http://ir.bdu.edu.et/handle/123456789/13 2001-01-13T06:32:17Z http://ir.bdu.edu.et/handle/123456789/16675 COMBINED EFFECT OF BLAST AND IMPACT LOAD ON EXTERNAL RC BEAM-COLUMN JOINT AND STRENGTHENING WITH CFRP Agdew, Amsalu Many Reinforced Concrete (RC) buildings are damaged by Terrorist attacks all over the world. It results in damages to assets, loss of life, and social panic. In principle, structural designs ensure the protection and safety of occupants and the integrity of the structure itself. However, in reality, this is not upheld when a structure is struck by extreme blast loading. There are limited previous studies that conducted the combined effect of blast and impact load on RC beam-column joints and the application of Carbon Fiber Reinforced Polymer (CFRP) strengthening mechanisms to increase the reduced load resistance capacity. The main aim of this study is to investigate the combined effect of blast and impact load on RC beam-column joints and the use of CFRP strengthening mechanisms. The explicit dynamic analysis software LS-DYNA 2022 is used to establish numerical investigations. The experimental results from the literature were used to validate the finite element analysis LS-DYNA explicit dynamic analysis software. The parametric studies were conducted with a variation of blast load stand-off distance, blast weight, blast load incident angle, weight of impact, impact load stand-off distances, and CFRP strengthening methods. The finite element investigation result shows that The blast load stand-off distance and blast weight variation have a considerable effect on displacement responses of RC beam-column joints under the combined effect of blast and impact loads. The maximum deflection is observed at 90⸰ blast load incident angle for both 5 kg and 50 kg blast weight at 2m SD of blast load. The 1 layer at 90 CFRP orientation is the best strengthening layout of RC Beam-column joint under the combined effect of blast and impact loads without debonding failure. Keywords: RC Beam-column joint, Impact–blast combined load, LS-DYNA, CFRP. 2024-10-01T00:00:00Z http://ir.bdu.edu.et/handle/123456789/16665 EVALUATING THE IMPACT OF NETWORK EXPANSION ON HYDRAULIC PERFORMANCE OF WATER SUPPLY DISTRIBUTION SYSTEM: A CASE STUDY OF DEBRE MARKOS TOWN, ETHIOPIA YILKAL, BEWKETU FEREDE Due to ever increasing of population, there is a challenge on water delivery systems. As a result, expanding system service to meet their demand is essential. However, network expansion of water supply distribution systems is done without detail assessment on the impact of expansion on the existing systems. The objective of this paper was evaluating the impacts of network expansion on the hydraulic performance of water delivery systems in case of Debre Markos town water supply system. WaterGEMS software was applied to analyze the existing water distribution system. The analysis result showed that pressures at sample nodes are within the limit before the extension were made on the model, with a maximum pressure of not less than 35.87m water column. From all existing distribution network 25.83% of pipes had a velocity below and above the limits. But 74.17% of pipes fall between 0.6 and 2.2m/s. and While 68.97% of nodes are in the permissible pressure range of between 15m and maximum 70m From model analysis, the coefficient of determination (R2) value was 0.93, it indicates that observed and simulated relation is acceptable. Then the additional pipe and demand expansion adopted for current settlements and future proposed expansion areas by made extensions from selected takeoff points. The system was checked for different expansion methods to find the system hydraulic property response regarding to pressure &velocity. The amount of network expansion analysis hydraulic property response was done from 10% to 80% of system demand expansion increment. Modeling result shows the area coverage having node pressure below 15m head varies from 30% to 80% after more than 50% network expansion done. These shows that the system service level drops as extent to which amount of network expansion increases. From this analysis, the current water supply distribution of Debre Markos town is not performed very well. Finally, before the expansion of the services from the initial designed systems, their impact should be assessed and for case of Debre markos further study should be done to enhance the hydraulic performance of the systems. Keywords: Hydraulic Properties, WaterGEMS, Water loss, Water network expansion, 2024-07-25T00:00:00Z http://ir.bdu.edu.et/handle/123456789/16664 ASSESSING SUSTAINABILITY OF ON-SITE SANITATION SYSTEM USING MULTI CRITERIA APPROACHES: THE CASE OF DEBRE BIRHAN, ETHIOPIA Wubet, Mitiku Shiferaw On-site sanitation systems have been used on a large scale and widely used in both developing and developed countries, whereas used the areas with no sewerage facilities. On-site sanitation includes excreta and wastewater which are collected, stored, and treated when they are generated; the objective of this study was to assess the sustainability of on-site sanitation system from user interfaces to disposal, in the case of Debre Birhan town. To meet the objective, a milt-criteria approach, which comprised of economical, socio-cultural, environmental, health, and technical function, was applied. The required data were collected through questionnaires, focus group discussions, and key informant interviews. Accordingly, a survey of 379 households, 10 focus group discussions and five key informative interviews were conducted in four sub-cities. The research formulated risk assessment matrix to identify the factors that are related to the sustainability of on-site sanitation system in Deber Birhan town by giving score and color coding from one to five (1-5) with one for poor performance and five for very good performance and red color for low result and blue color for very good result performance. The results of the research showed that the onsite sanitation in Deber Birhan is not properly managed. According to the research, many people are attacked by Diarrhea and cholera, which is because the onsite sanitation is not safe. The most dominant onsite sanitation technology in all the considered sub-cities is simple pit latrine. The shift flow diagram (SFD) shows that only 13% of fecal sludge is safely managed. Thus, it is required to work on improving the existing sanitation system so that risk of illness is reduced and to increase overall community resilience. Key words: Debre Birhan, on-site, pit latrine, sanitation system, sustainability 2024-09-01T00:00:00Z http://ir.bdu.edu.et/handle/123456789/16663 Assessing Sustainabiliy of Rural Water Supply Schemes in Awbare Distric Fafan Zone, Somali Region, Ethiopia Mohamed, Mohamoud Ibrahim The major sources of drinking water for the wide majority of the rural population (84% of the frequency dry total) in Ethiopia are surface runoff, unprotected springs, ponds, rivers, and hand-dug wells. Whose health risk is significant as they are exposed to contamination caused by human beings, livestock, wildlife, and uncontrolled flooding. However, the majority of the people in awbare woreda still did not have access to potable, sufficient, and sustainable water supply. The major objective of the study was to assess the challenges of rural water supply schemes and assess the main schemes' sustainability determinants related to community, consumer satisfactions, technology, rule and regulation, operation and maintenance management aspect in the rural water supply scheme. To address the research objectives, household surveys, field observation, focus group discussions, key informant interviews and relevant document reviews analyzed using SPSS software (Version 27). In awbare woreda were used 12 water supply schemes and a total of 108 heads of households were selected using a combination of purposively and simple random techniques. Lack of available materials, less water committee’s effort, fewer senses of ownership and poor cost recovery and management problems are identified as the main problems. Most of the communities were not actively participate starting from planning to post-construction management due to this most of the water supply schemes were not sustainable for multiple reasons. The finding of this research indicated that the schemes were performing well on only 39.9% of the technical, rule and regulation, operation and maintenance, and community aspects. Therefore, awbare woreda water development office needs to create and developed a sense of ownership, improve developing rules and regulation support, develop cost recovery management and rehabilitate existed water schemes by mobilizing the community in order to avoid a large community using a single water supply scheme. Keywords: Water supply, Access to water, Sustainability, Somali Region 2024-07-01T00:00:00Z