Assessment of High-Rise Buildings During the Operation Stage in Addis Ababa City
Issue:
Volume 6, Issue 2, December 2022
Pages:
80-84
Received:
16 August 2022
Accepted:
13 September 2022
Published:
31 October 2022
DOI:
10.11648/j.ajcbm.20220602.11
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Abstract: To afford extra built-up space vertically both for working and living, high-rise buildings are constructed. Living in high-rise buildings has advantages as well as disadvantages. On the constructive side high-rise buildings can accommodate more people closer to work places, thus decreasing the length of work journeys and energy consumption. When we see the disadvantage side high-rise buildings needs extra equipments and facilities for vertical transportation, safety, and parking space. The construction of high-rise buildings in Addis Ababa is increasing rapidly nowadays. But during accommodation many problems affect the operation of the building while the construction is completed. The aim of this study is to identify the major challenges of high-rise buildings; to measure the satisfaction level of occupants of high-rise buildings; and to check the presence and functions of safety measures which are fixed in high-rise buildings. This research involves both qualitative and quantitative approaches for data collection and analysis. To gather quantitative data, survey questionnaires were administered to owners and occupants of high-rise buildings. For qualitative approach, in-depth interviews were carried out to purposefully selected respondents. In addition, observation was used. Lastly, data were collected from documents such as policy documents and reports of the Addis Ababa construction bureau. The data collected was analyzed using descriptive statistics. This study identified major challenges of high-rise buildings during the operation stage. The research result indicates that the key problems during the operation stage identified as lack of sufficient parking space, vertical transportation problems, and cleaning and maintenance problems. The outcome of the study helps the occupants of high-rise buildings and as a whole the construction industry to understand the actual factors during the operation of high-rise buildings.
Abstract: To afford extra built-up space vertically both for working and living, high-rise buildings are constructed. Living in high-rise buildings has advantages as well as disadvantages. On the constructive side high-rise buildings can accommodate more people closer to work places, thus decreasing the length of work journeys and energy consumption. When we...
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Gamma Radiation as a Recycling Tool for Waste Materials Used in Concrete
Issue:
Volume 6, Issue 2, December 2022
Pages:
85-92
Received:
22 August 2022
Accepted:
14 September 2022
Published:
4 November 2022
DOI:
10.11648/j.ajcbm.20220602.12
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Views:
Abstract: This particular review paper considered the use of gamma radiation as a tool for structural modification of recovered materials from waste and its use for preparing concrete. The use of gamma radiation to enhance the mechanical properties of concrete as well as the reuse and recycling of waste materials have been taken into consideration. Reinforced concrete is now crucial to the technological advancement of the building sector. Major engineering projects and general construction frequently employ it. Numerous significant technological developments have helped to create stronger, more effective materials that offer great advantages. Most often, after a very brief period of usage, these things degrade the environment by becoming garbage. Due to this circumstance, there is now a major environmental problem on a global scale. Investigations should have concentrated on recycling utilizing cutting-edge and healthy technologies, such as gamma radiation, as an alternative to traditional mechanical and chemical recycling techniques in order to tackle this issue, promote sustainable development, and reduce environmental pollution. The mechanical qualities of concrete, such as the compressive strength and elastic modulus, are increased by the inclusion of waste particles and the use of gamma radiation, which are effective instruments for reusing and recycling waste materials.
Abstract: This particular review paper considered the use of gamma radiation as a tool for structural modification of recovered materials from waste and its use for preparing concrete. The use of gamma radiation to enhance the mechanical properties of concrete as well as the reuse and recycling of waste materials have been taken into consideration. Reinforce...
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Prediction of Target Mean Strength of Concrete Mixes
Masala Mwiko,
Michael Nshumfwa Mulenga
Issue:
Volume 6, Issue 2, December 2022
Pages:
93-104
Received:
4 October 2022
Accepted:
31 October 2022
Published:
15 December 2022
DOI:
10.11648/j.ajcbm.20220602.13
Downloads:
Views:
Abstract: In practice cured concrete strength may exhibit strength variation from batch to batch and within batch despite the mixes being of the same proportions and with quality control. On the other hand, structural concrete elements are designed to meet specific characteristic strength. In order to ensure compliance to the specified characteristic strength, concrete mix designers target strengths higher than the specified characteristic strengths, commonly known as Target Mean Strength. This study aimed at establishing the margins between characteristic strength and Target Mean Strength for various local concrete mixes. In order to achieve this overall objective, a semi structured questionnaire was used to identify the popular concrete mix design models in the country. The identified model was then validated through experimental mix designs, concrete mixes, cube casting, curing and strength testing. The mixes were designed for normal concrete classes; C20, C25 and C30. The sample size for each of these classes was guided by the British-DOE method of mix design that demands for standard deviation to be calculated from at least 20 results and the Indian Standard IS 456:2000 that demands a sample size of at least 30 for each concrete class. This study utilized 101 concrete mixes; 31 samples for C20 and 35 for each of the C25 and C30 classes. Three concrete cube specimens were cast for each mix, cured for 28 days and tested for compressive strength at the Civil Engineering Laboratory of the University of Zambia. From the compressive strength results, the probability density function for each class was generated using Microsoft Office excel. The determined standard deviations (s) from the distributions were 8.19, 8.00 and 8.27 MPa for concrete classes of C20, C25 and C30, respectively, which implied margins of 13.43, 13.12 and 13.56 MPa, respectively for 95% reliability (k=1.64). Therefore, the established margins (k x s) can be used for predicting Target Mean Strength of concrete mixes at 95% reliability for the Zambian concrete mixes provided the BS-DOE model is applied and constituent materials are similar to those used in the study.
Abstract: In practice cured concrete strength may exhibit strength variation from batch to batch and within batch despite the mixes being of the same proportions and with quality control. On the other hand, structural concrete elements are designed to meet specific characteristic strength. In order to ensure compliance to the specified characteristic strengt...
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