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Evaluation of Flexible Pavement Deflections with Respect to Pavement Depths Using Software (A Case Study Jimma to Seka Road)
Issue:
Volume 6, Issue 5, September 2018
Pages:
141-146
Received:
22 September 2018
Accepted:
24 October 2018
Published:
15 November 2018
Abstract: Road building in Ethiopia is increasingly in demand to meet medium and long terms development programs. Roads are constructed radiating from the capital city of the country in all direction. The objective of this research study is to evaluate the flexible pavement deflections with respect to pavement depth using Software along Jimma to Seka road segment and compare the laboratory results with the Ethiopian Road Authority (ERA) standards. Ever Stress Software (ESS) is a numerical analysis technique to obtain the deflection of pavement layers. The methodology of this research was finding the sensitivity of the road parameters (dimension, layers thickness, elastic modulus, Poisson’s ratio, loads and pressures) in reducing the major causes of failure in asphalt pavement fatigue cracking and rutting due to vertical surface deflections, the critical tensile strains at the bottom of the asphalt layer and the critical compressive strains on the top of subgrade. The analytical method used was the elastic modulus and Poisson’s ratio of the pavement materials as design parameters after CBR results of each layers was obtained. The expected outputs have shown that the displacement or deflection (uz) was as high as 0.38mm in the asphalt surface and gradually decreased as the pavement thickness increased. Large values of deflections indicates an over stressed condition which results in the pavement surface to crack and distortion as a results of fatigue or accumulated plastic deformation. Therefore, the relative deflection of pavement layer decreases as the pavement depth increases.
Abstract: Road building in Ethiopia is increasingly in demand to meet medium and long terms development programs. Roads are constructed radiating from the capital city of the country in all direction. The objective of this research study is to evaluate the flexible pavement deflections with respect to pavement depth using Software along Jimma to Seka road se...
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Effect of Special Shaped Column on Lateral Load Resistance Capacity of Reinforced Concrete (RC) Building
Atickur Rahaman,
Asif Mostafa Anik,
N. H. M. Kamrujjaman Serker
Issue:
Volume 6, Issue 5, September 2018
Pages:
147-153
Received:
9 August 2018
Accepted:
29 October 2018
Published:
26 November 2018
Abstract: Column plays very important role in reinforced concrete building as total load is transferred through column. When rectangular columns are used in structure, columns can protrude out of the walls and corners which reduce aesthetic view of structure. Concrete structures with specially shaped columns has been found out as a solution of this problem. Not only for aesthetical point of view but also for structural aspect, specially shaped columns perform well. The aim of this study is to evaluate the comparative lateral load resistance capacity of buildings with rectangular columns and buildings with specially shaped columns. Four different buildings (i.e. 6 storey, 10 storey, 15 storey and 20 storey) are analysed with conventional rectangular columns and same buildings are analysed with specially shaped (i.e. L, Tee, cross) columns with same equivalent cross section area as of rectangular columns. In this paper, at first, the proposed buildings are analysed with linear static analysis and Secondly, linear dynamic analysis. From analysis results, it has been found that maximum storey displacements of all building models i.e. 6, 10, 15 & 20 storeys are under acceptable limit for both rectangular and special shaped columns. For rectangular shaped column building, displacement increases 11.78%, 8.83% & 34.84% & 5.51% respectively for 6, 10, 15 & 20 storeys building compared with building with special shaped columns. After analysis and comparison it is concluded that the buildings with specially shaped columns perform better under lateral load conditions than the buildings with conventional rectangular columns under the same loadings.
Abstract: Column plays very important role in reinforced concrete building as total load is transferred through column. When rectangular columns are used in structure, columns can protrude out of the walls and corners which reduce aesthetic view of structure. Concrete structures with specially shaped columns has been found out as a solution of this problem. ...
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Experimental Performance Studies on the Improved Expansive Subgrade Soil Formation by Using Mechanical Stabilization with Natural Gravel Around Jimma Quarry Sites
Anteneh Geremew,
Basha Fayissa
Issue:
Volume 6, Issue 5, September 2018
Pages:
154-161
Received:
22 September 2018
Accepted:
2 November 2018
Published:
28 November 2018
Abstract: Expansive soil refers to a particular type of soils – almost clayey soils in property - that expand as they absorb water and shrink when they dry out. The process of swelling generates pressures that can cause lifting, or heaving of structures whilst shrinkage process can cause differential settlement on civil structure. A large number of buildings and roads are placed on such type of soil and exposed to the danger from this swelling and shrinkage processes. In order to avoid the previous mentioned risk from the expansive soil, a technique of soil stabilization should be made for this type of soil to enhance some of its properties. In this study, the experimental investigations have been made to study the suitability of natural gravel from jiren quarry site to improve properties of expansive soil. The important parameters to be determine the geo-technical properties such as Specific gravity, Liquid limit, Plastic limit, Plasticity index, dry density and California Bearing (CBR) ratio values. According to ERA 2002 this type of soils is poor for subgrade for road construction. In order to realize the desired objective, a purposive sampling technique which is non –probability method was adopted in order to collect disturbed soil samples at depth of 1.5m and natural gravel from jiren quarry site used for the preparation of different laboratory tests. The laboratory work involved sieve analysis along with consistence test to classify the soil sample. The preliminary investigation of the soil shows that it belongs to A-7-5 class of soil in AASHTO and CH in USCS soil classification system. Soils under this class are generally of poor for subgrade road construction. Atterberg limits, compaction and CBR tests were used to evaluate properties of stabilized soil. The soil was stabilized with natural gravel in stepped concentration of 5%, 10%, 15%, 20% and 25% by dry weight of the soil. Analysis of the results shows the addition of natural gravel improve the geotechnical properties of the expansive black cotton soil. The addition of natural gravel reduces plasticity index, swelling and OMC with an increase in MDD and CBR with all increased natural gravel contents. The addition of 20% and 25% of natural gravel established an increased CBR value by 670% and 958% respectively, indicating the subgrade class falling under S4 and S5 respectively. From this study it was found out that natural gravel stabilized with soil do meet the minimum requirement of ERA pavement manual specification for use as a sub-grade material in road construction.
Abstract: Expansive soil refers to a particular type of soils – almost clayey soils in property - that expand as they absorb water and shrink when they dry out. The process of swelling generates pressures that can cause lifting, or heaving of structures whilst shrinkage process can cause differential settlement on civil structure. A large number of buildings...
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Finite Element Modeling and Analysis of Precast Reinforced Concrete U-Shaped Box Culvert Using ABAQUS
Zenagebriel Gebremedhn,
Guofu Qiao,
Jilong Li
Issue:
Volume 6, Issue 5, September 2018
Pages:
162-166
Received:
10 December 2018
Published:
11 December 2018
Abstract: This paper presents the finite element results of a parametric investigation of the U-shaped box culvert of prefabricated reinforced concrete subject to loading conditions. It was included outer size span length 4.80m, rise of 4.80m, laying width 1.5m and 0.4m slab and wall thickness. Its components consisted of two symmetrical u-shaped structures joined together using the tip at the end of the bell. It was not recommended for areas with excessive settlement where deep foundations were required. The upper and side ground pressure was considered in the culvert, which depends on the depth of the canal. The finite element method has been chosen for purpose of modeling and analyzing the structural behaver of the standard three dimensional solid and wire elements of the u-shaped box culvert under different loading conditions using ABAQUS-V6.14-4 due to its flexibility in creating geometry and material modeling. The culvert has been modeled using 3-D solid (C3D8R) elements reduce integration for concrete and 3-D wire (T3D2H) elements for reinforcement having geometric and material linearity as well as hybrid formulation. The reinforcement was modeled as rebar elements embedded in the surface element. Finally, the Finite element analysis (FEA) results were showed deflection and stress as well as effect of with and without distribution steel on the culvert.
Abstract: This paper presents the finite element results of a parametric investigation of the U-shaped box culvert of prefabricated reinforced concrete subject to loading conditions. It was included outer size span length 4.80m, rise of 4.80m, laying width 1.5m and 0.4m slab and wall thickness. Its components consisted of two symmetrical u-shaped structures ...
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Seismic Response Evaluation of High-Rise Building with and Without Fluid Viscous Damper
Khalil Yahya Mohammed Almajhali,
Bin Xu,
Qingxuan Meng
Issue:
Volume 6, Issue 5, September 2018
Pages:
167-177
Received:
23 December 2018
Published:
24 December 2018
Abstract: The major lateral load of the high structures is the earthquake load. In the high rise buildings, the structural response increases exponentially in response to earthquake load. Therefore, the damping has significant function in design of Earthquake Resistant High Structures, which can decrease the response of the structure when exposed to lateral loads. The energy produced by earthquake will be absorbed by these devices and the load acting on the main structure of the building will reduce significantly. The fluid viscous dampers are used to dissipate energy and lessen the response of reinforced concrete buildings. The main function of structure is to carry the lateral loads and transmit them well to the foundation. The lateral loads enjoined on the structures are dynamic in nature, which cause vibrations in the structure. In the current study, the responses of the structures having square plans with different cross-sections are analyzed by the software ETABS 2015 based on the consideration of Fluid Viscous Damper. The results of numerical examples show that fluid viscous damper (250) can reduce the response of the structures effectively, including the base shear of the buildings, and the structures with square columns performs perfect and have good earthquake resistant characteristics when compared to structures with rectangular columns regardless of the flooring plan.
Abstract: The major lateral load of the high structures is the earthquake load. In the high rise buildings, the structural response increases exponentially in response to earthquake load. Therefore, the damping has significant function in design of Earthquake Resistant High Structures, which can decrease the response of the structure when exposed to lateral ...
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