AND TRANSPORTATION ENGINEERING

Abstract

In Ethiopia, the accumulation of vehicles is increasing day to day, results in the adoption of construction of the road commonly flexible pavement. It is not only country problems as well as it is regional and global issue. 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. Everstress Finite element method (FEM) is a numerical analysis technique to obtain the stress-strain and deflection of each pavement layers. The objective of this research was to study the value of parameters (Elastic modulus), from the laboratory test and use as input data in the Everstress finite element software. Then after determined the horizontal tensile strain, the vertical compressive strain, results of shear strain, and deflections that was affect the layresearch methods consider the data which was to collect and investigate the research problems. From here the research design, materials, data collection, sampling method and technique, data processing and analysis can did in order to express the analysis of this study. The method was show how the study can analyzed to get the results. This study was finding the sensitivity of road parameters that cause stress, strain, and deflection that are the load from the vehicle, axle load, wheel pressure, and elastic modulus of each of layers, road layer thickness, and poisons ratio. Due to the elasticity modulus was not in range and taken the minimum value in the range pavement failure was occurred. The horizontal tensile strain at the bottom asphalt surface indicates the pavement was failed due to fatigue caused by excessive traffic loading and vertical compressive strain at the top of the sub grade indicates the pavement was failed due to rutting, caused densification and shear deformation. Generally the horizontal tensile strain, vertical compressive strain, shear strain, deflection, and soon, all those had shown the failure the structural pavement. From that i.e displacement or deflection (uz) was h igh in the asphalt layer and gradually decreased as the thickness of the pavement increased. performance of flexible pavement along the Meshenti to BahirDar road section. The