Browsing by Author "Pasamehmetoglu, AG"
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Article Citation Count: 122The effects of gradation and admixture on the pumice lightweight aggregate concrete(Pergamon-elsevier Science Ltd, 2005) Paşamehmetoğlu, A. Günhan; Pasamehmetoglu, AG; Department of Civil EngineeringThe usage of lightweight concrete, which has some advantage over ordinary concrete, has increased to a remarkable level in recent years. Many researchers have investigated the possible uses of lightweight concrete in terms of its strength, density and other mechanical and physical properties. The desired quality for lightweight concrete can be obtained through the proper selection of admixtures and proper grading of the lightweight aggregate. In this article, an experimental investigation on the production of moderate-strength lightweight concrete with pumice, according to the ACI standard, is presented. The gradation curves' (which fall within A16-C16 gradation curves, Turkish Standard Code, TS706) performances were investigated in terms of strength and density. The addition of superplasticizer and air-entraining admixtures improved the strength-to-density ratio of the hardened concrete and the workability of fresh concrete. As a result of this study, lightweight concrete blocks having a minimum compressive strength of 6.56 N/mm(2) and a density of 1300 kg/m(3) were obtained. (c) 2004 Elsevier Ltd. All rights reserved.Article Citation Count: 13Ore-age: a hybrid system for assisting and teaching mining method selection(Pergamon-elsevier Science Ltd, 2003) Güray, Cenk; Çelebi, Neşe; Paşamehmetoğlu, A. Günhan; Pasamehmetoglu, AG; Industrial Engineering; Department of Metallurgical and Materials Engineering; Department of Civil EngineeringMining method selection is among the most critical and problematic points in mining engineering profession. Choosing a suitable method for a given ore-body is very important for the economics, safety and the productivity of the mining work. In the past studies there are attempts to build up a systematic approach to help the engineers to make this selection. But, these approaches work based on static databases and fail in inserting the intuitive feelings and engineering judgments of experienced engineers to the selection process. In this study, a system based on 13 different expert systems and one interface agent is developed, to make mining method selection for the given ore-bodies. The agent Ore-Age, to follow his goal of supplying the maximum assistance to engineers in selecting the most suitable method for a specific ore-body, tries to learn the experiences of the experts he has faced. After this learning process the knowledge base is evolved to include these experiences, making the system more efficient and intuitive in mining method selection work. To realize the above goal, the system's tutoring procedure is executed by the agent, in case an inexperienced user enters the system, to complete his/her missing knowledge about mining method selection. (C) 2002 Elsevier Science Ltd. All rights reserved.Article Citation Count: 25Proposed support design, Kaletepe tunnel, Turkey(Elsevier Science Bv, 2004) Paşamehmetoğlu, A. Günhan; Pasamehmetoglu, AG; Department of Civil EngineeringIn this paper, preliminary support design of Kaletepe tunnel, located on Bilecik-Istanbul highway, Turkey, was analyzed by empirical and numerical methods. The rock mass rating (RMR) and rock mass quality (Q) systems were employed for empirical rock mass quality determination. Numerical analysis for the stress-strain distribution of the tunnel excavation and support systems was also carried out. The applied support performance was investigated at different sections of the tunnel route. It was seen that empirical and numerical approaches showed similar results. This indicates that when the empirical method is supported by numerical method, the preliminary support design will be more reliable. (C) 2003 Elsevier B.V. All rights reserved.