Construction Technology and Management

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5D Planning, Scheduling and Control of Construction Projects by Integrating Project Management Software and GIS
(AAU, 2017-12) Sitota, Girma; Abebe, Dinku (Prof.)
Construction industry can be deemed as the most vital driving force of a country. Construction of vast projects such as township, stadiums, and dams is a challenging task both in terms of managing complexities of the project and addressing the demands of all stakeholders. Its success or failure largely depends on cost effectiveness, time-bound delivery, quality and amount of resources available throughout the lifecycle of the project. This clearly turns the focus towards effective construction project management. Today’s demand of construction industry requires highly accurate planning, scheduling and management of the process of a project which can enable the overall optimization of cost, time, and resources. With the advances in information technology, its use is being constantly explored in the area of construction planning and monitoring. The aim of this study is to demonstrate the methodology of integrating Geographic Information System (GIS) with construction project management to provide a better solution for optimization and real time monitoring of the progress of a project. GIS is a computer based tool and being used extensively to solve various engineering problems involving the use of spatial data. The technology provides capabilities to solve problems involving creation and management of data, integration of information, visualization and cost estimation to which most of the construction management software are lacking. In spite of the growing popularity its complete potential to the construction industry has not been realized. Integration of GIS and Project management might assist a planner in a better perception of a project as well as in the integration of other parties’ activities in the planning process. It will provide a common basis of understanding and communication among stakeholders. This helps in reducing construction errors occurring on sites and thereby reduces the amount of administrative time. In this research paper a review of up-to-date work on the applications of GIS technology in construction industry is presented. Methodology to generate 3D view of a building and to represent construction schedule within GIS environment is also discussed. With this, integration of GIS and Project Management is developed using AutoCAD, MS-Excel, ArcGIS, and Visual Studio to assist construction managers in controlling and monitoring a construction progress. With time as the fourth dimension, the progress of construction task can be displayed as 4D (3D + time) view. The 5D (3D + time + cost) model of progress monitoring is beneficial to all stakeholders and can be opted as the future of planning and monitoring in the fast developing construction industry. A case study of one story building is selected for the purpose of presenting the integrated tool for progress monitoring. Ultimately, an easy to use Graphic User Interface (GUI) named as “5D Construction Monitoring Application” is developed to enable project participants have an idea of the current status of a project at run-time. The paper explores the potential of GIS environment in developing a construction project information system for rate analysis; and safety and quality control recommendation. It also suggests that the proposed GIS based methodology may replace manual methods used to extract information from the available database and can be easily updated as most of the information is in digital format. Successful project control is a challenging responsibility, but the job becomes easier when it is complimented with visualization of information. The propositions presented herein could facilitate and accelerate this trend, and as well provide means of measuring the success of implementation of 5D planning in construction projects and be a basis for further research.
Alternative Concrete-Steel Building Construction for Social Housing Projects
(Addis Ababa University, 2008-11) Eshelll, Tsehaye; Taye, Shifferaw(PhD)
In this thesis an alternative steel-concrete social-housing is studied with the comparison of the existing cost-efficient construction projects. To accomplish the work the presenter has been point out the problems manifested in the country especially the capital city, Addis Ababa besides the historical development, role and policies of social-housing is presented. In addition the design of G+4, Type B social-housing building is considered in the course of this the design guide line from the design of roof to the footing design is carried out. To complete the design the 3D Model of the frame is analyzed using ETABS 9 software; all loads induced on the frame are considered. Besides the design of the building some construction defects of the normal concrete construction is stated. Since the main aim of this thesis is focused on the alternative steel-concrete social-housing building, the design guide line is specified. The steel process from the design to erection is accomplished by considering bill of materials, erection and detail drawing. And special consideration in structural design and construction is prepared. Finally, the comparison and structural evaluation of the two systems is carried out based on economy, and management and efficiency. From the comparison, some conclusion and recommendation are forwarded.
Alternative Dispute Resolution Methods in Construction Industry: An Assesment of Ethiopian Situation
(2005-07) bekele, Aberra; Dinku, Abebe(PhD)
The aim of every construction project stakeholder is the completion of a project that meets the objectives of time, cost and quality. However, the construction process is often fraught with disputes over the interpretation of construction documents, existing conditions, the legitimacy of variations, timely payments, etc. The emerging Alternative Dispute Resolution (ADR) methods which are non-litigation alternatives offer opportunities for effectively resolving disputes in the construction industry. Depending on the nature of the relationship between the parties involved in the disputes and the circumstances under which the dispute is evolved, different methods of dispute resolution mechanism may be preferable. This research reviews alternative dispute resolution methods in construction industry with an assessment of the Ethiopian situation. It provides insights into decisions making on appropriateness of dispute resolution method that suit their needs. These days both public and privately owned construction projects are increasing through out the country. The industry must change its treatment of conflicts, claims and disputes. Time should be used for works instead of wasting time for unnecessary litigation, and out-of-court dispute resolution methods need to be developed in the processing of construction management and project contract administration. The Ethiopian civil codes that deal with contract in general and construction contract in particular are reviewed in this thesis. Construction of public works made by the Statutory or other administrative authorities that is governed by administrative contract as stated in civil code is also considered in the research. Compromise and Arbitral Submission proceedings are addressed in the civil code with due procedure for detail implementation. The legal application of conciliation and arbitration relevant to public works and administrative contract, are examined in the research. The arbitrability of administrative contracts has controversial implications on the civil procedure code article 315 sub articles (2) and (4).
Alternative Project Delivery Methods for Public Constructions: Cases in Oromia Region
(Addis Ababa University, 2006-09) Mosissa, Lema; Jekale, Wubshet (PhD)
Ameliorated Design and Construction Techniques of Pavements on Expansive Soils.
(Addis Ababa University, 2003-02) G.hiwot, Tekeste
The main cause of the economic losses incurred for pavements built on swelling subgrade is the lack of appropriate selection of the design and construction method adopted to alleviate the swelling phenomena. The extent of the problem depends mainly on the degree of expansiveness of the soil and the corresponding climatic conditions. Current situation Ethiopia shows that random selection of design & construction methods is widely practiced despite the various soil and climatic condition. Most of the practices aim at undefined use of the design and construction method that results in uneconomical and unsafe pavement design. The effectiveness of the methods depends also on the selection of the design depth, a design depth that suits the technical and economical conditions. Chapter two consists the review of the performance and suitability of the various design and construction method adopted in most part of the world including Current practices in this country. In Chapter three, an attempt has been put to see the consideration of potential expansiveness and assessment of the various prediction methods of heave and swelling pressure for the existing experimental values.
Analysing the Planning and Scheduling of 40/60 Saving Houses Development Enterprise
(Addis Ababa University, 2016-11) Oumer, Hassina; Assefa, Abraham (PhD)
One of the major challenges of Addis Ababa city is lack of shelter and unemployment as identified by city administration of Addis Ababa, which needs an urgent remedy. In order to solve these challenges, the city administration has established an integrated housing development program which has to be planned to change the image of the city, to modernize the life style of the society, and to promote the construction industry. In Addis Ababa slum upgrading, public-private partnership for housing production, and direct government low-cost housing are undertaken with varying degrees of success. However, the vast majority are uncoordinated, small in scale compared with demand, and often do not reach the target low income beneficiaries. There is a critical problem in the construction of these saving houses in Addis Ababa that had limited the timely delivery of the houses. The objective of this research was to investigate the planning and scheduling phases of saving houses development enterprise construction projects by identifying the project planning elements and the project resource requirements by to comparing and contrasting the resource constrained and unconstrained schedules. To identify the resource availability the scheduling is done by as resource constrained schedule. This exploratory study applied an inductive approach with the use of both qualitative and quantitative case studies, by collecting and analysing textual data through document analysis, interviews, observations and resource determination using MS Project. To effectively evaluate a project planning and scheduling the schedules submitted by the contractors were collected and evaluated. The best contractor schedules were identified using a schedule goodness index. A resource driven schedule was also proposed and developed, and was compared with contractor’s submitted schedule to identify the resource gaps. The research results showed that the lacks of planning in saving houses development enterprise are due to: lack of technical knowhow, poor institutional arrangements, and weak legal frameworks. The gaps are identified and recommendations are forwarded for both the client and contractors. Key words: Project management, Housing, Planning, Scheduling
Analysis of Earthmoving Operation Using Discrete-Event Simulation
(Addis Ababa University, 2020-05) Yemane, Gebrezihier; Abraham, Assefa (PhD)
Earthmoving operations are a sizable and heavy portion of most civil construction projects. It includes cyclic work, expensive fleet, and a large volume of works. Earthmoving operations are difficult to plan and operate because of their operation complexity, uncertainty in the operation process, and environment. Due to this fact, and as the earthmoving operation process is cyclic, i.e., the events (activities) occur in a discretized manner. Therefore, Discrete-Event Simulation (DES) is found to be the most effective approach to analyze and model their improvement strategies for their operational performance. The main objective of this thesis is thus to analyze the current earthmoving operation practice, develop the DES model, and develop improvement strategies for the earthmoving operation production system. In this thesis, 421 field data instances were collected through observation from the sample road construction project. Out of this, 345 of the data instances were collected from the earthmoving operation process of selected materials. Simphony CYCLONE simulation software was used as a simulation tool. A detailed earthmoving operation simulation model with various adaptation (or scenarios) based on the types of loading equipment (loader and Excavator) and types of material (selected and crushed unbounded) is developed. The simulation experimentation and sensitivity analysis were performed to optimize production rates and resources' utilization levels of the earthmoving operation processes. Accordingly, in the case of selected material operation, assigning ten trucks, single dozer (stockpiling), Excavator, and dozer (spreading) is more effective in production rate and resource utilization. Besides, there is no significant difference in production rate and utilization of the resource between the overall and excluding the embankment work of retaining wall and box culverts of selected material. Additionally, in crushed unbounded material operation, assigning 27 trucks, two loaders, and a single grader is more effective.
Analysis of Supply Chain of Domestic Steel Reinforcement Bar For The Construction Projects in Addis Ababa
(Addis Ababa University, 2018-06) Robel, Awonchefew; Girma, Gebresenbet (Prof.)
Domestic production and supply of construction raw materials such as cement, steel reinforcement bars,sheet metals, aluminum, glasses, etc. have been far less than the domestic demand, therefore, by resulting in widening gaps and increasing prices.There is lack of integration of producers, wholesalers and retailers for fulfillment of consumers’ requirements withmaterials, cash and information flows.So, this research tries to show the flow of reinforcement bar across the supply chains with their bottleneck by identifying the major actors, levels of cost and lead times in the chain. The Primary data was collected through questionnaires and interviews, whilesecondary data wasfrom different sources through desk study. The collected data has been analyzed using Relative Importance Index (RII), Statistical Package for Social Science (SPSS) and GeographicalInformation System (GIS). Thefinding shows that, the major stakeholders and in the supply chain networks of domestic steel reinforcement bar for the construction projects of Addis Ababa city. Andalso the flow network of material, information and cash between each parties. The research also indicates that the major factors that affect the performance of domestic steel reinforcement barsupply chain network in the city. The astonishing finding of the research is the cost of steel reinforcement bars increased by 84%,as it moves across the supply chain network. At the same time95% of contractors complained with the high cost of domestic steel reinforcement bar. Theaverage delay for contractors is 26, for retailers is 33 and for wholesalersis 52 days respectively. In Addis Ababa city, the demand of domestically produced steel reinforcement bar has been increased in construction, throughout the years.There is a lack of integration between producers, wholesalers and retailers, in the supply chain network of domestic steel reinforcement bar.In order to develop successful and well-organized supply chain networkof steel reinforcement barfor construction industry, first, the problems mentioned in the research be solved.
Analysis of Suspended Rectangular Slab Panels Under Partial Rectangular Uniform Load
(Addis Ababa University, 2006-10) Tesfaye, Mikias; Zerayohannes, Girma(PhD)
In structural engineering there are different types of duties; amongst them the analysis part is the most important and crucial part. Because of this it has been given a great focus. Analysis techniques for most structural elements with different arrangement of externally applied loads are well developed and sufficiently covered with modern analysis theories. Further more, the application of today’s high-speed computers enable the analysis of complex structures with different load arrangements. In addition to these effective analysis tools, building design codes provide table of values and analysis charts for the analysis of different elements of structural systems. As one of the structural element in building structure, different analysis methods were proposed for the analysis of suspended slab panel subjected to uniform rectangular loads. Among the possible arrangement of externally applied loads on suspended slab panel a uniform rectangular load is the one which can best represent the weight of heavy machineries, water tankers, etc. Different simplified analysis methods were proposed to consider the contribution of this load to the design action effects. The current practice of accounting these loads in the analysis of suspended slab panel is to change it to the 'equivalent' uniformly distributed load. The analysis of regular slab panel subjected to uniformly distributed load may be carried out using computer soft wares or using coefficients which are presented in many design codes, the Ethiopian Building Code of Standards for concrete structures, EBCS 2 – 1995 can be one example. These methods analysis need to be investigated whether they can represent the actual load or not. Therefore, as it is important to address this problem, comparative analysis has been carried out. A new simplified method which considers the actual scenario has been developed. This newly proposed method makes use of coefficients derived from the basic principle of elastic analysis of plate. The results have been verified by comparing it with results of the finite element analysis. It enables us to make elastic analysis of suspended slab panel subjected to the weight of a uniform rectangular load and avoids the uncertain use of approximate methods.
Analysis, Design and Cost Effectiveness of Precast Beam-Slab System
(Addis Ababa University, 2009-07) Kebede, Matheas; Zerayohannes, Girma(PhD)
Pre-cast beam-slab is made of pre-cast reinforced concrete beam together with hollow blocks. The pre-cast beams are spaced at certain intervals and the hollow blocks are placed on them to form a working platform with out the use of formwork. The slab HCB, hanging between the pre cast beams are functioning like a formwork. They give only a temporary support during the installation phase. Only the pre-cast beams and the slab concrete are load bearing parts of the slab. In our country pre-cast beam-slab system is not widely used for construction of most buildings. The conventional cast institu constructions require lots of formwork and construction time, which increase the total cost of a project. When pre-cast beam slab systems are introduced in the construction of buildings, an economical construction could be achieved. In the present study, two types of pre-cast beam elements are chosen. Experimental studies are made on these beam elements by casting them in the laboratory condition. From experimental observation, there tried to come up with a new theoretical model. Loaddeflection data was taken from the experiment and compared with the theoretical output. Furthermore cost comparison is made between the two systems of slab construction. For the arrangement of panels used to compare cost, the pre-cast beam-slab system of construction is more economical than the conventional system. Finally, the model gives a hint for future study in trying to simulate the actual pre-cast beam slab system.
Analyzing Change Orders in Selected Ethiopian Road Authority Asphalt Concrete Road Projects Constructed by Foreign Contractors
(Addis Ababa University, 2015-08) Demeke, Fikreyesus; Dinku, Abebe(Professor)
The road construction process is a complex one and is associated with various changes. It is virtually certain that changes made during the course of work which affect cost and schedule. Currently ERA is constructing many asphalt concrete road projects which are susceptible to change orders and there is no enough study that addresses the frequent effects of the change orders in overall cost of the asphalt concrete road construction process and time of completion. This study investigated the causes of change orders and their impact on ERA asphalt road project performance. Causes and impacts of change orders are analysed by formulation of questionnaire based on extensively reviewed literature and case study on selected 10 ERA asphalt concrete road projects. It was concluded that change of plans or scope, change in design, error and omission in design, right of way issue, negligence during design, change in specifications, value engineering and lack of data for design and experience in predicting underground condition were some of the critical factors causing change orders. In the archival study of 10 selected Ethiopian road authority projects change order contribute 8.74% increase in average cost per project and design consultant initiated 65.38% of change order costs. The most frequent impacts are project cost increase, completion delay, source of additional payments for contractor, increases in overhead expense, and results in hiring new professionals. Interims of change order impacts severity rank increases in project cost, completion schedule delay, aadditional payments for contractor, increases in overhead expense, and productivity degradation factors constituted the most visible consequences of variation orders that affect project advisedly. ANALYZING CHANGE ORDERS IN SELECTED ETHIOPIAN ROAD AUTHORITY ASPHALT CONCRETE ROAD PROJECTS CONSTRUCTED BY FOREIGN CONTRACTORS The findings of the study will increase the awareness on causes of change order and its impact on overall construction project performance which will enable the development of proactive measures to reduce them. Key words: asphalt concrete ,cause, change order, control, cost, effect
Application of Data Mining Techniques for Conceptual Cost Estimation of Selected Building Projects in Addis Ababa
(Addis Ababa University, 2021-12) Biruk, Lemlem; braham, Assefa (PhD)
For project managers and decision makers, developing an accurate cost estimate in the conceptual stage of a project is a crucial but challenging task. Different techniques and methods have been devised and researched to accurately estimate the cost of building projects at the preliminary stages. These methods can broadly be divided into two based on the approach they follow. The cost –based or parametric cost modeling approach uses historical cost data and different Data Mining techniques to develop a cost prediction model. The second method uses a bottom-up or quantity strategy, in which data on the quantity of works is utilized to construct quantity prediction models for each work item. These predicted quantities can then be multiplied by their current unit rates to determine the respective costs. In this study a parametric cost model is first developed to assess its accuracy in predicting the final cost of building projects based on historical data collected from selected building projects in Addis Ababa. This was then followed by doing a comparison between the cost based and quantity based approaches by developing models for structural cost prediction as well as quantity models for the different work items that make up the structural work (concrete, reinforcement, and formwork). Concurrently, the study explored the effectiveness of four data mining techniques, namely Linear Regression (LR), Decision Trees (DT), Neural Networks (ANN), and Gradient Boosted Trees (GBT) in estimating the final and structural cost of building projects. With a relative error of 37.05%, the ANN model was the most accurate in forecasting the final cost of a construction project, while the GBT model performed better in predicting structural costs with a relative error of 22.67%. For quantity estimation models, the NN model showed superior performance for concrete and reinforcement quantity estimation with a relative errors of 16.44% and 19.32% respectively. The GBT model on the other hand performed better in formwork quantity estimation with a relative error of 19.58%. Accordingly, the total slab area was identified to be the most important variable for all prediction. The study indicated the quantity based approach provides more accurate cost prediction as opposed to the cost based approach for the case of structural cost estimation.
Application of Load Bearing Brick Wall for Low Rise Condominium Projects in Ethiopia and Assessment of Locally Produced Bricks
(Addis Ababa University, 2017-07) Betelhem Bayou; Abraham Assefa (PhD)
Bricks are one of the oldest building materials in construction. Application of bricks in construction of Ethiopia is not new. They are used for construction of internal and external walls in all over the country. Once more brick is commonly used building material; however, there is a tendency to use brick masonry more as cladding and in-fill material rather than as a structural material. In order to solve the housing problem in Ethiopia, saving-house condominium projects, realestates, and private residential buildings have been constructed in many regions of Ethiopia for the past decades, there is also a bigger plan set by the government for the next GTP. From the past experience of building projects, wastage of materials, unsafe construction process, poor quality of output, high time and cost overrun, and risk of failure due to structural errors and mistakes made during construction process have been observed. The objective of this study is to assess locally produced bricks quality and availability to recommend a load bearing brick wall construction for low rise residential building and compare the cost with concrete frame structure building of the same plan, form and story. Over centuries, the utilization of bricks in construction has evolved significantly. In developed nations, bricks have emerged as the primary load-bearing system for various types of buildings, spanning from modest single-story residences to relatively tall commercial and industrial structures. Extensive analysis conducted on developed countries showcases the cost-related benefits of employing bricks. Additionally, brick walls exhibit excellent thermal insulating properties, leading to reduced fuel consumption and manufacturing energy expenditure. The analysis establishes that a three-story load bearing building can be built from locally produced fired clay bricks. There is also overall saving in both materials and cost when using load bearing structure instead of reinforced concrete of the same selected apartment building. The encouragement of the load bearing structure will result in the establishing number of modern factories for brick and clay product in Ethiopia.
Application of Modern Formwork Systems in Ethiopia
(Addis Ababa University, 2014-04) Tarekegn, Argaw; Dinku, Abebe(Professor)
The quality of resulting concrete can be dictated by the quality of formwork materials and workmanship. Many concrete related problems such as discoloration, stains, and dusting are attributed to concrete formwork. Formwork operations are also risky and workers are exposed to unsafe working conditions. Moreover traditional formwork construction has negative impact on the environment. The objectives of this research are to assess the current practices of formwork construction in Ethiopia and identify problems such as loss of productivity, delay of projects, safety problems and environmental effects. Recommendations of modern formwork systems which alleviate such problems are also the objective of this thesis. The study was conducted by taking formwork systems of the famous formwork producing and renting company, PERI Germany, as the case study. Almost all the products of the company were studied through desk study. Questionnaires and interviews were conducted among contractors in Addis Ababa to get relevant data which helps to achieve the objectives of this thesis. Formwork rental companies and regulatory bodies in Addis Ababa were also interviewed. The results of the research show that alternative formwork materials are not well known and used in Ethiopian construction industry. Steel panels and timber are the prominent formwork materials. The use of modern formwork systems will increase the local labor productivity to ten times the traditional one. About 60% of the total time will be saved if new construction systems are adopted by construction firms in Ethiopia. Formwork construction practice in Ethiopia is not safe and environmentally friendly. Seventy nine percent of the respondents have recent record of injury and death which emanates from formwork construction. Finally, modern formworks such as MULTIFLEX, TRIO, QUATTRO and UZ are assessed and recommended for major construction projects in Ethiopia.
Application of Multi-Criteria Decision-Making Based on Combined Analytic Hierarchy Process and Linear Programming as an Alternative for Project Selection: The Case of Ethiopian Road Authority Road Projects
(Addis Ababa University, 2022-06) Tewodros, Abere; Abraham, Assefa (PhD)
Resources are limited for pursuing and funding new projects hence the challenge is to prioritize, select and allocate optimally. Ethiopian public projects encountered challenges in selecting best projects, finishing in time and cost. The project selection methods commonly used are quantitative in nature and they lack to account for intangible factors which can affect the outcome of project appraisals. An integrated Analytic Hierarchy Process and Linear Programming model that considered both quantitative and qualitative factors in choosing capital project is presented. The combined model is applied in Ethiopian Roads Authority road projects with Planning and Development Commission and Ministry of Finance as prime stakeholders in project selections. Research surveys were conducted in those organizations and secondary documents were used for the analysis. The results indicated project characteristics, with 0.5 weight, were ranked higher than other criteria related to the firm characteristic and external factors with weights of 0.36 and 0.14 respectively. The most important project selection sub-criteria found to be profit, measure of worth, project risk, financial standing, and resources with the overall weight of 0.15, 0.13, 0.12, 0.10 and 0.09 respectively. Others are economic factors, experience, technical ability, size & complexity, duration, organization culture, environmental, location factors, social responsibility, and political factors with weights of 0.07, 0.07, 0.07, 0.06, 0.04, 0.03, 0.02, 0.02, 0.02, and 0.01 respectively. Four projects out of six total projects were selected to have the most use of resources under the available resource constraints. The study provides a simple framework that can be used by organizations to make these challenging decisions. The integrated model is recommended for its ability to capture all possible factors, optimality advantage and applicability in different situations with refining the selection criteria.
Application of Self-Compacting Concrete for Dam Construction
(Addis Ababa University, 2017-05) Birbirsa, Derese; G/Youhannes, Esayas
SCC is mainly characterized by its flow ability to pass through and bond congested reinforcement under its own weight and high resistance to aggregate segregation. Now a day the use of this material in the construction industry is becoming common. However the use of SCC for mass concrete structures like dam construction is not common, because due to its high cement content, it can cause thermal cracking problems and increases the project cost significantly. But studies show that by increasing the maximum aggregate size in self-compacting concrete, and decreasing the unit cement content by partial substitution of cementations material, this problem can be minimized. The aim of this thesis is to find alternative construction material for dam construction from SCC and preplaced aggregate and compare its performance and material cost with that of conventional concrete. the new material in this research is a combination of SCC and preplaced aggregate. The maximum aggregate size used for the SCC mix is 12.5mm and for the preplaced aggregate is 300mm. To study the required performance of this material, three different mixes were used. The first mix is C-25 conventional concrete which is used as a reference mix and the second mix SCC in which only cement is used as a powder material. In the third mix the SCC was prepared by partially replacing the cement with limestone powder. Finally, a dam model was prepared in the laboratory to test the combined performance of SCC and the preplaced aggregate when it is used for dam construction. All the cubic and the core samples from the dam model was tested for its compressive strength and permeability and compered with each other. According to the test result, the SCCs are less permeable than the conventional concrete and the core sample from the dam model. The compressive strength of the core sample is much less than the conventional concrete. The cost analysis also shows that the material cost of conventional concrete is higher than the dam model. Keywords: dam model, limestone powder, self-compacting concrete, super- plasticizer.
Applications of Web Based Construction Communication in Ethiopian Federal Road Projects
(Addis Ababa University, 2014-06) Tilahun, Getu; Dinku, Abebe(Professor)
Due to fragmented nature of construction, real time communication is rarely possible requiring more efficiency and effectiveness in information exchange and decision making. Since an integral component of a construction process is accompanied by set of decisions, delay in response would lead to an integral component of delays in project execution accumulated over project life to an overall project cost and time overrun with possible loss in desired quality. Study application of Web Based Construction Communication aimed at assisting evidenced real time communication and decision making, information storage, retrieval, manipulation and transmission among project participants parallel to the paper based project communication scheme has been conducted using simple and user friendly web site designed to operate on locally used common browsers. Project information is collected from Ethiopia Roads Authority and imported to the database and file system designed for data storage and retrieval. The functionality of the website is then tested and found effective to enhance evidenced real time communication. Apart from serving as documentation and retrieval of project information, the website includes online discussions tools similar to forum type aimed for general discussion and RFI comment exchange. Project daily activity photographs and daily site records are uploaded to the site for display and comment by the parties. Therefore, the web based construction communication developed can help to have an evidenced real time communication for decision delivery and document management system to contribute to a way out of project overruns with competitive advantage in the complex construction industry. Keywords: construction project information management, real time communication, web based construction communication
Appropriate Solution for Impervious Core of Embankment Dams to be Constructed Using Highly Plastic Soils
(Addis Ababa University, 2007-10) Adane, Wuletaw; Seged, Hadush (PhD)
For a long time, highly plastic clays (CH soils) have been used extensively as impervious core material for many zoned embankment dams all over the world. In Ethiopia several dams are currently under construction (e.g. Tendaho dam) and more are planned to be constructed (e.g. Ribb, Megech, Meqa dams, etc.) using predominantly CH soils as the most available impervious core material. Nevertheless, several problems are associated with CH soils. The most common problems include high compressibility when saturated, potential for high swelling and cracking, slow rate of construction for safe dissipation of pore water pressure, large difference in stiffness with the surrounding shell materials leading to differential deformation, difficulty in moisture control during construction, and requiring extremely fine filters that can not be easily obtained or produced on site. In this thesis, a study has been conducted on the effects of blending the CH soils with naturally available granular materials using several laboratory tests. The laboratory tests include Atterberg limits, permeability, compaction, 1D-consolidation, and triaxial compression tests on samples collected from Tendaho dam site. The test results clearly reveal that blending with granular soils greatly improves the physical and mechanical behaviours of the CH soils. Based on the test results, an appropriate blending ratio has been recommended for the CH soils used in Tendaho dam.
Approximate Uniaxial Interaction Diagram For Slender Column Using Second Order Formula From Ebcs2, 1995
(Addis Ababa University, 2012-04) Getachew, Kabtamu; Zekaria, Adil(PhD)
In concrete buildings, recently the design of column is increasingly determined by architectural, aesthetic, and economic criteria leading to slender cross-sections of columns. However, slender column design requires rigorous analysis to account second order effect due to deflection of the column. Because the deflection provides additional eccentricity to axial load that induces additional second order moment. If second order effect is not considered adequately, it can cause stability failure, which is catastrophic. Since exact rigorous analysis demands more computational effort, simplified methods have been proposed in building codes such as EBCS_2, 1995, CEB_FIP1990 and ACI code still that involves iterative procedure. Moreover, even recently developed commercial computer programmes such as ETABS and SAP2000 do not consider second order effects due to the deflection of the column between its ends adequately as compared to relative deflection between ends of columns. In this thesis, approximate uniaxial P_M interaction diagram for non-sway slender RC rectangular column is presented based on the simplified method of EBCS_2, 1995-second order eccentricity formula (deflection between two ends of a column) which is rather simple and unsophisticated for design of slender column. For the preparation of the interaction diagram, cross section interaction diagram and column slenderness is used. Since the slender column capacity is smaller than short column capacity, the cross section interaction diagram is modified so that it would have a room for the slenderness effect. This is made by deducting additional moment due to second order and geometric imperfection eccentricity from cross section interaction diagram. Finally, the approximate interaction diagram is checked for its validity and satisfactory result is obtained. Therefore, the interaction diagram can be used as a design aid as well as preliminary cross section capacity estimation since it is very easy and quick method. Moreover, it can be used for checking of computer output
Assessing the Cause of Failure of SMM Construction Companies in Addis Ababa
(Addis Ababa University, 2019-05-17) Animut, Arega; Abraham, Assefa (PhD)
The importance of small, medium and micro enterprise contractors in Ethiopia has been recognized by many researchers and policymakers. The contribution of small contractors to the creation of jobs and to the alleviation of poverty has also been recognized by many developing countries including Ethiopia. However, these enterprises have got many problems which are causing failure in their business, especially in the construction industry. The main objective of this thesis is to assess the cause of failures that are facing on Small, Medium and Micro Enterprise (SMME) construction companies in Addis Ababa. The research used a questionnaire survey on 162 SMME construction companies and case studies to achieve the study objectives. The research was focused on organizational and economic- environmental related factors which were the cause of failure of these enterprises. The managerial, financial, expansion and information technology related factors were classified as organizational challenges while marketing, payment, regulation and policy related factors were studied as economic- environmental related factors. The research established that marketing factor is the most challenging factor which becomes the cause of failure of SMME construction companies in Addis Ababa. Next to marketing factor, another challenge which usually happens in SMME construction companies in Addis Ababa is a financial problem. This occurred due to late payment from the client and lack of working capital from an enterprise. According to research results, managerial, ethical, information- technology and government policy and regulation related factors were other challenges which has faced on SMME construction companies. The research has also suggested some recommendations for the concerning bodies, as they need to have an appropriate understanding about these factors in order to solve marketing, financial, managerial, ethical and government policy and regulation problems. These will assist SMME‘s to flourish and achieve their objectives of profit, growth and employment opportunities and also reduce poverty. Therefore, it is important for the government and nongovernmental organizations together to formulate their policies and strategies which makes easy to meet the goal of these enterprises.

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