http://etd.aau.edu.et:80/dspace/handle/123456789/1124 Search the Channel search http://etd.aau.edu.et:80/dspace/simple-search http://etd.aau.edu.et:80/dspace/handle/123456789/4605 Title: Development of a Program for dynamic Analysis of Building Frames <br/> <br/>Authors: Dessie, Ayelign <br/> <br/>Abstract: Earthquake analysis is normally a two-stage process: we first estimate the dynamic properties of the structure (natural frequencies and mode shapes) by analyzing it in the absence of external loads, and then use these properties in the determination of earthquake response. Earthquakes often induce non-linear response in structures. However, most practical seismic design continues to be based on linear analysis. The objective of this research is to develop a software program for Earthquake analysis of planar frames according to the provisions given by Ethiopian Building Code Standard (EBCS-8, 1995) and compare the results from the developed program with other sources. The most commonly used methods for dynamic analysis of structures subjected to earthquake loads are modal and spectral analysis. Response spectral analysis given by the provision of EBCS-8, 1995 is used for developing this computer program. In this thesis, an overview of various dynamic analysis procedures is presented with a detailed description for response-spectrum analysis, which is used to develop the computer program. Conclusions are drawn concerning the reliability of the responses given by the developed program. Recommendations for the use of the program are also provided. Wed, 13 Feb 2013 11:38:46 GMT http://etd.aau.edu.et:80/dspace/handle/123456789/4595 Title: A STUDY ON THE EFFECT OF REMOLDING ON THE MECHANICAL BEHAVIOR OF ADDIS ABABA RED CLAY SOIL <br/> <br/>Authors: Merihun, Lukas <br/> <br/>Abstract: This research work tries to see the effect of soil remolding on the mechanical behavior of red clay of Addis Ababa. It is tried to identify the effect of remolding by conducting a series of laboratory tests such as triaxial compression and consolidation tests on the undisturbed and remolded soil samples. The soil was remolded by compacting at OMC. It was also done basic tests to see the engineering properties of the soils. The one dimensional consolidation tests were done on samples of diameters of 50mm and 70mm and height of 18mm with the effective consolidation stresses of 50 kpa to 1600 kpa. A total of eight onedimensional consolidation tests were run, out of which four were undisturbed and four were remolded samples. The deformation and hydromechanical /permeability while loading/ behavior were examined using the one dimensional consolidation test. The triaxial tests were done on samples of 38mm and height of twice the diameter. Two triaxial testing machines were employed on the testing program. Soil samples collected from Kolfe areas were conducted on the newly acquired Automatic triaxial testing machines and samples collected from Addisu Gebeya area were tested on the semi automatic triaxial compression machine procured two years ago. The type of triaxial test employed was Consolidated undrained/CU/ with pore pressure measurement and with the effective consolidation pressure of 150 kpa, 250 kpa and 350 kpa. A total of twenty-four triaxial CU tests were run out of which twelve were undisturbed and twelve were remolded. The results of triaxial tests were used to examine the stress-strain and strength behavior.The results show that remolding reduces the peak deviator stress, effective cohesion and permeability and increases amount of compression and time required for consolidation.The results show that remolding reduces the peak deviator stress, effective cohesion and permeability and increases amount of compression and time required for consolidation. Fri, 08 Feb 2013 12:13:53 GMT http://etd.aau.edu.et:80/dspace/handle/123456789/4592 Title: ABAY BASIN WATER ALLOCATION MODELLING USING Hec-ResSim <br/> <br/>Authors: FANUEL, WONDYE <br/> <br/>Abstract: Despite Ethiopia possesses abundant water resources potential, second only to Congo in all of Africa, the country is at critical cross roads with large and increasing population, a depressed national economy, insufficient agricultural production and low no of developed energy sources. 83% of Ethiopians lack access to electricity; only 5 percent of irrigable land and 3% of the hydropower potential in the Blue Nile basin has been developed so far. Nowadays persisting drought and increasing competition for water have left Ethiopia with no more chance other than seeking solutions and assure sustainability of the resource. Even though Ethiopian portion of Blue Nile, Abay possesses a great potential of irrigation and hydropower developments, the financial and political constraints have long hindered the country’s development. This study aims at analyzing the effects of implementing the potential irrigation and hydropower projects that are contemplated in the country. Reservoir system simulation (Hec-ResSim) software has been used to study the out puts of executing different developments in the basin. This has been done by setting up the model and simulating for four scenarios including the base scenario referring to the current situation in the basin. After a curious filtering of all projects mentioned in the basin’s master plan and other project specific reports, 315,431ha (38.7% of total 815,581ha potential) of irrigation and 7,026Mw (89.6% of total 7845Mw potential) of hydropower potential; overall comprising 23 dams having a combined maximum storage capacity of 170.15Bm3 have been preferred to be analyzed and assessed using the model. After categorizing these projects under four scenarios; the simulation has been done based on 33 years (1960-1992) of monthly hydrologic flow series. This study under has indicated that If Ethiopia is to develop 315,431ha and 7,029Mw, the resulting decline in the cross border flow will be only 3,382.93Mm3 which is only 7.29% of the currently simulated (under current condition scenario,scenario-1) Abay discharge to Sudan which is 46,396.99 Mm3. Under this condition both Ethiopia and Sudan benefit from regulation of Abay by Ethiopian dams, in that it results in increasing of low flows, giving the whole system uniformity of balance, decreasing water escaping during flood seasons. As concluded from this study regulation works upstream in Ethiopia have resulted in a uniform monthly average flow of 3,584.51Mm3 throughout the year to Sudan. Currently as the base case simulation indicated, Sudan receives monthly average low flow of 1,233.54Mm3 through November to June which then turns to be increasing; August being flood month when 13,456.27Mm3 has been observed. In addition if Ethiopia is to develop 7,029Mw including hydropower projects on the tributaries, then some 38,385.81Gwh/annum of electricity will be produced. Even though Tana-Beles project imposes a big deal of inflow and power out put decline on the main stream hydropower plants, this power decrease was exceeded by the power generated at Tana-Beles power plant. Prior to Tana-Beles project Power output from main stream plants has been 34,284.23 Gwh/annum then increased to 34,736.14 Gwh/annum despite power decrease at Karadobi, Mabil, Mandaya and Border. Fri, 08 Feb 2013 11:41:51 GMT