- Service Life of Reinforced Concrete Infrastructure in Marine Environments
Authors: E.J. Okwori
Abstract: Reinforced Concrete (RC) is one of the most widely used man-made building materials, even in aggressive conditions. The marine environment is one such place with aggressive conditions, where reinforced concrete is widely used. The Service Life of a structure can be described as the amount of time for which the structure can carry the service loads imposed upon it without failure. Service life of RC infrastructure is determined by whichever environmental or loading effect most significantly contributes to the structural failure of RC. In marine areas, this effect is deterioration due to reinforcement corrosion, caused by chloride ingress. Chloride-induced corrosion has many causes, including concrete mix design, construction quality, initial concrete condition, and the surrounding environment. RC structures constructed from non-reactive dolomite aggregates have enhanced durability against corrosion. Cracks occur in most RC structures at the start of its service life. These cracks readily allow chloride ingress and thus reduce the service life of the RC. The exposure conditions and environment affect the aggressiveness of chloride-induced corrosion in an RC structure determine. These effects have complex causes and interactions and should be considered holistically. In marine environments an integral part of increasing service life involves preventing and mitigating the adverse effects of chloride-induced corrosion. Ways in which this can be achieved include: including mineral admixtures in concrete mix, using protective coatings on concrete surfaces, monitoring the condition of RC elements, suitable concrete design and adequate construction quality. Mineral admixtures are used to improve the durability of RC by chemically and physically improving concrete properties. Surface coatings are used on new and repaired RC surfaces in order to preserve initial alkaline environment of the concrete, stop electrolytic processes, and create a surface barrier to control the ingress of aggressive substances. Sensors and models are often used as part of an on-going monitoring system. This helps to ensure cost-effective maintenance and repair. A systematic quality control program ensures concrete reaches the required strengths while proactively managing corrosion risks due to poor construction quality. It can be seen that a holistic view of the considerations (and mitigation measures) related to chloride-induced corrosion is important in order to ensure an acceptable service life at the design and maintenance stages. Keywords: Concrete, Marin infrastructure
Issue No: Vol. 8
- Determinants of Household Participation in Water Source Management in
Authors: Fenet Belay Daba Alemayehu Oljirra
Abstract: Access to safe drinking water supplies and sanitation services in Ethiopia are among the lowest in Sub-Saharan Africa. While governmental and non- governmental organizations have been implementing water supply and sanitation projects in recent years, many fail shortly after construction due improper management. In this review I examine socio-economic, institutional and exogenous factors which affect households’ participation in the management of water sources. The results show that households’ demand for sustainable water services are positively affected by users’ participation during the project design and implementation, advocacy provided by the project and greater household income. Thus, for drinking water systems to be sustainable these factors should be included in planning water supply projects.
Issue No: Vol. 8
- Physico-Chemical Water Quality Assessment of Gilgel Abay River in the Lake
Tana Basin, Ethiopia
Authors: Yirga Kebede Wondim, Hassen Muhabaw Mosa, Manalebesh Asmara Alehegn
Abstract: The physico-chemical parameters such as PH, temperature, electrical conductivity, total dissolved solid, turbidity, total alkalinity, total hardness, ammonia, nitrate, nitrite, phosphate, sulphate, sulfide and iron were investigated to assess the various water quality parameters along the River course of Gilgel Abay River (GAR). The value of those parameters have been evaluated with respect to guidelines provided by World Health Organization(WHO), Ethiopian drinking water quality standards(EDWQS), Canadian Council of Minister for Environment(CCME) and European Community(EC) to indicate the pollution level of GAR. Overall compliance was 58.93%. From a total of 224 samples, 132 samples (58.93%) complied with WHO guidelines and EDWQS. Turbidity, followed by iron, phosphate and sulfide were the prime river water quality issues identified in GAR. Analysis of variance was used to examine the variations of water quality parameters between the dry and rainy seasons, and the variations along the river courses of Gilgel Abay (upper, middle and lower course). The majority of the parameters showed that there is a significant variation of the water quality parameters between the dry and rainy seasons. However, the variations along the river courses of GAR (upper, middle and lower course) were statistically insignificant. This implies that the GAR water quality is influenced by anthropogenic impacts from the upper course to the lower course of the River. Keywords: Water Quality; Physico-chemical Parameters; Gilgel Abay River
Issue No: Vol. 8
- Soil Physic Chemical Properties and Land Use and Land Cover at Agarefa,
South East Ethiopia
Authors: Fitsume Yemenu, Tadesse Bullulo
Abstract: Agriculture can only be sustained if soil physico-chemical properties of soils are in a good quality to cultivate crops. Investing the soil physico -chemical aspects of soils are therefore helpful in decision making for productive agriculture. The purpose of this study was to assess and measure the soil physical and chemical status of the land at Agarefa, South East Ethiopia where Weyib river is to be used as source for water for agriculture during the dry seasons. Proper field and standard laboratory procedures were followed to determine the soil physical and chemical properties of the soil in the selected study site. Accordingly, the results have showed that the land has reasonable fertile soil and can be used for irrigated agriculture
Issue No: Vol. 8
- Urban Optimization of Transit Oriented Development in Baghdad City
Authors: Abdelwehab A. Alwehab, Mohammed Qasim Abdul Ghafoor Al Ani
Abstract: Meeting the demands of the postmodern metropolis requires innovative urban planning approaches to promote a livable and resilient urban fabric. Transit-oriented development (TOD) is one such approach, and promises to add value to all public and private stakeholders. The concept maximizes transit usage, create a sense of place and community, and provide a vibrant mix of land uses that cater to existing and future residents. In general, TOD aims to create vibrant communities which promote walkability and provide attractive choices in employment, housing, and transportation choices. In its theoretical background, the paper attempts to outline the benefits and principles of TOD, and to highlight a number of case studies of cities that have implemented the concept successfully. An overview is presented of the cumulative results achieved by these cities to enhance both the quality of life, and the local economy.This research also tackles the applicability of TOD to the proposed future vision of the city of Baghdad. With its 6.5 million inhabitants, and a forecasted population of 11 million by 2030, the city has a number of shortcomings in providing a livable and efficient urban landscape. Transit, sprawl, excessive use of private cars, inappropriate land use mix and densities, and lack of well-designed urban spaces around transit hubs are among the pressing issues. The hypothesis of this research stresses the need to explore TOD as an urgent planning alternative to address such quandaries. The paper presents an overview of the pending “Baghdad Urban Development Plan 2030”, and submits a multi-parameter evaluation of the vision outlined in the plan with regard to transit and circulation problems, and solutions. The preliminary outcomes of the evaluation process indicate an evident deficiency in the utilization of TOD to optimize future urban movement proposals. Keywords: TOD, urban design, socio-economic growth, urban planning, comprehensive development.
Issue No: Vol. 8
- A Regulation (E.C.) 561/2006-Inspired Approach; Identification Required
Facilities for the Dry Canal Project over the Expressway No.1, Western
Authors: Ghassan Hassan Abdul Hadi, Tan Gangyi, Gelareh Sadeghi, Sarmed Ghassan Hassan
Abstract: T his paper aims by means of Regulation (E.C.)561/2006-inspired approach methodology and development its criteria in security and control to identifying the necessary facilities required to upgrade the Western Section of the Expressway No.1 performance in case of future operating of the Dry Canal Project over this route in Iraq. Fully considers this inspire approach, the study presents a method to enable this route to be incapable in the future to run the expected future huge Dry Canal Project in Iraq as a new intercontinental hub for trading and freight movement between the East and the West. The Grand Canal Project and its main route the Expressway No.1 needs to be capable to serve all the route’s numerous users according to world-class specifications and standards by following the European Council Regulation (E.C.)561/2006. Joining the international trade movements, Iraq should be started preparing all the necessary facilities for the future Dry Canal Project, and must begin the hard and enormous work by renewing, modernizing and reforming the entire infrastructure for suitable and safety transportation in the country, and to build primarily all the necessary facilities, in particular over the Expressway No.1, to insure the suitable running for this project on Earth. This qualitative research hopes to be serves as an academic document to be published and to be used as a main part in my PhD dissertation and hopes that it will also assist target groups of experts, designers and engineers who will work for this project in the future. Keywords:Dry Canal, Expressway No.1, Facilities, Amenities, Rest Area, Traveler Center.
Issue No: Vol. 8
- Modeling Trends of Temperature Effects on Water Level of Rivers in N/E
Authors: Dammo; M. N., Yadima S.G, Sangodoyin, A.Y
Abstract: This study investigates temperature variabilities in N/E Nigeria using observations of temperature (0C) from 6 stations from 1981-2010 (30years). Trends in annual and seasonal temperature series were modeled using Mann-Kendall test. The analysis revealed significantly higher (P<0.01) in April compare to all the other months with overall mean temperature ranged between 20.2 - 31.80C among all the locations over months and years. There was significant increase of 0.380C (positive trend) in temperature in all studied area except Taraba. Each degree rise of temperature of 0.740C (Gombe), 0.120C (Adamawa), 0.380C (Yobe), 0.530C (Borno) and 0,690C (Bauchi) and decrease 2.050C (Taraba) lead to a reduction and increase in water level by 78.77, 19,10, 74.26, 79.62, 20.65 and 209.29 mm respectively. Analyses of decadal trends in the time series further suggest a sequence of alternately decreasing and increasing trends in mean annual temperature in Nigeria during the study period. Keywords: Modeling, Temperature, Water Level, Rivers, N/E Nigeria.
Issue No: Vol. 8
- Experimental and Finite Element Analysis of Lateral Torsional Buckling of
Concrete Filled Tubular Flange Steel Girders
Authors: Haitham H. Muteb, Alaa Hussein Ali
Abstract: The structural behavior of concrete filled Tubular Flange Girders (CFTFGs) has been studied in this research. This study aims to investigate the ability of tubular flange to increase resistance of steel girders against Lateral- Torsional Buckling (LTB). For this purpose, experimental, and numerical analysis were carried out.The experimental work consisted of fabricating and testing of five specimens. The first specimen with flat plate flange considered as a control specimen and the other specimens with tubular flanges. In tubular flanges specimens the effect of filled and non-filled tubular flanges with concrete also, the geometry effect of tubular flange sections, i.e. depth (40 and 20 mm) were studied. These specimens have the same length (1920 mm) and the same overall depth (170 mm). The specimens were tested under two point loads applied at the third-span points. The second part was a numerical one using the finite element method by software package (ANSYS 14), then employed to investigate the nonlinear behavior of tubular flanges girders and a similar numerical study of conventional I-girders was conducted, then the results compared with those of tubular flange girders.The measured experimental results were; the ultimate load capacity, load- vertical deflection, load- lateral deflection and load- twisting angle. Finally, the tubular flange specimens increased the lateral torsional buckling capacity comparing with the standard I-shaped steel members by about (66-97%), while bending strength increased by about (33-55%) for tubular flange section filled with concrete of 42.5 MPa. The concrete filled tubular flange increased the LTB capacity by about (14- 22 %) comparing with the unfilled specimens, also increased the flexural strength by about (13-22%). Thus, tubular flanges girders allowed using for large unbraced girders due to increasing the torsional stiffness of the girder. The numerical models were carried out by software package (ANSYS 14). The results were found to be in a convergent state with those obtained from the experimental tests. Keywords: Lateral–torsional buckling, finite element analysis, and tubular flange girder.
Issue No: Vol. 8