Civil Engineering

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    ASSESSMENT OF TRAFFIC CONGESTION AND ITS IMPACT OVER SELECTED ROAD CORRIDOR IN ADDIS ABABA CITY
    (Hawassa Inversity, 2019-10-19) DAWIT GETACHEW ERGA
    Traffic congestion problem is becoming a common problem in most developing countries of world. This study was conducted with an objective making assessment of traffic congestion and its impact over the selected road corridor in Addis Ababa City. Through reconnaissance survey the corridor from ‘Awutobis Tera’ Bus station to ‘Lamberet Menahereya’ in Addis Ababa city was identified and for analysis purpose the corridor was divided into three sections. The study was conducted starting from June up to October, 2019. Both quantitative and qualitative approach were used. 384 samples were used to conduct questionnaire survey for traffic congestion cause analysis. Out of this 32.5% of the required sample were drawn from section A, 27% from section B and the rest 40.5% was from section C. For making analysis on the performance level of road corridors and economic cost of traffic congestion, traffic volume, travel time delay, average travel speed and vehicle occupancy data were collected manually for a period of 12 hours a day at 15 minutes intervals on respective road corridors and for intersections the data were collected for two hours interval during rush periods. In addition to traffic condition data, the geometric data were also measured as part of the study. The analysis on causal factors for traffic congestion was conducted by SPSS software and analysis on level and economic cost of traffic congestion of the selected road corridor was conducted by utilizing both SIDRA and Microsoft excel. Based on the result of analysis multi variable linear regression model, the imbalance between vehicle volume and road capacity, number of pedestrians that cross and move along the side of the road, inflexible work schedule, inadequate mass transit service along the corridor and illegal on street vehicle parking were identified as the main causes of traffic congestion over the road corridor. As the result from SIDRA and Microsoft excel showed that the intersections along the corridor and the road corridor in section C were operating beyond the standard set by HCM 2010 which recommends LOS ‘C’ or ‘D’. As per the economic analysis result of the study showed about 2667.8 person-hours/year and ETB104048.75 /year per individual traveler are being wasted due to traffic congestion over the study road corridor. Building vehicle parking apartment, elevated pedestrian crossway and improving performance of intersections were some of the engineering measures recommended to overcome the traffic congestion problem of the corridor.
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    MODELING LEVEL CROSSINGS’ TRAVEL TIME AND DELAY CHARACTERISTICS OF ADDIS ABABA LIGHT RAIL TRANSIT (AA-LRT)
    (Hawassa University, 2019-04-17) DARIC TESFAYE
    Traffic modeling is simplified representation of a part of traffic reality that provides a better understanding and interpreting of the complex traffic interactions. The objectives of this study is modeling level crossings travel time and delay characteristics of Addis Ababa light rail transit (AA-LRT) using simulation and mathematical models and evaluate the operational characteristics of the level crossings. In the process of achieving the objectives, the study investigate about peak period vehicle volumes, compositions, routings, LRV arriving frequency ,speed and the delays experienced. To meet the objective of this research intersection geometry data from field and traffic flow data at selected intersections is done by video recording and manual counting. In addition travel time data using light rail transit and minibus taxi is collected by traveling using these modes to a statistical number of repetitions. Suitable data inputs in forms of traffic volume, vehicle composition, vehicle routing, speed, train headway, travel time and delay at different incidences including level crossings are prepared. These suitable data inputs are introduced into VISSIM and SPSS analysis soft wares. Finally, the results were interpreted and the key research findings were presented in two types; i.e. through VISSIM simulation and SPSS statistical models. At the CMC level crossing the baseline without LRT scenario the average delay of traffic is 134.62s/veh ,the actual scenario with 00:05:41 LRV headway the average delay of traffic is 135.2 s/veh the delay increased by 0.43% and twice arrival frequency scenario the delay is 136.22s/veh with an increase in delay of 0.76% from the actual conditions. At the Sebategna level crossing the baseline without LRT scenario the average delay of traffic is 22.31s/veh ,the actual scenario with 00:06:30 LRV headway the average delay of traffic is 23.53 s/veh the delay increased by 5.47% and twice arrival frequency scenario the delay is 33.11s/veh with an increase in delay of 40.7% from the actual conditions. Additionally as observed in the mathematical model equation, the train’s travel time is dependent on running time, delay at grade intersection, open door close door time, close door start movement time and stop open door time in descending order. It is concluded that the average additional delays at level crossings increase from the base scenario and with increasing light rail crossing frequencies. In addition, delay at the level crossing is the second important variable that contributes for the variability of train travel time at peak hours.
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    OPERATIONAL ANALYSIS OF UNSIGNALIZED INTERSECTION AND ROUNDABOUT UNDER MIXED TRAFFIC FLOW CONDITION OF SELECTED INTERSECTIONS IN ADAMA CITY
    (Hawassa University, 2020-10-06) DARARA BERHANU KURU
    Urban traffic congestion is currently severe in most cities in the world due to economic and social development. Prevalently, Ethiopia is one of the countries that are in rapid economic development. This influences the travel pattern of the community from their origin to any destination. Adama is one of busy transportation center in Ethiopia. The city is situated along the road that connects Addis Ababa with Dire Dawa. A large number of trucks use this same route to travel to and from the seaports of Djibouti. A little attention has been paid to junctions and their capacities. There are a few studies conducted to assess the capacity of junctions in Adama. The main objective of this study was to evaluate operational performance on both unsignalized and roundabout junctions which are necessary for transport professional’s and governors to put tangible information for future traffic growth of Adama city. This thesis addresses the most important element of operational performance of unsignalized intersections and roundabouts traffic intersections in Adama City on capacity analysis. The methodology employed for this study was the quantitative descriptive research design which used quantitative data and analyzed using SIDRA 8.1 intersection software model. The movements of the vehicles were observed at three roundabouts and seven unsignalized intersections for a duration of two hours. The necessary geometric data for the analysis (average entry width, circulatory road width, number of entry and circulatory lanes, and island diameter), traffic movement data with vehicle characteristics and pedestrian volume were collected. The capacity analysis was done based on the gap acceptance method that is adopted by SIDRA 8.1 software program. Based on analysis results, Derartu Tulu roundabouts and six of selected unsignalized intersections i.e Mebrathayil,Sartera,Wonji,Tikur Abay and Alem Hotel junctions are currently serving in poor condition of level of service of F by having v/c ratio >1. Genda Gara and Medanihalem roundabouts are serving at their best operating condition having level of service A.The rest two unsignalized intersection Geda and Diamond Cafe have level of service of D and C respectively. The overall level of service of the unsignalized intersections and roundabouts are serving at poor level of service. Thus, after carrying out additional detail investigation and taking into consideration future traffic growth appropriate improvement should be made by concerned bodies
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    Land Degradation Dynamics Under Land Use Land Cover and Climate Change Projection Towards the Appraisal of Potential Soil and Water Conservation Practices in the Gidabo Watershed, Ethiopian Rift Valley Lakes Basin
    (Hawassa University, 2024-10-11) Rediet Girma Legesse
    The intricate relationship between land use, climate dynamics, and land degradation profoundly impacts the sustainability of ecosystems and human well-being in Ethiopia. This study, conducted in the Gidabo Watershed (GW) within the Ethiopian Rift Valley Lakes Basin (ERVLB), aimed to assess the long-term land use land cover (LULC), evaluate regional climate models (RCMs), assess land degradation indicators, and propose management alternatives. To address these objectives, multidisciplinary approach integrating, remote sensing, geospatial analysis, statistical metrics and hydrological modeling were used. The study identified nine major LULC classes i.e., water body, grass land, forest, agriculture, bare/barren land, built-up, agroforestry, shrub and marsh land. The watershed experienced significant LULC changes between 1985 and 2021, predominantly driven by agricultural expansion at the expense of forest, shrub, and grasslands. Future (2035 and 2050) projections using a hybrid Multi-Layer Perceptron (MLP) and Cellular Automata-Markov chain (CA-MC) model indicated further agricultural expansion, accompanied by declines in forest and grasslands. Furthermore, the study evaluated 11 CORDEX-Africa RCMs and their mean ensemble performance, revealing varied accuracies in reproducing rainfall and temperature patterns over GW from 1991 to 2005. The observed climate trends indicated a significant declining rainfall (-13.38 mm/year) and warming temperatures, with future projections (RCP4.5 and RCP8.5) showing consistent temperature increases. Additionally, the study investigated the impact of LULC and climate change on surface runoff and sediment yield using SWAT model. The results revealed notable increases in surface runoff and sediment yield attributed to LULC changes. Whereas, climate change alone exhibited a diverse influence, with both increases and decreases in surface runoff and sediment yield. Similarly, the combined effects of LULC and climate change demonstrated that certain scenarios led to the increases in surface runoff and sediment yield, while others reduced these processes. This might be attributed to the offset of runoff and sediment reduction by climate change. Soil erosion rates were found to be high, particularly most of the southern and eastern parts of the watershed will generate the highest amount of surface runoff and sediment yield in to the future. Addressing these concerns, soil/stone bund, terracing, contour farming, and reforestation practice can significantly reduce the annual sediment yield in the future. The land degradation neutrality (LDN) assessment from 1985–2003 to 2003–2021 revealed land productivity decline, land cover degradation, SOC loss, and the expansion of land degradation trajectories by 26%. Overall, the findings provide valuable information for stakeholders.
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    Assessment of causes of delay on selected asphalt road Projects in the Southern Region of Ethiopi
    (Hawassa University, 2017-10-18) Mengistu G/kirosGesesew
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    SKILLED LABOR PERFORMANCE ASSESSMENT ON SELECTED PUBLIC BUILDING CONSTRUCTION PROJECT OF SNNPRS
    (Hawassa University, 2019-10-13) BIZUNESH BEKELE
    Skilled labor force is one of the vital elements for the continuity and successful implementation of construction. This study explored the current status of skilled labor performance in building project of SNNPRS. The main approaches used in collecting information for the study were through a questionnaire survey, case study, interview and personal observations of some major construction sites of SNNPRS. Methodological triangulation and member checking bolstered the trustworthiness of those interpretations. The questionnaire survey was distributed to 114 respondents and a total of 105 responses were received and case studies of seven projects of three trades for each which are concrete, masonry and bar bending was taken. For the analysis of the data, statistical analysis by using SPSS software and descriptive statistics were employed. The finding of the research indicated that most trade not fulfills individual level performance criteria. The crew level performance for most projects with productivity performance ability ratio (PAR) was greater than one indicating that the studied crews’ productivity performance was low. The main factor which affect performance of skilled labor in the order of their rank were lack of follow up the work progress, cash flow and financial difficulties, Lack of Training for workers, Inadequate briefing, too much work load and absence of clear uniform standard to accept work. Skilled labor capability impacts the project objectives which are safety, quality, cost and schedule. Thus the researcher recommends possible ways to manage or reduce such factors. Periodic training should prepare in advance in order to improve skill performance and Project managers shall introduce performance management system at individual and crew level so as to have reliable planning and controlling system to manage their work. This study will contribute contractors which undertake construction projects and about ways of improving their current status of skilled labor.
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    CONSTRUCTION HEALTH AND SAFETY LEGISLATION, COMPARING ETHIOPIA AND UNITED STATES OF AMERICA
    (Hawassa University, 2020-10-12) BITSEAT ZELEKE TESFAYE
    Construction industry has various risks due to the activities, individuals and many companies in different scales that it contains. Besides, construction materials, machinery, tools, tasks and handling skills all come with their own risks. Therefore, construction industry is prone to many potential hazard and accident. Accidents can be avoided mostly by implementing health and safety laws and regulations by ensuring those protocols are continuously maintained. In this study, Ethiopian construction health and safety legislation are discussed and suggestions for amendments are recommended. As different researches show that the Ethiopia construction industry has a safety problem moreover, the safety legislations are not being enforced in careful way. Therefore, in order to minimize the problem observed, it is recommended to amend and modify current legislation and control strategies with different ways of enforcement in construction industry to more rigorous legislation and control practices to enhance construction safety level in Ethiopia. Moreover, for making a better legislation and for recommending on how to amend the current legislation, comparison is made with comparative study by document review. The comparison is between American and Federal Democratic Republic Ethiopia (FDRE) construction OHS legislations and laws from the point of view of thirteen topics, the two countries have different legislative systems and implementation method, and which are from different continents, but America has strong economy and strong construction industry better than Ethiopia. There is no hesitation that the America is one of the world’s leaders in Occupational Health and Safety (OHS) issue. As the comparison shows their exist key difference across the Legislations, from those the American Act states employer and employee’s right and responsibility in detail and obligate the employer to make the workers aware of their right under the Act but Ethiopian neither include any rights of workers nor obligate employers to aware workers right. Moreover, Best practice and lessons from American legislation is included on the comparison, like some crucial ideas are left out and not included in the legislation of Ethiopia. I.e. precaution for Concrete construction, Conveyor, Cranes and Derricks, Precaution for Confined space are some lessons. The differences of these two countries OHS legislation and weakness of the OHS legislation of Ethiopia were acquired, with some suggestions legislations were promoted to be more beneficial and the findings of the study provide the gap exist on Ethiopian construction health and safety legislation’s and recommend on gaps found and insights XVII and discussions are given and recommend for reviewing FDRE health and safety legislation. It was concluded from the study that the legislation of Ethiopia have some gaps which does not clearly state different terms in detail. Specifically Ethiopian Building Proclamation does not clearly identify the scope of application of the proclamation moreover, the scope of exclusion under Ethiopian Building Construction Standard (EBCS) 14 demolishing work, is narrow and does not provide sufficient information and do not consider current construction method of Ethiopia
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    ASSESING PERFORMANCE EVALUATION PRACTICE OF BUILDING CONSTRUCTION PROJECT IN HAWASSA CITY
    (Hawassa University, 2021-03-18) BIRUK KEBEDE BEKELE
    Project performance has been considered to be tied to project success and this is also tied to project objectives. Based on this to evaluate performance effectively and efficiently we should develop an objective and consistent measurable criteria. These criteria are called performance dimensions. According to many study performance dimension has been encounter performance shortfall in construction industry worldwide and in developing country at large. Especially in Ethiopia and the city Hawassa the problem is clearly shows. The research aimed at assessing the performance evaluation practice on four Dimensions namely Time, Cost, Quality and health and safety and its challenges and also develops a framework to efficiently practice performance evaluation in construction project in Hawassa city. The study adopts both quantitative and qualitative approach to assess the performance evaluation practice in Hawassa city. Simple random samplings were used to select the representative sample form entire population. Quantitative approach used questionnaire while qualitative approach uses semi-structure interview and case study to stimulate the relevant response from the major stakeholders in the Hawassa building construction project. The data collected by questionnaire were analyzed using frequency and mean for objective one and one sample t-test for objective two. In doing so The study concludes most contractors has limited budget set for evaluation purpose, most contractor evaluate their project in every phase of project. And most contractor use “time variation” formula to measure time, percent net variation over final cost formula to measure cost, system quality method to measure quality, fatality rate to measure safety. The study found that, limited financial resource, poor quality of data collected, poor communication, lack of monitoring and evaluation plans in planning, and budgeting, weak legal and institutional framework and Poor demand for monitoring and evaluation. Lack of monitoring and evaluation units within the organization and Weak linkage between planning and evaluation are the most challenges in Hawassa construction project. And all projects never use the most common framework like Balance score card, European foundation for quality management, Key Performance Indicator and Earned Value Management. Finally the research recommends that contractors in Hawassa should allocate budget, use reliable framework and organize independent unit for performance evaluation. The study develops performance evaluation framework helps to project success and uses as benchmark for other study in Hawassa cit
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    FINITE ELEMENT ANALYSIS OF REINFORCED CONCRETE COLUMN WITH CORE DRILLIN
    (Hawassa Unversity, 2021-07-17) BILISUMMAA ARARSA DEMISSIE
    Reinforced concrete column is one of the compression structural member carry axial or slightly slanted compressive loads, with or without moment. In RC column opening provided for multiple purpose such as plumbing of pipes and electric wiring. The provision of such openings may result in the loss of strength, stiffness and ductility. Therefore, providing core hole needs some precaution in account of failures of the column. Most of researchers have studied effect of opening considering, hole position, hole diameter, hole shape and grade of concrete. However, there is lack of study on drilling concrete core with considering of steel grade, reinforcement area ratio, level of service load. Therefore, this study demonstrates finite element analysis of reinforced concrete column with drilled concrete core considering effect of opening in account of steel grade, reinforcement area ratio, level of service, cross section of column and drilling location. It shows deformation versus column capacity, concrete vertical strain, bar strain distribution around hole, capacity reduction relative to controlling specimen, core position effect and P-delta effect. Finite element analysis consist initial step associated with boundary condition and first step which nonlinear static stress analysis takes place. For checking accuracy of finite element analysis validation performed with available experimental literature. The results from finite element simulation of hole effect indicates; Increase grade of reinforcement; improve capacity of drilled column and axial deformation decreased by the range 6.18 % up to14.59 % relative to solid column. Reinforcement area ratio reduces axial deformation 31.2% between drilled specimens and cross-section of column increases; deformation decrease 18.18% axial deformation. In addition to this; hole position at end side has large reduction in axial capacity of column and resulted increase lateral deformation. Hole at end side has greater effect in lateral deformation relative to axial deformation