Department of Civil Engineering

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Assessing the Impact of Improper Sidewalks on Pedestrian Safety and Level of Service in Mekelle City
(Mekelle University, 2025-07-22) Kibrom Weldu
Pedestrian safety is a vital yet often neglected aspect of urban development in rapidly growing cities like Mekelle, Ethiopia. This study examines how improper sidewalk conditions, such as narrow, obstructed, and poorly maintained paths affect pedestrian safety and the Pedestrian Level of Service. A mixed-methods approach was used to comprehensively assess pedestrian conditions in Mekelle City. Quantitative data collection involved measuring sidewalk widths, counting pedestrians, and conducting structured surveys to evaluate safety, usability, and infrastructure quality. Physical assessments also identified common obstructions like vendors, utility poles, and parked vehicles. PLOS was evaluated using the Highway Capacity Manual, considering factors such as surface condition, lighting, and crossing points. Complementing this, qualitative data were gathered through field observations and open-ended survey responses to capture pedestrian experiences, perceptions of safety, and challenges such as poor lighting, unmarked crossings, and obstructed walkways, especially during nighttime travel. The findings show that most sidewalks are narrower than the recommended 1.2 meters and often obstructed by vendors, poles, or construction materials, making them unsafe. PLOS ratings ranged from C to E, indicating poor walking conditions. Over half of respondents felt unsafe, mainly due to poor lighting, inadequate crossings, and lack of maintenance. This study concludes that Mekelle's pedestrian infrastructure significantly hinders walkability and compromises safety. Recommendations include adopting international design standards, enforcing clear regulations to prevent sidewalk encroachment, and incorporating inclusive urban design principles in future planning. These insights provide essential guidance for urban planners and policymakers aiming to create safer, more accessible pedestrian environments in Mekelle and similar urban contexts.
Developing a Predictive Model for CBR Value Using Soil Index Properties: A Case Study of the Mekelle Asphalt Road Project
(Mekelle University, 2024-04-15) Million Abrha Weldegeorgis
California Bearing Ration (CBR) value is an important soil parameter considered as main design input in the design of flexible pavements and runways of airfields. The design of pavement thickness determined depending on the strength and stability of sub-grade materials are evaluated before construction of pavement by using CBR test. And Index properties of soil are properties which are used to characterize soils and facilitate identification and classification of soils for engineering purposes. However, in a large-scale road project soil properties vary from region to region and season to season as it appears naturally. Thus, developing empirical equations specific to a certain region and soil type could be considered nearly as good insight of soil behavior. This study was conducted to developing a predictive model for CBR value using soil index properties of soils in the case study of the Mekelle Asphalt Road Project. The study was carried out using 27 samples collected from SUR Construction PLC Mekelle Asphalt Road Project. And test procedures were carried out based on the (ASTM) and (AASHTO) at Mekelle Asphalt Road Project Laboratory. This study tries to use a single linear regression model and multiple linear regression models to characterize the strength of the subgrade soils from the soil index properties using a statistical method. The laboratory test results and statistical analysis were carried out using Microsoft Excel and SPSS software. To develop the intended correlation and regression analysis CBR value at different blows such as 10, 30 and 65 blows were considered as dependent variable. And index properties of soil such as percent passing 2.0, 0.425, and 0.075 mm (sieve No. 10, 40, and 200) sieve size, LL, PI, OMC and DD at points 10, 30, 65 blows were considered as independent variables. From the regression analysis result, the equation and coefficient of determination developed are:  CBRat 10 Blow = -7.99 - 0.024LL - 0.025PI + 0.187P10 - 0.133P40 + 0.027P200 - 0.025OMC + 2.68DDat 10 blow, R2=0.913, adj R2=0.881  CBRat 30 Blows = -3.1 - 0.058LL + 0.006PI + 0.133P10 - 0.092P40 + 0.008P200 - 0.055OMC + 2.87DDat 30 Blows, R2=0.965, adj R2=0.953  CBRat 65 Blows = -3.301 - 0.113LL + 0.054PI + 0.085P10 - 0.004P40 + 0.050P200 - 0.088OMC + 1.373DDat 65 Blows, R2=0.928, adj R2=0.902
Developing Trip Production and Mode Choice Model for Home Based Trips: The Case of Hawelti Sub-City Residents, Mekelle - Ethiopia
(Mekelle University, 2020-03-25) Gerezgiher Gebrewahd Hagos
Hawelti sub City considered one of the most rapid increases in population and crowded subcity in Mekelle city. Hawelti sub-city does not have a transportation model; hence, developing a model is considered very important for predicting the average daily trips and use of each mode. The aim of this study is to develop trip production and mode choice model for home-based trips in Hawelti sub-city residents. The trip production includes a trip for work, education, shopping, social and recreation whereas the mode choice focuses on work and education trips. A household interview survey was used as a data source in addition to secondary data obtained from the municipality of Hawelti Sub-City. Trip production was analyzed using multiple linear regressions and multinomial logistic regression was utilized in the analyses of mode choice with statistical data processing software SPSS. The modes of transport considered in the model are Walking, Bajaj, Private car, Minibus Taxi, and Service (Company or school provided transport). Minibus taxi is found to dominate with 44% share followed by the company provided service with a 22.8% share for all trips. In the developed model the factors that affect the trip production are the number of students, employed persons, monthly income, the number of females and the age above 45 in the household. Moreover, the factors that significantly affect the choice of transport modes for employees were total travel time, work type and family size. The mode choice model developed for the case of students the significant factors were found to be travel time and gender. The developed models were significant at 95% confidence level and exhibits a good fit for the data with the coefficient of determination (R2 ) of 0.889 for the general trip production and the adjusted goodness of fit measure statistics rho square (ρ2) of 0.823 and 0.824 for the work and student models respectively for the whole study area. The models are validated to be capable of predicting 90.97% and 87.2% of the preference of trip makers for the work and education mode choice models respectively.
Effect of Filler Types (Crushed Stone, Gypsum and Lime Kiln-dust) on the Marshal Properties of Asphalt Concrete
(Mekelle University, 2020-05-18) FREWEINI WELU
Roads are one of the country’s basic infrastructural facilities, which needs a precise engineering design to minimize the life cycle cost by achieving reliable in-service performance. For the paved road types, pavement structure design and mix design of asphalt concrete mixture including adequate structure with proper drainage system and durable raw materials are the major considerations to attain reliable pavement performance that is adequately strong, durable and resistive to fatigue, and permanent deformation by considering economical aspect. The HMA contains coarse aggregate, fine aggregate and mineral filler coated with a bitumen binder and air and the mechanical properties of bituminous road pavement depend decisively upon the properties of its filler-bitumen. Although Mineral filler plays a major role in filling voids of the mixture and on the modification of the asphalt concrete properties like stiffness of the asphalt mortar matrix, improving the rutting resistance of pavements, it needs high intention on the content of the mineral filler since the excessive use have also weaken the properties of the mixture. In Ethiopia, crushed stone from dust extractor is conventional filler material in almost all flexible pavement construction projects but deficiency of this mineral filler happens and leads to crush aggregate for that purpose, which increase the production cost and environmental deterioration of the area. The main objective of this thesis is therefore to investigate the effect of the filler types (crushed stone, lime kiln-dust, and gypsum) on the marshal properties of asphalt concrete and to analyze the cost breakdown for the production of hot mix asphalt with these different filler types. To evaluate the effect of these selected filler types marshal mix design was used and conducted the laboratory test for marshal stability, flow, air void, voids in mineral aggregate and voids filled with bitumen by preparing a total of 90 specimens compacted by marshal compactor by 75 blows on the upper and lower sides of the mold. From the marshal laboratory test, asphalt concrete with crushed stone, gypsum and limekiln dust attains all the requirements specified on the ERA manual. Comparing the filler types, mixture with crushed stone filler attains the highest stability (9.45KN) at 2% filler content. For the asphalt concrete mixture at 3% filler content, mixture with gypsum filler attains the highest stability (9.4KN). From the cost break down analysis for the production of 1m3 HMA, lime kiln-dust and gypsum lowers the production cost by 1.34% and 1.21% respectively with the comparison of HMA with crushed stone filler.
Estimating Traffic Congestion Costs for selected Road of Mekelle City
(Mekelle University, 2020-06-28) Wahd Solomun
Traffic congestion is a problem which occurs on road network characterized by slower speed, longer trip time due to excessive vehicles from different direction. Traffic congestion have a negative impact on society such as late reach to work place by increasing travel time, on health by creating stress, mentality and physical discomfort, increasing fuel consumption and air pollution. Mekelle is one of the fastest growing city in Ethiopia. Accordingly, traffic congestion is growing extremely in the city and results time wastage on travel and other direct and indirect effects on the society. This study is concentrated on two selected intersection the first one is four leg signalized intersection which is found around commercial bank of Ethiopia, main branch and the second one is four leg intersection which is found around Relief Society of Tigray in this intersection traffic light is not functional for about two years but after data collection performed the traffic signal was maintained and the intersection become signalized. Then again traffic volume data was conducted at signalized case. The main objective of this study is to estimate traffic congestion costs for selected intersection of Mekelle city and to suggest the possible counter measure for the problem. Primary and secondary data was collected to accomplish the study objectives. Primary data traffic volume, vehicle occupancy, signal timing, geometric data and daily labor cost was collected. The traffic volume count was made using video recording starting in the morning peak time 7:00AM-10:00AM, at noon time 11:00 AM-2:30 PM and the evening peak time 4:30 PM- 7:30 PM at 15 minutes interval was done for both intersections. The vehicles were counted by type passenger car, bus and small and medium truck vehicles. The average vehicle occupancy was collected based on traffic engineering vehicle occupancy data collection manual. After the data was collected data analysis was made. Delay at the intersection was analyzed using SYNCHRO software. Then using the collected data and delay annual peak hour cost of traffic congestion in both intersection was estimated. The cost of congestion consists travel time cost, fuel consumption cost and cost of co2 emission gas due to excess fuel usage. The result is found about (5,339,609.37ETB annual peak hour cost) at CBE four leg signalized intersection, (3,789,746.99ETB annual peak hour cost) at REST four leg unsignalized intersection, and (3,181,684.41ETB annual peak hour cost) at REST four leg signalized intersection. Annual peak hour travel time cost represents the opportunity costs of wasted time on congested intersection which shows the largest category at CBE intersection found about 4,311,552.5ETB nearly 81% of total cost of the intersection, at REST unsignalized is about 3,116,165ETB about 82% of cost of intersection and REST signalized have 2,618,690.9ETB about 82% of total intersection cost. Meanwhile annual peak hour cost of fuel is the second contributor to the overall cost of congestion with 1,009,870.3ETB at CBE, 661,988.9 ETB at REST unsignalized intersection and 552,987.4 ETB at REST signalized intersection which is about 18% of the total cost. On the other hand annual peak hour emissions costs is the least contributor to the overall cost of congestion and estimated about 18,186.57ETB at CBE intersection, about 11,611.09ETB at REST unsignalized intersection and 10,006.11 ETB at REST signalized intersection. The cost of congestion result shows the effect of congestion is highly concentrated on the travel time of public transport users’ means 78% of the travel time cost is for the public transport users.
Evaluation of irrigation water allocation for improving water use efficiency and conflict resolution in Hatset irrigation scheme, Eastern Tigray, North Ethiopia
(Mekelle University, 2025-03-25) Lema Kiros Lema
Efficient water allocation is crucial for enhancing irrigation water use efficiency and mitigating conflicts among users, especially regions where water is limited. This study tried to evaluate the irrigation water allocation system to optimize water allocation and improve conflict resolution mechanisms in the Hatset irrigation scheme, Eastern Tigray, North Ethiopia. The primary data was collected through soil sampling, flow measurements, household surveys, key informant interviews, and focus group discussions, and the secondary data was collected through meteorological, hydrological and spatial data. WEAP model used to assess current water allocation scenarios and propose improved strategies. Additionally, CROPWAT model was used to estimate crop water demand and HEC-HMS also used to estimate reservoir inflows. The findings reveal, unmet demand 0 m³, 0 m³, 895,360 m³ and water losses 155,721 m³, 309,160 m³, and 430,479 m³, head, middle and tail-end users respectively. Three scenarios were analyzed: a reference scenario, an improved water use efficiency scenario, and an irrigation expansion scenario. The reference scenario was business-as-usual approach and the enhanced water uses efficiency scenario demonstrated a 37.5% reduction in water demand by incorporating canal lining, efficient scheduling, and efficient irrigation techniques and the irrigation expansion scenario, which increased the irrigated area but resulted in a 23% increase in water demand with no unmet demand. Moreover, the study investigated the effect of efficient water allocation in resolving conflicts within the Hatset irrigation scheme, where infrastructure issues and governance gaps created significant disparities. It conducted how inadequate access for tail-end users caused conflict, while traditional and formal mechanisms proved ineffective due to poor coordination. The proposed hybrid approach, which integrated community driven and IWUAs, addressed systemic challenges and promoted sustainable conflict resolution.
EVALUATION OF SUSTAINABLE URBAN MOBILITY IN THE CITY OF MEK’ELE
(Mekelle University, 2020-06-28) Yoseph Solomon
Currently, cities are looking for all round transport sustainability. Nevertheless, urban transportation can create a problem on economic, social and environmental aspect of the city. Up on observation residents have complaint on the fare for local transportation, vehicles noise disturbance and services provided by public transport. This thesis indexed eleven urban sustainable transport indicators. Based on the indexed results of the tool, SWOT analysis is conducted. The study also sought to identify the remedial measures that should be undertaken to mitigate the problems. The study area is defined to be Mek’ele city. The sustainable urban mobility indicators are assessed through a procedure that requires various method of data collection and data processing. World Bank backed online software was used after data legitimizing and confirmation was made between Tigray Construction Road and Transport Bureau and the world councils of urban sustainable development headquarter at Geneva, Switzerland. The indicator, access to mobility service, is based on percentage of people living within a radius of 400 meters from a public transport stops. Fatalities were considered as the number of deaths per annum per 100,000 inhabitants. For mobility space usage, area of roads, open parking, service areas and petrol stations were considered. Length of road network with sidewalks, with bike lanes, in zone 30 (km/h) and total length of city road network were served as input for the indicator of opportunity for active mobility .The social aspects such as, access for mobility impaired groups, comfort and pleasure, commuting travel time and security is indexed using structured questionnaire as part of the tool. For noise hindrance, sound measurements were taken. Affordability of public transport for the poorest quartile is measured by GDP and population’s lowest quartile income as a data. The sustainability for Mek’le city transport system is 4.93/10, suggesting weak sustainable mobility conditions for the city‘s transport system. The SWOT analysis has the prospects of being used in policymaking, defining strategic directions and the implementation of measures towards the fulfilment of sustainable urban mobility in the city of Mek’ele.
Identifying and evaluating various regulatory countermeasures to traffic congestion in selected intersections of Mekelle city
(Mekelle University, 2024-06-21) Rahwa Berhe Baryagabr
Traffic congestion reduces the effective accessibility of residents, activities and jobs resulting in lost opportunities for both the public and business. Longer journey times, higher fuel consumption and increased emissions of air pollutants are some of the impacts of congestion. Traffic congestion is a major phenomenon in most intersection of Mekelle city, especially in kedamay weyane sub city. Therefore, this thesis attempts to first evaluate the state of traffic congestion, then offers some suggested countermeasures to lessen the congestion, illustrates the results of applying the countermeasures at the chosen intersections, and finally outlines the factors that contribute to the congestion. The congestion is measured by determining the level of service (LOS) . And the LOS was analyzed by VISSIM software using peak hour turning traffic volume, vehicle composition and geometry of the intersections as input data. For determining peak hour turning traffic volume the calculation is made through the manual counting of vehicles and multiplying by passenger car unit factor (PCU factor) to determine passenger car equivalent (PCE). The LOS output among the 9 selected intersections around kedamay weyane sub city the 6 of them are below D. By applying some regulatory countermeasures for the only 6 congested intersections and reanalyze the LOS of all intersections, most LOS of the selected intersections is become to above LOS C. Even though the LOS of intersection 1 and some turning movements in intersection 8 are decrease after apply the counter measures; because some minibus taxi routes are changes to them, most LOS of the selected intersections are become A, B and C. At final this thesis concluded that high number of bajaj using the intersection, the route of minibus taxi concentrated to one direction, stop vehicles near intersections and illegal trading on walk way and traffic lane are the cause of the traffic congestion.
Investigating Challenges of Construction and Demolition Waste Management, in the Case of Mekelle, Tigray
(Mekelle University, 2025-07-18) Kiros Hailemariam Mesele
With rapid urbanization and economic growth, All the activities, new construction, renovation, and demolition of buildings and structures generate huge amounts of waste, which require reduction in generation and proper management. Nevertheless, due to several barriers and constraints this could not be implemented. The purpose of this study was investigating challenges of construction and demolition waste management in Mekelle construction projects. Based on this objective, the factors that contribute waste, effects of C&DW, current construction waste management practice and major challenges of C&DW management have been investigated. The study used semi structured interview and questionnaire survey for data collecting techniques, and relative importance index for descriptive data analysis. The result of the study shown the improper material handling and storage, poor supervision, lack of skilled man power and late design changes are the most contributing factors to waste generation. Whereas, Project cost overrun, Environmental Pollution, Reduction in profit, Resources depletion and public health and safety risks are the main effect of C&DW. In the current construction waste management practices, the governing strategies i.e. waste reduction and proper management were not effectively implemented. Furthermore, the following main challenges were identified in this research. The challenges are; Improper planning & waste management practice, Ineffective waste management plan, Insufficient waste management training programs, Poor supervision practice, Lack enforcement of regulations, Absence of training on waste minimization strategies for construction firms, insufficient legislation & regulation, Lack of Government incentives, Low Concern for socio-economic and environmental effect of wastage, Resistance to change traditional management practices, Poor coordination among construction stakeholders, Believing waste not a problem on site, High cost with low quality of recycled materials, Lack of demand for recycled materials, and High cost of waste disposal. The study also recommends that Managing C &D Waste needs a serious attention from all the stakeholders involved throughout the construction process.
Investigation of Ceramic Tile Waste as Partial Replacement of Cement in concrete
(Mekelle University, 2024-11-08) Tsegay Kassahun Gebreegzabihe
The construction industry's rapid growth coupled with increasing environmental concerns and necessitates sustainable practices. The study investigates grinded ceramic tile wastes as a partial replacement for cement for C-30 concrete grade having an aim to feel material scarcity and enhance sustainability in the construction industry. After the concrete ingredients test, mix design of C-30 concrete grade was prepared and concrete cube specimen with 0%, 5%, 10%, 15%, 20%, 25% and 30% of ceramic tile wastes in place of cement were casted, cured and tested for compressive and flexural strength. The experimental test results have revealed, an increase in the proportion of grinded ceramic tile waste in concrete production decreases workability. In terms of strength, both compressive and flexural strengths initially increased with ceramic tile waste, peaking at 10% replacement with a compressive strength of 40.26 MPa and a flexural strength of 4.31 MPa at 28 days. Beyond 10%, both strengths declined indicating that while moderate ceramic waste enhances concrete strength but excessive replacement negatively impacts performance. And the cost analysis revealed that incorporating ceramic waste significantly reduces the cement cost. It can therefore be concluded that in areas where cement scarcity or high costs are prevalent, the partial replacement of cement with grinded ceramic tile waste in concrete is a viable and sustainable alternative. The use of ceramic waste at optimal levels can improve strength properties and offers significant cost advantages while contributing to waste management and reducing the environmental impact of construction activities.
Investigation on Practice of Ethiopia Building Regulations and Codes of Standard in Mekelle City Municipality - Tigray
(Mekelle University, 2025-07-24) Mebrahatu Tadele
Since 1983, Ethiopia has established three Building Codes of Standards, along with national building regulations, a building proclamation, building directives, a construction policy, training institutions, a product standardization agency, and directives for licensing contractors and consultants. However, the proper enforcement of these laws, regulations, and standards remains questionable due to poor implementation, inadequate monitoring, and weak oversight by relevant authorities. Additionally, the compatibility of these regulations, policies, codes, and standards with the country's economic development, existing technologies, and available workforce is debatable. As a result, the country continues to experience significant loss of life, property damage, and economic setbacks. This research project aims to investigate the implementation of Ethiopia’s building regulations and codes of standards in the Mekelle City Municipality, Tigray. A review of relevant literature provides a foundation for the study, and data is collected through questionnaire surveys and records reviews. The data is then analyzed using SPSS v.20 software. The study reveals that out of 75 targeted respondents, 61 (86.7%) participated, including contractors, consultants, building officials, and regional professionals. The findings highlight a significant gap between established building regulations and actual practices due to inadequate inspections and weak enforcement mechanisms. The lack of a centralized authority and clearly defined procedures further contributes to non-compliance. Key issues identified include unclear professional responsibilities, insufficient regulation of building materials, and a lack of standardized practices. The failure to implement Ethiopian building regulations and codes of standards stems from multiple factors, including a lack of awareness, weak enforcement mechanisms, corruption, economic constraints, rapid urbanization, political instability, cultural preferences for traditional practices, and inadequate infrastructure for monitoring compliance.
Investigation the Causes of Delay and its Impact on Urban Road Projects in Shire Town –Tigray
(Mekelle University, 2025-02-21) Goitom Tsehaye
In construction, the word "delay" refers to something that happens later than expected, according to schedule, specified in the contract or beyond the date agreed by the parties to deliver the project and one of the most common issues considered during implementation of construction projects. Construction delays have an impact on more than just construction industry, but also an Influence on the overall economy of a country like Ethiopia. Relative Importance Index (RII) analysis was used to test the agreement between different groups of respondents participated in the questionnaire survey, and to rank the most causative factor of delay in urban road projects in case of shire town. This project identified thirty nine (39) causes of delay. There were forty (40) valid Questionnaires which received back from Contractors, Consultants, and employer. The objective of the project is to investigate the causes of delay and their impacts in construction of urban road projects in case of shire town. The causes of delay were grouped in to seven (7) as client related delays, consultant related delay, contractor related delay, material related delay, equipment related delay, Labor related delay and external related factors or outside the Control of Either Party to the Contract. The project study identified and ranked the top or most causative factor for delay in urban road construction projects are: Lack of construction materials with relative important index (RII) of (0.85). Escalation of materials prices with relative important index (RII) of (0.845). Force majeure with relative important index (RII) of (0.84). Material market instability with relative important index (RII) of (0.825). Poor communication and coordination with other parties with relative important index (RII) of (0.805). Inaccurate time estimate with relative important index (RII) of (0.77). Inaccurate site investigation with relative important index (RII) of (0.77). Lack of construction machinery with relative important index (RII) of (0.76). Poor quality of construction materials with relative important index (RII) of (0.74). Improper project feasibility study with relative important index (RII) of (0.715). Poor Communication and coordination with other parties with relative important index (RII) of (0.705). Conflicts between contractors and firm members with relative important index (RII) of (0.70). Economic, financial and environmental impacts have been found the most impacts of delay with relative important index (RII) of 0.93, 0.925 and 0.845 respectively.
Pavement management system development for Mekelle city road network and prioritization of roads for maintenance based on their performance index
(Mekelle University, 2020-06-28) Hadush Hagos
Pavement represents an important asset which is a pillar for the economy of one nation and this demands well-organized asset management. In Mekelle city, intensive investment has been made on constructing and maintaining roads at a network level. The current maintenance strategy followed by Mekelle city municipality is reactive. It responds to a problem after it has occurred. Instead of providing preventative maintenance at an early stage, roads are left until much more expensive reconstruction is needed and this maintenance delay will induce rising cost. This, in turn, causes spending a large amount of money to maintain extensively distressed pavements. The network needs great caution through periodic evaluation of pavement conduction and timely maintenance to keep the network operating under an acceptable level of service. This research work is intended to develop web-based flexible pavement management system software for Mekelle city road networks which will support the local road agency on road maintenance decisions. The developed decision supporting tool software compiles the basic components of a pavement management system using MySQL as a database creating quarry language and PHP software creating platform. The components of the pavement management system are framed as input data, analysis part and reporting tool for the outputs of the analysis section. The software uses road inventory data, road condition assessment data, road section data, and road traffic survey data as input. Storing all this data on its database the software utilizes those data to make pavement performance evaluation analysis employing the pavement condition index as a performance indicator. A case study of 6 km main access road segmented to eight sections was inspected to analyze the proposed pavement management system software. Finally, the software reports the results of the analysis part in the form of road Id, pavement condition index, rating scale, repair alternatives, and maintenance strategy as end results of the analysis for each road on the network then a priority for maintenance is made based on PCI value. In addition to this, the developed system can perform life cycle cost analysis for each road on the network employing net present value as economic evaluation criteria. According to the analysis result of the developed software, Alula Street i.e. form commercial bank of Ethiopia to Romanat roundabout is with least pavement condition index value, a PCI value of 11.17, a rating scale of very poor, and the corresponding maintenance strategy is reconstruction.
SELECTION OF SUITABLE TRAFFIC MODEL USING FUNDAMENTAL DIAGRAM UNDER DIFFERENT ROAD GEOMETRY AND OPERATING CONDITION IN MEKELLE CITY SUB-ARTERIAL ROADS
(Mekelle University, 2020-08-28) Bereket G/Egzabher Berhe
The relationship between macroscopic traffic flow parameters (flow rate, speed, and density) is represented graphically by fundamental diagrams. These diagrams play an important role in traffic flow theory and transportation engineering. Most conventional traffic stream models are mainly applicable for homogenous traffic conditions. These models are not suitable for the traffic condition of Mekelle city which is characterized by weak lane discipline and heterogonous in nature. This thesis select suitable traffic model for different roadway geometry and operating condition. It also compares the flow parameters for the stated traffic condition. For this thesis three different cases have been considered, those are road way with and without median structure, road way with and without footpath and road way with and without side market. Traffic data collection is done through video recording at midblock rod from six different locations. To select the suitable traffic model the speed –density plot of field data for different locations is fitted with five established FD models linear, polynomial 2nd degree, polynomial 3rd degree, exponential and logarithmic. From the result, polynomial 3rd degree is the best FD model for case one which compares the roadway with and without a structural median. For the second case which comprises roadway with and without footpath, exponential models are the best-fitted model, but hence it doesn't satisfy the boundary condition to compare the flow parameters polynomial 2nd degree is the second best model. Similarly, for case three which compares roadway with and without side market the exponential and 3rd-degree polynomial is the best-fitted models, but hence exponential model doesn't satisfy the boundary condition to compare the flow parameters 2nd-degree polynomial is the second-best fitted model. It is also found that free-flow speed trends decrease if there is no structural median, footpath and if there is a road side activity by (4.8%, 6.19% and,9.11%). The jam density increases if there is no structural median, footpath and if there is a road side activity by (41%, 8.8% and, 6.68%) consecutively.
STUDY ON TIME AND COST PERFORMANCE ASSESMENT OF PUBLIC CONSTRUCTION PROJECTS IN TIGRAY REGION: A CASE STUDY IN ABIADI TOWN
(Mekelle University, 2024-10-04) LEMLEM DESALEGN
Most of Ethiopian construction projects are affected by time and cost performance problems. This research was conducted in an attempt to identify major factors for such problems in the typical environment of Ethiopia Tigray region in case of Abi Adi town. The main objective of this study was to assess the performance of public construction projects in Abi Adi town with respect to their time and cost. And under this, specific objectives were also drown: To evaluate the performance of public construction projects in relation to project time and cost, to identify the factors influencing public construction projects to perform the construction project as per required time and cost in Abi Adi town. Quantitative research method was used to collect the data and questioners were prepared and distributed to the three professional bodies of the construction projects, such as owners, consultants, and contractors. To analysis the data collected from the respondents, performance index and relative important index statistical methods were used. The result of the finding indicated that, high number of time and cost performance of the projects was below target and poor performance. The study has identified client, consultant, contractor and external environment related factors that resulted on time overrun: such as, delay to payment and financial problem, delay to deliver the site, poor communication and coordination, absence of consultant site staff, poor skills and experience of labor, Poor site management and lack of site contractors’ staff, lack of equipment and tools on the market, poor economic condition, Lack of materials on the market and Delay in obtaining permits from municipality. The cost performance factors were; Inadequate project preparation, planning and implementation delay in construction, technical incompetence and poor organizational structure, delays in decisions making by government, failure of specific coordinating bodies, supply of raw materials and equipment by contractors, and resources constraint such as: funds foreign exchange, power associated auxiliaries not ready. Finally the main stakeholders of the construction projects should improve problems related them and use resource effectively and efficiently
Three-Dimensional Finite Element Analysis of Dowel-Concrete Contact Stresses In JPCP Using Abaqus 6.14.
(Mekelle University, 2020-09-21) Goytom Gidey Desta
Jointed Plain Concrete Pavements (JPCPs) are the most common and applicable type of rigid pavement in road and airfields. Yet, it has been very common to see JPCP failed at transverse joint, globally. Study of dowel-concrete contact interface behavior and induced concrete contact stresses at this interface has received significant attention in recent years because of its relevance to overcome transverse joint problem and design effective doweled joints in JPCP. However, most of the previous studies relied on simplifying assumptions that neglected the exact dowel concrete interface behavior. With the above context, this thesis addresses a numerical analysis of contact stresses and strains at dowel-concrete interface and load transfer efficiency (LTE) in JPCP by means of FEM. So as to attain this objective, a nonlinear 3D-FEA was performed using a commercial software package, ABAQUS (6.14). Moreover, theoretical calculations were done based on friberg‟s closed form solution for verification of the FEA result, and a slight difference was achieved. The analysis was made to understand the effect of transverse joint parameters on dowel-concrete contact stresses and LTE. According to the outcome of this thesis, the decreasing of friction value that represents dowel-concrete bonding form 1 to 0.05 resulted decrease in bearing stress and LTE by 0.66% and 0.69%. Also, as the concrete weight increased by 28.57% (from thickness of 250mm to 350mm), the bearing stress decreased by 3.05% and LTE increased by 0.69%, for the 15.78% increase in dowel bar weight, the bearing stress decreased by 12.5% and LTE increased by 2.56%, for the change in joint width form 10mm to 12mm the bearing stress increases with 3.45% and the LTE decrease about 0.86%, for 46.67% increase in axle load, the bearing stress increased by 60.90% and LTE decreased by 5.23%, for 96.5% increase in stiffness of the base course (from 350MPa. to 10,000MPa.) the bearing stress decreased by 60.90% and LTE increased by 7.93%. In addition, for a change in modulus of dowel support from 4.07MPa/m to 6MPa/m, the bearing stress increased by 0.79% and LTE by 1.22%. Form effect of dowel bar misplacement, for the 30mm vertical misplacement a single bar misplacement produced 2.66% higher bearing stress and 0.76% less in LTE than two bars. In general, it can be concluded that a 3D-FEM is a promising approach for modelling JPCPs.